Gastrointestinal Dysmotility: Clinical Consequences and Management of the Critically Ill Patient
Section snippets
Esophageal Motility
The gastroesophageal sphincter has reduced activity in critical illness, which can have important clinical consequences. Basal lower esophageal pressures are reduced when compared to health and acid reflux occurs frequently during fasting and gastric feeding. Furthermore, reflux contents remain in the esophagus for prolonged periods as clearance is markedly impaired. Most reflux episodes occur because of very low or, in some cases, absent lower esophageal sphincter pressures.2, 3 Reflux
Gastric Motility
Gastric motility can be markedly abnormal in critical illness resulting in slow gastric emptying and reduced ability to tolerate nasogastric delivery of nutrients. The stomach may be functionally divided into proximal and distal parts and, in order to achieve optimal gastric emptying, the motility of these regions needs to be coordinated. During critical illness, not only is the motility of each region disturbed, but also the motor integration between the proximal and distal stomach is
Small Intestinal Motility
Slow gastric emptying will delay delivery of nutrient to the small intestine resulting in a reduced rate of nutrient absorption. Small intestinal motility is also impaired in critical illness, which has the potential to further reduce nutrient absorption and contribute to the malnutrition of critical illness. Abnormalities in MMC activity may be characterized by changes in the proportion of time spent in the 3 phases, the coordination of contractions during the phases, and/or the direction of
Control of Gastrointestinal Motility
In health, nutrient interacts with small intestinal receptors and, via neurohumoral mechanisms, controls gastric emptying at a rate of about 2 to 3 kcal/min.30 This small intestinal feedback is exaggerated in the critically ill and appears to be the principal mechanism responsible for the abnormal slowing of gastric emptying during enteral feeding.1 The delivery of nutrient into the small intestine at a rate of as little as 1 kcal/min reduces antral and increases pyloric activity,1 which slows
Gastroesophageal Reflux and Aspiration
Reflux episodes combined with the loss of normal airway reflexes in the sedated and sometimes paralyzed patient results in aspiration,47 which can lead to impaired respiratory function. The relationship between gastric dysmotility and reflux is, as yet, unclear but there is some evidence that feeding directly into the small intestine reduces the risk of reflux and nosocomial pneumonia.48
Slow Gastric Emptying
Gastric emptying is delayed in about 50% of mechanically ventilated, critically ill patients.49, 50, 51, 52
General Management
There are a number of factors in the general management of the ICU patient that can be used to treat and/or prevent gut dysmotility and avoid its sequelae. These include patient posture, which should be at least 30° head up to reduce aspiration and nosocomial pneumonia in the setting of absent gastroesophageal pressure.47, 82 Reduction in the dosage of opiates62, 83 and catecholamines to minimal tolerated levels and avoidance of the use of dopamine21 will also reduce exogenous causes of delayed
Summary
Gastrointestinal dysmotility is a common feature of critical illness, with a number of significant implications that include malnutrition secondary to reduced feed tolerance and absorption, reflux and aspiration resulting in reduced lung function and ventilator-associated pneumonia, bacterial overgrowth and possible translocation causing nosocomial sepsis. Prokinetic agent administration can improve gastric emptying and caloric delivery, but its effect on nutrient absorption and clinical
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Protein prescription and delivery practices in critically ill adults: A survey of Australian and New Zealand intensive care dietitians
2022, Australian Critical CareCitation Excerpt :In practice, patients receive an average of 0.6 g protein/kg bodyweight/day in Australian and New Zealand (ANZ) ICUs,13 meeting <60% of international recommendations. In part, this disconnect between international recommendations and delivery in practice may be due to barriers such as fasting for medical procedures or management of gastrointestinal intolerance, which occurs in ∼50% of patients.13–15 However, as there is conflicting evidence on optimal protein delivery in critical illness, individual clinician beliefs on protein prescription and delivery are likely to influence clinical practice.
A retrospective evaluation of nutrition support in relation to clinical outcomes in critically ill patients with an open abdomen
2019, Australian Critical CareCitation Excerpt :Caring for critically ill patients with an open abdomen including how best to optimise their nutrition support is challenging.1,2 Gut dysfunction is likely to be disordered in these patients,3 and frequent fasting for return to surgery limits the hours of the day available to provide enteral nutrition. Limited data exist on how to feed the gut enterally when it is discontinuous, and few centres have extensive experience and confidence with the delivery of enteral nutrition distal to the site of a stoma.
This work was supported by grants from the National Health and Medical Research Council and the Australian and New Zealand College of Anaesthesia.
The authors have nothing to disclose.