ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The aim of this prospective study was to document postoperative myocardial infarction (PMI) by technetium pyrophosphate scan using single-photon emission computed tomography (TcPPi-SPECT) in 28 patients undergoing elective coronary bypass grafting (CABG). The relationships of intraoperative electrocardiographic myocardial ischemia, hemodynamic responses, and pharmacological requirements to this incidence of PMI were correlated. Radionuclide cardioangiography and TcPPi-SPECT were performed 24 h preoperatively and 48 h postoperatively. A standard high-dose fentanyl anesthetic protocol was used. Twenty-five percent of elective CABG patients were complicated with PMI, as documented by TcPPi-SPECT with an infarcted mass of 38.0 ± 5.5 g. No significant difference in demographic, preoperative right and left ventricular function, number of coronary vessels grafted, or aortic cross-clamp time was observed between the PMI and non-PMI groups. The distribution of patients using preoperative β-adrenergic blocking drugs or calcium channel blocking drugs was found to have no correlation with the outcome of PMI. As well, no significant differences in hemodynamic changes or pharmacological requirements were observed in the PMI and non-PMI groups during prebypass or postbypass periods, indicating careful intraoperative control of hemodynamic indices did not prevent the outcome of PMI in these patients. However, the incidence of prebypass ischemia was 39.3% and significantly correlated with the outcome of positive TcPPi-SPECT, denoting a 3.9-fold increased risk of developing PMI. Prebypass ischemic changes in leads II and V5were shown to correlate with increased CPK-MB release (P< 0.05) and tends to occur more frequently with lateral myocardial infarction. No association was found between patients with or without prebypass ischemia on intraoperative hemodynamic changes, drug requirements, or postoperative ventricular function. There was no correlation between postbypass ischemia and positive TcPPi-SPECT.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Placental transfer and neonatal effects of propofol were investigated in 21 women undergoing elective cesarean section under general anesthesia. This study was conducted in two separate phases according to the use of propofol. In both phases, anesthesia was induced with an iv bolus of 2.5 mg/kg of propofol. In phase 1 (n = 10), anesthesia was maintained with 50% nitrous oxide in oxygen and halothane. In phase 2 (n = 11), a continuous infusion of propofol at a rate of 5 mg · kg-1· h-1was started after the induction dose. Maternal venous and umbilical cord arterial and venous samples were obtained at delivery. The propofol concentration in whole blood was measured with a high performance liquid chromatography method. Where possible, breast milk/colostrum was expressed for both phases postoperatively and a sample of blood was collected during phase 2 from neonatesviaa heel prick 2 h after birth. Propofol crossed the placenta, as demonstrated by concentrations found in umbilical venous blood in phase 1 (0.13–0.75 μg/ml) and in phase 2 (0.78–1.37 μg/ml). At delivery, the ratio of the drug concentration in umbilical venous blood to that in maternal blood was 0.70 ± 0.06 for phase 1 and 0.76 ± 0.10 for phase 2. The ratio of propofol concentration in the umbilical artery to that in the umbilical vein was 1.09 ± 0.04 for phase 1 and 0.70 ± 0.05 for phase 2. The mean propofol concentration in samples takenviaa heel prick 2 h after birth in 8 neonates during phase 2 was low (0.078 ± 0.011 μg/ml) and represented about 10% of the corresponding umbilical cord artery concentration at time of delivery. The very limited milk/colostrum data indicated that propofol concentrations were low (phase 1: 0.089–0.24 μg/ml; phase 2: 0.04–0.74 μg/ml). Furthermore, propofol is cleared rapidly from the neonatal circulation and exposure of the neonate through breast milk/colostrum would be negligible compared to the placental transfer of the drug. In both phases, propofol seemed to have minimal effects on the healthy newborns. These results justify the performance of additional studies of propofol administration during general anesthesia for cesarean section, especially to compare propofol with thiopental and to evaluate the effect of this drug on the high risk fetus.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Hypertension is common following coronary artery bypass surgery. The safety of labetalol, a recently released combined α-1and β-adrenergic blocking agent for treatment of hypertension in this clinical situation is controversial. The authors compared the hemodynamic effects of labetalol with those of sodium nitroprusside (SNP) in 91 patients with good left ventricular function and equally severe coronary artery disease and in whom coronary artery bypass surgery had been just completed. They were anesthetized using fentanyl, diazepam, and enflurane. If hypertension developed postoperatively, patients were randomized to receive labetalol, 2 mg/min to a maximum of 300 mg (20 patients) or sodium nitroprusside in 0.5 μg · kg-1· min-1increments by infusion (20 patients) to return blood pressure to normal. Compared with control values, labetalol brought about significant (P< 0.05) reductions in heart rate, and cardiac index. No change was noted in stroke volume or systemic vascular resistance, but slight increases were found in central venous pressure and pulmonary capillary wedge pressure. Sodium nitroprusside treatment caused significant increases in heart rate and cardiac index while reducing diastolic blood pressure, central venous pressure, and pulmonary capillary wedge pressure. Stroke volume remained unchanged. Following the study period, blood pressure was controlled in all patients with SNP. Total doses of SNP in the 16 h following the study period were significantly less in the labetalol group (46.6 ± 11.7 mg)versus(116.1 ± 10.3 mg) in the SNP group (P< 0.05). In this clinical circumstance, labetalol can be safe and effective for controlling hypertension, but its mechanism of achieving this effect varies from that for sodium nitroprusside. Labetalol may improve myocardial oxygen balance and allow for reduced cumulative doses of sodium nitroprusside in this clinical setting.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

To determine whether neostigmine had different effects in pediatric patients during vecuronium neuromuscular blockade, the rate of recovery following neostigmine administration was compared in infants (n = 8), children (n = 10), and adults (n = 10) during nitrous oxide-halothane anesthesia. After induction of anesthesia, patients received 100 μg/kg of vecuronium. The EMG response of the adductor pollicis was monitored after train-of-four (TOF) stimulation of the ulnar nerve every 20 s. When the first twitch of TOF spontaneously recovered to 10% of control value, neostigmine was injected (40 μg/kg in adults, 30 μg/kg in infants and children). During the first few minutes following neostigmine administration, no differences were observed between the three groups. After the 8 min, recovery was more rapid in children than in infants and adults up to and including the 15th min. Ten minutes after neostigmine administration, the first twitch (mean ± SD) reached 97 ± 3%, 99 ± 2%, and 97 ± 5% of control value in infants, children, and adults, respectively; TOF ratio was greater in children (0.96 ± 0.03) than in either adults (0.82 ± 0.17) or in infants (0.83 ± 0.14) (P< 0.05). During the first minutes after neostigmine administration, the lack of difference in TOF recovery in the three groups suggests that neostigmine is the main factor of recovery. In contrast, the more complete recovery after the eighth minute in children could be due to the faster rate of spontaneous recovery from vecuronium induced neuromuscular blockade in children.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

This study was undertaken to illustrate the potential for subarachnoid injection during retrobulbar block as a cause of respiratory arrest. Cadaver orbits were used to document the connection between the optic nerve sheath and the subarachnoid space. Following dissections of the orbits on one side of 24 cadavers, the optic nerve sheaths were identified and injected with 0.5 ml of water for measurement of pressure generated during injection. This was followed by intrasheath injection of equal volume of methylene blue for demonstrating the subarachnoid space surrounding the optic nerves. All injections were performed with a 1-ml syringe with a one-and-one-half-inch 22-G needle over a period of 10 s. The blue dye was found to track along the subarachnoid space of the optic nerve sheath to the chiasmatic cistern in the middle cranial fossa. Retrobulbar injections were performed on the contralateral undissected orbits and intrascleral injections were performed on undissected eyes. The size of the syringes, the gauge of the needles, and the speed of injection were uniform for all injections. The pressure generated by injection into the optic nerve sheath or intrascleral injection (approximately 138 mmHg) was three- to fourfold that produced by injection into the retrobulbar adipose tissue (approximately 35 mmHg) (P< 0.05). The authors conclude that any resistance encountered during retrobulbar block should serve as a warning signal, mandating redirection of the needle, in order to prevent subarachnoid injection.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The authors conducted a two-part study to evaluate the efficacy of 1 ml of air as a “test dose‘’ for detection of intravenously located epidural catheters. In part 1, a Doppler fetal heart rate monitoring probe was placed over the precordium of 33 laboring patients in whom functioning epidural catheters were in place. Each patient received, more than 90 s apart, in random order: 10 ml of agitated saline (containing less than 0.5 ml of air microbubbles)viaa peripheral vein; 2 ml of airviathe epidural catheter; and a sham injection (i.e., nothing injected). In all 33 cases, a blinded observer identified Doppler changes 10–30 s following the injection of air (microbubbles)viaperipheral vein. Doppler changes were never heard following epidural air injection (P< 0.001 compared with iv air microbubble injection) or the sham injection (P< 0.001 compared with iv air microbubble injection). In part 2, the authors listened for Doppler heart tone changes while injecting 1 ml of airviacatheters that were accidentally inserted in the epidural veins of five other patients. Unequivocal Doppler changes compatible with intracardiac air always occurred within 3 s, and no signs or symptoms of air embolism developed. The results suggest that 1 ml of air may be a suitable indicator of iv epidural catheter location.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The tape recorded EEGs of 127 patients anesthetized with large doses of opioids were retrospectively analyzed for evidence of opioid-induced seizures, and in particular, correlated with movements that occurred during induction and could be clinically interpreted as seizures. Bilateral EEG leads in patients receiving fentanyl (20), sufentanil (20), or alfentanil (87) were recorded. Forty-six of these patients from all opioid groups manifested intense rigidity, as assessed both clinically and by EMGs recorded from eight muscles in 69 of the patients receiving alfentanil. This intense rigidity often resembled seizures, in that the phenomenon entailed severe stiffness of both limbs and trunk, with an explosive onset of myoclonic limb movements, and associated vertical nystagmus. Electroencephalographic observations were extensive, entailing 69 h of paper recordings played back from the tapes, at paper speeds of 30 or 60 mm/s, with detailed annotations from the voice track. These paper recordings were examined in detail independently by three of the investigators, who were unaware of the clinical phenomena that had occurred. The only observed EEG activity that could have been interpreted as epileptiform consisted of small sharp waves related to muscle activity or other artifact. The EEG never indicated seizure activity during these drug-induced movements and rigidity. Reports of opioid-induced seizures are reviewed and a set of criteria is offered to help achieve future consistency and credibility in evaluating this phenomenon. The available evidence does not support the existence of opioid-induced seizures in the clinical setting.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Prompted by reports of potentially deleterious cerebral vasodilation by the synthetic opoid sufentanil, the authors compared the effects of either isoflurane/N2O and sufentanil/N2O on cerebral blood flow (CBF), arteriovenous difference in oxygen content (AVDO2), and CBF reactivity to changes in Paco2during carotid endarterectomy. Cerebral blood flow was measured using the iv method of 133-Xe CBF determination and AVDO2was measured using systemic arterial-jugular venous oxygen content differences. Patients, age 68 ± 1 yr (mean ± SE), received either isoflurane (n = 10), 0.75% in O2and N2O, 1:1; or sufentanil (n = 10), 1.5–2 μg/kg bolus and then 0.2–0.3 μg ± kg-1· h-1infusion in addition to O2and N2O, 2:3. Measurements were made immediately before carotid occlusion, and then at two levels of Paco2(approximately 32 and 42 mmHg) after insertion of a temporary in-dwelling bypass shunt. Prior to carotid occlusion, there was no significant difference in CBF (ml · 100 g-1· min-1) between patients receiving isoflurane (22 ± 3) or sufentanil (20 ± 2). Similarly, there was no difference in AVDO2(vol-%) between isoflurane (4.5 ± 0.7) and sufentanil (5.4 ± 0.8) groups. Using a two-way ANOVA design with anesthetic as the between-group factor and elevation of Paco2as the within-group repeated measure, there was a significant effect of hypercarbia to increase CBF (P< 0.0001) and decrease AVDO2(P< 0.001). The product of AVDO2and CBF, which reflects cerebral metabolic oxygen consumption, remained constant (P= 0.364). There was no difference in AVDO2or CBF between anesthetic groups. CBF reactivity to changes in Paco2was similar for both anesthetic regimens. The average slope of the CO2response (ml · 100 g-1· min-1· mmHg-1) was 1.7 ± 0.3 for isoflurane and 1.1 ± 0.2 for sufentanil, respectively, and did not differ significantly. Both sufentanil and isoflurane in combination with N2O, when used in elderly patients with occlusive cerebrovascular disease, have similar effects on cerebrovascular hemodynamics.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Heparin is the anticoagulant used during cardiopulmonary bypass (CPB). Both the use of heparin and the reversal of its effect with protamine have well-documented complications. Ancrod is a defibrinogenating enzyme that has been used as an anticoagulant in humans, but its use as an anticoagulant for CPB has been limited to studies in animals. Twenty patients for elective aortocoronary bypass surgery were anticoagulated by means of an intravenous infusion of ancrod pre-operatively. Target plasma fibrinogen concentrations of 0.40–0.80 g/1 were achieved within 13.3 ± 2.5 h using an average dose of ancrod of 1.65 ± 0.55 U/g. All perfusions were without incident. Postoperative blood loss (2286 ± 1311 cc) was compared to that of 20 matched controls (1737 ± 973 cc), as was blood product use; 4.1 ± 2.1 U of packed cellsversus2.5 ± 2.3 U (P< 0.05) and 5.6 ± 3.1 U of plasmaversus2.6 ± 2.9 U (P< 0.05) in the ancrod and heparin-treated groups, respectively. There were no differences in the postoperative courses or recovery periods of the ancrod-treated and control patients. This study confirms the efficacy and feasibility of ancrod as an alternative form of anticoagulation for CPB.

ISSN:0003-3022    

出版商:OVID    

年代:1989

数据来源: OVID