Mechanism of the Hypotension Produced Protamine Sulfate in Dogs / 대한마취과학회지

INTRODUCTION: Protamine reversal of heparin anticoagulation often produces profound hypotension. However, the precise mechanisms of its hypotensive effect have not been fully elucidated. Using a canine model, we explored the effects of cyclo-oxygenase inhibitor, indomethacin (INDO), and nitric oxide synthetase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) either alone or both on the cardiopulmonary responses to protamine. METHODS: Fifty-four mongrel dogs in five groups were studied during 1.5% halothane anesthesia. GroupI (n=17) received heparin (300 IU/kg iv) followed by protamine (3 mg/kg iv over 30 s) 5 min after the heparin. The same protocol were used in groups II (n=11), III (n=12), and IV (n=7), except that L-NAME (20 mg/kg), INDO (10 mg/kg), and INDO (10 mg/kg) plus L-NAME (10 mg/kg) were infused over 10 min beginning 30 min before the protamine injection, respectively. Animals in group V (n=7) were given protamine (3 mg/kg) alone. Mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), left ventricular end-diastolic pressure (LVEDP), LVdP/dt and cardiac output and left circumflex coronary flow (LCX flow) via Doppler flowmeter and heart rate were continuously recorded in baseline conditions and up to 15 min. Plasma NOx (NO2-, NO3-) levels were also measured before (baseline) and 3, 5, 10, and 15 min after protamine injection. RESULTS: In group I, protamine caused immediate but transient decreases of MAP (41%), cardiac index (CI, 58%), dP/dt (28%), and LVEDP (62%) and increases of MPAP (38%) and systemic and pulmonary vascular resistance indices (SVRI, 30%; PVRI, 316%). INDO significantly attenuated the hemodynamic responses to protamine, whereas L-NAME did not affect them at all. INDO plus L-NAME prevented protamine-induced hypotension, but CI (-24%) and LVEDP (-30%) showed similar changes as those in group II. Protamine increased MPAP but inconsistently, meanwhile no correlation was found between the magnitude of increase of MPAP and decrease of MAP at peak responses in groups I-IV. LCX flow increased significantly (124~188%) immediately after protamine infusion without any changes in plasma NOx levels in groups I-IV. Neither significant hemodynamic effects nor NOx release was found in animals given protamine alone. CONCLUSION: Protamine in the presence of heparin induces profound hypotension which may be mediated by a prostanoid and other potent vasodilators. In addition, increase of PAP and NO release may not play a significant role in the protamine-induced hypotension.

The Effect of Preanesthetic Administration of Crystalloid for Prevention of Spinal Anesthesia-Induced Hypotension / 대한마취과학회지

BACKGREOUND: Despite many advantages of spinal anesthesia, hypotension after spinal anesthesia is a common complication. The practice of routine preemptive infusion of crystalloid before spinal anesthesia has been widespread acceptance. But the value of this practice has recently been questioned. This study was designed to determine whether preoperative administration of crystalloid decrease the incidence of hypotension after spinal anesthesia. METHODS: Thirty ASA I and II patients for elective lower extremities operations under spinal anesthesia were randomized to receive either 500 ml Ringer's lactate solution prior to induction of spinal anesthesia (group I) or no prehydration (group II). Hypotension was defined as a 30% decrease from baseline systolic blood pressure or systolic 70% of baseline, systolic blood pressure and heart rate were not significantly different between both groups. CONCLUSIONS: We conclude that, in normovolemic adult patients undergoing elective lower extremities surgery, an intravenous infusion of 500 ml of Ringer's lactate solution is ineffective in preventing hypotension during spinal anesthesia.

The Evaluation of the Incidence of Intraoperative Awareness, the Degree of Difficulty with Intubation and Postanesthetic Complication in Surgical Patients / 대한마취과학회지

Randomly selected 193 patients who received elective operation under general anesthesia and were able to communicate with anesthesiologists and follow up for 5 days between May and September 1994 at Chonnam University Hospital, were interviewed and evaluated on the night before, 2 and 5 days after their operation. Distribution of physieal status by ASA was that more than half the total patients belongs to class I and 36.8% of patients were under class II. Sedation scores did not chang between on the night before and the day of operation. A significant correlation existed among the visibility of pharyngeal structures, the exposure of glottis by laryngoscopy, and the degree of difficulty with intubation. About 83% of patients was readily intubated, and none of patient was impossible to intubate. All of the patients lost consciousness during induction of anesthesia, and did not recall during operation. Postanesthetic complications were sore throat(30%), nausea and vomiting(28%), lumbago(15%), urticaria(3%), and dizziness(3%).