ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

The cardiac and peripheral vascular effects of 15–20 per cent, 25–30 per cent, and 35–40 per cent alveolar concentrations of cyclopropane were determined in each of 11 nonmedicated human volunteers at normal Pacos and body temperature during controlled ventilation. Compared with awake values during controlled ventilation, cyclopropane caused little change in cardiac output (Q), heart rate (HR) or stroke volume (SV), while mean right atria! pressure (MRAP) increased markedly. Large increases in mean arterial pressure (AP), total peripheral resistance and forearm vascular resistance suggested arterial constriction. A profound decrease in venous compliance contributed to the elevated MRAP. Cutaneous blood flow increased 560 per cent. Rapid reduction of cyclopropane led to immediate increase in Q, SV, and at a lower MRAP within two minutes. After eight additional minutes at the lower cyclopropane concentration, Q, SV, and returned to the previous values (i.e., before reduction of cyclopropane), but at even lower MRAP.

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

In seven healthy, conscious volunteers, hyper-ventilation from Paco235 mm Hg to 23 mm Hg did not change cardiac index (QI), heart rate (HR), stroke volume (SV), total peripheral rete sistance (TPR), or mean right atrial pressure (MRAP). Hyperventilation from Paco237 mm Hg to 26 mm Hg during anesthesia with 15–20 per cent cyclopropane decreased QI and SV. When Paco2was restored to 37 mm Hg by elevating inspired CO: (tidal volume and respiratory rate constant), cardiovascular function was unchanged while the subjects were conscious, and rose only slightly during anesthesia. When the subjects were conscious, hypercapnia induced marked increases in QI, SV, and HR, while TPR and MRAP fell. Cyclopropane, 25–30 per cent, abolished the tachycardia of hypercapnia, and thereby halved the QI response to CO2. However, the QI response to CO- still was better preserved during cyclopropane anesthesia than during halothanc anesthesia or anesthesia with thiopcntal, narcotic and curare.

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

High peridural blocks with 2 per cent lidocaine were studied in 20 normal volunteers 21 to 43 years of age. Epinephrine 1:200,000 was incorporated into the local anesthetic solution used to produce blocks in ten of the subjects. The following control measurements were made: mean arterial pressure, central venous pressure, cardiac rate, output and stroke volume, total peripheral resistance, pH Paco2Paco2glomerular filtration rate {GFR) and effective renal plasma flow (ERPF). These measurements were repeated at 15-minute intervals until cutaneous analgesia disappeared. With lidocaine alone, there were BO significant systemic cardiovascular changes, although maximum decreases of 9 per cent in GFR and 15 per cent in ERPF were seen. Epinephrine caused highly significant cardiovascular changes attributable to beta-receptor stimulation. The maximum changes were: mean arterial pressure –21 per cent, cardiac rate +26 per cent, cardiac output +68 per cent, stroke volume +34 per cent, total peripheral resistance –49 per cent, CFR –11 per cent, and ERPF –26 per cent. The differences between GFR values in the two groups were not significant, but the greater decrease in ERPF when epinephrine was added was significant and was due primarily to decrease in mean arterial pressure.

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

The effects of anesthesia on the setting and sensitivity of baroreceptor reflex control of heart rate in man were studied. Modest increases in systemic arterial blood pressure were produced transiently by small amounts of phenylephrine intravenously. The quantitative relationship between individual systolic arterial pressure pulses and subsequent cardiac cycle lengths was evaluated as an index of reflex performance.Thiopental produced a decrease in baroreflex sensitivity, associated with tachycardia. Halo-thane and nitrous oxide resulted in marked reflex resetting, permitting the combination of bradycardia and reduced blood pressure. The mechanisms which may produce baroreflex resetting during anesthesia are discussed. We propose that barbiturate effects on heart rate control arc achieved primarily in the central nervous system, and perhaps at the heart itself. Halothane and nitrous oxide could operate at baroreceptor sites in addition.

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

摘要:

The effects of halothane on the responses of cardiac sympathetic ganglia to intra-arterial injection of ganglion stimulants were studied in spinal dogs using heart rate as the index of ganglionic activation. Halothane alone, in concentrations of 1 and 1.5 per cent, did not affect the response to injected acetylcholine. Only after blockade of muscarinic receptors in the ganglion did halothane depress the response to acetylcholine. In addition, halothane markedly inhibited the response to DMPP, a nicotinic receptor stimulant, while leaving unchanged the response to McN-A-343, a muscarinic receptor stimulant. We conclude that halothane specifically inhibits the response to nicotinic ganglionic receptors only, and does so through an effect on the postsynaptic neuron.

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1969

数据来源: OVID