PubMed Health⌕ Search

Biomedical subjects

P I Allen

Publications and source records attributed to P I Allen.

12 recordsLinked to original sources
PubMed1994

Improving the preregistration experience: the New Zealand approach.

There is currently much debate about how to improve undergraduate medical education, and in particular on how best to prepare students for clinical responsibility. For 20 years a period of trainee internship has formed part of New Zealand medical students' undergraduate training, and the model could have much to offer the United Kingdom. Students take their final examinations at the end of the second clinical year; they spend their final year in a series of eight clinical attachments, during each of which they shadow a preregistration house officer or senior house officer. As trainee interns they are paid 60% of a house officer's salary for their clinical work, which is supervised by the firm's registrars and consultants under the overall responsibility of the head of the academic department. The order of the attachments is determined on educational, not service, grounds, and trainees have to attend educational sessions and pass assessments on each attachment. The trainee internship, funded jointly by the education and health departments, offers a more seamless transition from student to house officer and aims at improving both general medical education and clinical training.

Clinical Clerkship↗
PubMed1990

Anastomosis: a craft workshop for surgical trainees.

Surgery is a very personal exercise and no two surgeons use an identical technique. Traditionally, operative expertise has been acquired through a system of apprenticeships. Pettigrew has shown that operative performance is the main factor in determining postoperative complications and therefore the length of hospital stay, and surgical journals have recently returned to technique as a topic of debate. Certain skills, such as knot tying, can be learned and tested outside the operating theatre, and this has been extended to craft workshops dealing with more complex procedures, including fracture fixation. This article describes an anastomosis workshop held in New Zealand recently for general surgical trainees.

Anastomosis, Surgical↗
PubMed1988

Human gastric perfusion: evidence for non-uniformity of blood flow.

Post-mortem injection studies have demonstrated marked differences in the course and distribution of arterioles in the stomach, but evidence of differential perfusion in man is lacking. Using the non-invasive laser Doppler technique, we studied 38 patients referred for gastroscopy for dyspeptic symptoms. Flux measurements were made at nine sites: distal oesophagus, cardia, mid-body and antrum on lesser and greater curves, and pre- and post-pylorus. In all cases the stomach was macroscopically normal. Flux in the proximal stomach was significantly greater than that in the antrum, (P less than 0.001, Student's t test). This in vivo study demonstrates a flow gradient related to the previously demonstrated anatomical differences.

Blood Flow Velocity↗
PubMed1988

Screening for abdominal aortic aneurysm.

Most abdominal aortic aneurysms are asymptomatic, but rupture is usually fatal. Elective surgery is now a relatively safe procedure, even in the elderly. Screening to identify those harbouring an aneurysm may allow preventive surgery to be offered. To be cost-effective a population at particular risk must be selected and factors predisposing to aneurysm formation include advancing age, hypertension, arteriosclerosis and family history. The screening technique selected should be acceptable to the population, accurate and rapid. Clinical examination and abdominal radiography are both less accurate than ultrasound examination by experienced personnel. Preliminary studies have confirmed a reasonable diagnostic rate.

Aged↗
PubMed1987

Non-invasive endoscopic technique to assess gastrointestinal perfusion.

Changes in mucosal blood flow may occur in many gastrointestinal disorders, but assessment is impossible without a non-invasive in vivo technique. We have compared endoscopic laser Doppler (LD) with oxygen electrode (OE) measurements in a dog isolated colon preparation, using variable perfusion measured with an electromagnetic flow probe. At maximum flow, LD measurements were made at three sites to compare mucosal with serosal readings. Flow rate was varied (1-38 ml/min) and measurements of microcirculatory flux obtained using LD, and of oxygen tension using a serosal OE. A progressive trend towards increasing flux was demonstrated from caecum to rectum-serosa: 46.8 +/- 18.7 V (caecum), 52.6 +/- 17.9 V (mid-colon) and 61.3 +/- 17.6 V (rectum). A parallel trend was observed in mucosal values: 41.1 +/- 18.2 V (caecum), 45.7 +/- 15.2 V (mid-colon) and 54.1 +/- 15.1 V (rectum). At all sites, serosal and mucosal values were not significantly different (Student's t test). LD serosal values correlated significantly with EM flow (r = 0.544, 0.01 greater than P greater than 0.001). A similar linear correlation was found between OE and EM flow (r = 0.65, P less than 0.001). Oxygen tension measurements varied as expected with microcirculatory flux (r = 0.441, 0.02 greater than P greater than 0.01). Endoscopic LD assessment of colonic microcirculation accurately reflects changes in blood flow.

Animals↗
PubMed1987

Skin blood flow: a comparison of transcutaneous oximetry and laser Doppler flowmetry.

In normal limbs skin blood flow (SBF) falls on standing, but in ischaemic limbs there is a characteristic blush on dependancy. We studied the effect of changing posture in a range of ischaemic limbs, using two non-invasive techniques--laser Doppler (LD) and transcutaneous oximetry (TcPO2). Warmed TcPO2 and LD probes were placed over the first metatarsal cleft and SBF recorded with the limb horizontal, dependant and elevated. Ankle to brachial pressure ratios (A:B) were also measured. Twelve patients with lower limb ischaemia, mean A:B ratio 0.5 +/- 0.21 (+/- S.D.) were compared with 21 asymptomatic controls, mean A:B ratio 1.2 +/- 0.15. In the controls, neither TcPO2 nor LD values changed significantly with limb position. Both flux and oxygen tension were significantly lower in ischaemic limbs in all positions; on lowering the ischaemic limb, flux unexpectedly rose to 23.5 +/- 17.7 V from a mean of 14 + 9.0 V (horizontal). Both TcPO2 and LD correlated well with A:B ratio in two positions: horizontal r (TcPO2) = 0.73, r(LD) = 0.57; elevated r(TcPO2) = 0.78, r(LD) = 0.68. Overall there was a highly significant correlation between LD and TcPO2 (r = 0.6, P less than 0.001, Student's test), but this was strongest in the elevated position (r = 0.87, P less than 0.001). LD and TcPO2 relate to A:B ratio and to each other, particularly in the stressed limb; in the well perfused limb, the poorer correlation suggests skin perfusion is not linearly related to tissue oxygen tension.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

Laser Doppler assessment of skin blood flow in arteriopathic limbs.

In severely ischaemic lower limbs, the skin response to changing posture from lying to standing is a diagnostic flush. We investigated this observation by measurements of the microcirculation using the non-invasive laser Doppler technique. Eleven patients with ankle: brachial pressure (A:B) ratios less than 0.7 were compared with 13 age-matched controls (A:B ratios greater than 1). In normal subjects, mean horizontal skin blood flow (SBF) was 30.2 +/- 14.9 (+/- SD), significantly greater than mean SBF in the ischaemic group: 12.4 +/- 9.2 (P less than 0.01, Student's t test). Mean SBF fell in the normal group on dependency to 27.5 +/- 16.4 but this change was not significant. Unexpectedly mean SBF rose in the ischaemic limbs to 20.7 +/- 13.8 (P less than 0.05). The pattern of SBF response to change in posture is different in normal and arteriopathic limbs.

Aged↗
PubMed1987

Rectal carcinoma: a new technique to allow safer postoperative irradiation of the pelvis.

Local recurrence after abdomino-perineal excision of the rectum for Dukes C carcinoma is common. The influence of postoperative radiotherapy in reducing this is currently under investigation, and one of the potential complications is radiation damage to the small bowel. This paper describes a simple and quick method of excluding the small bowel from the pelvis which, combined with more sophisticated radiation field planning, could dramatically reduce the incidence of enteric effects.

Adenocarcinoma↗
PubMed1985

Dissociation between emotional and endocrine responses preceding an academic examination in male medical students.

A study was made in 2 consecutive years of the emotional states and morning and afternoon serum levels of prolactin, cortisol and testosterone of male medical students during a 4- to 5-week period preceding a major university examination. 'Distress', 'anxiety' and, to a lesser degree, 'depression' increased during the 2 weeks immediately preceding the examination and were positively correlated with personality anxiety or neuroticism traits. Group means for hormones showed no consistent change over the same period. Neither was there evidence for a correlation between endocrine and emotional changes within individual students during the pre-examination period. A restricted study showed that there were significant increments in cortisol in samples taken during the examination itself. Changes in emotional state before an examination occurred in the absence of equally dramatic changes in levels of the three hormones studied, though this relationship may have altered during the examination itself. This suggests that the factors controlling the two categories of response may relate differently, in some way, to the imminence of this stressful event.

Adult↗