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Biomedical subjects

K H Simpson

Publications and source records attributed to K H Simpson.

36 records · Page 2Linked to original sources
PubMed1988

Effect of passive hyperventilation on seizure duration in patients undergoing electroconvulsive therapy.

The influence of end-expired carbon dioxide concentration (E'CO2) on seizure duration was studied in 30 depressed patients undergoing electroconvulsive therapy (ECT) on three separate consecutive occasions. Unpremedicated patients breathed 100% oxygen before the induction of anaesthesia with methohexitone and the provision of partial neuromuscular blockade with suxamethonium. They then received no further ventilation, 10 breaths, or 20 breaths of hyperventilation with 100% oxygen from a non-rebreathing system with a high fresh gas flow. Transcutaneous oxyhaemoglobin saturation (SaO2) was monitored continuously and E'CO2 was measured before and after the seizure. Observation of an isolated forearm was used to time the seizure duration. SaO2 remained greater than 90% in all patients. Passive hyperventilation with 20 breaths significantly reduced E'CO2 and prolonged seizure duration. E'CO2 before the seizure and change in E'CO2 during the seizure did not correlate significantly with seizure duration.

Adult↗
PubMed1988

Comparison of extradural buprenorphine and extradural morphine after caesarean section.

Fifty-seven women received extradural morphine 3 mg, buprenorphine 0.18 mg or buprenorphine 0.09 mg after elective Caesarean section carried out under extradural bupivacaine. Supplementary sublingual buprenorphine was available on demand. Ten-centimetre visual analogue pain scores were completed regularly; emesis, pruritus and urinary retention were recorded for 24 h. Patients who received buprenorphine 0.09 mg had more pain, and required more supplementary analgesia, than those who received morphine 3 mg. Pain scores and analgesic requirements after buprenorphine 0.18 mg were not significantly different from either of the other two groups. Emesis was not significantly different in the three groups. More itching occurred after morphine 3 mg and buprenorphine 0.18 mg than after buprenorphine 0.09 mg; pruritus of the face, legs and perineum was more common after morphine than buprenorphine. Twenty-eight percent of patients without a urinary catheter developed retention of urine. Seventy-five to 84% of patients were satisfied with analgesia during the first day after operation. Analgesia and adverse effects were similar when morphine 3 mg or buprenorphine 0.18 mg was given extradurally after Caesarean section.

Buprenorphine↗
PubMed1988

Premedication with slow release morphine (MST) and adjuvants.

Sixty-one women undergoing major gynaecological surgery received slow release morphine (MST) 60 mg, with placebo, hyoscine 0.6 mg or diazepam 10 mg, by mouth 2 h before surgery. Plasma morphine concentrations reached a steady level usually within 3 h after administration of MST, and did not increase after surgery unless supplementary opioid was given. Hyoscine delayed morphine absorption. Before operation no fewer than 50% of patients were sedated after MST alone, but this increased to 85% after MST and diazepam. Similarly, only the combination MST and diazepam produced anxiolysis. Postoperative mood was unhappier after MST and hyoscine. Emesis occurred in 40-57% of patients, and was not reduced by hyoscine. Therefore premedication with MST alone did not produce reliable sedation or anxiolysis. A combination of hyoscine and MST premedication cannot be recommended, as it did not produce sedation, anxiolysis or antiemesis and hyoscine may have delayed morphine absorption.

Absorption↗
PubMed1988

Propofol reduces seizure duration in patients having anaesthesia for electroconvulsive therapy.

Twenty-five patients received either methohexitone 1.0 mg kg-1 or propofol 1.3 mg kg-1 to induce anaesthesia during two separate electroconvulsive therapy (ECT) treatments. A forearm was isolated before administration of suxamethonium 0.5 mg kg-1, so that unmodified seizure duration could be measured. Bifrontotemporal electrodes were applied to administer a standard 3-s ECT shock. Median (quartile deviation) duration of seizure was reduced significantly after propofol (19.0 (9.0) s), compared with after methohexitone (33.0 (7.8) s). Therefore propofol may not be an appropriate anaesthetic for ECT because of its adverse effect on seizure duration.

Anesthesia, Intravenous↗
PubMed1988

Premedication with piroxicam in patients having dental surgery under general anaesthesia with halothane or isoflurane.

Pain, analgesic requirements, mouth opening and emesis were assessed in 60 patients who received either piroxicam 40 mg or placebo before dental surgery under general anaesthesia which included breathing either halothane or isoflurane. Patients went home on the day after surgery and completed a questionnaire concerning pain and emesis. There were four groups of 15 subjects: piroxicam-halothane, piroxicam-isoflurane, placebo-halothane or placebo-isoflurane. Pain increased at 2 and 4 h and had reduced by 18 h after surgery; there were no significant differences between the groups in pain scores. After operation, fewer patients in the piroxicam-isoflurane group required papaveretum compared with the piroxicam-halothane and placebo-halothane groups. Mouth opening was reduced between 2 and 4 h after surgery, but was less restricted after piroxicam-isoflurane than placebo-halothane. There was no difference between the groups in the incidence of emesis within 18 h of surgery. The postal questionnaire suggested that pain and emesis were reduced significantly during the 3 days after surgery in patients who had received piroxicam before surgery, compared with those who had received placebo.

Adult↗
PubMed1988

Anaphylactoid reaction to vecuronium followed by systemic reaction to skin testing.

An unusual case is presented of a systemic anaphylactoid reaction to tubocurarine and subsequently to vecuronium. Intradermal testing with vecuronium following the latter response was negative at recommended test dose levels but at a higher concentration it initiated a hazardous systemic response. The laboratory investigations and possible mechanisms involved in this unusual case are discussed in detail since they may relate to other patients who experience anaphylactoid responses to anaesthetic drugs and who then undergo intradermal testing.

Adult↗
PubMed1987

Effect of anxiety on gastric emptying in preoperative patients.

On the morning of operation 30 patients awaiting minor gynaecological surgery completed a Spielberger State Trait Anxiety Inventory. Gastric emptying was then measured using paracetamol absorption. Anxiety State scores, which reflected situational anxiety, were unrelated to Anxiety Trait scores, which assessed anxiety proneness. Paracetamol absorption was reduced and delayed in patients with low anxiety trait who developed high anxiety state before surgery, compared with patients whose anxiety state scores were lower than, or similar to, their anxiety trait scores. Therefore, it was concluded that gastric stasis occurred in patients with a low predisposition to anxiety who became apprehensive whilst awaiting surgery.

Acetaminophen↗
PubMed1987

Comparison of the effects of atropine and glycopyrrolate on cognitive function following general anaesthesia.

Tests of orientation, concentration and short-term visual memory were used to assess 72 patients 1 day before, and 2 days after, elective major surgery. Patients were premedicated with papaveretum and either atropine or glycopyrrolate, before receiving a standard general anaesthetic. Those who had received atropine showed significant postoperative short-term memory deficit (P less than 0.01), but no change in orientation or concentration. Those who had been given glycopyrrolate showed no significant cognitive changes after surgery. As glycopyrrolate does not cross the blood-brain barrier freely, these findings support the involvement of central cholinergic mechanisms in the deterioration of cognitive function in the postoperative period.

Adult↗
PubMed1987

Oxygen saturation during electroconvulsive therapy.

Oxygen saturation was measured during anaesthesia and electroconvulsive therapy (ECT) using ear oximetry. Significant hypoxia occurred during some treatments; desaturation related to the number of ventilations performed after muscle relaxation and prior to the shock. Desaturation did not correlate significantly with seizure duration. These findings highlight the need for adequate oxygenation during ECT.

Adult↗
PubMed1986

Comparison of the use of domperidone, droperidol and metoclopramide in the prevention of nausea and vomiting following gynaecological surgery in day cases.

The efficacy of domperidone 20 mg, droperidol 2.5 mg, metoclopramide 10 mg or placebo (saline) administered i.v. before induction of anaesthesia, was studied in 199 women undergoing gynaecological surgery as day cases. Following a standardized general anaesthetic technique, droperidol or metoclopramide significantly reduced the incidence of nausea and vomiting; domperidone decreased the incidence of postoperative nausea alone. The occurrence of extrapyramidal reactions was similar in all groups. Patients treated with antiemetics were no more sedated than those given placebo. Those receiving droperidol complained of significantly less postoperative pain than those who had received domperidone or metoclopramide.

Adolescent↗
PubMed1986

Comparison of the use of domperidone, droperidol and metoclopramide in the prevention of nausea and vomiting following major gynaecological surgery.

Domperidone 20 mg, droperidol 2.5 mg, metoclopramide 10 mg and placebo (saline) were given i.v. 10 min before the end of anaesthesia, to 200 women undergoing major gynaecological surgery, and the incidence of postoperative nausea and vomiting following a standard anaesthetic technique was assessed. Droperidol was significantly more effective than domperidone, metoclopramide or placebo in reducing emetic sequelae. There were no significant differences between the groups in the incidence of extrapyramidal effects and postoperative sedation. Patients given droperidol required less postoperative analgesia than those given domperidone or metoclopramide. It was concluded that, of the drugs studied, droperidol alone was effective in protecting against nausea and vomiting after major gynaecological surgery.

Abdomen↗
PubMed1986

Effects of atropine and glycopyrrolate on cognitive function following anaesthesia and electroconvulsive therapy (ECT).

Memory changes are known to be associated with electroconvulsive therapy (ECT). The anticholinergic drugs used prior to the procedure have also been suspected of causing cognitive deficits. The present study was designed to assess memory and concentration in depressed patients receiving 0.6 mg atropine, 0.2 mg glycopyrrolate or placebo before anaesthesia and ECT. Glycopyrrolate is an anticholinergic agent lacking central nervous system effects. Anaesthesia and bilateral ECT resulted in significant short-term memory deficit, but this was seen equally in each of the groups of patients irrespective of which premedication was given. As no regimen was superior, as far as effect on memory is concerned, premedication for ECT should be chosen according to other criteria.

Adult↗
PubMed1986

Effect of glycopyrrolate and atropine on thermoregulation after exercise.

The effects of two anticholinergic drugs on heat production (derived from oxygen consumption), sweating and core and skin temperature were compared with saline placebo in five healthy volunteers, before and after exercise. There were no significant differences between the groups in resting and peak heat production after exercise. Sweat evaporation rate increased after exercise in all cases, but there was individual variation in response to the drugs. Sweat evaporation was greater after saline placebo compared with atropine, but not after glycopyrrolate compared with saline placebo or atropine. In the saline placebo group, increased sweat evaporation following exercise was reflected by an initial fall, in skin temperature. Following anticholinergic drugs, skin temperature increased after exercise without an initial decrease. Core temperature increased following exercise, but there were no significant differences between the anticholinergic drugs and saline placebo. Although clinical doses of anticholinergic drugs, when compared with saline placebo, inhibited sweating after exercise, core temperature was not significantly increased. Therefore it is suggested that non-evaporative heat loss compensated for the reduction in sweating due to anticholinergic drugs.

Adult↗
PubMed1983

A central site of action for benzamide facilitation of gastric emptying.

Gastric emptying of the fed guinea-pig was measured using a non-invasive X-ray fluoroscopic technique to determine passage from the stomach of polystyrene-coated barium sulphate spheroids. Peripherally administered metoclopramide (0.1-10 mg/kg i.p.), clebopride (1-10 mg/kg i.p.), (-)-sulpiride (40 mg/kg i.p.), haloperidol (1 mg/kg i.p.) and domperidone (1-10 mg/kg i.p.) failed to modify gastric emptying. Stress inhibited emptying, and this was considered to explain the effects of eserine and high dose metoclopramide. Gastric emptying was decreased by peripherally administered atropine (0.5 mg/kg i.p.) and apomorphine (0.1-0.5 mg/kg s.c.); the apomorphine response was antagonised by pretreatment with haloperidol, domperidone, (-)-sulpiride, metoclopramide and clebopride but not by prazosin + propranolol. Gastric emptying was facilitated by intracerebroventricular (i.c.v.) administrations of metoclopramide and clebopride (40, 100 and 200 micrograms) but not by i.c.v. domperidone, haloperidol, fluphenazine or (-)-sulpiride (100, 200 micrograms) and was inhibited by i.c.v. apomorphine (100, 200 micrograms); the response to i.c.v. apomorphine was antagonised by i.c.v. pretreatments with haloperidol, domperidone, (-)-sulpiride, metoclopramide and clebopride (40-50 micrograms). Facilitation of emptying by i.c.v. metoclopramide was prevented by peripheral pretreatment with atropine (0.5 mg/kg i.p.). It is concluded that the actions of apomorphine and metoclopramide/clebopride to respectively inhibit and facilitate gastric emptying may be mediated, at least in part, via central mechanisms. Whilst apomorphine's action may be mediated via dopamine receptor mechanisms, metoclopramide and clebopride act at additional unspecified sites, metoclopramide's action being expressed via cholinergic mechanisms.

Animals↗
PubMedDate not supplied

Development of a blood urea monitoring system for the closed loop control of dialysis.

Optimal hemodialysis prescription through real-time blood urea (BU) monitoring and closed loop control of urea removal would be of significant clinical value. Progress toward a bedside BU analyzer and a control system is described here. An Amicon Minifilter inserted into the arterial bloodline provides a 1 ml/min stream of protein free ultrafiltrate for analysis. In vitro tests with bovine blood have shown excellent correlation between plasma (CP) and ultrafiltrate (CU) urea levels: CP = 0.961CU + 0.071, (n = 34, r = 0.998). In clinical hemodialysis studies, CU accurately represented the decay in CP. The BU analyzer uses a standard UV endpoint assay with a proportioning roller pump. The absorbance of the reacted mixture is read in a spectrophotometer after a 5 min incubation. For future control system design, the transfer function (TF) of the BU analyzer was measured using multifrequency binary testing. The data indicated that the analyzer may be modeled by a second order TF with a pure time delay. The same form of TF was also found to describe the Minifilter. Control of the removal rate of NaCl (substituted for urea) through automatic dialysate flow adjustment has been achieved with a simulated dialyzer-patient circuit (using a conductivity probe in place of the BU analyzer). A modified BU analyzer using computer controlled precision syringes for improved sample processing time and accuracy is also reported.

Animals↗