摘要:

The influence of two different concentrations of iv naloxone infusion on the analgesia and adverse effects of epidural morphine were compared in a double-blind, placebo-controlled study. Fortyfive patients undergoing gallbladder surgery were provided postoperative analgesia by 4 mg epidural morphine; they then received an iv infusion over a 12-h period consisting of either 5 μg · kg−1· h−1naloxone, 10 μg · kg−1· h−1naloxone, or saline. Pain relief was assessed by hourly visual analog scoring (VAS) and by direct questioning of the patient. Requirement of additional analgesia was noted. Respiratory frequency was monitored every 15 min and arterial blood gases were analyzed every 2 h for 24 h. Peak expiratory flow (PEF) was recorded 6 and 24 h postoperatively. Steady-state kinetics of naloxone were determined by a modified radioimmunoassay (RIA) method. All patients had good to excellent postoperative pain relief. Naloxone, 5 μg · kg−1· h−1, did not appear to have any effect on epidural morphine analgesia. However, naloxone infusion at the rate of 10 μg.kg−1h−1reduced the duration of analgesia by about 25%, and more frequent injections of epidural morphine were required to give effective analgesia. Complete reversal of analgesia was not seen in any patient. A dose-related stimulatory effect on respiratory frequency was noted in the groups receiving naloxone. Paco2values also were better in these groups as compared to values in the placebo group. The steady-state plasma concentration of naloxone was 2.8–3.7 ng/ml during infusion at the rate of 5μg.kg−1h−1and 4.3–5.1 ng/ml during 10 μg · kg−1h−1naloxone infusion. The plasma clearance of naloxone was 30.5 and 35.4 ml. min−1. kg−1for the low and high dose groups, respectively, and showed a four-fold interindividual variation. The authors conclude that naloxone reverses epidural morphine analgesia in a dose-dependent manner. Low-dose naloxone infusion (5 μg.kg−1h−1)prevents respiratory depression due to epidural morphine without affecting its analgesia.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Serum cholinesterse activity decreases 30% during pregnancy and remains depressed during the postpartum period. However, succinylcholine recovery is not prolonged in term-pregnant patients. This contrasts with results obtained in other patients with decreased serum cholinesterase activity. To better understand this paradox, the authors compared serum cholinesterase activity and recovery from succinylcholine, 1 mg/kg, in nonpregnant (with and without oral contraceptive use), in term-pregnant, and in postpartum patients. Serum cholinesterase activity was lower in both term-pregnant (3.66 ± 039 U/ml, X ± SE) and postpartum (2.84 ± 035 U/ml) patients than in nonpregnant patients not taking oral contraceptives (5.01 ± 0.33 U/ml,P< 0.05). Cholinesterase activity in postpartum patients also was significantly lower than in nonpregnant patients taking oral contraceptives (4.81 ± 0.63,P< 0.05). In contrast, the time to 25% twitch-height recovery did not differ between term-pregnant (470 ± 56 s) and nonpregnant patients taking (499 ± 29 s) or not taking (501 ± 21 s) oral contraceptives, but was significantly increased in postpartum patients (685 ± 22 s,P< 0.001). The similar duration of action of succinylcholine in term-pregnant patients (with decreased serum cholinesterase activities) and nonpregnant patients may be related to the increased volume of distribution of succinylcholine at term.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The effects of midazolam on coronary sinus blood flow (CSBF), myocerdial oxygen consmption (MVO2), and myocardial laclate balance were investigated in eight patients with stable coronary artery disease undergoing cardiac catheterization. Coronary sinus blood flow was measured by continuous thermodilution. Arterial and coronary sinus blood were analyzed for oxygen and lactate content. The determinants of left ventricular (LV) performance were obtained from the cardiac output measured by thermodilution and from left heart catheterization data. All data were obtained before, and 5 and 15 min after midazolam, 0.2 mg kg−1iv. Sleep was induced in all patients after administration of midazolam and persisted throughout the entire study period. Mean aortic and LV end-diastolic pressure were decreased from control values (−15 and −44%, respectively), as well as cardiac index and stroke index (−10 and −15%, respectively), Heart rate increased moderately (+8%), while no change in systemic vascular resistance and maximum velocity of shortening (Vmax) were observed, Midazolam administration was followed by a decrease of CSBF (−24%) and of MVO2, (−26%). Coronary vascular resistance did not change, but coronary sinus oxygen tension increased slightly, suggesting a mild alteration in normal autoregulation. However, no evidence of myocardial ischemia occurred, as judged by the absence of changes in the: 1) ECG, 2) myocardial lactate extraction, and 3) relaxation time constant. These results suggest tht midazolam may be used safely in patients with coronary artery disease

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Surgical conditions during conventional mechanical ventilation (CMV) and pulmonary gas exchange were compared with those during high-frequency ventilation (HFV) in 24 patients udergoing anesthesia for intrathoracic surgery. HFV at an oscillatory frequency of 3 Hz and a delivered gas volume of 1.3–1.9 ml/kg provided excellent surgical conditions for peripheral lung procedures. However, surgical conditions for procedures on the major airways or mediastinal structures were unsatisfactory during HFV. Adequate pulmonary gas exchange was achieved with HFV when the chest was open. Further evidence is presented for expiratory flow limitation during HFV. Expiratory flow limitation seems to occur particularly in patients with chronic obstructive airway disease, leading to increased lung volume. Currently, the authors do not recommend HFV for routine use during anesthesia for thoracic surgery.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The effects of flunarizine, a calcium entry blocker, were evaluated in a long term survival model of ischemia in rats. One group of animals received the drug orally at 24 and 4 h prior to the insult (40 mg'kg−1dose−1). Another group was given flunarizine following the insult, intravenously at 5 min (0.1 mg'kg−1), and orally at 8 and 24 h (40 mg'kg−1dose−1). A third group received the solvent for the oral suspension on the same schedule as the pretreated group. Six animals from each group were subjected to 9 min ischemia and recovery of 7 days, at which time the brains were harvested for histologic study. In another six animals from each group, cortical metabolites and fatty acids were determined during early redrculation. Local cerebral blood flow was measured at 60 min recirculation in a third set of animals. Flunarizine significantly improved histologkal outcome (fewer irreversibly damaged cells) in both treatment groups. This amelioration was not related to improvement of cerebral blood flow during the period of delayed hypoperfusion, nor the postischemic levels of high-energy phosphates or free fatty acids.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The ability of sufentanil to suppress noxiously evoked activity of wide dynamic range (WDR) neurons was studied in decerebrate, spinal-cord-transected cats. Sufentanil, 2.5 ug (n = 7) or 5.0 ug (n = 7), when administered spinally, produced a significant, dose-dependent suppression of noxiously evoked (51 °C radiant heat stimulus) activity of WDR neurons in the dorsal horn of the spinal cord. Spontaneous recovery from sufentanil suppression was not seen for up to 2 h. Reversal following intravenous naloxone, 0.12 mg, although present, was not as complete as that seen following other spinal opiates. Intravenous sufentanil, 5.0 ug/kg (n=4), produced significant but short-lasting depression of noxiously evoked WDR neuron activity. A comparison of the results of this study with data from a previous fentanyl study suggests that sufentanil may be more appropriate than fentanyl for spinal or epidural administration because of a possible longer duration of action. However, the lesser degree of naloxone reversal seen in this study may suggest that, clinically, reversal of sufentanil effects may be more difficult.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Previous studies on halotane's on effect on left ventricular diastolic compliance (LVDC) not only have had conflicting results, but are not directly applicable to most intraoperative settings. Therefore, the authors examined in dogs whether the depth of halothane anesthesia alters LVDC under surgical conditions over a wide range of hemodynamic stresses with the cardiovascular reflexes intact. The left ventricular diastolic pressure-volume relation was examined at 1 MAC and 2 MAC halothane in seven dogs over wide ranges of preload and afterload during left thoracotomy. Pulmonary capillary wedge pressure (PCWP), left ventricular end-diastolic pressure (LVEDP), and echocardiographic left ventricular end-diastolic volume (LVEDV) were analyzed with the exponential pressure-volume relation P = AeBV(where P = pressure, V = volume, and A and B are empirically derived coefficients). Multivariate analysis showed no significant differences for diastolic pressure-volume relations, comparing both levels of halothane using either PCWP or LVEDP for pressure. The authors conclude that in the intact cardiovascular system in the healthy open-chest dog: 1) LVDC does not change with the depth of halothane between 1 and 2 MAC (it is still possible LVDC changed between 0 and 1 MAC), and 2) PCWP does reflect the LVEDV during halothane anesthesia (between 1 and 2 MAC) under surgical conditions over a wide range of cardiovascular stresses.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Hemodynamic changes during four anesthetic techniques were studied in 80 preterm neonates. Atropine, 0.02 mg/kg, and pancuronium, 0.1 mg/kg, were given intravenously to all patients, who were veontilated with oxygen and air. Each group of 20 patients then received 0.75% isoflurane, 0.5% halothane, 20 ug/kg fentanyl, or 2 mg/kg ketamine. Heart rate (HR), systolic blood pressure (SAP), and mean blood pressure (MAP) were recorded at 1-min intervals until surgical stimulation. HR remained at or above control level in all groups. Statistically significant decreases (P<0.01) in SAP and MAP occurred following administration of each anesthetic. SAP decreased 30% during isoflurane administration, 25% during halothae, 21% following fentanyl, and 16% following ketamine. Clinically important decreases (25% or greater) in SAP were observed in some patients in each group, but the incidence was significantly less in patients receiving ketamine (P <0.02). The covariables of conceptual age, postnatal age, weight, urine specific gravity, hematocrit, and presence of patent ductus arteriosus did not have statistically significant effects on SAP and MAP changes. The authors conclude that SAP and MAP decrease significantly during each of the anesthetic techniques studied and that clinically important decreases in SAP occur less frequently during the technique using ketamine.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Administration of a subparalyzing dose of nondepolarizing muscle relaxant (priming dose) prior to its intubating dose hastens the onset time (time from muscle relaxant administration to 100% depression of twitch tension) of neuromuscular blockade. This study was undertaken to determine the optimal priming and intubating doses and time interval between these doses (priming interval) of vecuronium during rapid-sequence induction of anesthesia. The authors measured single-twitch tension in 79 healthy, awake, premedicated (fentanyl, 50–150 mg iv, and/or diazepam, 5–10 mg iv) patients. In Part A of the study, the priming dose was varied (0.0, 0.005, 0.01,0.0015, or 0.02 mg/kg iv). Decrement of twitch tension and symptoms were recorded 3 min later. Four minutes after the priming dose, thiopental, 4–6 mg/kg iv, and vecuronium, 0.1 mg/kg iv, were given. Onset times for the 0.01,0.015, and 0.02 mg/kg groups were significantly shorter than for 0.005 and 0.0 mg/kg groups. No breathing difficulties were encountered in any of the groups. Decrement of twitch tension greater than 25% of control only occurred in the 0.02 mg/kg group (4 of 11 patients). In Part B, the priming interval was varied (2, 4, or 6 min) after giving the optimal priming dose (0.01 mg/kg). Anesthesia was induced as in Part A. Onset times for the 4-min group were significantly faster than the 2− or 6-min groups. In Part C, the intubating dose was varied (0.07, 0.1, or 0.15 mg/kg iv) after the optimal priming dose and optimal priming interval (4 min). Onset times for the 0.1 mg/ kg and 0.15 mg/kg groups were significantly faster than the 0.07 mg/kg group. Intubating conditions were not evaluated. The authors conclude that when vecuronium is used for rapid establishment of neuromuscular blockade during induction of anesthesia, 0.01 mg/ kg iv should be given 4 min prior to 0.1 mg/kg iv.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The effect of physostigmine on the loss of consciousness and respiratory depression induced in rabbits by flunitrazepam, 1 mg/kg, was studied to demonstrate whether the restoration of consciousness and respiration rate result from an increase in central cholinergic activity or from an interference by physostigmine with specific binding of flunitrazepam to its receptors. Physostigmine, 0.1–0.4 mg/kg iv, caused a dose-related reversal of consciousness and respiration rate within 15 min of its injection, which lasted 15–30 min rain depending on the dose. This was associated with peak inhibition of acetylcholinesterase (AChE) in the frontal cortex and medulla, at 15 min, ranging from 35–51%. The analeptic effect of physostigmine in flunitrazepam-treated rabbits was prevented by pretreatment with scopolamine, 1 mg/kg. The effective dose range for physostigmine, 3–12 μmol/kg, is close to concentrations of this agent that inhibit activity in solubilized preparations of AChE from rabbit cortex, 1–3 x 10−8M. However, physostigmine, 10−9−10−4M, failed to displace3H flunitrazepam from specific binding sites on membranes prepared from rabbit cerebral cortex. It is concluded that physostigmine antagonizes the somnolence and respiratory depression induced by benzodiazepines by restoring cholinergic transmission to normal levels. The effective dose range of physostigmine is small, and serious side effects from overdose can occur as a result of excess cholinergic activity at neuromuscular synapses.

ISSN:0003-3022    

出版商:OVID    

年代:1986

数据来源: OVID