ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The authors investigated the value of high-dose thiopental (TH) therapy after 16-min complete global brain ischemia (GBI) in three groups of pigtailed monkeys, using a neck cuff model of GBI with 96 h intensive care postischemia (PI).Control group (n18):Normotension was restored within 2 min PI; paralysis/controlled ventilation was maintained for 48 h PI with 50% N2O/O2.Thiopental loading group (n13):Control treatment plus TH-loading with 90 mg/kg iv given from 5 to 65 min PI (mean peak TH plasma level 130 μg/ml).Thiopental anesthesia group (n14):Control treatment plus TH anesthesia with 90 mg/kg iv given over 12 h PI (sustained TH plasma levels of 25–35 μg/ml and EEG burst suppression). Norepinephrine requirement for blood pressure control PI was greater in the TH groups than in the control group (P< 0.05). Lidocaine was needed for control of arrhythmias in the TH loading group. There was no significant difference in mortality or neurologic outcome between the groups. At 96 h PI seven of 11 animals were awake in the control group, compared with seven of 12 and six of 12 in the two TH groups. Neurologic deficit scores (NDS) for the survivors at 96 h PI were 23 ± 6% (mean ± SD) (n10) in the control group, compared with 25 ± 9% (n11) and 26 ± 12% (n10) in the two TH groups (NDS 100% = brain death, 0% = normal). Seizures PI (in 1–2 of each group) were associated with worse neurologic deficits. At 96 h PI, all three groups had developed the same type and distribution of histologic lesions. Thus, the authors were unable to demonstrate any brain-damage-ameliorating effect of TH loading or TH anesthesia after 16 min GBI in pigtailed monkeys.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The response of the adductor of the thumb to ulnar nerve stimulation (0.1 Hz) was evaluated during continuous infusion of succinylcholine (SCh) in 20 infants anesthetized with halothane (1%) and N2O/O2. Train-of-four stimulation (2 Hz for 2 s) was used to differentiate between phase I and phase II block. Some infants were very resistant to the neuromuscular effects of SCh. These infants (Group 1) were younger in age, 57 ± 15 days (mean ± SE) and required 24.6 ± 3.3 mg · kg-1h-1SCh to achieve more than 90% depression of the twitch. Older infants (Group 2), 188 ± 33 days, required significantly less (P< 0.001) SCh (8.7 ± 0.5 mg · kg-1h-1) to achieve the same degree of twitch suppression. Group 1 infants recovered from the effects of SCh very rapidly. After 10 mg/kg SCh, the train-of-four ratio in Group 1 infants recovered to 75% in 4.7 ± 0.6 min, whereas it took 34 ± 10 min in Group 2 infants (P< 0.01). Tachyphylaxis developed in infants after 3.6 ± 0.3 mg/kg (mean ± SE) and phase II block after 5.3 ± 0.7 mg/kg (P< 0.05) SCh. Combining the data of infants with that of children from a previous study conducted in a similar fashion1resulted in significant correlation (P< 0.001) between the log age and SCh requirement. The rate of administration of a continuous infusion of SCh in infants should be based upon the response of infants and not on a fixed dose (mg · kg-1· h-1).

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

To determine the effect of the commonly used volatile anesthetics on a vecuronium-induced neuromuscular blockade, the authors studied 54 patients anesthetized with 1.2 MAC or 2.2 MAC enflurane, isoflurane, or halothane (MAC value includes contribution from 60% nitrous oxide). During 1.2 MAC enflurane, isoflurane, and halothane, the ED50s (the doses depressing twitch tension 50%) for vecuronium were 12.8, 14.7, and 16.9 μg/kg, respectively. During 2.2 MAC enflurane, isoflurane, and halothane, the ED50s for vecuronium were 6.3, 9.8, and 13.8 μg/kg, respectively (P< 0.05). Time from injection to peak effect was the same for each anesthetic group (6.5 ± 0.5 min, mean ± SD), except for the group given 2.2 MAC enflurane (9.7 ± 0.6 min) (P< 0.05). The duration of a 50% block from injection to 90% recovery was the same for each group (mean 20 ± 4 min), except for the group given 2.2 MAC enflurane (46.5 min) (P< 0.05). The authors conclude that enflurane is the most potent volatile anesthetic, followed by isoflurane and then halothane, in augmenting a vecuronium-induced neuromuscular blockade. Increasing the concentration of volatile anesthetic has less effect on a neuromuscular blockade produced by vecuronium than on one produced by other nondepolarizing relaxants (e.g., pancuronium andd-tubucurarine).

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Previous studies have demonstrated that if isotonic amino acid infusions were administered at a rate that approximated normal daily protein requirements, a leftward shift of the minute ventilation · PaCO2relationship occurred. This study examined the effect of the administration of parenteral nutrition, at a fixed caloric intake and two levels of nitrogen (N) intake, on the ventilatory response to CO2in nutritionally depleted patients. The intent was to determine whether increasing protein intake from normal to twice normal requirements would result in a further enhancement of the ventilatory response to CO2.Eight patients with nutritional depletion (greater than 10% weight loss) were studied. The resting energy expenditure (REE) was measured during administration of 5% dextrose, using principles of indirect calorimetry. Each patient received parenteral nutrition for a 2-week period. Two diets were examined for a 1-week period each: 1) a high N intake—15 mg nitrogen per kcal REE (approximately 21 g/day), or b) a low N intake—7.5 mg nitrogen per kcal REE (approximately 11 g/day). The initial diet was assigned randomly. Total energy intake was set at 1.35 X REE as measured during administration of 5% dextrose solution. Nonprotein calories were administered as 50% glucose and 50% fat. Breathing patterns at rest and during inhalations of 2 and 4% CO2were analyzed using a canopy-computer-spirometer system.With an increased nitrogen intake there was a significant reduction in resting arterial PaCO2from 39.9 to 37.6 mmHg (P< 0.05) with no significant change inpH. The relationship between VEand PaCO2observed during inhalation of CO2showed a marked leftward shift (P< 0.01), indicating an increased ventilatory sensitivity to CO2.These data indicate that increasing the protein component of a fixed caloric intake will enhance the ventilatory response to carbon dioxide.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The study of compound action potentials has not succeeded in determining exact limits to differential block of nerve fibers by local anesthetics. Further observations on individual neurons therefore were undertaken. Rabbit vagus nerve and ganglion were superfusedin vitroat 37° C,pH 7.4. Activity evoked by stimulating the distal end of the nerve was monitored extracellularly from individual somata by a microelectrode in the ganglion. Lidocaine HCl in steps of 0.2–0.1 mmol/l (0.0005–0.0025 g/dl) was applied to the intervening nerve to identify two concentrations, respectively, just sparing and extinguishing conduction in the axon belonging to the soma, the average being regarded as the blocking concentration. The mean blocking concentrations (mM,± SD) for axons conducting at control velocities between 3 and 26 m/s (myelinated axons) was 0.43 ± 0.15, N = 18, for axons slower than 1.4 m/s (unmyelinated axons) 0.63 ± 0.14, N = 11, for intermediate velocity axons 0.19 ± 0.18, N = 7. The differences were significant by Scheffé‘s multiple comparisons test (P< 0.01). Although the myelinated axons were blocked by a lower average concentration of lidocaine than unmyelinated axons, they manifested significantly more slowing of conduction before block (P< 0.001). No relation between blocking concentration or latency increase and conduction velocity (fiber size) was evident within any fiber group.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The ability of the heparin dose-activated coagulation time (ACT) response curve to predict doses of heparin during open-heart operations has been debated since its proposal. The dose-response method was examined in a statistically rigorous manner in 23 patients. The ACT response to 3 mg/kg heparin varied among patients from 308 to 520 s. Although at the start of bypass, ACTs often increased beyond the linear part of the dose-response curve (500 s), they returned to 483.7 ± 176.8 s (SD) within 1 h. After this first hour, one to four additional data points fit the initial two-point dose-response curve closely, and additional points did not significantly change dosage calculations for heparin and protamine. After a dose of protamine calculated to exactly neutralize heparin, the average ACT returned to within 7 ± 11% (SD) of control values. A two-point dose-response curve, generated for each patient before bypass begins, remains statistically valid and clinically useful throughout open-heart operations as long as the ACT is less than 500 s. The dose-response method is a simple, valid way to control coagulation during open-heart operations.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The changes in ventilation and breathing pattern induced by the substitution of pure oxygen for room air were tested in patients during stable halothane anesthesia before and after the administration of almitrine bismesilate, a specific stimulant of the peripheral chemoreceptors. Ventilation was monitored in 25 patients for 15 min while breathing an air-halothane (1.5%) mixture and while breaching then for 10 min an O2-halothane (1.5%) mixture. The maneuver was repeated in 11 of these patients after the infusion of 0.5 mg/kg of almitrine bismesilate. Before almitrine administration, O2inhalation caused a progressive decrease of minute-ventilation (VE) reaching 94.5 ± 1.4% (mean ± SEM) of the initial value at the tenth minute (P< 0.01). This decrease was secondary to a progressive increase of inspiratory and expiratory times. Almitrine bismesilate caused a significant increase in VE(+11.6%), tidal volume (+14.0%), and mean inspiratory flow (+10.0%) when breathing the air-halothane mixture. Ten minutes after O2administration, these variables were not different from those observed before almitrine infusion. This study shows that during halothane anesthesia, hypoxic ventilatory drive is not abolished but is depressed severely. Almitrine bismesilate can restore the hypoxic ventilatory drive.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The authors investigated the effects of treatment on ventricular performance when cardiac output (CO) was reduced significantly because of an acute increase in pulmonary vascular resistance (PVR).In eight anesthetized, ventilated dogs, the effects of volume expansion (100 ml 6% dextran) on ventricular performance were determined before and after PVR was elevated. Resistance was increased by microembolization of the pulmonary vascular bed with glass beads (80–100 μm). When PVR was normal, volume expansion increased (P< 0.05) stroke volume (SV) and mean blood pressure (BP). Alternatively, when RV afterload was increased, volume resulted in RV failure,i.e., decrease in SV (P< 0.01) from 9.1 to 6.3 ml and a decrease (P< 0.05) in mean BP from 97 to 65 mmHg, despite increased right ventricular end diastolic pressure (RVEDP) (P< 0.05). Right ventricular dysfunction occurred with volume expansion, despite constant PVR and a decrease (P< 0.01) in mean pulmonary artery pressure (PAP). In contrast to volume, norepinephrine infusion decreased biventricular filling pressures (P< 0.01) and increased (P< 0.01) SV from 6.2 to 11.3 ml. Accordingly, when RV afterload is increased significantly, even a relatively small increase in blood volume may result in RV dysfunction. Alternatively, inotropic agents with pressor effects may be the treatment of choice to increase CO when RV afterload is increased.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

This study determined the ED50and ED90of alfentanil for unconsciousness and anesthesia. A bolus of alfentanil was given to 28 healthy unpremedicated adults undergoing gynecologic or orthopedic procedures in one of four dosages: 100, 150, 200, or 250 μg/kg. Three indicators of induction were assessed 90 s later: eyelid reflex, response to verbal commands to breathe, and response to placement of a nasopharyngeal airway. Succinylcholine, given at 90 s, was followed by tracheal intubation 1 min later.From probit analysis, the ED50and ED90for loss of voice response were 92 and 111 μg/kg, respectively, and for loss of nasopharyngeal airway response, 111 and 169 μg/kg. A high incidence of chest wall rigidity (75%) and movements of the limbs (54%) or eyes (25%) was seen. There were statistically significant increases of the heart rate prior to stimulation and of both the heart rate (21% rise) and systolic blood pressure (10% rise) from control to the peak value following intubation. Differences between alfentanil doses were not significant. Naloxone was required in 36% of patients for end-tidal PCO2greater than 48 mmHg at emergence from anesthesia; no patient required additional naloxone. Nausea or vomiting occurred in 39% of all subjects. Two patients recalled placement of the nasopharyngeal airway.We conclude that alfentanil is an anesthetic, and its ED50(analogous to MAC of inhalational agents) is 111 μg/kg. The blood pressure and heart rate responses to laryngoscopy and intubation were modest after doses that allowed for extubation as early as 51 min after induction.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID