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Biomedical subjects

D A Rocke

Publications and source records attributed to D A Rocke.

At least 55 records · Page 3Linked to original sources
PubMed1990

Critical volume for pulmonary acid aspiration: reappraisal in a primate model.

We have studied, in the monkey, the critical volume for the production of severe pneumonitis following pulmonary aspiration of gastric contents. Aspiration of 0.4 ml kg-1 and 0.6 ml kg-1 at pH1 produced mild to moderate clinical and radiological changes, but no deaths. Aspiration of 0.8 ml kg-1 and 1.0 ml kg-1 at pH1 was associated with an increasingly severe pneumonitis. At 1.0 ml kg-1, 50% of the animals died--a mortality rate considerably less than that reported previously in animal studies. If these results were to be extrapolated to humans, the critical volume for severe aspiration could be increased from 25 ml to 50 ml (0.8 ml kg-1), considerably reducing the percentage of patients perceived to be "at risk".

Animals↗
PubMed1990

Effects of alfentanil and fentanyl on induction of anaesthesia in patients with severe pregnancy-induced hypertension.

Forty patients with severe pregnancy-induced hypertension presenting for Caesarean section under general anaesthesia were allocated randomly to receive either fentanyl 2.5 micrograms kg-1 or alfentanil 10 micrograms kg-1 as part of the anaesthetic induction sequence. In all patients, the cardiovascular response to tracheal intubation was measured. Both drugs attenuated the response equally but did not abolish it in all patients. Alfentanil 10 micrograms kg-1 is a suitable alternative to fentanyl 2.5 micrograms kg-1 for patients with pregnancy-induced hypertension.

Adult↗
PubMed1990

Prevention of hypotension following spinal anaesthesia for elective caesarean section by wrapping of the legs.

Twenty-four parturients undergoing elective Caesarean section were allocated randomly to have the legs wrapped with elasticated Esmarch bandages immediately following spinal anaesthesia or to serve as controls. Significant hypotension (systolic arterial pressure less than 100 mm Hg and less than 80% of baseline value) was treated with i.v. ephedrine in 5-mg boluses. Leg wrapped patients had a significantly (P = 0.0033) lower incidence (16.7%) of hypotension than controls (83.3%). Only two patients in the leg wrapped group required ephedrine compared with 10 in the control group. Systolic arterial pressure was significantly (P less than 0.05) less in control subjects at 4, 5 and 6 min following spinal injection. No patient in the leg wrapped group became hypotensive following removal of the elasticated bandages.

Anesthesia, Obstetrical↗
PubMed1988

Midazolam for induction of anaesthesia in patients with limited cardiac reserves. A comparison with etomidate.

The new water-soluble benzodiazepine, midazolam (Dormicum; Roche), was compared with etomidate as part of a balanced technique for induction of anaesthesia in 16 patients undergoing cardiac valve replacement. Monitoring revealed a significantly greater fall in blood pressure in patients receiving midazolam (reaching dangerous levels in 2 patients), which suggests that this agent is not suitable for induction of anaesthesia in haemodynamically compromised patients.

Adult↗
PubMed1988

Pneumonectomy in a patient with ventricular septal defect.

A young man with severe unilateral bronchiectasis and a ventricular septal defect presented for pneumonectomy. Intra-operative monitoring, which included continuous measurement of systemic and pulmonary oxygen saturations by oximetry, revealed transient reversal of the intracardiac shunt across the defect. The implications of this combination of cardiac and pulmonary disease for anaesthetic management are discussed.

Adult↗
PubMed1987

Endotoxemia associated with cardiopulmonary bypass.

Endotoxin (lipopolysaccharide) concentrations were determined in the systemic venous blood in nine patients undergoing cardiopulmonary bypass. Lipopolysaccharide concentrations were low and stable until institution of cardiopulmonary bypass (preanesthetic concentration 0.128 +/- 0.032 ng/ml [mean +/- standard error of the mean]; prebypass level 0.136 +/- 0.03 ng/ml). After the start of bypass, the plasma concentration of lipopolysaccharide rose progressively with time to a mean value of 0.347 +/- 0.044 ng/ml (p less than 0.01), which was 0.227 ng/ml above baseline. Upon release of the aortic clamp, an additional rise in lipopolysaccharide concentration occurred after to 5 to 15 minutes to a mean value of 0.428 +/- 0.06 ng/ml (p less than 0.001) above baseline. The concentration then decayed to the baseline level 45 to 75 minutes after termination of bypass. The peak lipopolysaccharide concentration above the baseline positively correlated with both the length of bypass (r = 0.839, p less than 0.005) and the duration of aortic cross-clamping (y = 0.0030X + 0.173 r = 0.85, p less than 0.001) when flow was nonpulsatile. The peak occurred during the period of myocardial and pulmonary reperfusion. This rise in endotoxin concentration may be one of the factors responsible for the prolonged postoperative recovery seen in some patients.

Adult↗
PubMed1986

Morphine in tetanus--the management of sympathetic nervous system overactivity.

Morphine was administered intravenously in bolus doses 6-hourly to 10 patients; 9 developed signs of sympathetic overactivity and required increased morphine dosage. The mean daily morphine dosage was 103 +/- 36 mg and the maximum daily dosage was 170 +/- 65 mg. In all cases morphine decreased the mean arterial blood pressure (mean 18%; P less than 0.01) and heart rate (mean 7%; P less than 0.01). In 7 cases the cardiac output fell minimally (mean 7%; P = 0.07), while the systemic vascular resistance decreased (mean 12%; P less than 0.01) in 8 cases. Nine patients survived, 1 died from renal failure and septicaemia. There were no apparent problems with either opiate withdrawal or addiction. No patient required either alpha- or beta-adrenergic blockers and the consequent simplified management constitutes a significant improvement in control of these patients.

Adolescent↗
PubMed1986

Smoking habits and attitudes of Durban metropolitan anaesthetists.

A modified World Health Organization questionnaire about the smoking habits and attitudes of health professionals was sent to all practising anaesthetists in the Durban metropolitan area. The most striking feature of the 102 replies (response rate 78%) was the trend away from smoking, 58% of respondents having smoked at some stage and only 19% currently smoking daily. The marked consensus on the steps which should be taken to curb public smoking correlated with the views of both the Medical Association of South Africa and the South African Medical Research Council. It was, however, disappointing that some anaesthetists smoked in the presence of patients (5%), did not advise pregnant patients to stop (9%), and disagreed with sales restriction to minors (13%). It is hoped that this study will provide the impetus for a larger study among all practitioners in order to define clearly attitudes towards smoking and to bring effective pressure upon Government to curb smoking.

Anesthesiology↗
PubMed1986

Folinic acid protection against nitrous oxide teratogenicity in the rat.

The Sprague-Dawley rat was used to demonstrate the effect of nitrous oxide, with and without folinic pretreatment, on reproductive indices and fetal development. One of the objectives of the investigation was to test the hypothesis that at least some of the teratogenic effect of nitrous oxide is related to interference with folate metabolism. Groups of animals were exposed to 70-75% nitrous oxide on day 9 of pregnancy with or without folinic acid 0.1 mg i.p. 12 h before, and immediately before, exposure. Subsequent fetal development was compared with that of various control groups. There were no significant differences in fetal survival, but fetal weights were reduced in both groups exposed to nitrous oxide. Of the indices of skeletal maturity, the number of ossified sternebrae was reduced only in the nitrous oxide group not receiving folinic acid. The incidence of major skeletal abnormalities in the untreated nitrous oxide group was significantly increased to five times that of the control groups, whereas the incidence in the nitrous oxide group receiving folinic acid was not significantly different from control. It is concluded that pretreatment with folinic acid can at least partially reduce the teratogenic effects of nitrous oxide in the rat.

Abnormalities, Drug-Induced↗
PubMed1985

Episodic postoperative oxygen desaturation: the value of added oxygen.

Six patients were studied following general anaesthesia for cholecystectomy or hip replacement. Intravenous morphine was given for postoperative pain relief. Continuous measurements were made of breathing pattern and arterial oxygen saturation for a 12-hour period postoperatively. The effect of breathing either air or 28% oxygen for alternate 2-hour periods was examined. There was no significant effect of oxygen on the number of periods of central apnoea, obstructive apnoea or partial upper airways obstruction. The number of episodes of decreases in oxygen saturation to below 80%, associated with these breathing disturbances, was reduced from 59 to zero by the administration of oxygen. There was a gradual improvement in oxygenation whilst breathing air during the 12-hour postoperative period. The administration of oxygen had a beneficial effect on average arterial oxygen saturation.

Airway Obstruction↗
PubMed1984

Renal function in tetanus.

In twenty-eight patients suffering from tetanus, renal function was evaluated from admission for a period of 2 weeks. Investigations included daily blood urea, osmolality and creatinine and urinary osmolality and sodium. Free water clearance (CH2O) was calculated. The patients were divided into those requiring tracheostomy and sedation alone (Group I) and those with more severe tetanus requiring total muscle paralysis and IPPV (Group II). The latter group also had evidence of sympathetic nervous overactivity (SOA). Daily blood urea, serum creatinine and osmolality showed no significant difference between the two groups except during the phase of uremia. Mean urinary sodium was significantly different between the two groups (p less than 0.001). Four patients in Group II developed an abnormal plasma urea (Group IIb). In one patient the rise in urea followed resuscitation from cardiac arrest and the remaining three patients had in common severe cardiovascular instability associated with SOA. All four patients were non-oliguric during the phase of uremia. Only one patient with renal failure survived, compared with a 75% survival in the patients with SOA without renal failure and a 100% survival in Group I. Tetanus complicated by renal failure has a poor prognosis.

Adolescent↗