Clinical experience of prophylactic enoxaparin dosage adjustment guided by AntiXa factor levels in critical care patients with COVID-19-induced pneumonia: observational study María del Carmen Bermúdez-Ruiz; Irene Vilar Sánchez; Clara Aparicio Pérez; Rosario Carmona Flores; Jorge Rodríguez-Gómez; Carmen de la Fuente-Martos;