array:23 [
  "pii" => "S2173572721001570"
  "issn" => "21735727"
  "doi" => "10.1016/j.medine.2021.08.014"
  "estado" => "S300"
  "fechaPublicacion" => "2021-12-01"
  "aid" => "1697"
  "copyright" => "The Author(s)"
  "copyrightAnyo" => "2021"
  "documento" => "article"
  "crossmark" => 1
  "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/"
  "subdocumento" => "sco"
  "cita" => "Med Intensiva. 2021;45:513-5"
  "abierto" => array:3 [
    "ES" => true
    "ES2" => true
    "LATM" => true
  ]
  "gratuito" => true
  "lecturas" => array:1 [
    "total" => 0
  ]
  "itemSiguiente" => array:18 [
    "pii" => "S2173572721001569"
    "issn" => "21735727"
    "doi" => "10.1016/j.medine.2021.03.001"
    "estado" => "S300"
    "fechaPublicacion" => "2021-12-01"
    "aid" => "1658"
    "copyright" => "Elsevier España, S.L.U. and SEMICYUC"
    "documento" => "article"
    "crossmark" => 1
    "subdocumento" => "fla"
    "cita" => "Med Intensiva. 2021;45:516-31"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:1 [
      "total" => 0
    ]
    "en" => array:13 [
      "idiomaDefecto" => true
      "cabecera" => "<span class="elsevierStyleTextfn">Original</span>"
      "titulo" => "OLA strategy for ARDS&#58; Its effect on mortality depends on achieved recruitment &#40;PaO<span class="elsevierStyleInf">2</span>&#47;FiO<span class="elsevierStyleInf">2</span>&#41; and mechanical power&#46; Systematic review and meta-analysis with meta-regression"
      "tienePdf" => "en"
      "tieneTextoCompleto" => "en"
      "tieneResumen" => array:2 [
        0 => "en"
        1 => "es"
      ]
      "paginas" => array:1 [
        0 => array:2 [
          "paginaInicial" => "516"
          "paginaFinal" => "531"
        ]
      ]
      "titulosAlternativos" => array:1 [
        "es" => array:1 [
          "titulo" => "Estrategia OLA para el SDRA&#58; su efecto en la mortalidad depende del reclutamiento alcanzado &#40;PaO<span class="elsevierStyleInf">2</span>&#47;FiO<span class="elsevierStyleInf">2</span>&#41; y la potencia mec&#225;nica&#46; Revisi&#243;n sistem&#225;tica y metaan&#225;lisis con metarregresi&#243;n"
        ]
      ]
      "contieneResumen" => array:2 [
        "en" => true
        "es" => true
      ]
      "contieneTextoCompleto" => array:1 [
        "en" => true
      ]
      "contienePdf" => array:1 [
        "en" => true
      ]
      "resumenGrafico" => array:2 [
        "original" => 0
        "multimedia" => array:7 [
          "identificador" => "fig0005"
          "etiqueta" => "Figure 1"
          "tipo" => "MULTIMEDIAFIGURA"
          "mostrarFloat" => true
          "mostrarDisplay" => false
          "figura" => array:1 [
            0 => array:4 [
              "imagen" => "gr1.jpeg"
              "Alto" => 2263
              "Ancho" => 2917
              "Tamanyo" => 315681
            ]
          ]
          "descripcion" => array:1 [
            "en" => "<p id="spar0090" class="elsevierStyleSimplePara elsevierViewall">PRISMA 2009 &#40;11&#41; Flow diagram of the study selection process&#46; PEEP&#58; positive end-expiratory pressure&#46; VT&#58; tidal volume&#46; RMs&#58; recruitment manoeuvres&#46; Exp&#46;&#58; experimental&#46;</p>"
          ]
        ]
      ]
      "autores" => array:1 [
        0 => array:2 [
          "autoresLista" => "V&#46; Modesto i Alapont, A&#46; Medina Villanueva, P&#46; del Villar Guerra, C&#46; Camilo, S&#46; Fern&#225;ndez-Ure&#241;a, F&#46; Gordo-Vidal, R&#46; Khemani"
          "autores" => array:7 [
            0 => array:2 [
              "nombre" => "V&#46;"
              "apellidos" => "Modesto i Alapont"
            ]
            1 => array:2 [
              "nombre" => "A&#46;"
              "apellidos" => "Medina Villanueva"
            ]
            2 => array:2 [
              "nombre" => "P&#46;"
              "apellidos" => "del Villar Guerra"
            ]
            3 => array:2 [
              "nombre" => "C&#46;"
              "apellidos" => "Camilo"
            ]
            4 => array:2 [
              "nombre" => "S&#46;"
              "apellidos" => "Fern&#225;ndez-Ure&#241;a"
            ]
            5 => array:2 [
              "nombre" => "F&#46;"
              "apellidos" => "Gordo-Vidal"
            ]
            6 => array:2 [
              "nombre" => "R&#46;"
              "apellidos" => "Khemani"
            ]
          ]
        ]
      ]
    ]
    "idiomaDefecto" => "en"
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2173572721001569?idApp=WMIE"
    "url" => "/21735727/0000004500000009/v2_202201010839/S2173572721001569/v2_202201010839/en/main.assets"
  ]
  "en" => array:11 [
    "idiomaDefecto" => true
    "cabecera" => "<span class="elsevierStyleTextfn">Editorial</span>"
    "titulo" => "Positive end-expiratory pressure&#44; or the perennial conundrum surrounding lung recruitment"
    "tieneTextoCompleto" => true
    "paginas" => array:1 [
      0 => array:2 [
        "paginaInicial" => "513"
        "paginaFinal" => "515"
      ]
    ]
    "autores" => array:1 [
      0 => array:4 [
        "autoresLista" => "P&#46;D&#46; Wendel-Garcia, F&#46; Roche-Campo, J&#46; Mancebo"
        "autores" => array:3 [
          0 => array:3 [
            "nombre" => "P&#46;D&#46;"
            "apellidos" => "Wendel-Garcia"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "aff0005"
              ]
            ]
          ]
          1 => array:3 [
            "nombre" => "F&#46;"
            "apellidos" => "Roche-Campo"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">b</span>"
                "identificador" => "aff0010"
              ]
            ]
          ]
          2 => array:4 [
            "nombre" => "J&#46;"
            "apellidos" => "Mancebo"
            "email" => array:1 [
              0 => "JMancebo@santpau.cat"
            ]
            "referencia" => array:2 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">c</span>"
                "identificador" => "aff0015"
              ]
              1 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">&#42;</span>"
                "identificador" => "cor0005"
              ]
            ]
          ]
        ]
        "afiliaciones" => array:3 [
          0 => array:3 [
            "entidad" => "Institute of Intensive Care Medicine&#44; University Hospital of Zurich&#44; Zurich&#44; Switzerland"
            "etiqueta" => "a"
            "identificador" => "aff0005"
          ]
          1 => array:3 [
            "entidad" => "Intensive Care Dept&#44; Hospital de Tortosa Verge de la Cinta&#44; Tortosa&#44; Tarragona&#44; Spain"
            "etiqueta" => "b"
            "identificador" => "aff0010"
          ]
          2 => array:3 [
            "entidad" => "Intensive Care Dept&#44; Hospital de la Santa Creu i Sant Pau&#44; Barcelona&#44; Spain"
            "etiqueta" => "c"
            "identificador" => "aff0015"
          ]
        ]
        "correspondencia" => array:1 [
          0 => array:3 [
            "identificador" => "cor0005"
            "etiqueta" => "&#8270;"
            "correspondencia" => "Corresponding author&#46;"
          ]
        ]
      ]
    ]
    "titulosAlternativos" => array:1 [
      "es" => array:1 [
        "titulo" => "Presi&#243;n positiva al final de la espiraci&#243;n o el perenne enigma que rodea el reclutamiento pulmonar"
      ]
    ]
    "textoCompleto" => "<span class="elsevierStyleSections"><p id="par0005" class="elsevierStylePara elsevierViewall">Six decades have passed since Ashbaugh and colleagues described the use of positive end-expiratory pressure &#40;PEEP&#41; to counteract alveolar collapse in adult &#40;acute&#41; respiratory distress syndrome&#44; leading to the conception of the <span class="elsevierStyleItalic">open lung</span><span class="elsevierStyleItalic">approach</span>&#46;<a class="elsevierStyleCrossRef" href="#bib0095"><span class="elsevierStyleSup">1</span></a> Elevating the static alveolar distending pressure and reducing cyclic alveolar distension&#44; were proposed as the optimal strategy to reduce the three mechanical components of ventilator-induced lung injury &#40;VILI&#41;&#44; namely baro-&#44; volu- and atelectrauma&#46;</p><p id="par0010" class="elsevierStylePara elsevierViewall">While today we have robust evidence that the use of high tidal volumes &#40;<span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>&#41; is accompanied by a significant increase in mortality risk&#44;<a class="elsevierStyleCrossRef" href="#bib0100"><span class="elsevierStyleSup">2</span></a> the role of PEEP setting has remained controversial&#46; For three decades randomized controlled trials attempting to prove the benefits of higher PEEP strategies &#40;&#8764;15<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O versus &#8764;8<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O&#41; have been following up to each other&#44; but compelling evidence has been lacking ever since&#46; Even the implementation of more sophisticated PEEP titration strategies&#44; such as oesophageal manometry<a class="elsevierStyleCrossRef" href="#bib0105"><span class="elsevierStyleSup">3</span></a> and the use of staircase recruitment manoeuvres<a class="elsevierStyleCrossRefs" href="#bib0110"><span class="elsevierStyleSup">4&#44;5</span></a> have only added to the list of negative trials&#46;</p><p id="par0015" class="elsevierStylePara elsevierViewall">In the current issue of the <span class="elsevierStyleItalic">Journal</span>&#44; Alapont and colleagues attempted to compile the current available evidence by pursuing a systematic review and meta-analysis of all randomized trials having investigated high PEEP strategies published to date&#46;<a class="elsevierStyleCrossRef" href="#bib0120"><span class="elsevierStyleSup">6</span></a> Not surprisingly&#44; the heterogeneity of the meta-analysis was moderate to substantial&#44; reflecting the high clinical and methodological variability in these studies&#46; The pooled relative risk for mortality was indicative &#40;0&#46;90&#44; 95&#37; Confidence Interval 0&#46;78&#8211;1&#46;03&#41;&#44; albeit inconclusively&#44; of a protective effect of the <span class="elsevierStyleItalic">open lung approach</span> and presented a low GRADE quality of evidence&#46; Similar results have been observed in a recently published large network meta-analysis&#44;<a class="elsevierStyleCrossRef" href="#bib0125"><span class="elsevierStyleSup">7</span></a> which indicated an inconclusive protective effect for a low <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> &#8211; high PEEP strategy &#40;defined in said study as <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>8<span class="elsevierStyleHsp" style=""></span>ml&#47;kg and PEEP<span class="elsevierStyleHsp" style=""></span>&#62;<span class="elsevierStyleHsp" style=""></span>10<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O&#41;&#46;</p><p id="par0020" class="elsevierStylePara elsevierViewall">This brings us to the perennial question as to why high PEEP resists conclusive proof as opposed to low <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>&#63; Conceptually we may break this apparent paradox down into the two opposite effects that <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> and PEEP exert on the total energy delivered to the lung&#46; This energy and the response of the lung&#39;s parenchyma to it can be expressed through the mechanical power&#46;<a class="elsevierStyleCrossRef" href="#bib0130"><span class="elsevierStyleSup">8</span></a> Consequently&#44; in contrast to the obvious reduction in mechanical power achieved by lowering <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span>&#44; a high PEEP setting will mostly be associated with an increase in delivered pulmonary energy&#46; As recently shown in an animal model&#44; VILI is directly dependent on the delivered mechanical power&#46;<a class="elsevierStyleCrossRef" href="#bib0135"><span class="elsevierStyleSup">9</span></a> Interestingly&#44; the sensitivity analysis performed by Alapont and colleagues does indicate exactly towards this relationship&#46; Studies in which a high PEEP setting induced a higher mechanical power relative to the control group were associated with a disappearing protective effect of high PEEP&#46;</p><p id="par0025" class="elsevierStylePara elsevierViewall">The high collinearity between the mechanical power and the driving pressure shown by the sensitivity analyses of Alapont et al&#46; illustrates that the main mediator between PEEP increase and mechanical power reduction is a decreasing respiratory system elastance&#46; In other words&#44; only when an increase in PEEP leads to an effective distension of alveoli does it reduce the applied mechanical power&#46; However&#44; as Gattinoni et al&#46; showed in their landmark paper&#44; lung recruitability is highly heterogeneous&#44; and less than 40&#37; of patients seem to actively recruit a significant proportion of lung tissue during a recruitment manoeuvre&#46;<a class="elsevierStyleCrossRef" href="#bib0140"><span class="elsevierStyleSup">10</span></a> Most strikingly&#44; the authors observed that up to 24&#37; of the total lung tissue cannot be recruited at end-inspiratory plateau airway pressures of 45<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O&#46;<a class="elsevierStyleCrossRef" href="#bib0140"><span class="elsevierStyleSup">10</span></a> Hence&#44; one can speculate that more than half of the patients included in PEEP trials did not experience any alveolar recruitment and in the worst-case scenario experienced alveolar overdistension due to excessive PEEP settings&#46; This possibly induced VILI&#44; increasing mortality in the intervention group and drastically reducing statistical power&#46; Ideally&#44; we should fine tune <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> according to elastance&#44; and PEEP according to lung recruitability&#46;</p><p id="par0030" class="elsevierStylePara elsevierViewall">But how do we recognize recruitable patients&#63; Performing two CT studies at different PEEP levels&#44; might be a very elegant option and the current gold standard&#44;<a class="elsevierStyleCrossRef" href="#bib0140"><span class="elsevierStyleSup">10</span></a> but is impractical at the bedside&#46; On the other hand&#44; recruitment assessment methods based on lung mechanics are generally limited in discerning between actual atelectatic tissue recruitment and overdistension of the baby lung&#46; The recently proposed recruitment-to-inflation ratio might provide guidance in balancing the risk of atelectrauma against the risk of overdistension during recruitment&#46;<a class="elsevierStyleCrossRef" href="#bib0145"><span class="elsevierStyleSup">11</span></a> Another emergent technique&#44; thoracic electric impedance tomography&#44; can enable to discern alveolar recruitment from overdistension in a more visual approach&#44; whilst concomitantly allowing assessment of regional pulmonary perfusion&#46;<a class="elsevierStyleCrossRefs" href="#bib0150"><span class="elsevierStyleSup">12&#44;13</span></a></p><p id="par0035" class="elsevierStylePara elsevierViewall">In a further sensitivity analysis&#44; Alapont et al&#46; illustrate that patients with a P<span class="elsevierStyleInf">a</span>O<span class="elsevierStyleInf">2</span>&#47;F<span class="elsevierStyleInf">i</span>O<span class="elsevierStyleInf">2</span> ratio below 160<span class="elsevierStyleHsp" style=""></span>mmHg profit from high PEEP as opposed to patients with higher P<span class="elsevierStyleInf">a</span>O<span class="elsevierStyleInf">2</span>&#47;F<span class="elsevierStyleInf">i</span>O<span class="elsevierStyleInf">2</span> ratios&#46; Briel et al&#46; showed a similar P<span class="elsevierStyleInf">a</span>O<span class="elsevierStyleInf">2</span>&#47;F<span class="elsevierStyleInf">i</span>O<span class="elsevierStyleInf">2</span> ratio dependant protective effect for high PEEP in their individual data meta-analysis&#46;<a class="elsevierStyleCrossRef" href="#bib0160"><span class="elsevierStyleSup">14</span></a> Indeed&#44; the fraction of pulmonary recruitable patients increases with decreasing P<span class="elsevierStyleInf">a</span>O<span class="elsevierStyleInf">2</span>&#47;F<span class="elsevierStyleInf">i</span>O<span class="elsevierStyleInf">2</span> ratio&#44;<a class="elsevierStyleCrossRefs" href="#bib0140"><span class="elsevierStyleSup">10&#44;15</span></a> a property that has already successfully been implemented to enrich ARDS trials targeting pulmonary recruitment by means of prone position&#46;<a class="elsevierStyleCrossRef" href="#bib0170"><span class="elsevierStyleSup">16</span></a> However&#44; and as the ART&#44;<a class="elsevierStyleCrossRef" href="#bib0110"><span class="elsevierStyleSup">4</span></a> EPVent-2<a class="elsevierStyleCrossRef" href="#bib0105"><span class="elsevierStyleSup">3</span></a> and PHARLAP<a class="elsevierStyleCrossRef" href="#bib0115"><span class="elsevierStyleSup">5</span></a> trials have exemplified&#44; simple enrichment of PEEP trials with a P<span class="elsevierStyleInf">a</span>O<span class="elsevierStyleInf">2</span>&#47;F<span class="elsevierStyleInf">i</span>O<span class="elsevierStyleInf">2</span> ratio below 200<span class="elsevierStyleHsp" style=""></span>mmHg does not suffice&#46;</p><p id="par0040" class="elsevierStylePara elsevierViewall">How do we proceed from here&#63; As exemplified by this meta-analysis&#44; pursuing larger and more complex trials attempting to show the benefit of high PEEP in heterogeneous ARDS populations is a futile enterprise&#46; Instead&#44; it is time to step back to mechanistic research and reassess how to best characterize the mechanical properties of the lung and best recognize patients with recruitable lungs&#46; It will be the task of phenotyping and <span class="elsevierStyleItalic">individualized</span> medicine to pave the way towards a successful implementation of the <span class="elsevierStyleItalic">open lung approach</span>&#46; If this will be achieved through biological and inflammatory phenotypes&#44;<a class="elsevierStyleCrossRef" href="#bib0175"><span class="elsevierStyleSup">17</span></a> by a more lung centred characterization of pulmonary morphology and mechanical properties<a class="elsevierStyleCrossRef" href="#bib0165"><span class="elsevierStyleSup">15</span></a> or if advanced pulmonary imaging tools are the key&#44;<a class="elsevierStyleCrossRef" href="#bib0180"><span class="elsevierStyleSup">18</span></a> remains unknown&#46; However&#44; it all points to an exciting future&#44; full of research possibilities&#44; ahead of us&#46;</p><p id="par0045" class="elsevierStylePara elsevierViewall">Up until then&#44; we suggest a do no harm approach&#46; From a pragmatic point of view&#44; PEEP settings of 8&#8211;12<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O will likely provide for a balanced choice&#44; while we employ a simple and proven lifesaving intervention in ARDS&#58; low <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf">T</span> and prone position&#46;</p></span>"
    "pdfFichero" => "main.pdf"
    "tienePdf" => true
    "bibliografia" => array:2 [
      "titulo" => "References"
      "seccion" => array:1 [
        0 => array:2 [
          "identificador" => "bibs0015"
          "bibliografiaReferencia" => array:18 [
            0 => array:3 [
              "identificador" => "bib0095"
              "etiqueta" => "1"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Continuous positive-pressure breathing &#40;CPPB&#41; in adult respiratory distress syndrome"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "D&#46;G&#46; Ashbaugh"
                            1 => "T&#46;L&#46; Petty"
                            2 => "D&#46;B&#46; Bigelow"
                            3 => "T&#46;M&#46; Harris"
                            4 => "W&#46;R&#46; Waddell"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "J Thorac Cardiovasc Surg"
                        "fecha" => "1969"
                        "volumen" => "57"
                        "paginaInicial" => "31"
                        "paginaFinal" => "41"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/4883575"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            1 => array:3 [
              "identificador" => "bib0100"
              "etiqueta" => "2"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:1 [
                      "titulo" => "Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress&#44; syndrome"
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1056/NEJM200005043421801"
                      "Revista" => array:6 [
                        "tituloSerie" => "N Engl J Med"
                        "fecha" => "2000"
                        "volumen" => "342"
                        "paginaInicial" => "1301"
                        "paginaFinal" => "1308"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/10793162"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            2 => array:3 [
              "identificador" => "bib0105"
              "etiqueta" => "3"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Effect of titrating positive end-expiratory pressure &#40;PEEP&#41; with an esophageal pressure-guided strategy vs an empirical high PEEP-FiO<span class="elsevierStyleInf">2</span> strategy on death and days free from mechanical ventilation among patients with acute respiratory distress syndrome&#58; a randomized clinical trial"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "J&#46;R&#46; Beitler"
                            1 => "T&#46; Sarge"
                            2 => "V&#46;M&#46; Banner-Goodspeed"
                            3 => "M&#46;N&#46; Gong"
                            4 => "D&#46; Cook"
                            5 => "V&#46; Novack"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1001/jama.2019.0555"
                      "Revista" => array:6 [
                        "tituloSerie" => "JAMA"
                        "fecha" => "2019"
                        "volumen" => "321"
                        "paginaInicial" => "846"
                        "paginaFinal" => "857"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/30776290"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            3 => array:3 [
              "identificador" => "bib0110"
              "etiqueta" => "4"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:1 [
                      "titulo" => "Writing group for the alveolar recruitment for acute respiratory distress syndrome trial I&#46; Effect of lung recruitment and titrated positive end-expiratory pressure &#40;PEEP&#41; vs low PEEP on mortality in patients with acute respiratory distress syndrome&#58; a randomized clinical trial"
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1001/jama.2017.14171"
                      "Revista" => array:6 [
                        "tituloSerie" => "JAMA"
                        "fecha" => "2017"
                        "volumen" => "318"
                        "paginaInicial" => "1335"
                        "paginaFinal" => "1345"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/28973363"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            4 => array:3 [
              "identificador" => "bib0115"
              "etiqueta" => "5"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Maximal recruitment open lung ventilation in acute respiratory distress syndrome &#40;PHARLAP&#41;&#46; A phase II multicenter randomized controlled clinical trial"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "C&#46;L&#46; Hodgson"
                            1 => "D&#46;J&#46; Cooper"
                            2 => "Y&#46; Arabi"
                            3 => "V&#46; King"
                            4 => "A&#46; Bersten"
                            5 => "S&#46; Bihari"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1164/rccm.201901-0109OC"
                      "Revista" => array:6 [
                        "tituloSerie" => "Am J Respir Crit Care Med"
                        "fecha" => "2019"
                        "volumen" => "200"
                        "paginaInicial" => "1363"
                        "paginaFinal" => "1372"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/31356105"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            5 => array:3 [
              "identificador" => "bib0120"
              "etiqueta" => "6"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "OLA strategy for ARDS&#58; its effect on mortality depends on achieved recruitment &#40;PaO<span class="elsevierStyleInf">2</span>&#47;FiO<span class="elsevierStyleInf">2</span>&#41; and mechanical power Systematic review and meta-analysis with meta-regression"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "V&#46; Modesto i Alapont"
                            1 => "A&#46; Medina Villanueva"
                            2 => "P&#46; del Villar Guerra"
                            3 => "C&#46; Camilo"
                            4 => "S&#46; Fern&#225;ndez-Ure&#241;a"
                            5 => "F&#46; Gordo-Vidal"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/j.medin.2021.03.016"
                      "Revista" => array:2 [
                        "tituloSerie" => "Med Intens"
                        "fecha" => "2021"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            6 => array:3 [
              "identificador" => "bib0125"
              "etiqueta" => "7"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Comparative effectiveness of protective ventilation strategies for moderate and severe acute respiratory distress syndrome&#46; A network meta-analysis"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "S&#46; Sud"
                            1 => "J&#46;O&#46; Friedrich"
                            2 => "N&#46;K&#46;J&#46; Adhikari"
                            3 => "E&#46; Fan"
                            4 => "N&#46;D&#46; Ferguson"
                            5 => "G&#46; Guyatt"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1164/rccm.202008-3039OC"
                      "Revista" => array:6 [
                        "tituloSerie" => "Am J Respir Crit Care Med"
                        "fecha" => "2021"
                        "volumen" => "203"
                        "paginaInicial" => "1366"
                        "paginaFinal" => "1377"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/33406009"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            7 => array:3 [
              "identificador" => "bib0130"
              "etiqueta" => "8"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Ventilator-related causes of lung injury&#58; the mechanical power"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46; Gattinoni"
                            1 => "T&#46; Tonetti"
                            2 => "M&#46; Cressoni"
                            3 => "P&#46; Cadringher"
                            4 => "P&#46; Herrmann"
                            5 => "O&#46; Moerer"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "Intens Care Med"
                        "fecha" => "2016"
                        "volumen" => "42"
                        "paginaInicial" => "1567"
                        "paginaFinal" => "1575"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            8 => array:3 [
              "identificador" => "bib0135"
              "etiqueta" => "9"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Does Iso-mechanical power lead to Iso-lung damage&#63; An experimental study in a porcine model"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "F&#46; Vassalli"
                            1 => "I&#46; Pasticci"
                            2 => "F&#46; Romitti"
                            3 => "E&#46; Duscio"
                            4 => "D&#46;J&#46; A&#223;mann"
                            5 => "H&#46; Gr&#252;nhagen"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1097/ALN.0000000000003189"
                      "Revista" => array:6 [
                        "tituloSerie" => "Anesthesiology"
                        "fecha" => "2020"
                        "volumen" => "132"
                        "paginaInicial" => "1126"
                        "paginaFinal" => "1137"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/32032095"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            9 => array:3 [
              "identificador" => "bib0140"
              "etiqueta" => "10"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Lung recruitment in patients with the acute respiratory distress syndrome"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46; Gattinoni"
                            1 => "P&#46; Caironi"
                            2 => "M&#46; Cressoni"
                            3 => "D&#46; Chiumello"
                            4 => "V&#46;M&#46; Ranieri"
                            5 => "M&#46; Quintel"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1056/NEJMoa052052"
                      "Revista" => array:6 [
                        "tituloSerie" => "N Engl J Med"
                        "fecha" => "2006"
                        "volumen" => "354"
                        "paginaInicial" => "1775"
                        "paginaFinal" => "1786"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/16641394"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            10 => array:3 [
              "identificador" => "bib0145"
              "etiqueta" => "11"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Potential for lung recruitment estimated by the recruitment-to-inflation ratio in acute respiratory distress syndrome&#46; A clinical trial"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46; Chen"
                            1 => "L&#46; Del Sorbo"
                            2 => "D&#46;L&#46; Grieco"
                            3 => "D&#46; Junhasavasdikul"
                            4 => "N&#46; Rittayamai"
                            5 => "I&#46; Soliman"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1164/rccm.201902-0334OC"
                      "Revista" => array:6 [
                        "tituloSerie" => "Am J Respir Crit Care Med"
                        "fecha" => "2019"
                        "volumen" => "201"
                        "paginaInicial" => "178"
                        "paginaFinal" => "187"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/31577153"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            11 => array:3 [
              "identificador" => "bib0150"
              "etiqueta" => "12"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Electrical impedance tomography for positive end-expiratory pressure titration in COVID-19-related acute respiratory distress syndrome"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "P&#46; van der Zee"
                            1 => "P&#46; Somhorst"
                            2 => "H&#46; Endeman"
                            3 => "D&#46; Gommers"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1164/rccm.202003-0816LE"
                      "Revista" => array:6 [
                        "tituloSerie" => "Am J Respir Crit Care Med"
                        "fecha" => "2020"
                        "volumen" => "202"
                        "paginaInicial" => "280"
                        "paginaFinal" => "284"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/32479112"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            12 => array:3 [
              "identificador" => "bib0155"
              "etiqueta" => "13"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Unmatched ventilation and perfusion measured by electrical impedance tomography predicts the outcome of ARDS"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "E&#46; Spinelli"
                            1 => "M&#46; Kircher"
                            2 => "B&#46; Stender"
                            3 => "I&#46; Ottaviani"
                            4 => "M&#46;C&#46; Basile"
                            5 => "I&#46; Marongiu"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1186/s13054-021-03615-4"
                      "Revista" => array:5 [
                        "tituloSerie" => "Crit Care"
                        "fecha" => "2021"
                        "volumen" => "25"
                        "paginaInicial" => "192"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/34082795"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            13 => array:3 [
              "identificador" => "bib0160"
              "etiqueta" => "14"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Higher vs lower positive end-expiratory pressure in patients with acute lung injury and acute respiratory distress syndrome&#58; systematic review and meta-analysis"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "M&#46; Briel"
                            1 => "M&#46; Meade"
                            2 => "A&#46; Mercat"
                            3 => "R&#46;G&#46; Brower"
                            4 => "D&#46; Talmor"
                            5 => "S&#46;D&#46; Walter"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1001/jama.2010.218"
                      "Revista" => array:6 [
                        "tituloSerie" => "JAMA"
                        "fecha" => "2010"
                        "volumen" => "303"
                        "paginaInicial" => "865"
                        "paginaFinal" => "873"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/20197533"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            14 => array:3 [
              "identificador" => "bib0165"
              "etiqueta" => "15"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Latent class analysis to predict intensive care outcomes in Acute Respiratory Distress Syndrome&#58; a proposal of two pulmonary phenotypes"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "P&#46;D&#46; Wendel Garcia"
                            1 => "A&#46; Caccioppola"
                            2 => "S&#46; Coppola"
                            3 => "T&#46; Pozzi"
                            4 => "A&#46; Ciabattoni"
                            5 => "S&#46; Cenci"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1186/s13054-021-03578-6"
                      "Revista" => array:5 [
                        "tituloSerie" => "Crit Care"
                        "fecha" => "2021"
                        "volumen" => "25"
                        "paginaInicial" => "154"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/33888134"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            15 => array:3 [
              "identificador" => "bib0170"
              "etiqueta" => "16"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Prone positioning in severe acute respiratory distress syndrome"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "C&#46; Gu&#233;rin"
                            1 => "J&#46; Reignier"
                            2 => "J&#46;-C&#46; Richard"
                            3 => "P&#46; Beuret"
                            4 => "A&#46; Gacouin"
                            5 => "T&#46; Boulain"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1056/NEJMoa1214103"
                      "Revista" => array:6 [
                        "tituloSerie" => "N Engl J Med"
                        "fecha" => "2013"
                        "volumen" => "368"
                        "paginaInicial" => "2159"
                        "paginaFinal" => "2168"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23688302"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            16 => array:3 [
              "identificador" => "bib0175"
              "etiqueta" => "17"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Subphenotypes in acute respiratory distress syndrome&#58; latent class analysis of data from two randomised controlled trials"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "C&#46;S&#46; Calfee"
                            1 => "K&#46; Delucchi"
                            2 => "P&#46;E&#46; Parsons"
                            3 => "B&#46;T&#46; Thompson"
                            4 => "L&#46;B&#46; Ware"
                            5 => "M&#46;A&#46; Matthay"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1016/S2213-2600(14)70097-9"
                      "Revista" => array:6 [
                        "tituloSerie" => "Lancet Respir Med"
                        "fecha" => "2014"
                        "volumen" => "2"
                        "paginaInicial" => "611"
                        "paginaFinal" => "620"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/24853585"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            17 => array:3 [
              "identificador" => "bib0180"
              "etiqueta" => "18"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Early individualized positive end-expiratory pressure guided by electrical impedance tomography in acute respiratory distress syndrome&#58; a randomized controlled clinical trial"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "H&#46; He"
                            1 => "Y&#46; Chi"
                            2 => "Y&#46; Yang"
                            3 => "S&#46; Yuan"
                            4 => "Y&#46; Long"
                            5 => "P&#46; Zhao"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1186/s13054-021-03645-y"
                      "Revista" => array:5 [
                        "tituloSerie" => "Crit Care"
                        "fecha" => "2021"
                        "volumen" => "25"
                        "paginaInicial" => "230"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/34193224"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
          ]
        ]
      ]
    ]
  ]
  "idiomaDefecto" => "en"
  "url" => "/21735727/0000004500000009/v2_202201010839/S2173572721001570/v2_202201010839/en/main.assets"
  "Apartado" => array:4 [
    "identificador" => "406"
    "tipo" => "SECCION"
    "en" => array:2 [
      "titulo" => "Editorial"
      "idiomaDefecto" => true
    ]
    "idiomaDefecto" => "en"
  ]
  "PDF" => "https://static.elsevier.es/multimedia/21735727/0000004500000009/v2_202201010839/S2173572721001570/v2_202201010839/en/main.pdf?idApp=WMIE&text.app=https://medintensiva.org/"
  "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2173572721001570?idApp=WMIE"
]
Share
Journal Information
Vol. 45. Issue 9.
Pages 513-515 (December 2021)
Share
Share
Download PDF
More article options
Vol. 45. Issue 9.
Pages 513-515 (December 2021)
Editorial
Open Access
Positive end-expiratory pressure, or the perennial conundrum surrounding lung recruitment
Presión positiva al final de la espiración o el perenne enigma que rodea el reclutamiento pulmonar
Visits
2533
P.D. Wendel-Garciaa, F. Roche-Campob, J. Manceboc,
Corresponding author
JMancebo@santpau.cat

Corresponding author.
a Institute of Intensive Care Medicine, University Hospital of Zurich, Zurich, Switzerland
b Intensive Care Dept, Hospital de Tortosa Verge de la Cinta, Tortosa, Tarragona, Spain
c Intensive Care Dept, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
This item has received

Under a Creative Commons license
Article information
Full Text
Bibliography
Download PDF
Statistics
Full Text

Six decades have passed since Ashbaugh and colleagues described the use of positive end-expiratory pressure (PEEP) to counteract alveolar collapse in adult (acute) respiratory distress syndrome, leading to the conception of the open lungapproach.1 Elevating the static alveolar distending pressure and reducing cyclic alveolar distension, were proposed as the optimal strategy to reduce the three mechanical components of ventilator-induced lung injury (VILI), namely baro-, volu- and atelectrauma.

While today we have robust evidence that the use of high tidal volumes (VT) is accompanied by a significant increase in mortality risk,2 the role of PEEP setting has remained controversial. For three decades randomized controlled trials attempting to prove the benefits of higher PEEP strategies (∼15cmH2O versus ∼8cmH2O) have been following up to each other, but compelling evidence has been lacking ever since. Even the implementation of more sophisticated PEEP titration strategies, such as oesophageal manometry3 and the use of staircase recruitment manoeuvres4,5 have only added to the list of negative trials.

In the current issue of the Journal, Alapont and colleagues attempted to compile the current available evidence by pursuing a systematic review and meta-analysis of all randomized trials having investigated high PEEP strategies published to date.6 Not surprisingly, the heterogeneity of the meta-analysis was moderate to substantial, reflecting the high clinical and methodological variability in these studies. The pooled relative risk for mortality was indicative (0.90, 95% Confidence Interval 0.78–1.03), albeit inconclusively, of a protective effect of the open lung approach and presented a low GRADE quality of evidence. Similar results have been observed in a recently published large network meta-analysis,7 which indicated an inconclusive protective effect for a low VT – high PEEP strategy (defined in said study as VT<8ml/kg and PEEP>10cmH2O).

This brings us to the perennial question as to why high PEEP resists conclusive proof as opposed to low VT? Conceptually we may break this apparent paradox down into the two opposite effects that VT and PEEP exert on the total energy delivered to the lung. This energy and the response of the lung's parenchyma to it can be expressed through the mechanical power.8 Consequently, in contrast to the obvious reduction in mechanical power achieved by lowering VT, a high PEEP setting will mostly be associated with an increase in delivered pulmonary energy. As recently shown in an animal model, VILI is directly dependent on the delivered mechanical power.9 Interestingly, the sensitivity analysis performed by Alapont and colleagues does indicate exactly towards this relationship. Studies in which a high PEEP setting induced a higher mechanical power relative to the control group were associated with a disappearing protective effect of high PEEP.

The high collinearity between the mechanical power and the driving pressure shown by the sensitivity analyses of Alapont et al. illustrates that the main mediator between PEEP increase and mechanical power reduction is a decreasing respiratory system elastance. In other words, only when an increase in PEEP leads to an effective distension of alveoli does it reduce the applied mechanical power. However, as Gattinoni et al. showed in their landmark paper, lung recruitability is highly heterogeneous, and less than 40% of patients seem to actively recruit a significant proportion of lung tissue during a recruitment manoeuvre.10 Most strikingly, the authors observed that up to 24% of the total lung tissue cannot be recruited at end-inspiratory plateau airway pressures of 45cmH2O.10 Hence, one can speculate that more than half of the patients included in PEEP trials did not experience any alveolar recruitment and in the worst-case scenario experienced alveolar overdistension due to excessive PEEP settings. This possibly induced VILI, increasing mortality in the intervention group and drastically reducing statistical power. Ideally, we should fine tune VT according to elastance, and PEEP according to lung recruitability.

But how do we recognize recruitable patients? Performing two CT studies at different PEEP levels, might be a very elegant option and the current gold standard,10 but is impractical at the bedside. On the other hand, recruitment assessment methods based on lung mechanics are generally limited in discerning between actual atelectatic tissue recruitment and overdistension of the baby lung. The recently proposed recruitment-to-inflation ratio might provide guidance in balancing the risk of atelectrauma against the risk of overdistension during recruitment.11 Another emergent technique, thoracic electric impedance tomography, can enable to discern alveolar recruitment from overdistension in a more visual approach, whilst concomitantly allowing assessment of regional pulmonary perfusion.12,13

In a further sensitivity analysis, Alapont et al. illustrate that patients with a PaO2/FiO2 ratio below 160mmHg profit from high PEEP as opposed to patients with higher PaO2/FiO2 ratios. Briel et al. showed a similar PaO2/FiO2 ratio dependant protective effect for high PEEP in their individual data meta-analysis.14 Indeed, the fraction of pulmonary recruitable patients increases with decreasing PaO2/FiO2 ratio,10,15 a property that has already successfully been implemented to enrich ARDS trials targeting pulmonary recruitment by means of prone position.16 However, and as the ART,4 EPVent-23 and PHARLAP5 trials have exemplified, simple enrichment of PEEP trials with a PaO2/FiO2 ratio below 200mmHg does not suffice.

How do we proceed from here? As exemplified by this meta-analysis, pursuing larger and more complex trials attempting to show the benefit of high PEEP in heterogeneous ARDS populations is a futile enterprise. Instead, it is time to step back to mechanistic research and reassess how to best characterize the mechanical properties of the lung and best recognize patients with recruitable lungs. It will be the task of phenotyping and individualized medicine to pave the way towards a successful implementation of the open lung approach. If this will be achieved through biological and inflammatory phenotypes,17 by a more lung centred characterization of pulmonary morphology and mechanical properties15 or if advanced pulmonary imaging tools are the key,18 remains unknown. However, it all points to an exciting future, full of research possibilities, ahead of us.

Up until then, we suggest a do no harm approach. From a pragmatic point of view, PEEP settings of 8–12cmH2O will likely provide for a balanced choice, while we employ a simple and proven lifesaving intervention in ARDS: low VT and prone position.

References
[1]
D.G. Ashbaugh, T.L. Petty, D.B. Bigelow, T.M. Harris, W.R. Waddell.
Continuous positive-pressure breathing (CPPB) in adult respiratory distress syndrome.
J Thorac Cardiovasc Surg, 57 (1969), pp. 31-41
[2]
Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress, syndrome.
N Engl J Med, 342 (2000), pp. 1301-1308
[3]
J.R. Beitler, T. Sarge, V.M. Banner-Goodspeed, M.N. Gong, D. Cook, V. Novack, et al.
Effect of titrating positive end-expiratory pressure (PEEP) with an esophageal pressure-guided strategy vs an empirical high PEEP-FiO2 strategy on death and days free from mechanical ventilation among patients with acute respiratory distress syndrome: a randomized clinical trial.
JAMA, 321 (2019), pp. 846-857
[4]
Writing group for the alveolar recruitment for acute respiratory distress syndrome trial I. Effect of lung recruitment and titrated positive end-expiratory pressure (PEEP) vs low PEEP on mortality in patients with acute respiratory distress syndrome: a randomized clinical trial.
JAMA, 318 (2017), pp. 1335-1345
[5]
C.L. Hodgson, D.J. Cooper, Y. Arabi, V. King, A. Bersten, S. Bihari, et al.
Maximal recruitment open lung ventilation in acute respiratory distress syndrome (PHARLAP). A phase II multicenter randomized controlled clinical trial.
Am J Respir Crit Care Med, 200 (2019), pp. 1363-1372
[6]
V. Modesto i Alapont, A. Medina Villanueva, P. del Villar Guerra, C. Camilo, S. Fernández-Ureña, F. Gordo-Vidal, et al.
OLA strategy for ARDS: its effect on mortality depends on achieved recruitment (PaO2/FiO2) and mechanical power Systematic review and meta-analysis with meta-regression.
[7]
S. Sud, J.O. Friedrich, N.K.J. Adhikari, E. Fan, N.D. Ferguson, G. Guyatt, et al.
Comparative effectiveness of protective ventilation strategies for moderate and severe acute respiratory distress syndrome. A network meta-analysis.
Am J Respir Crit Care Med, 203 (2021), pp. 1366-1377
[8]
L. Gattinoni, T. Tonetti, M. Cressoni, P. Cadringher, P. Herrmann, O. Moerer, et al.
Ventilator-related causes of lung injury: the mechanical power.
Intens Care Med, 42 (2016), pp. 1567-1575
[9]
F. Vassalli, I. Pasticci, F. Romitti, E. Duscio, D.J. Aßmann, H. Grünhagen, et al.
Does Iso-mechanical power lead to Iso-lung damage? An experimental study in a porcine model.
Anesthesiology, 132 (2020), pp. 1126-1137
[10]
L. Gattinoni, P. Caironi, M. Cressoni, D. Chiumello, V.M. Ranieri, M. Quintel, et al.
Lung recruitment in patients with the acute respiratory distress syndrome.
N Engl J Med, 354 (2006), pp. 1775-1786
[11]
L. Chen, L. Del Sorbo, D.L. Grieco, D. Junhasavasdikul, N. Rittayamai, I. Soliman, et al.
Potential for lung recruitment estimated by the recruitment-to-inflation ratio in acute respiratory distress syndrome. A clinical trial.
Am J Respir Crit Care Med, 201 (2019), pp. 178-187
[12]
P. van der Zee, P. Somhorst, H. Endeman, D. Gommers.
Electrical impedance tomography for positive end-expiratory pressure titration in COVID-19-related acute respiratory distress syndrome.
Am J Respir Crit Care Med, 202 (2020), pp. 280-284
[13]
E. Spinelli, M. Kircher, B. Stender, I. Ottaviani, M.C. Basile, I. Marongiu, et al.
Unmatched ventilation and perfusion measured by electrical impedance tomography predicts the outcome of ARDS.
[14]
M. Briel, M. Meade, A. Mercat, R.G. Brower, D. Talmor, S.D. Walter, et al.
Higher vs lower positive end-expiratory pressure in patients with acute lung injury and acute respiratory distress syndrome: systematic review and meta-analysis.
JAMA, 303 (2010), pp. 865-873
[15]
P.D. Wendel Garcia, A. Caccioppola, S. Coppola, T. Pozzi, A. Ciabattoni, S. Cenci, et al.
Latent class analysis to predict intensive care outcomes in Acute Respiratory Distress Syndrome: a proposal of two pulmonary phenotypes.
[16]
C. Guérin, J. Reignier, J.-C. Richard, P. Beuret, A. Gacouin, T. Boulain, et al.
Prone positioning in severe acute respiratory distress syndrome.
N Engl J Med, 368 (2013), pp. 2159-2168
[17]
C.S. Calfee, K. Delucchi, P.E. Parsons, B.T. Thompson, L.B. Ware, M.A. Matthay.
Subphenotypes in acute respiratory distress syndrome: latent class analysis of data from two randomised controlled trials.
Lancet Respir Med, 2 (2014), pp. 611-620
[18]
H. He, Y. Chi, Y. Yang, S. Yuan, Y. Long, P. Zhao, et al.
Early individualized positive end-expiratory pressure guided by electrical impedance tomography in acute respiratory distress syndrome: a randomized controlled clinical trial.
Copyright © 2021. The Author(s)
Download PDF
Idiomas
Medicina Intensiva (English Edition)
Article options
Tools