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Biomedical subjects

D R Biehl

Publications and source records attributed to D R Biehl.

16 recordsLinked to original sources
PubMed1991

Pneumocephalus following attempted epidural anaesthesia.

This report describes iatrogenic pneumocephalus in an obstetrical patient following attempted epidural anaesthesia using the loss of resistance technique. On the fourth attempt at epidural injection, an apparent loss of resistance was identified and 5 ml air was injected. The patient complained immediately of severe bifrontal headache followed by emesis. The baby was eventually delivered by Caesarean section, with general anaesthesia and avoiding nitrous oxide. The patient's headache resolved within 24 hr without further sequelae.

Adult↗
PubMed1990

Pulmonary oedema in two parturients with hypertrophic obstructive cardiomyopathy (HOCM).

Two patients with hypertrophic obstructive cardiomyopathy (HOCM) presented for delivery. The first had a repeat Caesarean section with general anaesthesia and the second gave birth vaginally with epidural analgesia. Both patients developed pulmonary oedema in the peripartum period. These cases highlight the delicate fluid requirements of the pregnant patient with HOCM. The fluid management of the parturient is discussed with particular emphasis on the pathophysiology of HOCM. The indications for invasive monitoring are presented.

Adult↗
PubMed1990

The anesthetic management of obstetrical hemorrhage.

This has been a brief overview of the major causes of obstetrical hemorrhage in the parturient. Owing to improved diagnosis and obstetrical care, the risks to both mother and fetus have decreased in the last decade. Constant vigilance is still required, however, if mortality and morbidity are to be further decreased. The role of the anesthesiologist is to provide resuscitation first and anesthesia second. To do this successfully, the anesthesiologist should plan carefully and assume that "worst-case scenarios" will occur, so that he or she will have anticipated problems in advance.

Anesthesia, Obstetrical↗
PubMed1988

Inadvertent epidural administration of potassium chloride. A case report.

A 24-year-old black female presented for repeat elective Caesarean section. The procedure was performed under epidural anaesthesia. Sufentanil 25 micrograms, intended for postoperative analgesia, was inadvertently diluted to 10 ml with 15 per cent potassium chloride (KCl) instead of preservative-free normal saline (0.9 per cent NaCl). This solution was then injected via an epidural catheter into the epidural space at the conclusion of surgery. Two hours after injection of the sufetanil-KCl mixture, the patient had a level of sensory blockade to T1 and diaphoresis above this level. Painful muscle spasms had also developed below T1. One hour later she developed hypertension which required hydralazine 10 mg and labetalol 25 mg IV for treatment. The patient was treated supportively with oxygen. Dexamethasone 10 mg was administered intravenously to reduce spinal cord oedema. Intravenous diazepam 10 mg and meperidine 75 mg were given for sedation and analgesia. Complete recovery occurred within 12 hours.

Adult↗
PubMed1986

Isoflurane potency and cardiovascular effects during short exposures in the foetal lamb.

Isoflurane is a relatively new volatile anaesthetic in clinical practice and increasing use for obstetrical patients might be expected. A previous study demonstrated that a 60-90 minute exposure of the foetus to isoflurane resulted in a significant fall in foetal cardiac output with development of foetal acidosis. To determine the cardiovascular effects of a shorter exposure of the foetal lamb to isoflurane and the potency (MAC) of isoflurane in the foetus, the following study was done. Eleven pregnant ewes were surgically prepared by placing indwelling arterial and venous catheters into the mother and foetus. After a 48-hour recovery period, isoflurane, two per cent in oxygen, was administered to six ewes via a tracheostomy for 30 minutes. Foetal cardiac outputs and regional blood flows were measured by the microsphere method. In five ewes the concentration of isoflurane was varied and MAC determinations were done on both ewe and foetus. Arterial blood levels of isoflurane were used to determine foetal MAC. Exposure to isoflurane resulted in a significant decrease in maternal and foetal mean arterial blood pressures and in foetal heart rate. Exposures up to 30 minutes did not result in foetal acidosis or a significant fall in cardiac output. Maternal and foetal MAC for isoflurane were determined to be 0.86 and 0.34 per cent respectively.

Anesthetics↗
PubMed1985

Spinal cord blood flow following sub-arachnoid lidocaine.

Twelve mongrel dogs were randomized into two equal groups. Cervical, thoracic and lumbosacral spinal cord and spinal dural blood flows were measured using the radioactive microsphere technique. Blood flow determinations were made prior to and 20 and 40 minutes following lumbar subarachnoid injection of: two per cent lidocaine (100 mg) or two per cent lidocaine (100 mg) with 1/25,000 epinephrine (200 micrograms). Dogs receiving subarachnoid lidocaine demonstrated a decrease in mean arterial blood pressure of 23 per cent and 14 per cent (p less than 0.05), while dogs receiving lidocaine with epinephrine had a decrease of 38 and 34 per cent (p less than 0.05) at 20 and 40 minutes respectively. Cardiac index was not significantly changed in either group. Lumbar subarachnoid lidocaine (100 mg) produced a rapid regional dural hyperemia (observed at 20 minutes postinjection) and a delayed regional spinal cord hyperemia (observed at 40 minutes postinjection) which were not observed following the addition of epinephrine (200 micrograms).

Animals↗
PubMed1983

Intrauterine transfusion: kinetics of absorption of donor cells in fetal lambs.

The absorption of red cells from the peritoneal cavity of fetal lambs was studied in 29 pregnant ewes at approximately 120 days' gestation. Onset of absorption was early, absorption was rapid, and virtually complete absorption was shown in 96% of the fetuses by 92 hours after intrauterine transfusion. The mean time to complete 99% absorption was 75.8 hours, about half the time supposed for human fetuses. The rate of absorption and the maximum level of donor cells in the fetal circulation are both directly related to the transfusion volume. The time required to complete absorption does not vary with the volume transfused: The more blood given at intrauterine transfusion, the faster the fetus absorbs it. This study suggests that absorption in the fetus following intrauterine transfusion is very efficient, and may be faster than previously thought.

Absorption↗
PubMed1983

The effect of halothane anaesthesia on the asphyxiated foetal lamb in utero.

In a previous study, we examined the effects of halothane on the normal foetal lamb in utero. The most significant finding was a 33 per cent fall in foetal mean arterial blood pressure (MABP). Cardiac output and placental blood flow were not affected. To determine if the asphyxiated foetus would respond similarly, the following study was performed. Seven pregnant ewes were surgically prepared two days prior to study with maternal and foetal indwelling arterial and venous cannulas. An inflatable occlusion loop was secured around the umbilical cord. On the day of study, a tracheostomy was performed on each ewe. Microspheres were injected into the foetal circulation during the control period. The occlusion loop was inflated to produce foetal asphyxia and microspheres were again injected. The ewe was then anesthetized with halothane; and after 15 minutes, microspheres were injected into the asphyxiated foetus and halothane levels were measured. The asphyxiated foetuses showed a significant rise in MABP, fall in heart rate and fall in cardiac output from control. Blood flow to the brain was significantly increased and flow to the placenta and gut decreased. Exposure of the asphyxiated foetus to halothane resulted in a fall of MABP to control but no significant change in cardiac output or brain blood flow. The mean halothane level in the foetus was 46.0 mg X l-1 or 0.32 vol%. Exposure of the asphyxiated foetus to halothane for 15 minutes does not produce significant further deterioration of the foetal lamb in utero.

Acid-Base Equilibrium↗
PubMed1983

The uptake of isoflurane by the foetal lamb in utero: effect on regional blood flow.

Because isoflurane has recently been approved for clinical use in anaesthesia, we have studied the effect of this agent in the foetus using the pregnant ewe as an animal model. Eight pregnant ewes of 120-125 days gestation were surgically prepared with indwelling catheters and tracheostomy. Prior to anaesthesia, labelled microspheres were injected into the foetal circulation to determine cardiac output and regional blood flows to all organs. The ewes were anaesthetized with a constant inspired concentration of 2.0 per cent isoflurane in oxygen. Blood samples were drawn to construct an uptake curve for both mother and foetus. At 60 and 96 minutes of anaesthesia, microspheres were injected into the foetal circulation to measure changes in organ blood flow from the control period. Isoflurane crossed the placenta and appeared in the foetal circulation within two minutes. By 96 minutes, maternal and foetal arterial levels were 116.3 +/- 9.9 and 99.3 +/- 9.1 mEq/L (0.98 vol% and 0.75 vol%). There were no significant changes in foetal blood pressure or pulse rate but foetal pH decreased significantly from 7.39 +/- 0.02 to 7.26 +/- 0.2 (mean +/- SEM) and base excess decreased from -1.1 +/- 1.5 to -6.2 +/- 0.7. Foetal cardiac index decreased from 390.8 +/- 26.9 ml X kg-1 X min-1 to 292.0 +/- 13.8 after 96 minutes of anaesthesia. There were no significant changes in any of the maternal cardiovascular or acid-base parameters.

Animals↗
PubMed1983

Effect of halothane on cardiac output and regional flow in the fetal lamb in utero.

We studied the effect of halothane on the fetal cardiovascular system of six lambs in utero by measuring fetal heart rate and femoral arterial blood pressure and by injecting labeled microspheres during a control period and again after 60 and 90 min of halothane anesthesia administered to six pregnant ewes at an inspired concentration of 1.5%. There were no significant effects on maternal cardiovascular function or acid-base balance, but fetal blood pressure decreased significantly by 27% after 8 min of halothane anesthesia and remained at this level for the duration of the experiment. However, there were no significant changes either in fetal regional blood flow to the vital organs or in fetal cardiac output. Fetal oxygenation and acid-base status remained stable. We conclude that in normal fetal lamb in utero the decrease in mean fetal arterial blood pressure associated with maternal halothane anesthesia is due to a decrease in peripheral vascular resistance because regional blood flow and acid-base status are well maintained.

Anesthesia, Inhalation↗
PubMed1979

Dopamine treatment of spinal hypotension decreases uterine blood flow in the pregnant ewe.

In seven pregnant ewes, 3--5 min of hypotension resulting from spinal anesthesia decreased uterine blood flow 17 per cent. Dopamine, in doses sufficient to maintain blood pressure at control values (20--40 micrgram/kg/min) for 3--5 min, further decreased uterine blood flow to 56 per cent less than control and increased uterine vascular resistance to 50 per cent more than control. Following 30 min of hypotension, 30 min of dopamine administration in doses sufficient to restore blood pressure to control values (5--20 microgram/kg/min) similarly decreased uterine blood flow to 29 per cent less than control and increased uterine vascular resistance to 35 per cent more than control.

Anesthesia, Spinal↗
PubMed1978

Dopamine administration in the normotensive pregnant ewe.

Dopamine was administered to pregnant ewes at randomly selected rates of 1, 3, 5, 10, 20, 30, or 40 microgram/kg/min. Doses less than 10 microgram/kg/min produced no significant change in maternal areterial blood pressure, cardiac output, or renal or uterine blood flow. Higher doses increased maternal cardiac output and blood pressure, did not change renal blood flow, but decreased uterine blood flow. Dopamine consistently caused mild maternal and fetal respiratory acidosis.

Animals↗