Chapter 42: Infectious Disease Emergencies

IMMEDIATE MANAGEMENT OF LIFE-THREATENING PROBLEMS

SEPTIC SHOCK

Sepsis is a state of systemic inflammation triggered by infection, affecting virtually every organ system. Although the mortality rate from sepsis has been falling, its incidence is increasing and septic shock now accounts for 10% of admissions to intensive care units (ICUs). Septic shock peaks in the sixth decade of life, and factors that can predispose to it include immunodeficiency, cancer, malnutrition, and genetics. Early recognition of sepsis is essential to providing effective care.

The systemic inflammatory response syndrome (SIRS) is characterized by a complicated interplay of multiple inflammatory mediators and may result from trauma, infection, burns, or diseases such as pancreatitis. It is defined as two or more alterations in the following physiologic parameters:

• Body temperature greater than 38°C or less than 36°C

• Heart rate greater than 90 beats/min

• Respiratory rate greater than 20, Paco₂ less than 32 mm Hg, or need for mechanical ventilation

• White blood count (WBC) greater than 12,000/mm³ or less than 4000/mm³, or greater than 10% bands

Sepsis is defined as SIRS with a documented infection, with the identification of microorganisms from a normally sterile fluid or visual inspection of a focus of infection. Severe sepsis consists of sepsis with evidence of end-organ hypoperfusion or dysfunction (eg, prolonged capillary refill, acute respiratory distress syndrome (ARDS), mental status changes, or elevated lactate). Septic shock is severe sepsis with persistent hypotension despite adequate fluid resuscitation, with refractory septic shock defined as septic shock requiring high doses of vasopressors.

Immediate Measures

A. Maintain Airway and Ventilation

Provide supplemental oxygen in order to maintain pulse oximetry greater than 92%. Patients with profound mental status changes or hypoxia unresponsive to noninvasive ventilation may require intubation. Early on, arterial blood gas samples may show a respiratory alkalosis, with a metabolic acidosis becoming more prominent as the disease state progresses.

B. Establish Adequacy of Circulation

Adequate intravenous access should be obtained early on and consideration could be given to placing a central line, but it is not always necessary and should not be an absolute priority. Crystalloid infusion should be given if the patient is without signs of volume overload. Bedside ultrasound of the inferior vena cava (IVC) along with echocardiography can be used to help determine volume status and further need for volume versus vasopressors. The current vasopressor of choice is norepinephrine. Routine use of low-dose (“renal protective”) dopamine is not recommended. An arterial line should be considered for all patients receiving vasopressors.

Traditional clinical measures of perfusion (urine output, capillary refill, tachycardia) may miss hypoperfusion in a significant number of patients. In patients with systolic pressure less ...