Richard J. Palahniuk

University of Minnesota

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Maternal halothane anesthesis reduces cerebral blood flow in the acidotic sheep fetus.

PubMed (1980)

Richard J. Palahniuk George A. Doig Garry N. Johnson Michael P. Pash

Cerebrovascular autoregulation is lost during fetal asphyxia as cerebral vessels undergo compensatory vasodilation. In such a situation, maternal anesthetics, which decrease fetal arterial blood pressure and cardiac output, may further aggravate cerebral hypoxia. To examine this possibility, we prepared six pregnant ewes in such a manner as to be able to measure fetal regional cerebral blood flow in utero during acidosis produced by partial umbilical cord compression both before and after 15 minutes of halothane anesthesia given to the mother. Umbilical cord compression in the absence of anesthesia caused fetal metabolic and respiratory acidosis as evidenced by a decrease in arterial pH from 7.34 to 7.05; fetal arterial oxygen saturation simultaneously decreased from 29 to 17%. Halothane anesthesia administered to the mother of the acidotic fetus caused further aggravation of fetal acidosis (arterial pH 6.85) and oxygen desaturation (10%) and the fetus became markedly hypotensive. Blood flow to four cerebral areas increased 27 to 69% above control levels in the fetus during acidosis in the absence of maternal anesthesia but decreased to levels 30 to 42% below acidosis values when maternal anesthesia was combined with fetal acidosis. These data suggest that potent cardiovascular depressant anesthetics administered to the mother in the presence of fetal acidosis could decrease fetal cerebral oxygen delivery by interfering with fetal cardiovascular compensation during acidosis and reducing fetal cerebral blood flow.

Respiratory acidosis

Umbilical artery

Hypoxia

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Citations (12)

Update on obstetrical anaesthesia

Canadian Anaesthetists Society journal / Journal de la Société canadienne des anesthésistes (1986)

Diane R. Biehl Richard J. Palahniuk

Casual

Mistake

Specialty

10.1007/bf03010839

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Citations (1)

Paresthesias and Motor Dysfunction After Labor and Delivery

Obstetric Anesthesia Digest (1987)

B. Y. Ong Marsha M. Cohen A. Esmail M. Cumming R. Kozody

Ong, B. Y.; Cohen, M. M.; Esmail, A.; Cumming, M.; Kozody, R.; Palahniuk, R. J. Author Information

10.1097/00132582-198710000-00007

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Citations (0)

PRESSURE PASSIVE CEREBRAL BLOOD FLOW AND BREAKDOWN OF THE BLOOD‐BRAIN BARRIER IN EXPERIMENTAL FETAL ASPHYXIA

Acta Paediatrica (1979)

H. Lou Niels A. Lassen W. A. Tweed Garry N. Johnson Michael Jones

Cerebral blood flow (CBF) was studied in non-exteriorized near-term sheep fetuses using the radioactive microsphere technique. By partially occluding the umbilical vessels for a period of 1--1 1/2 hours a progressive and severe asphyxia with a final arterial pH of 6.90 was achieved. Varying the mean arterial blood pressure in the fetuses by blood withdrawal or infusion in this state, CBF was measured at different perfusion pressures (mean arterial blood pressure (MABP) minus central venous pressure (CVP)). A passive flow/pressure relationship--loss of autoregulation--was found, with hyperemia reaching CBF values up to 6 times normal at normal MABP of about 60 to 70 mmHg, and severe ischemia reaching CBF values close to zero in large cortical areas at MABP of 30 mmHg. CVP remained essentially unchanged at 10--15 mmHg. The severe and prolonged asphyxia rendered the blood-brain barrier leaky to the albumin tracer Evans blue. In four other fetuses umbilical cord clamping was omitted. However, only in one of these cases was acidosis completely avoided, and CBF autoregulation maintained. The three other fetuses were acidotic at the end of the surgical procedure and had impaired autoregulation.

Perinatal asphyxia

10.1111/j.1651-2227.1979.tb04430.x

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Citations (158)

Lorazepam and diazepam as adjuncts to epidural anaesthesia for caesarean section

Canadian Anaesthetists Society journal / Journal de la Société canadienne des anesthésistes (1982)

B. Y. Ong Brian Pickering Richard J. Palahniuk M. Cumming

Lorazepam

10.1007/bf03007945

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Citations (13)

Maternal Halothane Anesthesia Reduces Cerebral Blood Flow in the Acidotic Sheep Fetus

Anesthesia & Analgesia (1980)

Richard J. Palahniuk George A. Doig Garry N. Johnson Michael P. Pash

Cerebrovascular autoregulation is lost during fetal asphyxia as cerebral vessels undergo compensatory vasodilation. In such a situation, maternal anesthetics, which decrease fetal arterial blood pressure and cardiac output, may further aggravate cerebral hypoxia. To examine this possibility, we prepared six pregnant ewes in such a manner as to be able to measure fetal regional cerebral blood flow in uteri during acidosis produced by partial umbilical cord compression both before and after 15 minutes of halothane anesthesia given to the mother. Umbilical cord compression in the absence of anesthesia caused fetal metabolic and respiratory acidosis as evidenced by a decrease in arterial pH from 7.34 to 7.05; fetal arterial oxygen saturation simultaneously decreased from 29 to 17%. Halothane anesthesia administered to the mother of the acidotic fetus caused further aggravation of fetal acidosis (arterial pH 6.85) and oxygen desideration (10%) and the fetus became markedly hypotensive. Blood flow to four cerebral areas increased 27 to 69% above control levels in the fetus during acidosis in the absence of maternal anesthesia but decreased to levels 30 to 42% below acidosis values when maternal anesthesia was combined with fetal acidosis. These data suggest that potent cardiovascular depressant anesthetics administered to the mother in the presence of fetal acidosis could decrease fetal cerebral oxygen delivery by interfering with fetal cardiovascular compensation during acidosis and reducing fetal cerebral blood flow.

Respiratory acidosis

Umbilical artery

Hypoxia

10.1213/00000539-198001000-00008

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Citations (13)

Maternal and Fetal Cardiovascular and Acid–Base Changes during Halothane and Isoflurane Anesthesia in the Pregnant Ewe

Anesthesiology (1974)

Richard J. Palahniuk Sol M. Shnider

To determine the nature and extent of fetal metabolic changes during administration of inhalation anesthesia to the mother, the authors studied maternal and fetal cardiovascular and acid-base changes during general anesthesia with halothane and isoflurane in 16 near-term pregnant ewes with chronical

10.1097/00000542-197411000-00010

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Citations (127)

Kidney Transplantation

International Anesthesiology Clinics (1991)

Kumar G. Belani Richard J. Palahniuk

Department of Anesthesiology B515 Mayo Memorial Building, Box 294 420 Delaware Street, SE University of Minnesota Medical School Minneapolis, MN 55455 Department of Anesthesiology, B515 Mayo Memorial Building, Box 294, 420 Delaware Street, SE, University of Minnesota Medical School, Minneapolis, MN 55455

Immunosuppression

10.1097/00004311-199122000-00003

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Citations (22)

Effectiveness of Preoperative Sedation With Rectal Midazolam, Ketamine, or Their Combination in Young Children

Anesthesia & Analgesia (1992)

David S. Beebe Kumar G. Belani Pi‐Nian Chang Peggy S. Hesse James S. Schuh

To determine which of three types of rectal sedation was most effective preoperatively in facilitating parental separation and intravenous cannulation in young children, 100 children 3.0 ± 1.7 (mean ± SD) yr of age were randomly assigned to four equal groups. One group (M-K-A) received rectal midazolam (0.5 mg/kg), ketamine (3 mg/kg), and atropine (0.02 mg/kg). The other sedation groups received the same doses of midazolam and atropine (M-A) or ketamine and atropine (K-A) alone, and the control group (A) received only rectal atropine. Most children in either the M-K-A (100%) or M-A (92%) groups separated easily from their parents without struggling or crying, significantly more than in the K-A (60%) or A (64%) groups. However, more children in the M-K-A group (44%) were asleep during separation than in the M-A group (8%; P < 0.05). Only 20% of the children in the M-A or M-K-A groups cried during intravenous catheter placement, significantly less than in the K-A (56%) or A (92%) groups. Intravenous catheter placement was also successful significantly more often in the M-A (80%) and M-K-A (84%) groups than in the K-A (48%) or A (40%) groups. Complications were similar among the groups, but there was evidence that midazolam prolonged recovery time in some patients. Rectal midazolam with or without ketamine is a useful technique when intravenous catheter placement before induction of anesthesia is desired.

Midazolam

10.1213/00000539-199212000-00003

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Citations (70)

Pregnancy Decreases the Requirement for Inhaled Anesthetic Agents

Anesthesiology (1974)

Richard J. Palahniuk Sol M. Shnider Edmond I. Eger

The effects of pregnancy on requirements for inhalation anesthetic agents were evaluated. The minimum alveolar concentrations (MAC) of halothane, methoxyflurane, and isoflurane needed to prevent movement in response to a standard stimulus were determined in six pregnant and six nonpregnant ewes. Pre

10.1097/00000542-197407000-00021

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Citations (219)