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Biomedical subjects

V A Clark

Publications and source records attributed to V A Clark.

At least 19 recordsLinked to original sources
PubMed2005

Ephedrine requirements are reduced during spinal anaesthesia for caesarean section in preeclampsia.

BACKGROUND: Despite controversy over the haemodynamically safest blockade for caesarean section in women with severe preeclampsia, an increasing number of anaesthetists now opt for spinal anaesthesia. In a previous study we found that spinal compared to epidural anaesthesia offered an equally safe but more effective option for these patients. The current study was designed to compare the hypotension induced by spinal anaesthesia, as measured by ephedrine requirement, between 20 normotensive and 20 severely preeclamptic but haemodynamically stabilised women. METHOD: Standardised spinal anaesthesia was instituted and ephedrine was given in boluses of 6 mg if the systolic pressure fell >20% from the baseline, or if the patient exhibited symptoms of hypotension. RESULTS: The mean ephedrine requirement of the normotensive group (27.9+/-11.6 mg) was significantly greater (P<0.01) than that of the preeclamptic group (16.4+/-15.0 mg). CONCLUSION: This suggests that the hypotension induced by spinal anaesthesia in women with severe but haemodynamically stabilised preeclampsia, is less than that of normotensive patients.

Adult↗
PubMed2004

Epidural anaesthesia for caesarean section in a patient with quadriplegia and autonomic hyperreflexia.

The anaesthetic management of a pregnant quadriplegic woman with a history of autonomic hyperreflexia is discussed. Autonomic hyperreflexia is a life-threatening complication of high spinal cord transection, for which labour is a well known stimulus. It can lead to uncontrolled hypertension. We discuss the anaesthetic considerations in planning the care of this patient, who was managed for elective caesarean section and post partum hypertension with epidural anaesthesia.

Adult↗
PubMed2002

Supplementary oxygen administration for elective Caesarean section under spinal anaesthesia.

We investigated the necessity for administration of supplementary oxygen to mothers undergoing elective Caesarean section under spinal anaesthesia. Sixty-nine women undergoing elective Caesarean section were randomly allocated to one of three groups to be given either oxygen (40%) by facemask, air by facemask or oxygen at 2 l x min(-1) by nasal cannulae. Umbilical arterial and venous blood samples were taken and analysed immediately after delivery. The results showed that there were no significant differences in the umbilical arterial or venous pH, partial pressure of oxygen and partial pressure of carbon dioxide between any of the three groups. We also assessed the patient acceptability of oxygen administered by facemask vs. nasal cannulae should the need for supplementary oxygen arise. It was found that use of the facemask impeded communication.

Administration, Intranasal↗
PubMed1999

Evaluation of prostate-specific antigen as a quantifiable indicator of condom failure in clinical trials.

The ability of condoms to retain all elements of semen during intercourse has been assessed by postcoital visual inspection and in vitro permeability studies. Yet, these observations may not be sufficiently precise or realistic. This pilot study evaluated prostate-specific antigen (PSA) as a semen marker of inapparent failure of the condom barrier under conditions of actual use. Twelve couples collected samples from the vagina and surfaces of the condom using sterile cotton swabs. We obtained precoital and postcoital samples for 24 acts of unprotected intercourse, 54 acts of intercourse using intact condoms, and 40 acts of intercourse using condoms that had been deliberately punctured. We used electrophoresis to determine the amount of PSA present in the samples. PSA was detected in 100% (24/24) of vaginal samples collected immediately after unprotected intercourse and in none of the vaginal samples collected more than 24 h after intercourse (0/90). PSA was also present in 98% (83/85) of the samples collected from the inside of the condom that had failed during intercourse. Excluding uses where the condom failed during intercourse, PSA was detected in 2% (1/47) of the postcoital vaginal samples collected after use of intact condoms and in 41% (14/34) of the samples collected after use of condoms with known 1-mm punctures. We conclude that PSA shows great promise as a semen biomarker in clinical trials of barrier methods. We recommend that future studies further investigate the ability of this biomarker to identify condom failures and quantify the extent of semen exposure associated with various types of condom failures.

Adolescent↗
PubMed1996

An audit cycle of blood ordering practice in a district maternity unit reduces unnecessary crossmatching.

We audited the appropriateness of blood ordering in our obstetric unit, by analysing the ratio of number of units of blood cross-matched to number transfused (C:T ratio), both overall and for specific indications. Based on this information, we devised a new blood ordering policy, and repeated the audit once this was in operation. The new policy resulted in a substantial increase in the efficiency of blood ordering. The overall C:T ratio fell from 10.9 to 3.0, and there were particularly large falls for caesarean section (from 34.3 to 6.2), high risk labours (from 67.8 to 9.1) and post-partum haemorrhage/retained placenta (from 4.3 to 1.9).

Journal Article↗
PubMed1995

Preoperative oral naproxen for pain relief after day-case laparoscopic sterilization.

Analgesia with preoperative naproxen after laparoscopic sterilization was assessed in a prospective, double-blind, randomized study of 80 women; 42 women received oral naproxen 1 g, approximately 90 min before surgery, and 38 received placebo. Preoperative naproxen did not significantly influence postoperative pain scores, but was associated with a reduction in parenteral opioid administration (P = 0.04).

Adult↗
PubMed1994

Screening asymptomatic patients for colorectal lesions.

PURPOSES: To determine: 1) prevalence of significant colorectal lesions by demographics and risk factors; 2) frequency of 1 and 2 or more lesions by type, location, and size; 3) relation among villous component, location, and size of adenomas; and 4) frequency of nonsignificant lesions among patients with and without significant lesions.; METHOD: One thousand asymptomatic patients, 45 years of age and older, with negative fecal occult blood tests, were screened using 60-cm flexible sigmoidoscopy and, if indicated, using colonoscopy. RESULTS: Thirty-six of the patients had 62 significant lesions (11 patients had 2 or more lesions). Fifty-four of the lesions were discovered by sigmoidoscopy in 1,000 patients, and 8 additional lesions were discovered in 5 of the 36 patients by colonoscopy. Lesions with villous components were more likely to be found in patients with 2 or more lesions (P = 0.0006). Smokers were more likely than nonsmokers to have significant lesions (P = 0.002). Among these patients, smoking and drinking were associated (P = 0.007). Males were more likely to have significant lesions than females (P = 0.006). Hemorrhoids, diverticulosis, and hyperplastic polyps were not associated with significant lesions. CONCLUSIONS: The relationship between smoking and significant lesions provides further evidence that asymptomatic patients should stop smoking. Physicians should pay particular attention to men who smoke, even if they have negative occult blood tests.

Adenocarcinoma↗
PubMed1993

Factors influencing backache following epidural analgesia in labour.

262 obstetric patients received epidural analgesia during labour or for delivery. 6-8 weeks post partum they received a postal questionnaire. No association was found between backache and maternal age, height, weight, parity or mode of delivery, operator or difficulty with epidural insertion. However, in women who had had epidural analgesia, post-partum backache was associated with shorter labours. Difficult epidural insertions were more common in short women.

Journal Article↗
PubMed1993

Blood ordering practices in obstetric units in the United Kingdom.

A postal questionnaire on blood ordering practices and blood availability was sent to 89 randomly selected maternity units within the United Kingdom. The replies demonstrated a wide variation in crossmatching practices. Of those units that replied, 56% crossmatch for elective and 64% for emergency Caesarean section, 54% for manual removal of placenta, and 29% for fetal distress in labour. The remainder 'group and screen' for these indications. Lack of 24 h cover by a resident haematology technician, and location of blood banks distant to the obstetric unit were associated with significant delays in blood availability. More extensive use of the 'group and screen' technique may reduce unnecessary crossmatching without jeopardizing patient safety, and is advocated for maternity units.

Blood Banks↗
PubMed1992

Flexible sigmoidoscopy in asymptomatic patients with negative fecal occult blood tests.

BACKGROUND: Although the American Cancer Society and others have established guidelines for colorectal cancer screening, questions of who and how to screen still exist. METHODS: A 60-cm flexible sigmoidoscopy was performed on 1000 asymptomatic patients, 45 years of age or older, with negative fecal occult blood tests, who presented for routine physical examinations. Patients with clinically significant lesions were referred for colonoscopy. The proportion of lesions that would not have been found if the 24-cm rigid or the 30-cm flexible sigmoidoscope had been used was identified. RESULTS: Using the 60-cm flexible sigmoidoscope, lesions were found in 3.6% of the patients. Eighty percent of the significant lesions were beyond the reach of the 24-cm rigid sigmoidoscope and 37% were beyond the reach of the 30-cm sigmoidoscope. Thirty-six patients with lesions were referred for colonoscopy; additional lesions were found in 14%. A total of 62 lesions were discovered, including tubular adenomas, villous adenomas, tubular villous adenomas (23 of the adenomas with atypia), and one adenocarcinoma. The highest percentage of lesions discovered were in the sigmoid colon and the second highest percentage were in the ascending colon. CONCLUSIONS: The 60-cm flexible sigmoidoscope was able to detect more lesions than either the 24-cm or 30-cm sigmoidoscope when used in asymptomatic patients, 45 years of age and over, with negative fecal occult blood tests. When significant lesions are discovered by sigmoidoscopy, colonoscopy should be performed.

Adenocarcinoma↗
PubMed1991

Demographic and health characteristics of heavy marijuana smokers in Los Angeles County.

The demographic, life-style, and self-reported health characteristics of a convenience sample of 207 male and 70 female, non-Hispanic White, heavy marijuana users in Los Angeles County were compared with those of more representative county and national samples. Consistent with other researchers' findings, heavy marijuana users were found to differ significantly in living arrangements, job stability, and income. Heavy marijuana users did not differ in completed education, self-reported physical health, or use of alcohol and cigarettes. Heavy marijuana users were less likely to be married than nonusers, but reported the same number of close friends with whom they interacted more frequently than same-aged comparison groups. Our findings suggest that heavy marijuana users are not homogeneous, and that female users differ significantly from male users.

Adult↗