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Patient Care Vignette

A 68-year-old obese male, 40-pack-year smoker, with a history of hypertension, chronic obstructive pulmonary disease (COPD), and coronary artery disease presents to the emergency department with 3 days of progressively worsening abdominal pain, nausea, and vomiting. On arrival he has low blood pressure, a high heart rate, low oxygen saturation, and he is breathing quite quickly. He has a distended abdomen that was diffusely tender suggesting infection and inflammation. He has an IV placed and receives intravenous fluids and supplemental oxygen by face mask. Laboratory testing reveals evidence of infection as well as impaired kidney function that is new. A CT scan demonstrates much more than normal fluid in his pelvis as well as gas outside of the bowel indicating intestinal perforation and the need for an urgent operation to which he agrees.

He is started on broad-spectrum antibiotics and undergoes an urgent exploratory laparotomy to remove the perforated section of colon and create a colostomy, as the highly contaminated abdomen made a single stage operating unsafe. He did well in the OR and had the breathing tube removed at the end of the operation. He is transferred directly to the ICU where he develops difficulty breathing and recurrent low oxygen saturation that does not improve despite the ICU team’s best efforts. Therefore, he has the breathing tube replaced to support oxygenation and removal of carbon dioxide. His chest X-rays and arterial blood gasses indicate that he has developed acute respiratory distress syndrome (ARDS)—a serious and life-threatening condition that may occur after severe infection or injury—and requires intensive care and frequent ventilator adjustments as well as secretion clearance from the breathing tube by a registered respiratory therapist (RRT).

Breathing is fundamental to life, and many acute illnesses threaten life by compromising respiratory function. Respiratory failure requiring support beyond supplemental oxygen via conventional nasal cannula is sufficient to justify ICU admission in many hospitals. In this chapter, we discuss critical illness and recovery from the perspective of a registered respiratory therapist (RRT) and other ICU clinicians who support the respiratory system.


Critical illness may compromise respiratory function directly, as with pneumonia or respiratory muscle failure, or indirectly, as when sepsis and metabolic acidosis dramatically increase the body’s drive to breathe. When a patient cannot continue to support the work required to maintain normal oxygen levels or to eliminate carbon dioxide, respiratory support is required.

Most patients with respiratory insufficiency or respiratory failure will first be supported with supplemental oxygen provided using nasal prongs or a face mask. When additional support is needed, noninvasive ventilation (NIV; ventilation support without a breathing tube) is often pursued. NIV approaches have been more widely known in the wake of the SARS-CoV-2 pandemic. These approaches include continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), and high-flow nasal cannula oxygen (HFNCO2). Unlike supplemental oxygen ...

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