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Biomedical subjects

M Yaster

Publications and source records attributed to M Yaster.

49 records · Page 3Linked to original sources
PubMed1989

Interaction of fentanyl and pentobarbital on peripheral and cerebral hemodynamics in newborn lambs.

The effects of 3.0 mg.kg-1 fentanyl on cerebral and peripheral hemodynamics alone and when combined with subanesthetic doses of pentobarbital (4.0 mg.kg-1), were studied in 11 unanesthetized, newborn lambs, in whom catheters had been previously inserted. After a control period, drugs were administered at 20-min intervals by intravenous bolus injection. Group 1 animals (n = 5) received fentanyl, pentobarbital, and naloxone (0.01 mg.kg-1), whereas Group 2 animals (n = 6) had the order of fentanyl and pentobarbital reversed. All animals responded to pain (withdrawal to tail clamping) and appeared conscious (eyes open, alert to sound) when either fentanyl or barbiturate was given alone. The combination of drugs, however, produced complete unresponsiveness. All of these effects were reversed by naloxone. Cardiac output did not change after either fentanyl or pentobarbital was administered individually but decreased significantly (29% in Group 1, 21% in Group 2) after administration of the combination of both. Mean arterial pressure and heart rate were unchanged. Cerebral blood flow, oxygen (O2) transport, and O2 consumption did not change after either administration of fentanyl or pentobarbital alone but decreased significantly after both (22%, 30%, 19%, respectively, in Group 1 and 35%, 40%, 38%, respectively, in Group 2). The decrease in cerebral O2 transport nearly paralleled the decrease in cerebral O2 consumption such that the ratio, the fractional O2 extraction, increased slightly. Fentanyl decreased kidney blood flow alone (24%) and in combination with pentobarbital (25%), although pentobarbital did so only when combined with fentanyl.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The pharmacologic management of pain in children.

We have attempted to dispel many of the myths and misconceptions surrounding the use of narcotic analgesics in the treatment of childhood pain. Our hope is that an improved understanding and application of effective and safe therapies will minimize the suffering of the child with acute or chronic pain.

Analgesia, Epidural↗
PubMed1988

Management of pediatric pain with opioid analgesics.

We have attempted to dispel many of the myths and misconceptions surrounding the use of narcotic analgesics in the treatment of childhood pain. Our hope is that an improved understanding and the application of effective, safe therapy will minimize the suffering of the child with acute or chronic pain.

Analgesics, Opioid↗
PubMed1988

Hemodynamic effects of primary closure of omphalocele/gastroschisis in human newborns.

To determine whether they could establish reliable, objective criteria that would predict safe, primary closure of abdominal wall defects (omphalocele/gastroschisis) in newborn infants, the authors measured intraoperative changes in intra-gastric pressure (IGP), central venous pressure (CVP), cardiac index (CI), systolic arterial blood pressure (BP), and heart rate (HR). Eleven neonates, who averaged 2.7 kg (range 1.5-4.1 kg) and 36 weeks gestation (range 30-41 weeks) were anesthetized with fentanyl (7.5-12.5 micrograms/kg), metocurine (0.3 mg/kg), and oxygen. Three infants had defects that were too large to close primarily. Of the eight infants who underwent primary closure, four required re-operation within 24 h because of oliguria or poor peripheral perfusion. Infants who required re-operation had intra-gastric pressures of 20 mmHg or more, a decrease in CI of 0.78 1.min.m2 or more, and an increase in CVP of 4 mmHg or more. Heart rate, BP, and systemic vascular resistance did not differ in infants requiring and not requiring re-operation. The authors conclude that intraoperative measurement of changes in IGP, CVP, and/or CI can reliably predict success or failure of primary operative repair of abdominal wall defects in human neonates.

Abdominal Muscles↗
PubMed1987

Effects of fentanyl on peripheral and cerebral hemodynamics in neonatal lambs.

The effects of fentanyl or cardiovascular function, regional distribution of cardiac output, and the dose required for producing anesthesia were studied in ten previously catheterized, newborn lambs. In addition, the effects of fentanyl on cerebral blood flow and oxygen utilization were examined. Fentanyl in cumulative doses as high as 4.4 mg/kg (average plasma levels of 646 +/- 95 ng/ml, maximum plasma level of 862 ng/ml) did not reliably produce anesthesia as assessed by tail and foot clamping, although it did cause profound respiratory depression. With normocapnia maintained by mechanical ventilation, fentanyl did not alter cerebral oxygen delivery or consumption, and the two remained coupled. Fentanyl did not affect cardiac output, heart rate, or mean arterial blood pressure at the highest dose level, nor did it reduce blood flow to specific organ beds, other than the kidney. Thus, the hemodynamic stability seen with fentanyl in the lamb does not occur at the expense of reduced blood flow to organs, such as the gastrointestinal tract or brain, that are particularly vulnerable in the neonate.

Animals↗
PubMed1987

Penile nerve block for newborn circumcision.

Circumcision in neonates is performed, almost universally, without anesthesia or analgesia. It is associated with pain, crying, agitation, and physiologic stress. Twenty infants receiving penile nerve block for circumcision were compared with ten infants having circumcision without anesthesia. Heart rate and blood pressure rose 34 and 15%, respectively, in unblocked infants, and were unchanged in infants receiving local anesthesia. Oxygen saturation declined 16% in unanesthetized infants compared with 6% in blocked infants (P less than .03). Anesthetized infants were less agitated and cried less. Peak plasma concentrations of the local anesthetic lidocaine averaged 0.51 +/- 0.17 microgram/mL (range 0.1-1.6), well below accepted toxic levels. There were no local or systemic complications.

Blood Pressure↗
PubMed1986

A comparison of nitroglycerin and nitroprusside for inducing hypotension in children: a double-blind study.

Intravenous nitroglycerin (NTG) and sodium nitroprusside (SNP) were compared as hypotensive agents in anesthetized children and adolescents. The drugs were studied in a prospective, randomized, double-blind fashion in 14 patients anesthetized with nitrous oxide: oxygen, morphine, and thiopental. NTG in doses as high as 40 micrograms X kg-1 X min-1 was ineffective at decreasing mean arterial pressure (MAP) below 55 mmHg or causing a decrease in MAP greater than one-third of baseline values. SNP was uniformly successful at inducing hypotension in all patients, including those patients in whom NTG failed. The dose of SNP required to induce hypotension was 6-8 micrograms X kg-1 X min-1. Both NTG and SNP decreased systemic vascular resistance, although SNP did so to a much greater degree than NTG (64% vs. 29%; P less than 0.01). Only SNP increased cardiac index significantly (2.27 +/- 0.35 to 4.44 +/- 1.36; P less than 0.003). Both drugs reflexly increased heart rate, necessitating the use of intravenous propranolol (range from 1 to 3 mg) in all patients. Both drugs produced small decreases in arterial oxygen tension and increases in the average alveolar-arterial oxygen tension gradient (SNP, 44 +/- 13 vs. NTG, 41 +/- 6). SNP use was associated with a slight metabolic acidosis (pH = 7.38 +/- 0.01; base excess [BE] = -6 +/- 1). Neither drug produced any other untoward reaction. SNP appears to be the agent of choice for the reliable and sustained induction of deliberate hypotension in children and adolescents.

Adolescent↗
PubMed1985

Life-threatening airway obstruction as a complication to the management of mediastinal masses in children.

Life-threatening airway obstruction from large mediastinal masses in children poses a difficult diagnostic and therapeutic dilemma, requiring the close coordination of a pediatric surgeon, anesthesiologist, radiologist, and oncologist. To focus on this problem, the anesthetic and surgical management of 50 consecutive children with mediastinal masses treated between 1978 and 1984 were reviewed. Thirty children presented with respiratory symptoms; nine had life-threatening respiratory compromise with dyspnea, orthopnea, and stridor. Thirteen of these symptomatic children had marked compression of the trachea and/or mainstem bronchi on radiographic studies. The tracheal cross-sectional area which was measured by computed tomography was decreased by 35% to 93% of the normal tracheal dimensions in these children. Nonresectable malignant neoplasms including lymphoma, Hodgkin's disease, rhabdomyosarcoma, and neuroblastoma were the eventual diagnoses in 10 of these patients. The other 3 patients were less than 4 years old and had benign lesions. General anesthesia was judged to be prohibitively risky in 5 of 13 patients. The diagnosis was established by node or needle biopsy under local anesthesia, and general anesthesia was deferred until the compromised airway was alleviated by radiation and chemotherapy. General anesthesia with endotracheal intubation was administered to 8 patients, 5 of whom developed total airway obstruction. Using a variety of maneuvers, ventilation was reestablished in all 5 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗