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Biomedical subjects

K H Simpson

Publications and source records attributed to K H Simpson.

At least 19 recordsLinked to original sources
PubMed2002

Individual choice of opioids and formulations: strategies to achieve the optimum for the patient.

The role of opioid therapy in chronic musculoskeletal disease continues to be controversial. However, recent years have seen a gradual shift towards the use of opioid therapy in chronic non-malignant pain (CNMP) following recognition that at least a subpopulation of such patients appears to benefit from long-term opioid treatment. Misconceptions about opioids and the associated risk of dependence stemmed from older research that was fundamentally flawed. More recent, rigorous research has yielded clearer statistics on opioid dependence and has highlighted the need for screening to identify individuals who may require closer monitoring during long-term opioid therapy. Controlled-release formulations (oral and transdermal) for the management of steady pain, in conjunction with fast-acting, immediate-release formulations for the management of breakthrough pain, may be available for a wide range of opioid analgesics, providing comprehensive therapy systems for use in CNMP. However, there are no universal criteria that can be confidently used to select CNMP patients who might profit from or be responsive to opioid therapy. Opioid treatment must therefore be individualised for each patient, based on a clear understanding of drug absorption, metabolism, toxicity and binding characteristics, using opioid switching strategies where appropriate. Practical guidelines for opioid therapy in CNMP include regular and systematic checks of treatment results to adjust therapy for each individual patient and to ensure optimum benefit.

Analgesics, Opioid↗
PubMed1996

Prediction of outcomes in 150 patients having microvascular free tissue transfers to the head and neck.

Medical records of 150 patients who had undergone microvascular free tissue transfer to the head and neck (85% for malignancy) were retrospectively assessed to identify predictors of postoperative outcomes and complications. 5% of flaps failed and 20% required re-exploration. Surgical and medical problems occurred in 23% and 67% patients respectively; mortality was 4.7%. 132 records were analysed by logistic regression. Mortality and stroke were commoner in patients with previous myocardial infarction or steroid medication. Chest infection was commoner in men and with increasing age. Hypoxaemia was associated with bronchodilator therapy. Thromboembolism was commoner in patients on diuretics. Nutritional problems were more frequent in patients on opioids, with low weight or hypertension. Donor site infection was related to haemoglobin concentration, cerebrovascular disease, hypertension, opioid consumption or previous radiotherapy. Recipient site infection was associated with hypertension. Flap failure was related to nitrate or bronchodilator treatment. Re-exploration was associated with opioid or bronchodilator therapy. It was concluded that several factors predicted complications and death following microvascular surgery to the head and neck.

Adolescent↗
PubMed1996

An audit of Björk flap tracheostomies in head and neck plastic surgery.

Patients undergoing head and neck surgery for malignancy especially resection of parts of the upper aerodigestive tracts need a secure airway intra- and postoperatively. A tracheostomy is an effective method of achieving this objective. In our unit the Björk flap technique1 has been the preferred type of tracheostomy. Ninety-five consecutive Björk flap tracheostomies performed by one surgeon preceding major head and neck resection for malignancy in patients aged 17-79 years (median = 61 years) were retrospectively evaluated. The technique was quick and provided a secure airway. The tracheostomy tubes were left in situ for a median of 5 days (range 1-17 days). After extubation subsequent stoma closure was uneventful, 60% healing within 1 week. No patient developed tracheal fistula, clinical tracheal stenosis or cosmetically unacceptable scarring. There was no tracheostomy-related mortality. It is concluded that the Björk flap tracheostomy technique can be safely used in head and neck cancer surgery in adults.

Adolescent↗
PubMed1996

Microvascular free-tissue transfers in elderly patients: the leeds experience.

Free-tissue transfer in the elderly has received increasing attention in the literature. Existing reports are limited by small samples or inadequate definition of the term elderly. This study reviewed 5 years' experience with free-tissue transfer in a geriatric population (mean age 75 years, range 70 to 83 years). Forty-nine free flaps were performed in 42 patients between 1986 and 1991. This review focuses on the 39 flaps undertaken in 33 head and neck cancer patients, the main indication being reconstruction after tumor resection (80 percent). In the head and neck cancer group, donor sites included the radial forearm (20), rectus abdominis (6), jejunum (5), and others (8). Thirty-four flaps (87 percent) were primarily successful. Reexploration was required in 10 patients (26 percent) for compromised flaps (5) and bleeding (5). Three of the compromised flaps were salvaged, giving an overall flap success rate of 95 percent. One patient (3 percent) died within 30 days of surgery. These results compare favorably with other published series in elderly patients, as well as with larger cohorts of younger subjects. Free flaps are safe in the elderly. Chronologic age alone should not be an exclusion criterion when selecting patients for free-tissue transfer.

Age Factors↗
PubMed1996

Medical student attrition: a 10-year survey in one medical school.

Medical student wastage leads to adverse emotional and social consequences for individual students and financial difficulties and morale problems for medical schools. This study retrospectively assessed the records of all students at Leeds School of Medicine who left the course prematurely between 1983 and 1992. The demographic data of the leavers were compared with those of all students entering the school during the 10 years studied. A-level examination choices and results of the leavers were compared with those of a control group of all students who entered the school in 1990. The attrition rate over the 10 years was 14% (283 students), with more males than females leaving. Fewer mature students than expected left the course. More leavers had A-level physics and lacked A-level biology compared with the control group. The leavers were academically less able than the controls. Fifty-three per cent of leavers were asked to withdraw from the course for academic reasons; the rest left voluntarily. Thirty per cent had personal problems, 9% had a combination of academic and personal problems and 8% had health problems (psychological difficulties were the commonest). Seventy-one per cent of leavers entered another degree course; science degrees were the most popular. Reasons for medical student wastage and possible solutions are discussed.

Attitude↗
PubMed1996

Clinical pharmacokinetics of ondansetron. A review.

5-HT3 receptors are ubiquitous in the enteric, sympathetic, parasympathetic and sensory nervous systems and in the central nervous system (CNS) (Kilpatrick et al 1990). In man 5-HT3 receptors are mainly situated on enterochromaffin cells in the gastrointestinal mucosa, which are innervated by vagal afferents (Reynolds et al 1989), and the area postrema of the brain stem, which forms the chemoreceptor trigger zone. Ondansetron is a selective antagonist at 5-HT3 receptors. It is 100 times more potent than metoclopramide at this site (Tyers 1992). It shows limited binding to other receptors and has a wide therapeutic window. Ondansetron is a useful antiemetic which probably has both central and peripheral actions in patients undergoing radiotherapy, cytotoxic chemotherapy or general anaesthesia (Naylor & Rudd 1992). This paper reviews the pharmacokinetics of ondansetron in health and disease to provide information for clinicians; it might alter prescribing and alert them to possible drug interactions.

Age Factors↗
PubMed1994

Management of spinal infusions in palliative care.

Spinal analgesia can provide excellent pain relief for a small group of patients in whom conventional modalities have failed. The role of spinal analgesia in the palliative care setting is discussed and illustrated by the experience at St Gemma's Hospice over a two-year period. Special emphasis is placed on the difficulties that may need to be overcome when using this form of analgesia. The management of spinal infusions can produce some unique problems to the hospice or home care team, but the benefits often far outweight the difficulties.

Adult↗
PubMed1992

Concentration of ondansetron in cerebrospinal fluid following oral dosing in volunteers.

This study measured the concentrations of ondansetron in plasma and cerebrospinal fluid (CSF) in six volunteers after oral dosing to steady state. Ondansetron concentrations ranged from 39.5-147 ng ml-1 in plasma and from 2.6-15.4 ng ml-1 in CSF. There was good correlation between plasma and CSF concentrations (r = 0.89, p = 0.017). CSF concentrations were less than 15% of plasma concentrations in all cases, indicating that the rate of penetration of the blood brain barrier by ondansetron is low.

Aged↗
PubMed1992

Effect of addition of hyaluronidase to bupivacaine during axillary brachial plexus block.

We have studied in 22 patients the effect of adding hyaluronidase to bupivacaine during axillary brachial plexus block (BPB) in a double-blind design. Patients received BPB using bupivacaine 2 mg kg-1 with adrenaline 1 in 200,000, either with or without hyaluronidase 3000 iu, in a volume of 0.5 ml per 2.54 cm of the patient's height. The use of hyaluronidase did not increase the speed of onset of anaesthesia or reduce the incidence of inadequate nerve block. Hyaluronidase produced a significant reduction in the duration of anaesthesia. Changes in grip strength and skin temperature were useful in assessing the onset and progress of BPB.

Adult↗
PubMed1992

ECT anaesthetics.

Explore the source record for details and available documents.

Contraindications↗
PubMed1989

Pain on injection of methohexitone. The use of lignocaine to modify pain on injection of methohexitone during anaesthesia for electroconvulsive therapy.

The present study was designed to assess the incidence of pain when methohexitone was administered to 35 depressed patients who had electroconvulsive therapy, and to determine whether the use of lignocaine could modify this, without affecting seizure duration. The same patients were studied during three separate treatment sessions; they received either methohexitone alone or mixed with, or preceded by, lignocaine 10 mg. Six (17%) patients spontaneously complained of pain during injection of methohexitone alone; the use of lignocaine prior to methohexitone reduced this to zero (p less than 0.05). A total of 49% patients reported pain during injection of methohexitone; the use of lignocaine either mixed with, or given prior to, methohexitone significantly reduced this to 23% and 20% respectively (p less than 0.05). Seizure duration was not significantly different during the three treatments.

Adolescent↗
PubMed1989

An investigation of premedication with morphine given by the buccal or intramuscular route.

1. Premedication with 30 mg buccal morphine or 10 mg intramuscular morphine was evaluated in 40 healthy women undergoing major gynaecological surgery. 2. Buccal administration of morphine produced lower plasma morphine concentrations than intramuscular injection of morphine (P less than 0.01). 3. The mean systemic availability of the buccal tablet, during the first 5 h after administration, was approximately 3% relative to that of the intramuscular preparation. 4. Poor absorption of buccal morphine resulted in inadequate sedation prior to surgery and poor post-operative analgesia. 5. Patients experienced difficulty with the buccal formulation of morphine; tablet bitterness and failure to dissolve were particular problems.

Administration, Buccal↗
PubMed1988

Pregnancy delays paracetamol absorption and gastric emptying in patients undergoing surgery.

Gastric emptying may be delayed during pregnancy by hormonally mediated relaxation of the musculature of the stomach and by mechanical effects. In the present study, the rate of paracetamol absorption was used to measure gastric emptying in 14 non-pregnant women undergoing minor gynaecological surgery, and in 28 women undergoing termination of pregnancy. Of the pregnant patients 16 were of 8-11 weeks gestation and 12 were 12-14 weeks gestation. Paracetamol absorption was delayed in those who were 12-14 weeks pregnant compared with non-pregnant controls. Paracetamol absorption in the 8-11 weeks pregnant group was between the other two groups, but was not significantly different from either.

Acetaminophen↗
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↗