Obstetric spinal hypotension: Preoperative risk factors and the development of a preliminary risk score - the PRAM score.

BACKGROUND: Obstetric spinal hypotension is a common and important problem during caesarean delivery. Identifying patients at risk for hypotension may guide clinical decision-making and allow timeous referral. OBJECTIVE: Using preoperative risk factors, to develop a simple scoring system to predict systolic hypotension. METHODS: This prospective, single-centre, observational study of patients undergoing elective or urgent caesarean delivery assessed body mass index, baseline heart rate, baseline mean arterial pressure (MAP), maternal age, urgency of surgery (elective v. non-elective) and preoperative haemoglobin concentration as predictors of spinal hypotension (systolic blood pressure <90 mmHg). We used empirical cut-point estimations in a logistic regression model to develop a scoring system for prediction of hypotension. RESULTS: From 504 eligible patients, preoperative heart rate (odds ratio (OR) 1.02, 95% confidence interval (CI) 1.00 - 1.03; p=0.012), preoperative MAP (OR 0.97, 95% CI 0.95 - 0.98; p<0.001) and maternal age (OR 1.05, 95% CI 1.02 - 1.08; p=0.002) were found to be predictors of hypotension. We derived a preliminary scoring system (pulse rate >90 bpm, age >25 years, MAP <90 mmHg - the PRAM score) for the prediction of systolic hypotension following obstetric spinal anaesthesia. Patients with three factors had a 53% chance of developing hypotension, compared with the overall incidence of 30%. The PRAM score showed good discrimination, with a c-statistic of 0.626 (95% CI 0.576 - 0.676) and good calibration. CONCLUSIONS: Preoperative heart rate, preoperative MAP and maternal age were predictive of hypotension in elective and emergency caesarean delivery. The PRAM score shows promise as a simple, practical means to identify these patients preoperatively, but requires prospective validation.

Heart rate variability as a predictor of hypotension following spinal for elective caesarean section: a prospective observational study.

Post-spinal hypotension remains a common and clinically-important problem during caesarean section, and accurate pre-operative prediction of this complication might enhance clinical management. We conducted a prospective, single-centre, observational study of heart rate variability in 102 patients undergoing elective caesarean section in a South African regional hospital. We performed Holter recording for ≥ 5 min in the hour preceding spinal anaesthesia. The low-frequency/high-frequency ratio component of heart rate variability was compared, using a logistic regression model, with baseline heart rate and body mass index (BMI) as a predictor of hypotension (defined as systolic arterial pressure < 90 mmHg) occurring from the time of spinal insertion until 15 min after delivery of the baby. We also assessed clinically relevant cut-point estimations for low-frequency/high-frequency ratio. Low-frequency/high-frequency ratio predicted hypotension (p = 0.046; OR 1.478, 95%CI 1.008-1.014), with an optimal cut-point estimation of 2.0; this threshold predicted hypotension better than previously determined thresholds (p = 0.003; c-statistic 0.645). Baseline heart rate (p = 0.20; OR 1.022, 95%CI 0.988-1.057) and BMI (p = 0.60; OR 1.017, 95%CI 0.954-1.085) did not predict hypotension. Heart rate variability analysis is a potentially useful clinical tool for the prediction of hypotension. Future studies should consider a low-frequency/high-frequency ratio threshold of 2.0 for prospective validation.

Modern imaging of renal tuberculosis in children.

Renal tuberculosis is relatively uncommon in children. Imaging of renal tuberculosis in children differs from adults in that intravenous urography is rarely performed for urinary symptoms in childhood because of radiation dose considerations. Modern imaging modalities include cross-sectional techniques such as ultrasound, CT and MRI, which successfully show renal, calyceal, ureteric and bladder pathology of renal tuberculosis in children.

Morphology of the human internal vertebral venous plexus: a cadaver study after latex injection in the 21-25-week fetus.

The morphology of the anterior and posterior internal vertebral venous plexus (IVVP) in human fetuses between 21-25 weeks of gestational age is described. The results are compared to the findings of a previous morphological study of the IVVP in the aged. The morphological pattern of the anterior IVVP in the fetus is very similar with the anterior IVVP in the aged human. In contrast, the posterior IVVP in the fetus lacks the prominent transverse bridging veins that are present in the aged lower thoracic and the lumbar posterior IVVP. The background of these morphological differences is unclear. Maybe the thoracolumbar part of the posterior IVVP is subject to "developmental delay," or the observed differences in the aged may result from functional and age-related factors that trigger this part of the vertebral venous system during (erect) life. The observed age related morphological differences of the posterior IVVP support the concept of the venous origin of the spontaneous spinal epidural hematoma (SSEH).

The early experience of general practitioners using Green Prescription.

AIM: Sedentary lifestyle is a significant risk factor for increased morbidity and mortality in many medical conditions. A Hillary Commission initiative, Green Prescription is a written exercise prescription given by general practitioners (GPs) to sedentary patients to encourage physical activity. Our aim was to establish the extent to which GPs in the North Health region in 1997 issued with Green Prescription packages had used them, the circumstances under which they were used, and barriers to their use. METHODS: 433 GPs issued with packs were faxed a one-page questionnaire for immediate completion, with follow-up of non-responders. RESULTS: The response rate was 73%, with 65% of respondents having written Green Prescriptions. Their main reasons for use were patient need for more exercise and presence of high-risk medical conditions such as hypertension, cardiovascular disease, obesity and diabetes. Reasons for non-use were: GP already giving advice about physical activity; concern that Green Prescription was patronising and simplistic; compliance issues and time restraints. Some requested a computerised version. CONCLUSION: Non-responders may be non-users, hence we estimate that 48-65% of targeted GPs used Green Prescription. Barriers identified by GPs have assisted in Green Prescription development, which is now nationwide and assessed by independent researchers tri-annually.