ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Cardiovascular effects of morphine (1 mg/kg) with and without 60 per cent nitrous oxide were determined in spontaneously breathing patients before operation for aortic and/or mitral valve replacement or coronary artery reconstruction. In patients who had valvular heart disease infusion of morphine was associated with significantly increased cardiac index (CI) and stroke volume index (SVI) and decreased mean arterial pressure (MAP) and systemic vascular resistance (SVR). Ten minutes after completion of the infusion, all values had returned to near awake control levels except the elevated CVP and Paco2. Changes in the patients who had coronary-artery disease were in the same direction but less marked, and HR decreased significantly.When nitrous oxide was substituted for nitrogen before operation or after cardiopulmonary bypass and during controlled respiration, MAP, CI, and SVI decreased in both groups to about the same degree. HR decreased significantly in patients with coronary-artery disease only. When nitrous oxide was discontinued, MAP and SVI returned to control values, but CI and HR remained depressed. Incision of the skin increased MAP and HR, but CI increased in the coronary-artery disease patients only.The authors conclude that morphine produced transient peripheral vasodilation and cardiovascular stimulation in patients with heart disease. Changes were more prominent in patients with valvular heart disease. Nitrous oxide added to morphine produced cardiovascular depression in all patients before operation and after cardiopulmonary bypass.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

The effect of respiratory alkalosis on oxygen consumption after passive hyperventilation was studied in eight dogs. PaCo2decreased from 32.1 to 13.6 torr,pH increased from 7.43 to 7.72, and oxygen consumption increased from 116.5 to 147.5 ml/m2/min. Venous admixture decreased from 17.1 to 8.8 per cent during passive hyperventilation, while cardiac index, PaO2, SaO2, and CaO2did not change significantly. Using a model, it can be shown that if oxygen consumption did not increase, PaO2, SaO2, and CaO2during hyperventilation would be higher than the values observed experimentally. The observed increase in VO2during respiratory alkalosis prevents a maximal increase in arterial oxygenation in the normal animal.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Ventilation-perfusion relationships of the fast ventilated and slowly ventilated compartments of the lung were estimated from analysis of nitrogen clearance curves and rate of increase of arterial oxygen tension during nitrogen clearance. Six subjects were studied first awake, breathing spontaneously, and then again during anesthesia, muscle paralysis, and mechanical ventilation in the supine position. Five other subjects were studied in the lateral position, first awake and then during anesthesia. Induction of general anesthesia, muscle paralysis, and mechanical ventilation did not significantly alter the mean ΔPetN2/ΔPao2ratio in supine subjects; this suggests no increased difference between the ventilation-perfusion ratios in the fast ventilated and slowly ventilated compartments. This conclusion is supported by data that showed no significant increase in arterial-alveolar CO2tension difference, alveolar deadspace, or shunt. Unlike the ratios for awake subjects in the lateral position, the ΔPetN2/ΔPao2ratios decreased consistently after induction of anesthesia. In the awake lateral subjects, mean ΔPetN2/ΔPao2was 0.08 above unity, whereas in the anesthetized lateral subjects, the mean value was 0.25 below unity; this suggests a larger difference between the ventilation–perfusion ratios in the two compartments. Also, arterial–alveolar CO2tension difference and alveolar deadspace increased significantly after induction of general anesthesia in the lateral subjects.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

The effects of 0, 5, 10, and 15 cm H2O end-expiratory pressure (EEP) were studied in 24 patients receiving nitrous oxide–d-tubocurarine anesthesia for intra-abdominal operations. Functional residual capacity (FRC) of every patient was increased during continuous positive-pressure breathing (CPPB). Pao2increased an average of 1.6 torr/cm H2O EEP in the 12 patients with the lowest Pao2's (<100 torr at zero EEP). Nonobese patients more than 50 years old showed the greatest improvement in Pao2. The other 12 patients (Pao2> 100 torr at zero EEP) had variable changes in Pao2, averaging 0.2 torr/cm H2O EEP. No patient suffered an important decrease in Pao2with CPPB. Clinical signs suggesting interference with cardiac output did not occur in the absence of blood loss.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Using a Van Slyke manometric apparatus, the solubility of nitrous oxide in water from 20 to 80 C was measured. Representative values for the Ostwald solubility coefficient are 0.693 at 20, 0.607 at 25, and 0.462 at 37 C, with standard errors 0.001 or less. All measured values were within 0.003 of those calculated from the third-degree polynomial curve which best fit the observed data. As expected for solubility of an inert gas in water, the data also very closely fit the equation log L = bo+ b1/T + b2log T, where T represents absolute temperature.

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1973

数据来源: OVID