COMFORT AND DISTRESS IN THE ICU: SCOPE OF THE PROBLEM

The management of sedation, analgesia, and neuromuscular blockade (NMB) is extensively woven into the fabric of contemporary care of critically ill patients. A decade ago, Hansen-Flaschen and colleagues1 documented the near-universal usage of sedating and paralytic medications in U.S. intensive care units (ICU). Over one third of surveyed ICUs reported using sedating drugs in at least 70% of their mechanically ventilated patients. The authors noted a wide variability in utilization patterns and called for research to determine optimal use. Recent national surveys of Danish2 and Australian3 ICUs confirm the common practice of administering sedative medications to mechanically ventilated ICU patients. In a prospective study, 62 critical care pharmacists documented administration of sedative, analgesic, and paralytic drugs on 62% of patientdays during a 5-day period.4 Dasta and coworkers5 prospectively documented use of drugs for sedation, anxiety, pain, or neuromuscular blockade in 91% of consecutive adult surgical ICU patients. In a recent analysis of 200 adult ICU patients at our institution, 57% of patients receiving mechanical ventilation and 42% of patients breathing without support had been given sedative or narcotic analgesic medications in the previous 24 hours. Continuous infusion delivery was utilized in 26% of treated patients, most of whom were receiving mechanical ventilation. Sedative and analgesic drugs were used in the majority of patients in the medical, surgical, and cardiac surgical ICUs, and less frequently in the neuroscience and coronary ICUs. Common indications for analgesic and sedative drugs are to minimize anxiety, to relieve pain and discomfort, to improve patient tolerance of mechanical ventilation and thereby optimize patient–ventilator synchrony, and to control agitated behavior and distress. Additional indications include enhancing amnesia, promoting sleep, reducing oxygen consumption, and preventing myocardial ischemia. The commonly cited indication of enhanced patient tolerance of mechanical ventilation arises in part from ongoing advances in mechanical ventilator technology as well as our understanding of pathophysiology of conditions such as the acute respiratory distress syndrome (ARDS) and status asthmaticus. We increasingly use unconventional, and often uncomfortable, forms of mechanical ventilation such as small tidal volume ventilation, permissive hypercapnia, inverse ratio ventilation, and pressure control ventilation.6–8 The development of intrinsic or auto positive end-expiratory pressure (PEEP), among the most insidious and potentially dangerous complications of mechanical ventilation, can be dramatically worsened by inadequately controlled anxiety or pain. Prevention of self-induced injury or injury to caregivers is another high priority for effective sedation. Unplanned extubation or self-removal of other critical tubes or vascular catheters is a common, and potentially immediately life-threatening, action. Approximately 9% of ICU endotracheal (ET) tube extubations are unplanned, the vast majority being self-extubation rather than accidental dislodgment.9 Recently Carrion et al10 documented self-removal rates of 24.7, 73.9, 12.4, and 46.5 per 1000 days for ET tubes, nasoenteric (NE) tubes, central venous catheters, and arterial catheters, respectively. In a prospective study of 128 medical ICU patients, 35 (ET) tubes, NE tubes, and vascular catheters were removed by agitated patients for a total rate of 132 tube or catheter removals per 1000 patient-days.11 Further, events characterized by aggressive behavior toward nurses and other caregivers occurred at a rate of 91 per 1000 patient-days.11 Additional important adverse consequences of inadequate analgesia and sedation range from myocardial ischemia resulting from an exaggerated stress response characterized by increased sympathetic nervous system activity, to diminished immune function and impaired wound healing associated with persistent pain.12,13 For such simple therapeutic end-points of patient comfort and safety, the issues that influence man-