ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Effects of three patterns of mechanical ventilation on pulmonary mechanics, lung phospholipid and surface activity were studied in the normal closed-chest dog. The patterns were continuous mechanical ventilation with: 1) tidal volume (VT) = 15 ml/kg; 2) VT = 15 ml/kg with 10 cm H2.O positive end-expiratory pressure (PEEP); 3) VT = 50 ml/kg. The dogs in each group were ventilated for 24 hours, with careful attention paid to maintenance of normal blood gases, fluid balance, and cardiac output. The animals were sacrificed and the lungs studied to determine pressure-volume curves, dry lung weight/wet lung weight ratios, phospholipid contents and surface activities. The results were compared with control values in acutely sacrificed unventilated dogs. No significant change from controls was found with any pattern of ventilation employed with the exception of the tendency for lungs ventilated with PEEP to retain fluid (decreased dry lung weight/ wet lung weight ratio).

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Cultured human lymphocytes treated with phytohemagglutinin (PHA) had higher rates of RNA and protein synthesis, as judged by incorporation of the labelled precursors 3H-uridine and 14C-leucine, than did control cultures without PHA. These cultures were prepared from cells of the same donor, as were a third set of cultures which were equilibrated with 2 per cent halothane. The increased rates of RNA and protein synthesis six and 16 hours after PHA addition were inhibited by the halothane, modestly at six hours and strikingly at 16 hours. These experiments provide further evidence that halothane prevents recruitment of resting cells into the active cycle of cell division.

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The effects of halothane on canine ventricular automaticity and contractility' were studied in intact and isolated heart preparations in which the right anterior papillary muscle and sinoatrial node of a recipient dog were separately perfused with arterial blood from a donor animal. One per cent halothane inhaled by the donor dog decreased blood pressure and heart rate in the donor animal and sensitized the ventricle of the donor dog to the arrhythmic effects of norepinephrine. One per cent halothane inhaled by donor dogs also produced negative inotropic and chronotropic responses in the isolated, perfused sinoatrial and ventricular preparations, but had no effect on positive chronotropic or inotropic responses to norepinephrine or perivascular nerve stimulation. Norepinephrine administered to donor dogs produced no arrhythmia in either spontaneously beating or electrically paced recipient hearts even though producing ventricular fibrillation in the donor. The results suggest that re-entry mechanisms play an important role in halothane-catecholamine-induced arrhythmias.

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Serum ionic fluoride concentrations during and following low-dose (6.0 mg/100 ml, 3 hours) methoxyflurane anesthesia and elective operation were measured in 13 pediatric patients (mean age 10.2 years; mean weight 34.5 kg). Peak measured serum ionic fluoride concentration was 21.6 ± 3.3 μmol/1 24 hours after anesthesia. In a previously reported study of adult patients (47.5 years; 71.9 kg), the peak measured serum ionic fluoride concentration was 43.9 = 5.7 μmol/l 24 hours after low-dose (6.S mg/100 ml, 3 hours) methoxyflurane anesthesia. Possible explanations forlowerserum ionic fluoride concentrations in pediatric patients compared with adults include 1) slower metabolism of methoxyflurane; 2) increased renal clearance of ionic fluoride from the blood; 3) greater storage of ionic fluoride in bone; 4) more rapid methoxyflurane elimination in the postoperative period. Serum uric acid increased (4.4 to 6.4 mg/100 ml, not significant) 24 hours after anesthesia and operation, while blood urea nitrogen and serum creatinine and osmolality were unchanged postoperatively.

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The effects of morphine-nitrous oxide anesthesia on cerebral autoregulation were studied in healthy male volunteers. Anesthesia was morphine, 2 mg/kg. and 70 per cent nitrous oxide in oxygen. Ventilation was controlled and carbon dioxide added to keep Paco, constant at 40 torr. Cerebral blood flow was measured first at the subject's normal mean arterial blood pressure, then at 60 torr and at 120 torr in a randomly assigned balanced order. Last, in five subjects cerebral blood flow was measured again at normal mean pressure. Blood pressure alteration was accomplished using phenylephrine ortrimethaphan. Cerebral blood flow and cerebral metabolic rate for oxygen were unaffected by changes in cerebral perfusion pressure. Cerebral blood flow was 38.9 = 6.4 (SEM) ml/100 g/min at normal mean pressure, 49.5 = 9.8 ml/100 g/min at 120 torr, and 44.0 = 10.7 ml/100 g/min at 60 torr. These values are not different atP< 0.05. The data were analyzed for the possible effect of time on cerebral blood flow, and no change could be demonstrated. It is concluded that with Pa±, constant at 40 ton-morphine-nitrous oxide anesthesia does not significantly affect cerebral autoregulation in normal man.

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The present study was designed to determine whether there were differences between the effects of isoflurane and halo thane on canine whole-body and individual organ oxygen uptake (V0J. Whole-body VO2, and myocardial, splanchnic, renal, and skeletal muscle Vo2's were determined at isoflurane concentrations equivalent to those used in a previous study with halothane. With increases in isoflurane, whole-body VO2, decreased progressively. As with halothane, the major component of the decrease was a reduction in myocardial VO2, that was related to a reduction in cardiac output and arterial blood pressure; contributions from other organs were minor. No significant difference between the effects of isoflurane and halothane on whole-body or individual organ Vo2's was found. These findings support the view that anesthetic agents are not general metabolic depressants and that observed changes in whole-body Vo2, reflect the summated changes in individual organ Vo2's occasioned by an anesthetic-induced change in organ function and metabolic requirements.

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The effects of subparalytic doses of succinylcholine andd-tubocurarine on epinephrineinduced cardiac arrhythmias during halothane anesthesia were evaluated in dogs. Succinylcholine markedly increased (P< .05) the arrhythmogenicity of epinephrine andd-tubocurarine slightly decreased (P< .05) its arrhythmic effect. Prior administration of atropine resulted in a partial, but significant, reversal of this action of succinylcholine.

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The effects of mechanical ventilation with and without positive end-expiratory pressure (PEEP) on hemodynamic performance and blood-gas exchange were studied in ten patients following open-heart surgery. Ventilation at constant tidal volume (15 ml/kg body weight) with 10 cm H2O PEEP following aortic valve replacement (AVR) in five patients without pulmonary vascular disease was associated with the following significant changes: a rise in arterial Po2, a fall in the alveolar-arterial Po2gradient when F1o2, = 1.0, decreases in calculated Os/Otand cardiac index. Using a similar pattern of ventilation following mitral valve replacement (MVR) in patients with elevated pulmonary vascular resistance, we found a significant decrease in cardiac index (but less than in the AVR group), a significant elevation of calculated physiologic deadspace (VD/VT) and no change in &OV0422;s/&OV0422;t. An hour after removal of PEEP, intravascular pressures, blood flow and blood-gas exchange values of all patients with AVR had returned to control levels; patients with MVR had persistently significantly low cardiac indices, while &OV0312;D/&OV0312;Treturned to pre-PEEP values. These findings suggest that evaluation of responses to different ventilation patterns must take into account preexisting &OV0312;/&OV0422; abnormalities secondary to pulmonary vascular disease, particularly when these are secondary to chronic congestive heart failure. Following AVR, &OV0422;s/&OV0422;tchanged in the same direction as cardiac index (CI) irrespective of ventilatory pattern: CI decreased and rose as CI increased. The authors conclude that with increasing severity' of pulmonary vascular disease, changes in airway pressure will have an unpredictable effect on cardiac index unless the level of myocardial competence is taken into account In the presence of ventricular failure, changes in pleural (and therefore transmural) pressures will be minimal compared with the high filling pressures and exert no influence on stroke volume.Although pulmonary venous hypertension was more propounded in the MVR than in the AVR group, there was no significant difference between the postoperative values for Os/Ot(F1o2= 1.0), a condition probably fostered by marked differences in pre-existing &OV0312;/&OV0422;.

ISSN:0003-3022    

出版商:OVID    

年代:1975

数据来源: OVID