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Biomedical subjects

J Thorburn

Publications and source records attributed to J Thorburn.

96 records · Page 6Linked to original sources

The effects of ketamine on the canine coronary circulation.

Systemic and coronary haemodynamic measurements have been made in six healthy greyhounds anaesthetized with trichloroethylene. The administration of ketamine in bolus doses of 5 mg/kg, 10 mg/kg and 5 mg/kg followed by an infusion 0.1 mg/kg/min was found to be accompanied by a decrease in arterial pressure and an increase in cardiac output produced by an increase (84%) in stroke volume. Coronary blood flow increased greatly as did myocardial oxygen consumption and there was no change in myocardial oxygen extraction.

Animals↗

An evaluation of the AVL 937C blood-gas and pH microanalyser.

The AVL 937C blood-gas and pH microanalyser was evaluated with particular reference to its use in obsterics and in neonatal paediatrics in which its ability to analyse blood smaples as small as 40 micronlitre would be of particular value. Analysing samples of cord blood, maternal venous blood and foetal scalp blood, the reproducibility over the range of values measured was excellent with samples of 40-100 micronlitre. SD of the variation in values measured on samples collected in syringes were po2 0.11 kPa; Pco2 0.21 kPa; PH 0.005 unit. The same values for specimens collected in capillary tubes were: Po2 0.19 kPa;Pco 0.43 kPa; pH 0.013 unit. Analysis of tonometered blood samples showed a similar high standard of accuracy. The 91-98% confidence limits for the measurement of blood-gas values in samples collected in syringes were: Po2-0.22 to +0.49kPa; Pco2-0.53 to +0.42 kPa. The same values for samples collected in capillary tubes were: Po2 -0.38 to +0.70 kPa; Pco2 -0.97 to +0.86 kPa.

Blood Gas Analysis↗

Extradural analgesia in obstetrics: a controlled trial of carbonated lignocaine and bupivacaine hydrochloride with or without adrenaline.

Four local anaesthetic solutions (2% carbonated lignocaine with or without adrenaline and 0.5% bupivacaine HCl with or without adrenaline) were used randomly for 335 continuous lumbar extradural blocks in labour. Carbonated lignocaine caused a more rapid onset of analgesia than bupivacaine HCl. The addition of adrenaline made little difference to the onset times, prolonged markedly the duration of analgesia with carbonated lignocaine and had little effect on the duration of analgesia with bupivacaine HCl. Tachyphylaxis was a feature with carbonated lignocaine and adrenaline, but not with the other solutions. The incidence of unblocked segments was 7-9% in the four groups. The incidence of unilateral analgesia was 6% with plain lignocaine and 13% in the other groups. Complete pain relief occurred more frequently with bupivacaine HCl than with carbonated lignocaine and the use of adrenaline had little effect on the degree of analgesia.

Anesthesia, Epidural↗

The combined effect of halothane-induced hypotension and hypocapnia on canine myocardial blood-flow and oxygen consumption.

In eleven intact mechanically ventilated dogs anaesthetized with pentobarbitone, mean arterial pressure was reduced to 55% of the control value by ventilating with 1-1.5% halothane. At normocapnia this resulted in decreases in myocardial blood-flow and oxygen consumption to 47% and 55% of their respective control values and an increase in myocardial vascular resistance to 123% of control value. When hypocapnia (mean PaCO2=26 mm Hg) was superimposed on hypotension, myocardial blood-flow was further decreased to 38% of control value whereas oxygen consumption did not alter significantly. When halothane was discontinued, allowing recovery from hypotension, the rate of recovery of myocardial blood-flow and cardiac output was much slower than that of arterial pressure.

Animals↗