Gerard DeSouza

Comparison of Propofol With Isoflurane for Maintenance of Anesthesia in Patients With Chronic Obstructive Pulmonary Disease: Use of Pulmonary Mechanics, Peak Flow Rates, and Blood Gases

Patients with chronic obstructive pulmonary disease (COPD) are usually anesthetized with an inhalation agent. After Institutional Review Board approval, informed consent was obtained from 60 patients with moderate to severe COPD according to a preoperative severity scoring system, which took into account history and objective findings. By using objective criteria, such patients were randomly assigned to receive propofol (group I) or isoflurane (group II) as primary maintenance agents. Preoperative and postoperative arterial blood gases, peak expiratory flow rates (PEFR), and chest X-rays were compared. Total dynamic compliance (CDYN) and V1 (% volume exhaled in first second) were measured using Pitot tube sidestream spirometry. A 1,000-mL super-syringe was used to measure total static compliance (CST). Measurements were recorded postintubation, midanesthesia, and pre-extubation. All patients received fentanyl, lidocaine, and propofol, 1.5 to 2.0 mg/kg, for induction. Succinylcholine, 1-1.5 mg/kg, was administered to facilitate intubation. Maintenance was with N2O-O2, vecuronium, and either propofol (n = 30) or isoflurane (n = 30). Both groups showed decreases in postoperative PaO2, SaO2, and PEFR (p 0.05). There were no significant chest X-ray differences. There were no differences between groups with respect to intraoperative pulmonary mechanics (p > 0.05). The only difference between groups was an increase in postoperative PaCO2 in group I and a decrease in group II (p < 0.05). Use of Pitot tube sidestream spirometry is a practical and noninvasive technique for monitoring pulmonary mechanics during anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Shy-Drager syndrome and severe unexplained intraoperative hypotension responsive to vasopressin.

IMPLICATIONS We describe the first case of Shy-Drager syndrome diagnosed on the basis of intraoperative hemodynamic changes. The initial hypertension in the supine position followed by severe hypotension after hydralazine administration, ultimately responsive to vasopressin, led to a diagnosis of Shy-Drager syndrome. We suggest that vasopressin may be the drug of choice in patients with Shy-Drager syndrome with refractory hypotension.

Severe hypoglycemia after labor epidural analgesia.

A healthy, 30-yr-old, 154-cm, 54-kg primigravida taking only prenatal vitamins presented for the induction of labor at 38.5 wk of gestation. The induction began with a dinoprostone vaginal insert followed by oxytocin infusion titrated to produce contractions every 5 min. Per obstetric protocol, she received 1 L of D5NS over 4 h and then lactated Ringer’s solution at 125 mL/hr. Approximately 6 h after admission, the patient complained of severe pain at a cervical dilation of 3 cm and requested epidural analgesia. An IV bolus of 500 mL of normal saline was given, and the patient was placed in the sitting position. A 17-gauge Tuohy epidural needle was inserted at the L3-4 interspace after 1% lidocaine skin infiltration. When loss of resistance was felt, a multi-orifice catheter was threaded 3 cm. Aspiration for blood or cerebrospinal fluid was negative, and a test dose using 3 mL of 1.5% lidocaine with 5 mg epinephrine/mL was negative for signs of intrathecal or IV administration. Five milliliters of 0.25% bupivacaine was injected, and within 15 min, the patient had a sensory dermatomal level of T4 and was pain free. She did not exhibit a motor block, but because of the high sensory level, a continuous epidural infusion was not started. Approximately 75 min after the initial bolus, the patient’s pain returned and examination revealed a sensory level of T12. After negative aspiration for blood or cerebrospinal fluid and another negative test dose, 5 mL of bupivacaine 0.25% was injected. Approximately 10 min later, she complained of lightheadedness, facial tingling, and lethargy and stated “this is how I feel when I’m very hungry.” Her heart rate and blood pressure were unchanged, and her sensory level was T6. Suddenly, she became stuporous and responded only to loud verbal commands. An immediate fingerstick (Surestix; Johnson & Johnson, Milpitas, CA) revealed a glucose of 18 mg/dL, and a repeat fingerstick was 16 mg/dL. Fifty milliliters of 50% dextrose was administered IV with almost immediate improvement of her mental status. A fingerstick (240 mg/dL) and blood glucose (223 mg/dL) at that time reflected her clinical improvement. Pelvic examination revealed a completely dilated and effaced cervix, and uneventful delivery of a newborn male with Apgar scores of 9 and 10 (1 and 5 min, respectively) occurred 30 min later. Approximately 60 min postpartum, a repeat blood glucose was 40 mg/dL, however the patient remained asymptomatic at that time. Her sensory level of anesthesia subsided by 90 min after delivery. The infant’s glucose was monitored for the first 24 h, remained normal, and he is healthy at 1 yr. Postpartum follow-up for the parturient included normal results of oral glucose-tolerance test, adrenocorticotropic hormone, cortisol, glucagon, insulin, and thyroid function tests. By exclusion, she was diagnosed with “reactive hypoglycemia” and advised to have her blood glucose closely monitored during subsequent pregnancies.