ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

&NA;Major traumatic injury frequently causes hemodynamic instability that necessitates reducing the usual dose of anesthetic given for surgery. Nevertheless, a lower dose may be sufficient to provide anesthesia because of conditions present in trauma victims that are known to reduce anesthetic requirement (hypotension, hypothermia, and acute alcohol intoxication). To determine the incidence and patient perception of recall of surgery, 51 patients were interviewed after surgery for major trauma. Patients were assigned to one of two groups. Thirty‐seven patients were given an anesthetic for endotracheal intubation and had continuous or almost continuous anesthesia during surgery. Of the four who recalled surgery (11%), two considered this awareness their worst hospital experience. Fourteen other patients, who were more severely injured, were not given an anesthetic for endotracheal intubation and/or for 20 or more consecutive minutes during surgery. Of the six patients in this group who recalled surgery (43%), two considered this awareness their worst hospital experience. No condition known to reduce anesthetic requirement did so reliably enough that recall of surgery did not occur when the anesthetic dose had to be reduced because of major trauma. The authors conclude that the incidence of recall of surgery in victims of major trauma is considerable, and that reducing the dose of anesthetic increases this incidence, despite the presence of conditions known to reduce anesthetic requirement.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

&NA;The cardiovascular effects of the calcium channel blockers verapamil (V), nifedipine (N) and diltiazem (D) were compared in halothane‐anesthetized swine. Equipotent hypotensive doses of the three calcium channel blocking drugs were administered randomly by continuous infusion to three groups of six animals each to produce a uniform 25‐30% reduction in mean systemic arterial blood pressure (BP). An additional group of six animals received sodium nitroprusside (S) to demonstrate the effects of lowering blood pressure with a pure vasodilator on this experimental preparation. Hemodynamic indices monitored before and after drug administration included ECG, mean systemic and pulmonary artery blood pressure, mean central venous and pulmonary capillary wedge pressure, thermodilution cardiac output, left ventricular pressure, and left ventricular dP/dt. All four study drug infusions reduced BP an average of 28%. V and D reduced BP by decreasing cardiac output (41% and 42%, respectively) without affecting systemic vascular resistance. N and S produced hypotension by decreasing systemic vascular resistance (36% and 21%, respectively) without affecting cardiac output. D reduced heart rate (18%) and both D and V increased the PR interval (60% and 40%, respectively). Calcium chloride (20 mg • kg‐1intravenous bolus) improved indices of myocardial contractility but did not affect drug‐induced changes in cardiac electrophysiology. These data demonstrate that in this halothane‐anesthetized swine model the administration of equihypotensive doses of verapamil or diltiazem has a more pronounced affect on cardiac conduction and myocardial contractility than does nifedipine, which predominantly reduces systemic vascular resistance with minimal effects on cardiac function.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

&NA;The aim of the study was to establish whether there exists a relationship between blood methadone concentration and analgesic response and the intrasubject and intersubject variability in this relationship. Sixteen general surgical (upper abdominal) and orthopedic (spinal fusion) patients were administered methadone (20 mg, iv) as part of the general anesthetic and supplementary methadone doses (usually 5 mg, iv) in the recovery ward until postoperative pain was controlled effectively. The criteria established for the administration of supplementary methadone doses were the coexistence of 1) spontaneous reporting of significant pain by the patient; 2) an unstimulated respiratory rate of greater than 10 breaths/min, and 3) no significant depression of the level of consciousness.A median of two supplementary iv methadone doses (range 13) were administered to the patient by a titration method in the recovery ward to obtain effective pain control. This was achieved by a median dose of 10 mg (range 5‐20 mg) in addition to the 20 mg intraoperative dose. Serial blood samples were collected for the estimation of blood methadone concentration following all doses. The methadone concentration in the blood sample collected immediately prior to a supplementary dose was termed the minimum effective concentration (MEC [methadone]). The mean (±SD) coefficient of variation in MEC (methadone) for the 16 patients was 21 ±10% (range: 7‐38%), while the mean MEC for methadone was 57.9 ± 15.2 ng/ml (range: 34.5‐80.3 ng/ml) in these patients. The small intrapatient coefficient of variation in MEC (range: 7‐38%) provides additional experimental evidence in support of the concept that there is a relationship between blood concentration and analgesic response within an individual.Following methadone titration, the mean duration of analgesia (±SD) was 21 ± 13 h (range: 5‐48 h), while the mean pain score (visual analogue scale of 0 [no pain] to 10 cm [worst pain]) was 1.5 ±1.3 cm during this period of effective analgesia. After this sustained period of analgesia, additional methadone (usually 5 mg iv) resulted in a further period of prolonged analgesia (range from 7.4 h to prolonged, i.e., no further analgesia required for the hospital stay). The mean (±SD) total methadone dose was 42 ± 10 mg (range: 30‐70 mg).These results indicate that prolonged and safe postoperative analgesia can be obtained from methadone following the proposed intravenous titration method, which cautiously and reliably elevates the blood methadone concentration to a level in excess of the MEC, thereby providing prolonged analgesia as a result of the low methadone clearance.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

&NA;The effects of age, sex, and obesity on the kinetics of single intravenous (iv) and oral doses of midazolam were evaluated in healthy volunteers who received 2.5‐5 mg of iv midazolam on one occasion and 5‐10 mg orally on another. Kinetics were determined from multiple plasma midazolam concentrations measured during 24 h after dosage. Midazolam elimination half‐life (t1/2) after iv dosage was significantly prolonged in elderly (aged 60‐74 yr) versus young (24‐33 yr) males (5.6 vs. 2.1 hours,P< 0.01) and total clearance was significantly reduced (4.4 vs. 7.8 ml • min‐1• kg‐1,P< 0.01), leading to increased systemic availability of the oral dose (50% vs. 41%,P< 0.05). However total volume of distribution calculated by the area method (Vd) (1.6 vs. 1.3 1/kg) and protein binding (3.5 vs. 3.4% unbound) did not differ between groups. Among women there were no significant differences between elderly (64‐79 yr) and young (23‐37 yr) volunteers in t1/2(4.0 vs. 2.6 h), clearance (7.5 vs. 9.4 ml • min‐1• kg‐1), Vd(2.1 vs. 2.0 1/kg), protein binding (3.7% vs. 3.7% unbound), or oral bioavailability (38% vs. 36%). In obese volunteers (mean weight 117 kg; 173% of ideal weight) versus control subjects of normal weight (66 kg, 95% of ideal weight) matched for age, sex, and smoking habits, midazolam Vdwas increased significantly (311vs.114 1,P< 0.001). Vdwas greater in the obese subjects even after correction for total weight (2.7 vs. 1.7 1/kg,P< 0.001), indicating disproportionate distribution of midazolam into adipose weight. Since clearance was not different between groups (472 vs. 530 ml/ min), the prolonged t1/2in obese subjects (8.4 vs. 2.7,P< 0.001) was due to the increased Vd. The clinical consequences of age‐ and obesity‐related changes in midazolam kinetics will depend on the circumstances of administration.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

&NA;The hemodynamic effects of halothane anesthesia in chronically anemic mongrel dogs were evaluated. Control and anemic animals (13.7 ± 0.4 g/dl hemoglobin mean ± SE vs. 3.4 ± 0.3 g/dl) were exposed to 0.75, 1.5, and 2.25% inspired halothane and changes in cardiac output (CO), heart rate (HR), dp/dt, heart work, heart efficiency, myocardial oxygen consumption (MVO2), mean arterial blood pressure (MABP), central venous pressure (CVP), left ventricular end‐diastolic pressure (LVDP), left coronary blood flow (CBF), systemic vascular resistance (SVR), and myocardial lactate metabolism were measured and compared. Anemic dogs showed a significantly lower SVR at each halothane dose when compared with controls. In addition, SVR progressively decreased with increasing halothane in anemic dogs, while SVR remained unchanged in controls. CO, CBF, MVO2, and heart work all were significantly greater in anemic canines compared with controls with each halothane concentration. Heart efficiency, dp/dt, HR, and MABP were not significantly different in anemic and control dogs. Neither control nor anemic dogs demonstrated myocardial hypoxia as evidenced by a lack of myocardial lactate production. The results from this study suggest that anemic animals appear to tolerate large concentrations of halothane.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

&NA;The authors examined the inhibition of aerobic metabolism in monkey kidney cell cultures exposed to halothane, enflurane, and isoflurane. The ability of hyperbaric pressure to reverse the halothane‐induced metabolic inhibition also was examined. Incubation of two monkey kidney cell lines for 24 h with clinically equipotent concentrations (2.6 MAC) of halothane, enflurane, or isoflurane vapors increased the concentration of lactate in the media by 126 to 244% relative to nonexposed control cultures. The increased rate of lactate accumulation was proportional to the concentration of halothane and was accompanied by a decrease in media pH. Removal of halothane restored the normal rate of lactate production. Hyperbaric pressures of 25, 50, and 100 atmospheres did not alter the halothane‐stimulated rate of lactate production relative to non‐anesthetic‐treated controls, although pressure alone did depress the rate of lactate accumulation in all cultures. The stimulation of lactate production likely reflects the known ability of halothane to inhibit mitochondrial respiration. The failure of pressure to reverse the stimulation of lactate production by halothane suggests that inhibition of mitochondrial metabolism cannot be reversed by pressure.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

&NA;The effect of preanesthetic cimetidinc and metoclopramide on gastric contents in inpatients undergoing elective surgery was studied. One hundred and fifty patients were allocated randomly into six groups with 25 patients in each group. Patients in Group 1 served as control. Group 2 patients received metoclopramide in the morning. Group 3 patients received cimetidine at bedtime and in the morning. Patients in Group 4 received cimetidine at bedtime and metoclopramide in the morning. Group 5 patients received cimetidine and metoclopramide in the morning, while patients in Group 6 received cimetidine at bedtime and metoclopramide and cimetidine in the morning. Cimetidine 300 mg and metoclopramide 10 mg were administered by mouth with a sip of water at bedtime or in the morning 1‐4 h prior to the induction of anesthesia. Patients with gastricpH ≤2.5 or gastric content volume ≥25 ml were defined to be at risk of pulmonary damage if aspiration should occur. In the control group the meanpH and volume of gastric contents were 2.89 and 22.3 ml, respectively, with 64% of patients with pH ≤2.5 and 32% of patients with volumes of ≥25 ml. Cimetidine and metoclopramide favorably modified the risk factors in all the experimental groups. This study demonstrated that the three groups receiving cimetidine in the morning (Groups 3, 5, and 6) had significantly greater mean gastricpH than the other groups. Gastric volumes were significantly less in all experimental groups. In Group 6, which received cimetidine in two doses and metoclopramide in the morning, the risk of aspiration pneumonitis theoretically was abolished, as the gastric pH was ≥5 and the gastric volume was ≤25 ml, in all the patients.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

&NA;The effects of intravenous pentobarbital versus nitrous oxide/ halothane inhalation anesthesia on blood gases, distribution of ventilation‐perfusion ratios (VA/Q), and lung volume (FRC) were compared in 8 tracheostomized sheep in the lateral decubitus position. Pentobarbital anesthesia produced no significant changes (from awake control) in arterial blood PO2, or PCO2ventilationperfusion inequality, intrapulmonary shunt, or FRC during either spontaneous breathing or mechanical ventilation with muscle paralysis. With inhalation anesthesia, PaO2, decreased from 132 ± 13 mmHg awake to 106 ± 11 mmHg and 104 ± 6 mmHg (FIO2, all 0.3) during spontaneous and mechanical ventilation. Shunt increased from 1.4 ± 1.0% awake to 10.6 ± 4.5 and 13.9 ± 5.3%, respectively. Mean VA/Q decreased from 0.39 ± 0.07 awake, to 0.21 ± 0.06 and 0.29 ± 0.07. Log standard deviation of VA/Q increased from 0.66 ± 0.12 awake to 0.83 ± 0.28 and 0.89 ± 0.15. FRC decreased from 1.66 ± 0.65 1 to 1.46 ± 0.62 and 1.22 ± 0.63 1, respectively. Differences in response to intravenous versus inhalation anesthesia for the above variables all were statistically significant at P < 0.05. FRC and shunt changes with anesthesia showed significant correlation for both spontaneous (r = ‐0.80) and mechanical ventilation (r = ‐0.77), P < 0.005 for both. We therefore propose that the differences between lung volume and gas exchange effects of intravenous versus inhalation anesthesia in sheep may have been related causally.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID