Have you ever wondered why that patient coded after endotracheal intubation? As it turns out, it is not uncommon after critically ill patients are intubated. Approximately 60% of critically ill patients require endotracheal intubation and are at high risk for hemodynamic collapse during this procedure. Prior studies suggest that there is up to a 25% risk of hemodynamic instability even in successful critical care unit intubations. Therefore, it is crucial to prevent peri-intubation hemodynamic instability to avoid poor patient outcomes through hemodynamic optimization prior to endotracheal intubation.

Point-of-care ultrasound has evolved as a simple, portable, and noninvasive tool for assessment of hemodynamic status. It can provide invaluable information about diagnoses and direct resuscitation in critically ill patients. This bedside imaging modality can help determine the etiology of shock, guide appropriate interventions prior to patient decompensation, and assess patient response to management changes. It can also assist in the evaluation of intravascular volume status and fluid responsiveness of critically ill patients.

Endotracheal intubation is especially perilous for a patient with right ventricular failure. Performing this procedure in patients with right ventricular failure can result in catastrophic hemodynamic collapse since the right heart is very sensitive to increases in afterload. Right ventricular failure resulting in hemodynamic collapse is an underappreciated complication of patients undergoing intubation and invasive mechanical ventilation.

Echocardiography during the preparation period of intubation allows for direct and noninvasive visualization of the right ventricle at the bedside and can play a major role in the stabilization of critically ill patients. Pre-intubation echocardiography can prevent hemodynamic deterioration by identifying a failing right ventricle, which is extremely sensitive and unable to compensate for any increase in afterload or decrease in preload from endotracheal intubation. Pre-intubation echocardiography can detect signs of a deteriorating right ventricle (pressure and volume overload) such as right ventricle dilation, bowing of the interventricular septum into the left ventricle, decrease in the size of the left ventricular cavity, and decreased left ventricular filling leading to decreased cardiac output (Figures 1–4). If acute right ventricular failure is identified prior to endotracheal intubation, it can help the physician select appropriate management strategies prior to intubation and avoid hemodynamic instability.

Figure 1. D-sign. Interventricular septum is flattened during diastole and forms D-shaped left ventricle.

Figure 2. Four-chamber apical view demonstrating enlarged right ventricle.

Figure 3. Parasternal long-axis view demonstrating dilated right ventricle.

Figure 4. Parasternal short-axis view showing decrease in the size of left ventricular cavity.

With pre-intubation detection of right ventricular failure, different strategies can be implemented prior to endotracheal intubation to avoid hemodynamic collapse. Non-invasive positive pressure ventilation can be an alternative in some cases, which has a less pronounced effect on venous return and preload compared to invasive mechanical ventilation. In the setting of pulmonary embolism (or pulmonary arterial hypertension), inhaled nitric oxide can be used to decrease pulmonary artery pressure through pulmonary vascular dilation. Other strategies to avoid worsening right ventricular failure include administration of vasopressors prior to endotracheal intubation and avoiding intravenous fluid boluses.

Pre-intubation echocardiography is a crucial step in the protocol during endotracheal intubation of critically ill patients to prevent poor patient outcomes. It allows clinicians to approach endotracheal intubation-associated hemodynamic instability in a specific, targeted manner. Integration of pre-intubation echocardiography can vastly improve the management and safety of critically ill patients, in hopes of decreasing the risk of poor outcomes.

Srikar Adhikari, MD, MS, FAIUM, is a professor in the Department of Emergency Medicine at the University of Arizona Medical Center.

Interested in learning more about POCUS? Check out the following posts from the Scan:

• POCUS: A Holiday in the Sun, by David Mackenzie, MDCM
• Novice to Competence to Understanding Our Role as POCUS Educators, by Kevin Piro, MD
• Who Owns POCUS? by Jonathan Monti, DSc, PA-C, RDMS
• The Place of POCUS in Prevention of Physician Burnout, by Janice Boughton MD, FACP, RDMS