Diagnosis and management of acute hypoxemia after drainage of massive pericardial effusion

Abstract

A 35-year-old, 99-kg female, with a history of hypertension, hypothyroidism, and asthma, complained of fatigue, weight loss, dyspnea, and pedal edema. Her medications included oral thyroxine, omeprazole, iron sulfate, and inhaled beclomethasone. Physical examination revealed clear lung fields, distant heart sounds, and pitting edema in both legs. The chest radiograph showed cardiomegaly and clear lung fields; the electrocardiogram showed sinus tachycardia and low QRS voltage. A transthoracic echocardiogram (Fig 1) showed a large pericardial effusion with diastolic collapse of the right ventricle and both atria. Thyroid function tests performed shortly after admission were normal. On arrival to the operating room for pericardial drainage, the patient's blood pressure was 116/94 mmHg, her pulse rate was 107 beats/min, and her oxygen saturation by finger pulse oximeter (on 2 L/rain nasal oxygen) was 100%. After the operative field was prepared, intravenous ketamine and succinylcholine were administered, and a cuffed endotracheal tube inserted in the trachea. A subxyphoid incision was made, and 1.8 L of hemorrhagic pericardial fluid drained. Hemoglobin saturation remained 100% for 10 minutes before drainage of the pericardial effusion, whereupon saturation declined acutely to 85%. Normal breath sounds were heard over each lung field. An arterial blood gas revealed a PaO2 of 57 mmHg, PaCO2 of 53, and pH of 7.35, despite an FIO2 of 1.0, tidal volume of 800 mL, and ventilation rate of 8 breaths/min. Bronchoscopy revealed normal airways and the endotracheal tube tip in proper position. A pulmonary artery catheter was placed, revealing a central venous pressure of 10 mmHg, pulmonary artery pressure of 30/16 mmHg, pulmonary capillary wedge pressure of 13 mmHg, and a cardiac output (CO) of 7.0 L/rain (by thermodilution). A complete TEE examination was performed, revealing a 1.5-cm ostium secundum ASD (measured in the horizontal plane, four-chamber view) with a large right-to-left atrial shunt (by color-flow Doppler), mild global hypokinesis of the left ventricle, severe hypokinesis of the right ventricle, and moderate tricuspid regurgitation (by color-flow Doppler). The patient remained hypoxemic (arterial saturation 63% on FIO 2 of 1.0), despite infusions of norepinephrine (0.07 pg/kg/min) and dopamine (15 ~g/kg/min) to raise systemic vascular resistance and improve right ventricular function, and inhaled nitric oxide (60 ppm) to lower pulmonary vascular resistance. She was