摘要:

The authors examined inspired humidity using a controlled partial rebreathing anesthesia method (CPRAM) and a circle system in 16 healthy adults and five healthy children. The patients were divided into five study groups (A-E). All patients except those in Group E were anesthetized with fentanyl, pancuronium, nitrous oxide—oxygen, 66–33 per cent, and their lungs were mechanically ventilated; patients in Group E received halothane and nitrous oxide-oxygen, 66–33 per cent, with spontaneous ventilation. Group A (five children) had inspired humidity measured within a modified coaxial (Bain) anesthesia circuit using CPRAM. Groups B and C (five adults each) had humidity measured within the modified coaxial circuit and at the end of a non-modified coaxial circuit using CPRAM. Groups D and E (three adults each) had humidity measured in the semi-closed and closed circle systems, respectively. Initial, mid-, and end-inspired humidity were measured in all groups for two hours by interrupting the controlled ventilation at 30-min intervals, except in patients of Group E, who had humidity measured at similar intervals for two hours during spontaneous ventilation. No significant difference was found among initial, mid-, or end-inspired humidity, nor was there a significant difference between inspired humidities in children and in adults using CPRAM. The humidity measured in adults within the circuit near the endotracheal tube was not significantly different from that measured distal to the fresh gas flow. The humidities in all CPRAM patients exceeded those of both the semi-closed and closed circle systems, stabilizing within 30 min and remaining constant between 24 and 26 mg H2O/1.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Cardiac output and distribution of blood flow using 15-μm radioactively labelled microspheres were determined in 25 Wistar rats. In seven awake control animals, first and second injections of microspheres did not change cardiac output (137 ± 8 ml/min) or result in alteration in apparent blood flow to the various organs studied. Halothane anesthesia (n = 6) (1.3 per cent inspired) resulted in a decrease in cardiac output, with increases in the percentages of cardiac output going to the brain, kidney, liver and large intestine. Enflurane anesthesia (n = 6) (2.2 per cent inspired) did not decrease cardiac output. The percentages of cardiac output going to the liver, lung, spleen, and large intestine increased. Both halothane and enflurane caused decreases in the percentages of cardiac output going to the heart and skeletal muscle. Ketamine anesthesia (n = 6) (125 mg/kg, im) differed from the other two agents in that few changes occurred from the awake state except in brain, lung and muscle. Microspheres that were trapped after the first injection were released from muscle and skin with ketamine anesthesia, resulting in an apparent decrease in the distribution of cardiac output to muscle in the controls and an apparent increase in “flow” to the lung. The microsphere method gives reliable information about cardiac output and distribution of flow in rats anesthetized with halothane or enflurane. Further studies are necessary to determine whether microsphere studies are valid indicators of organ flow during ketamine anesthesia in the rat.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The authors examined the thesis that a dose of dantrolene producing 95 per cent of maximal muscle relaxation (ED95) would effectively prevent or treat malignant hyperthermia (MH). In one group of four pigs sensitive to malignant hyperthermia (MHS) a dose response to intravenous dantrolene was determined by quantitation of toe twitch tension. From these data, the ED95relaxant dose (S.5 mg/kg) was derived. In a second group of four MHS pigs, the ED95dantrolene dose was administered prior to MH challenge with succinylcholine, 2 mg/kg, and halothane, 1.5 per cent. MH was prevented in each animal, while measurements of arterial pressure, arterial blood-gas,pH and lactate values, rectal temperature, and heart rate were done. Later, MH rapidly developed in the same four animals when they were again challenged. When treated with the ED95dose, each animal survived. Finally, each pig was challenged without dantrolene prophylaxis or therapeusis, and all succumbed from MH. Previous studies have shown the efficacious use of dantrolene in prevention or treatment of porcine MH, but doses used have varied, without rationale. The present study shows that in MHS pigs the ED95muscle relaxant dose of dantrolene (3.5 mg/kg) successfully prevents and treats MH.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The neonatal neurobehavioral effects of bupivacaine, mepivacaine, and 2-chloroprocaine used in random sequence for pudendal block anesthesia were studied. The neurobehavioral status of 54 infants was studied 4 and 24 hours after delivery. Except for a significant difference in the responses to pinprick, there was no significant effect of any of these agents on infant neurobehavior, and no differences were found among the agents themselves. Mean mepivacaine levels in neonatal capillary blood at 4 hours of age were low (0.10 ± .02 μg/ml) compared with those in previous studies because of the short interval between maternal injection and delivery (13 ± 3 min). Bupivacaine gave higher neonatal capillary blood levels (0.15 μg/ml at 4 hours of age) than previously reported, but the drug still produced no detectable neonatal neurobehavioral effects.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The Sentorr is a gas chromatograph that monitors PaO2and PaCO2every 4 min from a probe placed through an intraarterial cannula. The accuracy of this device and complications resulting from its use were studied in 46 patients undergoing cardiac surgical procedures with oxygen to nitrous oxide-halothane anesthesia. Sentorr blood-gas values were compared with simultaneous samples analyzed with standard electrodes. During relatively steady states of respiration and circulation, and in the lower (50–125 torr) range of oxygen tensions, the measurements correlated closely (r = 0.92). The device also functioned well during low-flow states, but during hypothermic cardiopulmonary bypass, the correlation was only fair (r = 0.62). When nitrous oxide was present in the inspired gas, Sentorr PaO2readings were a third lower than actual PO2measurements, an effect corroborated by anin-vitroexperiment. Directional changes of oxygen and carbon dioxide tensions were always correct in all situations. Placement of the probe in a radial artery was unsatisfactory because it significantly interfered with blood pressure measurement and resulted in inaccurate results for this patient population. The brachial artery was a satisfactory site for insertion, although attenuation of the arterial pressure tracing by the presence of a Sentorr probe resulted in systolic pressure readings that averaged 12 torr lower with mean arterial pressure readings 5 torr lower. No increase in morbidity due to use of a Sentorr probe for brachial arterial pressure monitoring could be identified. The most potentially serious complication encountered was transient loss of a palpable pulse without interruption of blood flow in one or more distal arteries after decannulation. This was observed in seven patients (four of whom had diminished distal pulses with normal flow before cannulation).

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Twenty-four patients survived life-threatening clinical anaphylaxis due to anesthesia. In each case the diagnosis of anaphylaxis was confirmed and the responsible drug was found by intradermal testing. To determine whether the reactions were anaphylactic or anaphylactoid, serum from each patient was tested for reaginic activity using Prausnitz-Kustner (PK) testing in human subjects and monkeys and passive cutaneous anaphylaxis (PCA) testing at four and 24 hours in monkeys. Positive results of PCA testing at four hours were repeated with serum that had been heated to 56 C for two hours. Drugs used in testing were Althesin, thiopental, succinylcholine, gallamine,d-tubocurarine, and alcuronium. Vehicles and antioxidants were tested separately. Positive tests suggestive of the presence of reaginic antibodies occurred with sera from 15 patients who had had previous exposure to the drug. Nine patients had tests suggestive of IgE antibodies on first exposure, suggesting that cross-sensitivity may be a factor in such reactions to muscle relaxants. Two patients had positive tests for IgG antibodies. This is further evidence of the role of this mechanism in immediate allergy and demonstrates another mechanism by which anaphylaxis can occur without previous sensitization. Four patients had positive tests for IgE antibodies after previous exposure. It was concluded that it is not possible to determine the mechanism of anaphylaxis from a history of previous exposure.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Increasing the resting lower esophageal sphincter (LES) tone is a useful method of preventing gastroesophageal reflux. The effects of a new antiemetic, domperidone, on LES were studied in 28 subjects. Group I included eight normal nonpregnant control subjects. The remaining 20 pregnant women were divided into two groups, Groups II and III—ten parturients without and ten with symptoms of heartburn. Domperidone increased LES pressure by 19, 11 and 10 cm H2O in Groups I, II and III, respectively (P< 0.05). Domperidone may be a valuable premedicant in some patients to decrease the chance of gastroesophageal reflux.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

To assess the effects of endotracheal intubation on normal cough function, the tracheas of eight healthy volunteers were intubated with a standard 8.0-mm-I.D. tube. Measurements were made of expiratory flow, transpulmonary pressure, and expired volume during a cycle of three successive bursts of maximum voluntary coughing initiated after inspiration to total lung capacity. Results following intubation were compared with findings with subjects breathing through a 25-mm-I.D. mouthpiece (control). Maximum cough pressures (Pmux) following tracheal intubation were similar to control values, but with the tube in place, airflow began well before Pmuxwas reached and did not cease fully between cough bursts. Flows at Pmuxdeclined with each successive burst of coughing during both experimental conditions, but with tracheal intubation, the flows were significantly lower than control. Resistance to flow at Pmuxincreased with each successive cough and increased significantly above control during the third burst of coughing while the subjects' tracheas were intubated. The total volume of the three control coughs was 76 ± 3 per cent of vital capacity. This was similar following intubation, although cough duration was significantly longer. These findings indicate that tracheal intubation does not impair ability to develop normal cough pressures despite preventing glottic closure. The normal timing of flow and pressure is disrupted such that flow occurs early—as in a forced expiratory maneuver, and the flow is not fully interrupted during the cough sequence. Flows are submaximal as a result of the resistance of the tube and continue to decline as the lung volume decreases and airways are compressed. Because the tube is noncollapsible, high flow rates may be necessary to achieve the linear velocities required for normal airway cleansing through the tube. Such flows may be achieved only during the initial cough after full inspiration.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Ketamine appears to induce both excitatory and depressant actions in the brain; however, it is not clear which regions are affected. The 2-deoxyglucose functional mapping method of Sokoloff et el. was used to determine regional variations in metabolic activity of rat brain caused by injection of ketamine, 25–75 mg, intramuscularly. To compare the effects of ketamine with those of hippocampal-induced seizures, the 2-deoxyglucose method was used, following injection of penicillin C, 400–800 units, into the hippocampus. The findings from five control, seven ketamine-treated, and three penicillin C-treated rats are given. Ketamine caused a significant increase of metabolic activity in the hippocampal sulci and a decrease of activity in the medial geniculate and the inferior colliculus. Similar changes were found with hippocampal seizures caused by penicillin. The inhibition of the regions associated with sensory systems (medial geniculate and inferior colliculus) may account in part for the anesthetic action of ketamine, while the intense activity of the hippocampus may be related to the excitatory manifestations. The results indicate that ketamine produces seizures in the hippocampus, which in turn inhibit auditory and visually associated nuclei. Thus, the anesthesia may follow from the sensory depression and the cataleptic phenomena may be related to the hippocampal excitation.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The pharmacokinetics ofd-tubocurarine (dTc) and the urinary excretion ofdTc were studied in 18 neurosurgical patients with normal renal function, over a period of 96 hours. The effects of an osmotic diuretic (mannitol) on urinary elimination ofdTc were determined. Following a single intravenous dose ofd-tubo-curarine (dTc, 0.3 mg/kg), serum levels and urinary excretion of the drug were measured. A specific radioimmunoassay was used for the analysis ofdTc. Nine of the patients also received mannitol, 1 g/kg, after the injection ofdTc for surgical indications. The study showed that only 45 per cent of the injected dose ofdTc was excreted in 24 hours. Between 24 and 96 hours, an additional 7 per cent of the drug was excreted in the urine. The administration of mannitol, an osmotic diuretic, did not increase the excretion ofdTc. The time-concentration relationship of serum concentration ofdTc was analyzed. Using the four-exponential equation (data to 96 hours), the calculated volume of distribution (Vdnren) was 3.4 l/kg. This volume, which is greater than the volume of total body water, suggests thatdTc is stored in certain tissues in the body and slowly released over a period of days to weeks.

ISSN:0003-3022    

出版商:OVID    

年代:1980

数据来源: OVID