ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Using a randomized double-blind protocol, the authors prospectively compared three nondepolarizing muscle relaxants with respect to their influence on hemodynamics and on the electrocardiogram. Thirty-three patients undergoing elective coronary artery bypass grafting (CABG) with high-dose (100 μ/kg) fentanyl anesthesia were studied. Patients received 1.5 X ED95of either pancuronium (n = 12), metocurine (n = 9), or a metocurine-pancuronium combination (4:1 ratio by weight) (n = 12) for muscle relaxation. Heart rate and rate pressure product (RPP) were significantly higher postinduction in the pancuronium group. Myocardial ischemia, indicated by new ECG ST-segment depression occurred significantly more frequently, and exclusively, in the pancuronium group. The authors' data suggest that since pancuronium is associated with tachycardia and an increased incidence of myocardial ischemia, it is best avoided in patients with severe coronary artery disease undergoing CABG with high-dose fentanyl. Either metocurine or the metocurine-pancuronium combination provides greater hemodynamic stability, without precipitating myocardial ischemia, and can be safely and effectively substituted for pancuronium.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The dose of thiopental required to induce anesthesia in adults decreases with age. The pharmacokinetic and pharmacodynamic properties of thiopental were studied in two groups of surgical patients to determine the mechanism of this decrease. In one group (29 patients 19–88 yr of age), thiopental was infused at a demonstrated early burst suppression (phase III). Arterial blood samples were obtained frequently during and after the infusion to measure serum thiopental concentrations, and power spectral analysis was used to calculate the spectral edge (Hz), defined as the frequency below which 95% of the EEG power is located. Pharmacodynamic modeling was used to relate the serum thiopental concentrations to the spectral edge in order to estimate the individual patient's brain sensitivity to thiopental. In a second group (28 patients 24–88 yr of age), pharmacokinetics were determined after a bolus or rapid infusion of thiopental. Arterial blood samples were obtained frequently to characterize the initial distribution phases, sampling continued for 24–48 h to characterize elimination processes.The dose of thiopental required to achieve early burst suppression on the electroencephalogram (EEG) decreased linearly and significantly with age. Pharmacodynamic modeling also demonstrated that brain sensitivity to thiopental does not change with age. The age-related decrease of the thiopental dose requirement is due to a change in the initial distribution of the drug. That is, the initial distribution volume (central compartment, or V1) of thiopental decreases exponentially with age. This smaller initial distribution volume in the elderly results in higher serum levels after a given dose of thiopental.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The efficacy, safety, and hemodynamic response to 5 μg/kg, 10 μg/kg, or 20 μg/kg of sufentanil and 0.1 mg/kg pancuronium was evaluated in children between 4 and 12 years of age scheduled for open heart surgery. Systolic time intervals, 2-D echocardiograms, systolic blood pressures (SBP), diastolic blood pressures (DBP), and heart rates (HR) were recorded before and after induction of anesthesia. Significant changes 10 min following induction of anesthesia but before intubation included increases in SBP in the 5 μg/kg group (P< 0.01) and in the ratio of preejection period to left ventricular ejection time in the 20 μg/kg group (P< 0.05). Instances of myoclonic jerking and coughing episodes were observed in all three study groups.Following intubation there were significant (P< 0.05) increases in SBP in all groups, in DBP in the 5 μg/kg group, and in HR in the 5 μg/kg and 10 μg/kg groups. Smaller increases in SBP, DBP, and HR were seen in all groups after skin incision and sternotomy. Mean plasma catecholamine levels showed nonsignificant increases following periods of intraoperative stimulation with wide patient variationsRecovery of responsiveness to command occurred in all groups within one hour from the end of surgery but extubation was impeded by shallow periodic breathing and hypercapnea. The authors conclude that for children undergoing open heart surgery use of sufentanil as a sole anesthetic in bolus form did not provide a reliable depth of anesthesia with any of the induction doses studied.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Oxygen consumption, cardiac output, and tissue oxygen delivery were measured in normoxic and hypoxic 1–3-day-old lambs during the following six conditions: 1) (control) paralysis with pancuronium and controlled ventilation with room air; 2) paralysis, controlled ventilation and hypoxia (Pao1= 30 ± 3 mmHg, [SD]; 3) paralysis, controlled ventilation with room air and 0.5 MAC halothane; 4) paralysis, controlled ventilation, hypoxia, and 0.5 MAC halothane; 5) paralysis, controlled ventilation with room air, and 1 MAC halothane; and 6) paralysis, controlled ventilation, hypoxia, and 1 MAC halothane. During normoxia, 0.5 and 1 MAC halothane decreased total body oxygen consumption, cardiac output, and arterial blood pressure. One-half MAC halothane had no effect on blood flow to any organ except muscle, whose flow decreased 64%. One MAC halothane decreased blood flow to the brain, heart, kidney, muscle, and gut. Both concentrations of halothane decreased serum catecholamine levels below control values and prevented hypoxia from increasing catecholamine levels. Hypoxia decreased the oxygen consumption about 40% from the immediately previous normoxic value, whether the animals were anesthetized or not. Tissue oxygen delivery followed changes in blood flow. The cardiac output, arterial blood pressure, and heart rate of anesthetized, hypoxic animals were not different from those in the previous normoxic condition. Halothane didnotprevent redistribution of blood flow to the heart and brain of hypoxic animals, nor did halothane prevent hypoxic pulmonary vasoconstriction. Halothane did prevent the increase in serum catecholamine levels that occurs in unanesthetized, hypoxic animals. If halothane has similar effects in humans, it may be useful in treating hypoxic infants in the operating room and intensive care unit.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The authors have developed a method for studying the action of volatile anesthetics inCaenorhabditis elegans(C.e.), a free living nematode. C.e. appears to be a useful model for the study of the influence of genetics on susceptibility to anesthetics. This worm has a small, completely defined nervous system, easily manipulated genetics, and a large number of nervous system mutants. Under normal conditions C.e. moves almost constantly. When exposed to anesthetics there is an initial phase of increased locomotion, followed by uncoordinated motion that progresses to immobility. Motion returns quickly when the nematodes are removed from the anesthetic. The authors called loss of locomotion “anesthesia.” The ED50s of various anesthetics with C.e. are as follows: methoxyflurane 0.45%, chloroform 1.25%, halothane 2.7%, enflurane 4.2%, isoflurane 5.6%, fluroxene 9.9%. The authors also studied the action of a convulsant, flurothyl, on C.e. Flurothyl has anesthetizing properties in these animals with an ED50of 8.1%. No convulsant activity was noted. However, mixtures of halothane and flurothyl were antagonistic in their effects, while halothane and enflurane were additive. Furthermore, the authors isolated a mutant strain (HS1) of C.e. that shows altered responses to several anesthetics and a convulsant. HS1 is uncoordinated when not exposed to anesthetics. Like the normal strain (N2) HS1 loses mobility when exposed to anesthetics. The ED50s for various anesthetics in HS1 were as follows: methoxyflurane 0.04%, chloroform 0.52%, halothane 0.85%, isoflurane 4.9%, enflurane 6.0%, fluroxene 10.9%. When compared with the normal C.e., HS1 exhibits a marked increase in sensitivity to methoxyflurane, chloroform, and halothane. No alterations in sensitivity to isoflurane or fluroxene were noted. HS1 exhibited decreased sensitivity to enflurane. HS1 reverts to normal motion when exposed to low concentrations of flurothyl and shows decreased sensitivity to the anesthetic effects of flurothyl with an ED50of 11.8%. The slope of the curve of the log ED50versusthe log oil/gas partition coefficient is steeper in mutant than in normal nematodes.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The authors produced metabolic acidemia acutely in human subjects awake, sedated with halothane (0.1 MAC), and anesthetized with halothane (1.0 MAC) by infusing L-arginine hydrochloride, 5–6 mmol ± kg−1, over 3 h. Ventilation was recorded at resting arterial hydrogen ion concentration ([H+]a) and at 2–4 isocapnic increments of [H+]a, in each case, while end-tidal oxygen tension (PETo,) was varied between >300 mmHg and 45 mmHg. Total increments of [H+]a in awake, sedated, and anesthetized subjects were 13 ± 4, 12 ± 2, and 12 ± 3 nmol ± I−1(means ± SD). In the awake state, metabolic acidemia increased ventilation (VI) in proportion to [H+]a. The magnitude of response increased with reduced PETo2, such that the response to acidemia and hypoxemia combined was synergistic. The Δ&OV0312;I/Δ[H+]a slopes at PETo2values of >300, 100–120, and 45 mmHg were 0.47 ± 0.27, 0.85 ± 0.24, and 3.01 ± 1.30 1 ± min−1· nmol−1· 1, respectively (means ± SD). Halothane sedation reduced the responses to added [H+]a determined at PETo2values of 100–120 and 45 mmHg, as well as the response to hypoxemia and to the interaction of acidemia and hypoxemia, each to less than half awake values. Halothane anesthesia further impaired the responses to [H+]a and virtually abolished the response to hypoxemia and to acidemia-hypoxemia interaction. A small residual response to added [H+]a during anesthesia could be accounted for by a slight concurrent increase of Paco2, leaving no response attributable to metabolic [H+]a itself. The lack of ventilatory response to metabolic [H+] during anesthesia, when a response to CO2was clearly present, suggests that the metabolic acid stimulus did not reach the medullary chemoreceptors. We conclude that halothane in humans markedly reduces the peripheral chemoreceptor-mediated responses to metabolic acidemia and to acidemia-hypoxemia interaction, in parallel with its previously described effect on the response to hypoxemia. During light halothane anesthesia, ventilation is virtually unaffected by either the acidity or the oxygen tension of the blood.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

In a canine model of acute respiratory failure, the authors investigated acute cardiopulmonary effects of nitroglycerin (TNG) and compared the results with those obtained after phlebotomy. Oleic acid increased intrapulmonary shunt (Qs/Qt) from 7.4 to 31% (P< 0.001) and decreased (P< 0.01) cardiac output (CO). In the presence of assumed low-pressure pulmonary edema, TNG was infused to decrease mean blood pressure (BP) by 40%; this was associated with a 26% decrease (P< 0.05) in CO. Qs/Qt increased from 31 to 42% (P< 0.01). There was a slight increase (P< 0.01) in pulmonary vascular resistance (PVR) with TNG, and mean pulmonary artery pressure (PAP) decreased (P< 0.05). In contrast, when CO was decreased by a similar amount with phlebotomy, mean Qs/Qt did not significantly change. There were similar changes in PVR and PAP and mixed venous O2tension with TNG and phlebotomy. Accordingly, current results rule out increased flow, increased Pvo2, and mechanical alterations in pulmonary vascular pressures as contributory to the increase in Qs/Qt with TNG. Alternatively, the increase in Qs/Qt with TNG may be explained by a direct pharmacologic decrease in pulmonary hypoxic vasoconstriction and/or by nonspecific pharmacologic effects.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Dosc-response relationships for a 1:4 weight ratio-mixture of pancuronium and metocurine were studied during inhalational anesthesia with halothane and isoflurane in patients with and without renal failure. The time for recovery from 10 to 20% of control thumb twitch tension also was determined. In subjects with normal renal function, relaxant doses required for 95% twitch height suppression (ED95) were 50% of those predicted by simple addition of effects when used with a balanced anesthetic technique, 37% of predicted when used with 1.3 MAC halothane, and 25% of predicted when used with 1.3 MAC isoflurane (P< 0.05). In subjects with renal failure, ED95values for the combination were 40% of predicted when used with 1.2 MAC halothane and 45% of predicted when used with 1.2 MAC isoflurane (NS). For relaxants used singly in renal failure, pancuronium alone was slightly enhanced by 1.2 MAC halothane (85% of predicted), while 1.1 MAC isoflurane reduced the ED95to 57% of predicted (P< 0.05). Similar results were obtained for metocurine alone when used in renal failure (77 and 58% of predicted when used with halothane and isoflurane, respectively) (NS). Predicted values are published results for balanced anesthesia in normals. Recovery times were prolonged twofold in renal failure (P< 0.05). Thus, the combination of pancuronium and metocurine is synergistic to the same degree in normals and in renal failure patients, but the total blockade produced by the combination is enhanced by halothane and isoflurane only in normals.

ISSN:0003-3022    

出版商:OVID    

年代:1985

数据来源: OVID