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Biomedical subjects

M A Tobias

Publications and source records attributed to M A Tobias.

16 recordsLinked to original sources
PubMed1988

Computation of haemodynamic power and input impedance in the ascending aorta of patients undergoing open heart surgery.

Ascending aortic blood pressure and flow were successfully measured shortly after sternotomy in 16 patients undergoing coronary artery bypass graft surgery. Total haemodynamic power in the aorta was 953.9(444.7) mJ.s-1 (mean (SD], of which 11.65% was pulsatile. Quadrature components accounted for 50.8% of the pulsatile power. The mean (SD) term of the input impedance spectrum was 149.3(51.1) X 10(6) kg.m-4.s-1 and the characteristic impedance was 81.6(3.88) X 10(6) kg.m-4.s-1. Arterial pulsations are thought to be important for adequate tissue perfusion and the movement of tissue fluids and lymph. It is suggested that atheroma may increase the workload of the heart by diminishing the capacitative coupling between the aorta and the peripheral resistance vessels as well as pathological changes in other organs by impeding the lateral transmission of energy into the tissues.

Aorta↗
PubMed1988

Assessment of cardiovascular function in patients undergoing coronary artery bypass grafting.

Blood pressure and flow in the ascending aorta were measured in 16 patients undergoing coronary artery bypass grafting. The analog records were digitized and the data used to compute total hemodynamic power and aortic input impedance, which may be considered to be direct indices of cardiac performance and the state of the cardiovascular system. Various indirect indices were also computed from the same data and statistically compared with the two direct indices. The results showed that it is necessary to measure both pressure and flow to achieve statistically significant correlations, and that none of the indirect indices was capable of describing either cardiac performance or the state of the cardiovascular system comprehensively, or unambiguously, in these patients.

Adult↗
PubMed1981

Comparison of nitroprusside and nitroglycerine for controlling hypertension during coronary artery surgery.

The haemodynamic effects of infusing sodium nitroprusside or trinitroglycerine to control hypertension during operation were compared in 22 patients undergoing coronary artery surgery. Measurements were taken before induction of anaesthesia, during median sternotomy, and upon attainment of a stable decrease in arterial pressure. Both drugs significantly decreased arterial pressure without affecting heart rate or cardiac output. Systemic vascular resistance, pulmonary capillary wedge pressure and left and right ventricular stroke work were decreased also. Although nitroglycerine significantly decreased pulmonary vascular resistance, and produced a significantly greater decrease in central venous pressure than nitroprusside, these differences are unlikely to be important clinically.

Adult↗
PubMed1979

Intra-aortic balloon counterpulsation. Clinical experience.

From March 1975 until September 1978, seventy patients were referred for intra-aortic balloon counterpulsation for cardiogenic shock complicating acute myocardial infarction or for the treatment of low cardiac output states following cardiopulmonary bypass. Sixty of these received adequate intra-aortic balloon pump assistance; fifty-two ped successfully off the balloon pump. Twenty-three patients survived to leave hospital.

Assisted Circulation↗
PubMed1978

0.125% bupivacaine for obstetric analgesia?

A prospective trial was designed to assess the effectiveness of three different concentrations of bupivacaine (Marcain) for use in obstetric epidural analgesia. The purpose of the study was to see if reduction of the concentration of bupivacaine to 0.125% would reduce the total dose of the drug given without reducing the efficiency of the epidural block. The concentrations studies were 0.125%, 0.25% and 0.375%. The trial was limited to fit primiparous patients at term with singleton pregnancies and vertex presentation. Patients with intercurrent medical disease or with toxaemia were excluded. A total of ninety-three patients were studied, and once admitted to the trial they were randomly allocated to one of the three concentrations. In general the results of the trial show that 0.125% bupivacaine had a significantly higher failure rate than either of the other two concentrations, but in those cases where 0.125% was effective and achieved total pain relief there was a significant reduction in the amount of the drug used.

Anesthesia, Epidural↗
PubMed1977

Shock lung.

Explore the source record for details and available documents.

Humans↗
PubMed1977

Naso--tracheal jet ventilation for micro-laryngeal procedures.

Adequate pulmonary ventilation during general anaesthesia in completely relaxed patients during laryngoscopy has been provided with the aid of a readily available suction catheter and a manual oxygen valve. Operating conditions for the surgeon are excellent, clear photography through the operating microscope is facilitated and the exposure is a considerable improvement on other methods of anaesthesia.

Aged↗
PubMed1976

Tetany, tetanus or drug reaction? A case report.

An 8-year-old child was given perphenazine to prevent vomiting after surgery and developed an acute dystonic reaction; There were features of both tetany and tetanus without any of the classical features of extrapyramidal disturbance. The diagnostic difficulties are discussed. The reaction was treated successfully with i.v. diazepam. The prescribing of anti-emetics after surgery is examined critically with special reference to children.

Antiemetics↗
PubMed1971

Comparison of the antinociceptive activities of physostigmine, oxotremorine and morphine in the mouse.

1. Morphine, oxotremorine and physostigmine showed antinociceptive activity in mice using the hot plate reaction time test.2. The action of morphine, but not that of oxotremorine, was antagonized by naloxone and by nalorphine, whereas the effect of physostigmine was unaffected by naloxone and increased by nalorphine.3. The antinociceptive effects of morphine and of physostigmine were increased by procedures reported to increase the ratio of 5-hydroxytryptamine to dopamine in the brain. It was decreased by procedures reported to cause a fall in brain 5-hydroxytryptamine or a rise in dopamine relative to 5-hydroxytryptamine.4. The antinociceptive effect of oxotremorine was potentiated by procedures reported to decrease brain noradrenaline and was unaffected by procedures altering brain 5-hydroxytryptamine.5. The results suggest differences in the mode of action of morphine and physostigmine on the one hand and of oxotremorine on the other.

5-Hydroxytryptophan↗