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Biomedical subjects

S C Robson

Publications and source records attributed to S C Robson.

At least 181 records · Page 10Linked to original sources
PubMed1993

Spontaneous recovery after severe metabolic acidaemia at birth.

Twenty-two severely acidaemic babies (mean umbilical artery pH 7.00), born at term but not requiring resuscitation, were matched for gestational age, mode of delivery and birthweight with non-acidaemic infants. Skin-puncture pH, PCO2 and base deficit were measured at 1 h of age in the acidaemic group. Mean respiratory and heart rates at 30 and 60 min in the two groups were not significantly different. The improvement in pH and base deficit in the acidaemic group correlated with PCO2 at 1 h of age but not with respiratory rates, heart rates or birthweight. However, all four small-for-gestational age infants and one other showed a significantly smaller rise in pH (mean 0.09) compared with the others (mean 0.33). This was associated with a smaller fall in PCO2 and no change in base deficit and these babies were not identified by clinical observations at 1 h of age. Thus, clinical observations of respiratory and heart rates over the first hour of life did not distinguish babies born with severe metabolic acidaemia and did not identify babies who were less efficient at compensating for the acidaemia.

Acidosis↗
PubMed1993

The use of saline solution as a contrast medium in suspected diaphragmatic hernia and renal agenesis.

OBJECTIVE: Our purpose was to determine the value of saline solution instillation as a contrast medium in suspected congenital diaphragmatic hernia and renal agenesis. STUDY DESIGN: Intrathoracic (n = 3) or intraperitoneal (n = 2) instillation was performed in five cases of suspected congenital diaphragmatic hernia. Amnioinfusion combined with intraperitoneal instillation was performed in five cases of suspected renal agenesis. RESULTS: Instillation clearly demonstrated the diaphragmatic defect in four of the five cases. In the cases with suspected renal agenesis, amnioinfusion led to recognition of a previously unsuspected sirenomelia, and intraperitoneal instillation demonstrated empty renal fossae in four cases. The final fetus with bilateral renal agenesis was thought antenatally to have a contralateral multicystic kidney. CONCLUSIONS: We suggest that intrathoracic or intraperitoneal saline solution instillation is a useful diagnostic procedure in carefully selected cases where confident ultrasonic diagnosis is often difficult and yet would significantly alter management. In cases of severe oligohydramnios amnioinfusion is a complementary procedure. In 80% of cases in this series there was significant improvement in visualization after the procedure.

Amnion↗
PubMed1993

Fetal urine analysis for the assessment of renal function in obstructive uropathy.

OBJECTIVES: The assessment of fetal renal function plays a key role in the evaluation of posterior urethral valve obstruction cases. The aim of our study was to determine the value of several urinary compounds, including beta 2-microglobulin, N-acetyl-beta-D-glucosaminidase, and microalbumin in the assessment of prenatal renal function in cases of posterior urethral valve and their potential role in the selection of such cases for in utero shunting. STUDY DESIGN: A range of urinary compounds was measured, including beta 2-microglobulin, N-acetyl-beta-D-glucosaminidase, and microalbumin in 25 cases of posterior urethral valve obstruction. These cases were divided into four groups based on outcome. The Mann-Whitney test and analysis of covariance were used. RESULTS: Sodium, calcium, and beta 2-microglobulin were the best predictors for fetal survival. beta 2-Microglobulin values > 13 mg/L were almost invariably associated with fatal outcome. CONCLUSION: The estimation of beta 2-microglobulin may help in counseling parents and in selecting cases for in utero shunting.

Acetylglucosaminidase↗
PubMed1993

Toxic hepatic injury is associated with proliferation of portal nerve fibers.

Hepatic innervation is thought to play an important role in the regulation of metabolism. Regenerating liver nodules in cirrhosis have a paucity of nerve fibers. The situation in chronic necroinflammatory and cholestatic liver diseases is unclear. We have therefore evaluated hepatic innervation in toxic hepatitis and non-specific reactive hepatitis. Liver biopsies from 42 patients considered to have chronic toxic liver injury, 25 patients with chronic reactive inflammatory infiltrates and variable degree of hepatic fibrosis and the control group comprising of 23 individuals who had undergone laparotomy for non-hepatic reasons (trauma etc.) and who had entirely normal hepatic histology were studied histologically and immunohistochemically for the presence of nerve fibres. Semiquantitative analysis showed significant proliferation of portal nerve fibers in biopsies confirmatory of toxic liver injury. Assessment of hepatic neural elements may be useful in the differential diagnosis of unspecified liver injury where toxic injury may be implicated.

Adolescent↗
PubMed1993

Incremental spinal anaesthesia for elective caesarean section: maternal and fetal haemodynamic effects.

We have performed serial haemodynamic investigations in 20 women undergoing elective Caesarean section under continuous spinal anaesthesia with a 32-gauge catheter with 0.5% heavy bupivacaine. Cardiac output was measured by Doppler and cross-sectional echocardiography at the aortic valve. Doppler flow velocity waveforms were recorded also from the umbilical artery. A block to T4 or above was achieved in all patients. The median dose of 0.5% bupivacaine administered was 2.0 ml (range 1.5-4.5 ml). Mean cardiac output increased from 7 to 8 litre min-1 after preloading with Ringer lactate solution 1.5 litre and then remained unchanged after injection of bupivacaine. Two subjects developed hypotension, although mean values of arterial pressure and umbilical artery pulsatility index did not change. The median umbilical artery pH was 7.27 (range 6.98-7.32) and there was a significant correlation between pH and the maximum percentage decrease in cardiac output. The results suggest that continuous spinal anaesthesia is associated with greater haemodynamic stability than single bolus spinal injection.

Adult↗
PubMed1993

Phenytoin prophylaxis in severe pre-eclampsia and eclampsia.

OBJECTIVE: To determine plasma phenytoin levels and seizure outcome in women given phenytoin for seizure prophylaxis in severe pre-eclampsia and eclampsia. DESIGN: Prospective observational study comparing two phenytoin loading regimens. SETTING: Two UK teaching hospitals. SUBJECTS: Sixty-seven consecutive women with severe pre-eclampsia and five with eclampsia. INTERVENTIONS: The first 29 women were given a 15 mg/kg intravenous loading dose of phenytoin. The next 43 received 17.5 mg/kg. All were given 500 mg phenytoin 12 h after completion of the loading dose and then 250 mg every 12 h for four doses. MAIN OUTCOME MEASURES: Total plasma phenytoin levels at 30 min, 6 h and 12 h after loading dose, 6 h after first maintenance dose and on days 2 and 3 of maintenance therapy; eclamptic seizures after starting phenytoin. RESULTS: Mean plasma phenytoin levels were higher at 30 min and 6 h after the 17.5 mg/kg loading dose. Nine of 29 (31%) phenytoin levels 30 min after the loading dose were above the therapeutic range in the 15 mg/kg group compared with 26/38 (68%) in the 17.5 mg/kg group (P < 0.01). Six of 27 (22%) phenytoin levels 12 h after the loading dose were subtherapeutic in the 15 mg/kg group compared with 2/38 (5%) in the 17.5 mg/kg group (P < 0.05). Three women, two in the 17.5 mg/kg group, developed seizures after starting phenytoin. All three had plasma levels within the therapeutic range. CONCLUSIONS: Compared with a loading dose of 17.5 mg/kg, loading with 15 mg/kg phenytoin was associated with a lower incidence of high plasma levels at 30 min but a higher incidence of subtherapeutic levels at 12 h. Seizures occur in 2 to 3% of pre-eclamptics despite apparently therapeutic phenytoin levels.

Adult↗
PubMed1993

Serial measurements of circulating tissue plasminogen activator and fibrin(ogen) degradation products predict outcome in gestational proteinuric hypertension.

Gestational proteinuric hypertension (GPH), a major cause of maternal death, may be characterised by hypertension and proteinuria alone or may progress to disturbed coagulation and multiorgan failure. Since the condition can only be reversed by termination of pregnancy, there is a need for reliable indicators of severity. We found circulating levels of tissue plasminogen activator (tPA) (27.98 +/- 2.12 v. 7.17 +/- 0.81 ng/ml, mean +/- SEM), fibrin(ogen) degradation products (FDP) (7.55 +/- 1.99 v. 1.92 +/- 0.47 micrograms/ml) and fibronectin (221 +/- 15.2 v. 120 +/- 15.2 micrograms/ml) to be significantly increased in 21 patients with severe GPH when compared with 21 normotensive, age- and gestational age-matched pregnant controls. More importantly, patients who developed severe GPH showed a progressive increase in tPA and FDP levels with time. This was in contrast to patients who had hypertension and proteinuria alone, in whom tPA and FDP concentrations did not increase. Parallel measurements did not reveal a fall in platelet count or an increase in urinary protein excretion in patients who subsequently progressed to severe disease. Our findings may be of assistance to clinicians faced with the need to prolong pregnancy in patients with GPH in order to ensure fetal viability.

Enzyme-Linked Immunosorbent Assay↗
PubMed1993

Identification of fetal growth retardation: comparison of Doppler waveform indices and serial ultrasound measurements of abdominal circumference and fetal weight.

OBJECTIVE: To compare the serial ultrasound assessment of abdominal circumference (AC) and fetal weight versus single values of umbilical artery pulsatility index (PI) and the aortic-middle cerebral PI ratio in the identification of fetal growth retardation (FGR). METHODS: Serial AC measurements and estimates of weight were obtained in 104 small fetuses in the third trimester of pregnancy. These serial values (expressed as a change in standard deviation [SD] scores) were compared with the final value of AC and estimated fetal weight (EFW), umbilical artery PI, and the aortic-middle cerebral artery PI ratio (all expressed as SD scores) for their ability to predict a reduced neonatal ponderal index, mid-arm circumference-head circumference (HC) ratio, and skinfold thickness. Receiver-operating characteristic (ROC) curves were derived and the ultrasound measurements evaluated by calculating the areas under the ROC curves. RESULTS: Serial estimates of fetal weight resulted in a significantly larger area under the ROC curve compared with the final aortic-middle cerebral PI ratio in the prediction of an abnormal mid-arm circumference-HC ratio and compared with the final AC, EFW, and umbilical artery PI in the prediction of all neonatal morphometric indices. CONCLUSION: In small fetuses, fetal growth failure as determined by the serial assessment of AC and EFW was superior to the final AC and EFW, umbilical artery PI, and the aortic-middle cerebral PI ratio in the prediction of abnormal neonatal morphometry indicative of FGR.

Adult↗
PubMed1993

Ultrasonic estimation of fetal weight: use of targeted formulas in small for gestational age fetuses.

OBJECTIVE: To derive a formula for calculating fetal weight in small for gestational age (SGA) fetuses and to determine prospectively whether the use of such a targeted formula reduces birth weight prediction errors. METHODS: Standard ultrasonic measurements were made in 159 SGA fetuses within 7 days of delivery. Three classes of fetal weight formulas (linear, quadratic, and cubic) were fitted to the data using stepwise regression analysis. Birth weight predictions using these three formulas were then compared prospectively with five previously reported formulas in 187 SGA fetuses. RESULTS: R2 was 0.97 for each of the three derived formulas. The 95% prediction intervals were comparable for the three formulas (eg, cubic model -11.6, 17.8%), and none were statistically superior to previous formulas. Each of the formulas evaluated prospectively had a systematic error and, with the exception of the present study's linear formula, all had percentage errors that varied systematically over the range of actual birth weights. CONCLUSION: Clinically useful birth weight predictions can be made in SGA fetuses, although no particular formula estimates birth weight significantly more accurately than any other.

Birth Weight↗
PubMed1992

Intra-amniotic pressures following vaginal gemeprost prior to first and second trimester termination of pregnancy.

Intra-amniotic pressures were measured following 1 mg gemeprost for cervical preparation before first trimester vacuum aspiration (n = 10) and following 2 mg gemeprost before second trimester dilatation and evacuation (n = 15). Twenty-five women, matched for gestational age and parity, who did not receive gemeprost served as controls. Compared to control values (2-8 mmHg), basal intra-amniotic pressure (IAP) was significantly increased after 1 mg and 2 mg of gemeprost (median 20.0, range 4-45 mmHg, median 20.0, range 8-60 mmHg, respectively). Uterine contractions were recorded in 8 of 10 subjects after 1 mg (median delta IAP 28.0, 95% CI 10.0-42.6 mmHg) and 14 of 15 subjects after 2 mg (median delta IAP 52.5, 95% CI 26.7-60.3 mmHg). Gemeprost produces an increase in uterine contractility which may be additional to cervical softening properties and which may be responsible for the adverse effects of pain and bleeding experienced by some women prior to termination.

Abortion, Induced↗