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Biomedical subjects

M Rosen

Publications and source records attributed to M Rosen.

At least 289 records · Page 16Linked to original sources
PubMed1977

Measurement of carbon dioxide output, alveolar carbon dioxide concentration and alveolar ventilation in the neonate.

A system is described for measuring carbon dioxide output and alveolar carbon dioxide concentration in the neonate and for deriving the volume of alveolar ventilation. Air is drawn through a soft rubber face mask applied loosely to the face so that all expired gas is entrained. A fraction of the flow is sampled by an infra-red analyser, the signal from which is integrated to provide a measure of carbon dioxide output. Alveolar carbon dioxide concentration is measured by continuous sampling of expired gas through a nasal catheter. The response time of the catheter-analyser system is 140 ms. In 20 healthy 1-day-old neonates the mean carbon dioxide excretion was 5.86 ml/min. kg-1 (STPD) and the mean alveolar PCO2 was 4.85 kPa. From these measurements mean alveolar ventilation 147 ml/min. kg-1 (BTPS) was calculated. These results are similar to those obtained by other methods.

Carbon Dioxide↗
PubMed1977

Intramuscular diazepam in labour. A double-blind trial in multiparae.

Diazepam 0.2 mg/kg, diazepam 0.3 mg/kg or a placebo were administered i.m., during labour, in a double-blind fashion to 28 multiparous patients. Although there were no significant differences in the requirements for i.m. pethidine during labour, diazepam was associated with a superior quality of pain relief. Diazepam 0.3 mg/kg i.m. produced no obvious adverse effects upon the neonate.

Clinical Trials as Topic↗
PubMed1977

Correlation of alveolar PCO2 estimated by infra-red analysis and arterial PCO2 in the human neonate and the rabbit.

The performance of an infra-red analyser (Beckman LB-2) in sampling alveolar gas at ventilatory frequencies and volumes occuring in the human neonate has been examined. The optimum sampling flow rate was found to be 300 ml/min; at this flow the 90% response time of the analyser-catheter system was 140 ms. Correlation of estimated alveolar PCO2 and arterial PCO2 was performed in the rabbit which has a ventilatory rate and tidal volume similar to those of the human neonate. There was a good correlation between maximum end-expired PCO2 (PE'CO2) and arterial PCO2 over a wide range of ventilatory rates (10-100 b.p.m.); maximum PE'CO2 was a better index than mean PE'CO2 or alveolar plateau PE'CO2.

Animals↗
PubMed1977

Urinary excretion and metabolism of pethidine and norpethidine in the newborn.

In seven neonates, whose mothers were given pethidine during labour, urine was collected for the first 24-40 h of life. Urinary volume and pH, and concentrations of pethidine and norpethidine in the urine were measured. Urine flow rate was low for the first 7-22 h, and then high for about 12 h. The rate of excretion of pethidine and norepethidine was approximately parallel to the urine flow rate. However, the ratio of the rate of excretion of norpethidine to that of pethidine increased with time and the concentration of norpethidine in urine decreased first and then, after 18 h, increased significantly. These findings that the neonate can metabolize pethidine, although the rate of metabolism is probably less than in the adult. The total amounts of pethidine and norpethidine excreted in the first 24 h after birth were positively related to the dose-delivery interval in the mother for intervals up to at least 5 h. From the data it is estimated that 95% of the total pethidine transferred from the mother would be eliminated by the baby by the 2nd to 3rd day after birth.

Humans↗
PubMed1977

Entonox analgesia--a method of reducing the delay between demand and supply.

Mothers in labour using a self-administered 50% N2O and 50% O2 (Entonox) demand system, experience a time lag between making a demand at the onset of a contraction and pain relief. A practical method is described of reducing this time lag by supplementing the intermittent supply from the demand valve system with a continuous nasal flow of N2O and O2. Consequently a basal arterial N2O tension is maintained and when a demand is made, a higher level of N2O is attained in any time interval compared with that using the demand system alone. In six trained volunteers under laboratory conditions, the N2O levels measured at the mouth on a breath-by-breath basis using a mass spectrometer, showed a substantial and statistically significant reduction in the time taken to attain end-tidal N2O concentrations in the range 10-25%. This method seems worthy of a clinical trial.

Anesthesia, Inhalation↗
PubMed1977

Response to a Valsalva manoeuvre before and after epidural block.

In pregnant patients at term the cardiovascular response to a Valsalva manoeuvre has been evaluated in the lateral and supine positions, before and after epidural block (T8-S5). There was no difference in the pattern of response under these four conditions. After epidural block, there was a tendency to a greater degree of hypotension and a slower recovery. In labour such repeated hypotension could account for the increase in fetal acidosis when the second stage of labour is conducted in the supine position.

Anesthesia, Epidural↗
PubMed1977

The effect of doxapram on fetal breathing in the sheep.

In five ewes of 105 to 120 days gestation intravenous doxapram (1.8 to 3.85 mg/kg) administered to the mother produced a dose-related increase in fetal breathing. This effect of doxapram might prove useful as a test of human fetal health. Fetal breathing movements could be a sensitive indication of the effects of drugs on the human fetal respiratory system.

Animals↗
PubMed1976

Reversal of narcotic depression in the neonate by nalozone.

Naloxone 40 mug was administered intravenously one minute after birth to 20 out of 44 neonates whose mother had been given pethidine in labour. These neonates were compared with 20 others whose mothers had had only lumbar epidural block. Alveolar PCO2, alveolar ventilation, and ventilatory rate were measured 10 and 30 minutes after birth. The untreated neonates of mothers who had had pethidine showed significant ventilatory depression compared with infants in the epidural and naloxone-treated groups. The naloxone-treated neonates were comparable with the epidural group, although the effects of naloxone were diminishing at 30 minutes. Naloxone is an effective narcotic antagonist which should be considered to be the drug of choice for treating narcotic depression in the neonate.

Anesthesia, Obstetrical↗
PubMed1976

Apparatus for patient-controlled administration of intravenous narcotics during labour.

The intermittent intravenous administration of narcotic analgesics had advantages over intramuscular administration, but is often impracticable. The design of a prototype apparatus is described, from which analgesic, pethidine, can be self-administered intravenously during labour. The apparatus consists of a syringe pump and control system from which the patient can demand an increment of analgesic. The minimum interval between increments and the dose of the increment are preset. A demand for analgesia is only successful when the patient passes a reaction-time test, subsequently modified. The apparatus has been used by forty-two mothers in labour. The mean total dose self-administered (2.2 mg/kg) was well within the prescribed limits, suggesting that mothers regulated their demand. The apparatus appears acceptable and safe in labour. The apparatus will probably be of value in comparative studies of analgesics.

Anesthesia, Intravenous↗
PubMed1976

Perinatal mortality after epidural analgesia.

A retrospective survey has been carried out of 6442 births during 1973-1974 in Cardiff. Lumbar epidural block had been administered to the mothers of 13-7% (885) of the births, the principle indication being relief of pain. In the management of the mother special emphasis was laid upon avoiding aorto-caval compression. The perinatal mortality associated with epidural block (14-8 per 1000) was not significantly different from that after other forms of analgesia (19-2 per 1000). There were less first week deaths in babies weighing less than 2-5 kg after epidural block (0 of 45) than in those who had other methods of pain relief (41 of 414) (P = 0-023). The choice of maternal medication did not influence the perinatal mortality rate of the immature baby, but there is a positive but non-significant, trend in favour of epidural block in the premature baby. This improvement in mortality could simply be related to the increased use of forceps delivery associated with epidural block. A controlled trial of epidural block is therefore indicated in the management of the premature fetus. In babies over 2-5 kg, or, those who were immature, epidural block was not associated with a reduction or increase in perinatal mortality.

Adult↗
PubMed1976

The reliability of a linear analogue for evaluating pain.

A linear analogue for rating pain with 10, 15 and 20 cm lines is significantly less variable than a 5 cm line (mean error of 15 cm line is 0-19%, 95% confidence limits for the group +/- 2% and an inood correlation between repeated ratins of a recalled pain distant in time. The variance of the rating is significantly less than the repeated rating of a random mark. The linear analogue rating of a constant pain stimulus is reproducible and changes in rating are likely to be real changes of opinion. Pethidine 150 mg intramuscularly had no significant effect, tested 30 minutes after the administration, on the accuracy or reproducibility of the analogue rating. A linear analogue seems a suitable method of recording the patient's opion of a severe pain such as that of labour.

Adult↗