Monitoring and managing the critically ill patient in the intensive care unit

The need for monitoring of patients has grown as the health care system has developed the ability to care for more critically ill patients. Monitors serve several purposes including identification of shock and abnormal cardiac physiology, evaluation of cardiovascular function, and/or to allow for optimizing titration of therapy. An important function of an effective monitoring device is reliable detection of abnormal physiology. Despite much research on the use of monitoring techniques in critical care, there is little evidence of improved outcome related to use of monitors. Mainstays of invasive monitoring in the ICU include central venous pressure monitoring and arterial pressure monitoring, with pulmonary arterial monitoring reserved for occasional patients with multisystem disease. Recent trends in monitoring have included development of less invasive monitoring techniques that yield a number of cardiovascular parameters potentially useful to clinicians. New noninvasive measures of tissue perfusion (StO₂, sublingual capnometry) have significant potential in identification and treatment of pathophysiologic states resulting in inadequate tissue perfusion. Developers of new monitors, despite regulatory requirements that are less stringent than those of drug manufacturers, will increasingly be expected to demonstrate clinical efficacy of new devices. In the final analysis, the most important monitor is a caring health care provider at the patient bedside carefully evaluating the patient's response to intervention and therapy.