Severe bronchospasm following cardiopulmonary bypass in an asthmatic.

A 67-year-old woman with aortic stenosis was scheduled for aortic vak replacement. There was also a history of asthma, treated with an albuterol inhaler, beclomethasone inhaler, and theophylline. The patient was hospitalized 6 months prior to her current admission for asthma, and had been treated with steroids. She had never required intubation for treatment of asthma. The medical history was otherwise significant for a hiatal hernia, steroid-induced noninsulin-dependent diabetes mellitus, and allergy to penicillin and aspirin. There was no history of nasal polyps. The patient’s other medications included ranitidine and glyburide. Physical examination revealed an elderly woman in no acute distress with a blood pressure (BP) 120190 mmHg, heart rate (HR) of 80 beats/min, (regular), height 157 cm, and weight 80 kg. There were bilateral carotid bruits present, and decreased carotid upstrokes. The examination was otherwise remarkable for a IVIVI systolic murmur at the right upper sternal border, radiating to the neck. The lung fields were clear. The laboratory studies included a hemoglobin of 14.3 gm/dL, hematocrit 43.6%, and white blood cel1 count of 5.6 x 103, with normal eosinophil counts. The electrocardiogram (ECG) showed normal sinus rhythm, left ventricular hypertrophy, and smal1 Q waves in V, and Vz. Chest x-ray was normal, with no evidente of cardiomegaly, infiltrates, or effusions. Cardiac catheterization revealed severe aortic stenosis. The aortic valve area was 0.7 cm*, and the mean gradient was 39 mmHg. The coronary arteries were normal, and left ventricular function was good. Left ventricular end-diastolic pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance, and right ventricular pressure were normal. The patient was premedicated with morphine sulfate, 8 mg, and scopolamine, 0.3 mg, intramuscularly, and ranitidine, 150 mg, and metoclopramide, 10 mg, orally. The chest was clear by auscultation upon arrival in the operating room. A lo-gauge peripheral venous catheter, a 20-gauge radial artery catheter, and an internal jugular pulmonary artery catheter were placed. The vital signs prior to induction were BP 120170 mmHg and HR 90 beatsimin. Pulmonary artery mean pressure (PAP) was 18 mmHg, pulmonary capillary wedge pressure (PCWP) was 10 mmHg, central venous pressure (CVP) was 6 mmHg, and cardiac output (CO) was 6.5 L/min. A modified rapid-sequence induction of anesthesia was done with fentanyl, 4 mg, and vecuronium, 20 mg. Following trachea1 intubation, auscultation of the chest revealed breath sounds equal bilaterally with no wheezing. The capnogram appeared normal in configuration, and the peak inspiratory pressure was 15 mmHg. The patient wasventilated with 100% oxygen, with a tidal volume 800 mL at 7 breaths/min. The pulse oximeter indicated an arterial saturation of 99% to 100%. A pre-CPB arterial blood gas showed pH 7.47, PaC 28, Pa02 517, and base excess -2 mEq/L. The PAP ranged from 20 to 25 mmHg and the CVP was 9 to 13 mmHg. Gentamycin and vancomycin were administered prior to skin incision without adverse effect. Anesthesia was maintained with oxygen, fentanyl, midazolam, and metocurine. There were no sequelae related to the administration of metocurine. Breath sounds ausculted with an esophageal stethoscope remained clear throughout the pre-CPB period. CPB was instituted using a bubble oxygenator, and the CPB proceeded uneventfully. After 105 minutes of CPB and aortic valve replacement, ventilation of the lungs was attempted in anticipation of weaning from CPB. Inflation of the lungs required extremely high pressures (peak inspiratory pressure was above the 80 mmHg maximum reading). Neither lung would deflate. NO breath sounds were audible. A suction catheter was easily passed down the endotracheal tube to rule out obstruction of the endotracheal tube. NO secretions were removed upon suctioning. The heart remained decompressed on CPB, and there was no evidente to suggest that the difficulty in ventilation was due to cardiac failure. A diagnosis of severe bronchospasm was made. Isoflurane, 1.5%, was administered via the pump. Terbutaline, 0.25 mg, was given subcutaneously, and hydrocortisone, 100 mg, was given intravenously. An infusion of epinephrine was started, and was increased to 100 nglkgimin. Albuterol was given via the endotracheal tube. After 15 minutes of treatment, ventilation of the lungs was easier, the peak inspiratory pressure was 40 mmHg, and bilateral wheezing could be heard. The patient was easily weaned from CPB and protamine was administered without problems. A loading dose of 400 mg of aminophylline was infused over 30 minutes, and then an infusion at 0.9 mgikgih was started. Isoflurane, 0.8%, was administered via the vaporizer, and then weaned off as the wheezing decreased and the ventilation improved. An arterial blood gas showed a pH 7.41, PaC 35 mmHg, Pa02 593 mmHg, and base excess -2 mEq/L. The pulse remained at 90 to 95 beats/min, and the MAP was 65 to 80 mmHg. The CO was 5.3 L/min. Postoperative chest x-ray was remarkable only for a smal1 right pleura1 etiusion; no infiltrates were seen. The patient required exploratory median sternotomy on postoperative day 1 due to bleeding, at which time smal1 amounts of muscular and periosteal bleeding were noted, and surgical hemostasis was achieved. She was extubated uneventfully on postoperative day 2. The patient received perioperative corticosteroid treatment for asthma. The epinephrine and aminophylline infusions were continued postoperatively, and slowly weaned over 3 days. The patient was discharged home on the 11th postoperative day.