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Biomedical subjects

D Fell

Publications and source records attributed to D Fell.

At least 37 records · Page 2Linked to original sources
PubMed1992

Cardiovascular responses to insertion of the laryngeal mask.

We have compared, in 40 healthy patients, the cardiovascular responses induced by laryngoscopy and intubation with those produced by insertion of a laryngeal mask. Anaesthesia was induced with thiopentone and maintained with enflurane and nitrous oxide in oxygen; vecuronium was used for muscle relaxation. Arterial pressure was measured with a Finapres monitor. The mean maximum increase in systolic arterial pressure after laryngoscopy and tracheal intubation was 51.3% compared with 22.9% for laryngeal mask insertion (p less than 0.01). Increases in maximum heart rate were similar, (26.6% v 25.7%) although heart rate remained elevated for longer after tracheal intubation. We conclude that insertion of the laryngeal mask airway is accompanied by smaller cardiovascular responses than those after laryngoscopy and intubation and that its use may be indicated in those patients in whom a marked pressor response would be deleterious.

Adult↗
PubMed1992

Impaired cardiopulmonary response to exercise in moderate hypertension.

OBJECTIVE: To identify the limiting factors of exercise performance in subjects with hypertension associated with left ventricular hypertrophy. The secondary objective was to establish relationship between peripheral function and exercise capacity. DESIGN: Cardiopulmonary exercise testing was conducted using two protocols: a graded exercise test to maximal effort established maximal exercise capacity, followed by a step-incremental test combining gas-exchange measures and radionuclide angiography. The exercise responses were compared within and between groups. SETTING: All hypertensive subjects were selected from the Toronto Tri-Hospital Hypertension Clinic. Normal subjects were recruited from the surrounding community. PATIENTS: Twelve patients with established hypertension and left ventricular hypertrophy (determined by echocardiography) were studied as a referred/volunteer sample. All had no evidence of coincident diseases and were unmedicated at time of testing. A volunteer sample of normal, healthy subjects acted as a control. INTERVENTIONS: Graded exercise to maximum and step-incremental (submaximal and steady-state) exercise was used to quantify cardiopulmonary function during exercise stress. MAIN OUTCOME MEASURES: These included (for exercise performance) maximal oxygen intake (VO2max), the ventilatory anaerobic threshold, total peripheral resistance and blood lactate. Cardiac function measures included ejection fraction and ventricular volumes. RESULTS: Cardiac function data obtained during exercise in hypertensive subjects included an increase in the pressure to volume ratio, but a blunted ejection fraction response at peak exercise (P less than 0.05). Although end-diastolic volume increased during exercise (P less than 0.05), values were lower during both levels of exercise compared with normal subjects. Mean +/- SD end-systolic volume increased from 39 +/- 22 at rest to 42 +/- 23 mL during peak exercise. Hypertensive subjects had a lower VO2 max (mean 27.4 +/- 4.8 mL/kg/min) compared with normals (40.0 +/- 8.5 mL/kg/min) and a lower ventilatory anaerobic threshold (14.4 +/- 2.9 versus 27.6 +/- 5.8 mL/kg/min, P less than 0.005). Furthermore, hypertensive patients had a significantly elevated total peripheral resistance at rest (2.5 +/- 1.0 versus 1.8 +/- 0.4 peripheral resistance units) and at peak exercise (1.6 +/- 0.7 versus 0.8 +/- 0.2, P less than 0.01) compared with normal subjects (P less than 0.05). A correlation coefficient of 0.92 was found between total peripheral resistance and VO2 max in hypertensive subjects (P less than 0.01). CONCLUSIONS: These data suggest that peripheral factors, specifically a failure to reduce significantly total peripheral resistance, limits exercise performance despite a maintenance of left ventricular function during exercise in patients with moderate hypertension. The use of cardiopulmonary exercise testing can help in identifying the underlying cause of exercise intolerance in this population and limited left ventricular reserve at peak exercise, and may offer a sensitive measure of therapeutic end-points.

Adult↗
PubMed1991

Wound infiltration of local anaesthetic after lower segment caesarean section.

The analgesic efficacy of subcutaneous wound infiltration with 20 ml of 0.5% bupivacaine after elective lower segment section Caesarean section was studied in 28 patients in a double-blind randomised controlled manner using a patient-controlled analgesia system. The mean 24-hour morphine consumption of the placebo group and the bupivacaine group was similar (76 mg and 68 mg respectively). Analysis of the cumulative hourly morphine consumption failed to show any statistically significant differences between the groups. However, on a weight-adjusted basis statistically significant differences in morphine consumption were demonstrated, although these may not be clinically important. Subjective experiences of pain, nausea and drowsiness assessed by linear analogue scoring were similar in both groups.

Administration, Topical↗
PubMed1991

Nausea and vomiting with use of a patient-controlled analgesia system.

The incidence of nausea and vomiting following patient controlled analgesia and intramuscular morphine injections on demand was compared in a double-blind randomised study of 32 healthy patients undergoing elective cholecystectomy. There were no significant differences between the two groups in mean 24 hour postoperative morphine consumption, subjective experience of pain, nausea and sedation assessed by visual linear analogue scoring, and the postoperative requirements for antiemetic therapy.

Adult↗
PubMed1991

Serum bupivacaine concentrations following wound infiltration in children undergoing inguinal herniotomy.

Serum bupivacaine concentrations were measured in 12 children who underwent elective herniotomy and who received analgesia in the form of wound infiltration. Mean (SD) peak concentration was 0.36 (0.14) micrograms/ml and time to peak concentration was 14.6 (7.2) minutes after infiltration of 1.25 mg/kg of bupivacaine. These concentrations are lower than those associated with other local anaesthetic blocks and well below potentially toxic levels. Wound infiltration provides a simple, effective and safe method of providing postoperative analgesia for hernia repair in children.

Analgesia↗
PubMed1990

Disruption of thymidylate synthesis and glycine-serine interconversion by L-methionine and L-homocystine in Raji cells.

Excessive concentrations of L-methionine inhibited the folate-dependent de novo synthesis of thymidylic acid (TMP) in Raji cells, demonstrating the usefulness of this cell line for the study of methionine-folate antagonism. The effect was also produced by L-homocystine but not by other amino acids including D-methionine and L-ethionine, suggesting that this effect is exerted by a common intermediate of methionine and homocystine metabolism. L-Methionine, L-homocysteine, S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH) are not inhibitors of thymidylate synthase activity. On the other hand the capacity of the cells to incorporate serine 3-carbon and glycine 2-carbon into DNA is impaired by the presence of L-methionine or L-homocystine. Studies with cell-free extracts demonstrated that the glycine cleavage enzyme is inhibited by 45% by L-methionine, L-homocysteine, SAM or SAH. Serine hydroxymethylase on the other hand was slightly stimulated by these sulfur-containing compounds and this stimulation was shown to occur in the intact cell as well. These findings suggest that when levels of L-methionine metabolites are elevated, there is an increase in the use of glycine to maintain the intracellular concentration of serine, which is required for homocysteine detoxification by conversion to cystathionine. The reduction in TMP synthesis caused by excess L-methionine or L-homocystine may result from increased utilization of one-carbon units for serine synthesis.

Amino Acids↗
PubMed1990

Paediatric postoperative analgesia. A comparison of rectal diclofenac with caudal bupivacaine after inguinal herniotomy.

Forty-three children for day case inguinal herniotomy under general anaesthesia were assigned randomly to receive either 1 ml/kg caudal bupivacaine 0.25% or rectal diclofenac 0.25 mg/kg intra-operatively to provide postoperative analgesia. Pain and demeanour were assessed by an observer in the early postoperative period after operation and by questionnaire for the parents over the first 24 hours. Caudal bupivacaine provided more pain-free patients at first but later the incidence of pain was similar in the two treatment groups. Rectal diclofenac is a useful alternative to caudal blockade in this group of patients.

Administration, Rectal↗
PubMed1990

A comparison of the effects of alfentanil/droperidol or fentanyl/droperidol on intra-ocular pressure.

The influence of two intravenous sedative regimens on intra-ocular pressure was investigated in conjunction with retrobulbar local anaesthesia. Forty patients were allocated randomly to either group A (alfentanil and droperidol) or group F (fentanyl and droperidol). Measurements of intra-ocular pressure, arterial pressure and oxygen saturation were made before operation, after premedication, after intravenous sedation and after surgery. Paco2 was also measured before and after operation. Each sedation technique caused a similar reduction in intra-ocular pressure. There was less effect on Paco2 and oxygenation in group A.

Aged↗
PubMed1989

Plasma concentrations of catecholamines following intraocular irrigation with adrenaline.

Plasma concentrations of adrenaline and noradrenaline were measured in 13 patients undergoing cataract surgery after intraocular irrigation with an adrenaline-containing solution. Venous blood samples were withdrawn before, during and after intraocular irrigation with a solution of adrenaline 1:500,000. Plasma concentrations of both adrenaline and noradrenaline did not differ significantly from those noted before induction of anaesthesia.

Absorption↗
PubMed1989

Haemodynamic changes after induction of anaesthesia and tracheal intubation following propofol or thiopentone in patients of ASA grade I and III.

Thirty-six ASA I patients received either propofol 2.25 (0.07) mg kg-1 (mean (SEM] or thiopentone 4.8 (0.18) mg kg-1, for induction of general anaesthesia together with fentanyl and a neuromuscular blocking drug. This technique was repeated in 12 ASA III patients, using propofol 1.8 (0.18) mg kg-1 or thiopentone 4.7 (0.37) mg kg-1. There was a significant decrease in systolic arterial pressure following induction of anaesthesia with both drugs; this was more pronounced after propofol, and in ASA III patients. Plasma noradrenaline concentrations increased after tracheal intubation only in the thiopentone group, but the pressor response to tracheal intubation was not attenuated by the use of propofol.

Adult↗
PubMed1989

Hypertensive and catecholamine response to tracheal intubation in patients with pregnancy-induced hypertension.

The pressor and catecholamine responses to laryngoscopy and intubation were studied in nine patients with pregnancy-induced hypertension (PIH) and in eight normotensive controls. Five of the PIH patients had received oral labetalol as antihypertensive therapy. Mean arterial pressure (MAP) increased significantly from the pre-induction value in all groups 1 min after intubation, and also at 3 min in those with PIH who had not received labetalol. Arterial pressure was significantly greater in both PIH groups than in the control group at all times. However, the percentage increase in MAP on intubation was significantly less in the labetalol treated group than in either the untreated or the control groups. There were no significant differences between the groups in plasma concentrations of either noradrenaline or adrenaline; noradrenaline concentration increased significantly after intubation only in the control group. Labetalol appears to confer some protection against the pressor response to intubation in parturients with PIH.

Adult↗
PubMed1989

Failure of rectal diclofenac to augment opioid analgesia after cholecystectomy.

The analgesic efficacy of a single 100-mg suppository of diclofenac sodium given after elective cholecystectomy was studied in 30 healthy patients in a double-blind randomised controlled manner. The mean 24-hour postoperative morphine consumption of the placebo group and the diclofenac group was similar (45 mg). Analysis of the cumulative hourly morphine consumption from the patient-controlled analgesia system failed to show any statistically significant differences between the groups. Peak expiratory flow rate, forced expiratory volume at 1 second and forced vital capacity decreased 24 hours after operation to less than 50% of pre-operative values in both groups. Subjective experiences of pain, nausea and drowsiness assessed by linear analogue scoring were similar in both groups.

Administration, Rectal↗
PubMed1988

Affinity chromatography of naturally occurring folate derivatives.

In a previous report (1980, in Methods in Enzymology, Vol. 66, p. 686, Academic Press, New York) we described the preparation and use of purified milk folate-binding protein covalently linked to a Sepharose matrix. The present study was undertaken to test the capacity of this preparation to purify quantitatively folates from tissue extracts. In experiments that employed tissue extracts containing biologically synthesized [3H]folates, recovery of radioactivity from columns of the immobilized folate-binding protein (affinity columns) was consistently 90-95%. Folates eluted from the affinity column were practically pure. Anion-exchange chromatography of the purified fraction from rat liver extract yielded a number of uv-absorbing peaks which corresponded to the elution profile based on 3H counts, with respect to both the position and the area of the peaks. Treatment of the original extracts with folylpolyglutamate hydrolases resulted in the shift of these peaks to lower retention times, which corresponded to mono- or diglutamyl folate derivatives. Similar results were obtained with extracts from Lactobacillus casei. The purification of tissue folates by affinity chromatography allows determination of folate activity by direct physiochemical methods, which is particularly useful for analysis of folate composition in tissues.

Animals↗
PubMed1988

A comparison of rectal diclofenac with intramuscular papaveretum or placebo for pain relief following tonsillectomy.

A controlled investigation was conducted to compare the effectiveness of diclofenac and papaveretum in the prevention of pain and restlessness after tonsillectomy in children. Sixty children between 3 and 13 years of age were randomly allocated to receive rectal diclofenac 2 mg/kg, intramuscular papaveretum 0.2 mg/kg or no medication immediately after induction of anaesthesia. Pain and appearance were assessed 1, 3 and 6 hours postoperatively, and the following morning. The assessments were double-blind and performed by the same observer. No significant differences in postoperative pain were found between the groups at any time. The use of diclofenac was associated with a significantly more rapid return to calm wakefulness and had significantly less effect upon respiratory rate. Consumption of paracetamol on the day of operation was significantly less in the diclofenac group. Diclofenac may offer advantages compared to papaveretum with regard to safety and convenience for use in the treatment of pain after tonsillectomy in children.

Administration, Rectal↗
PubMed1988

Paediatric postoperative analgesia. A comparison between caudal block and wound infiltration of local anaesthetic.

Fifty children who underwent day case herniotomy received either a caudal injection of 1 ml/kg bupivacaine 0.25% or infiltration of the wound edges at the end of surgery with 0.5 ml/kg bupivacaine 0.25%, allocated at random. Postoperative pain and demeanour were assessed initially by an observer and later by use of a parental questionnaire. Wound infiltration of local anaesthetic solution provided analgesia which was comparable to that associated with caudal block, and the incidence of side effects was similar in the two groups. Wound infiltration of local anaesthetic offers a simple, safe alternative to caudal block for provision of postoperative analgesia in this group of patients.

Analgesics↗