Illustration by George Folz, © 2020 McGraw-Hill Education
Critical care is a field in healthcare devoted to managing patients having, or at risk of having, acute life-threatening failure of organs, such as the lungs, heart, and kidneys.1 The terms “critical care” and “intensive care” are used interchangeably to describe this specialized area of practice. Essentially, critical care specialists from a host of different professions provide care for the sickest of all patients. The most prevalent health conditions treated in this setting are respiratory failure, acute myocardial infarction (i.e., heart attack), and head bleed or stroke.2 The primary goals are to stabilize the patient (i.e., prevent their condition from worsening), determine the underlying causes of the illness/problem if unknown, and begin treatment to correct identified issues.1
Critically ill patients are cared for in intensive care units (ICUs), which are areas of the hospital dedicated to the management and monitoring of patients with life-threatening conditions. ICUs are equipped to provide intensive and specialized care, including organ support.1,3 Several types of equipment are commonly used in ICUs to accomplish this, including mechanical ventilators to support breathing, extracorporeal membrane oxygenators (ECMOs) to maintain heart and lung function, and hemodialysis machines to filter the blood when kidney function declines or stops.1 Patients with severe head injuries due to an accident may have a monitor placed inside their head, while patients with other conditions may have tubes inserted into their chest attached to suction to drain excessive fluid buildup.1 As shown in the illustrated cases “Shocking” and “Type 1” later in this chapter, bedside monitors display real-time data on blood pressure, heart rate, breathing rate, amount of oxygen in the blood, and body temperature.
Use of such equipment can have profound impacts on medication therapy, particularly in the setting of kidney failure. The kidneys are a major route of elimination from the body for many medications used in critically ill patients, particularly antibiotics.4 Underdosing antibiotics is associated with treatment failure, and overdosing antibiotics is associated with adverse effects.5 Cefepime (Maxipime) is an antibiotic commonly used for the treatment of severe infections, and 85% of it is cleared from the body by the kidneys.6 Patients with kidney failure are at a higher risk of adverse effects including confusion and seizures.7 Since cefepime is cleared by hemodialysis machines, determining the right dose in critically ill patients with kidney failure is difficult.7,8
The ability to monitor real-time data on blood pressure and heart rate has important implications for drug therapy, as well. Critically ill patients can develop low blood pressure, also called shock, from certain diseases; for example, severe infections or heart failure.9 Patients who develop shock are at an increased risk of dying.9 Medications called vasopressors are used to increase blood ...