Complications of long term mechanical ventilation in critically ill patient

Abstract

Mechanical ventilation is an essential, life-saving therapy for patients with critical illness and respiratory failure. Studies have estimated that more than 300, 000 patients receive mechanical ventilation in the United States each year. Some modes guarantee a constant volume (volume-targeted or volume controlled) with each machine breath, whereas other modes guarantee a constant pressure (pressure-targeted or pressure-controlled). An additional option on some ventilators is a dual- controlled mode that combines the features of volume- and pressure- targeted ventilation to ensure a minimum tidal volume (Vt) or minute ventilation (VE) while limiting pressure. Providing nutrition support to the mechanically ventilated patient is the standard of care. When delivered appropriately, nutrition support provides energy, protein, and nutrients needed to fuel the immune system; promotes wound healing; and prevents excess breakdown of lean body mass. However, if not properly managed, nutrition support can induce complications. Accumulated data suggest the route of nutrition support may influence the incidence of complications. Evidence exists for the preferred use of enteral support over total parenteral nutrition (TPN) whenever possible. Patients on mechanical ventilation are at high risk for complications and poor outcomes, including death, Ventilator-associated pneumonia (VAP), sepsis, Acute Respiratory Distress Syndrome (ARDS), barotrauma, pulmonary embolism and pulmonary edema are among the complications; such complications can lead to longer duration of mechanical ventilation, longer stays in the ICU and hospital, increased healthcare costs, and increased risk of disability and death. Mortality in patients with acute lung injury on mechanical ventilation has been estimated to range from 24% in persons 15-19 years of age to 60% for patients 85 years. Weaning from mechanical ventilation can be defined as the process of abruptly or gradually withdrawing ventilatory support. However two large trials have demonstrated that mechanical ventilation can be abruptly discontinued in 75% of patients whose underlying cause of respiratory failure has either improved or resolved. Hence the term discontinuation is preferable though the term weaning continues to remain popular.