MAC reduction of isoflurane by sufentanil.

We have shown previously that a plasma fentanyl concentration of 1.67 ng ml-1 reduced the MAC of isoflurane by 50%. By comparing equal degrees of MAC reduction by sufentanil, we may determine the potency ratio of these opioids.

[The art of reasonable combining drugs in anesthesia].

As yet no single intravenous anaesthetic drug can effectively and safely provide hypnosis, analgesia and amnesia. Thus intelligent combinations of hypnotics and opioids are necessary, especially for total intravenous anaesthesia (TIVA). Inescapable interactions occur, most of which are synergistic and should be evaluated for the optimal care of the patient.

Evaluation of flumazenil for reversing the effects of midazolam-induced conscious sedation or general anesthesia.

To evaluate the effectiveness of flumazenil in reversing midazolam-induced conscious sedation and general anesthesia, we gave either flumazenil or placebo to 55 patients in a double-blind manner after surgery. Whether surgery was done under conscious sedation (CS group) or general anesthesia (GA group) depended on the procedure. Recovery was assessed by an Observer Assessment of Alertness and Sedation (OAAS) Scale, Finger-Nose (F-N) test, and picture recall and recognition.

Preliminary pharmacokinetics and pharmacodynamics of an ultra-short-acting opioid: remifentanil (GI87084B).

Remifentanil is a newly synthesized 4-anilido-piperidine with an ester side chain susceptible to esterase metabolism. We evaluated the safety, analgesic efficacy, and pharmacokinetics of remifentanil in 48 male volunteers. Volunteers were randomized to receive increasing doses of remifentanil, alfentanil, or placebo.

Midazolam and fentanyl continuous infusion anesthesia for cardiac surgery: a comparison of computer-assisted versus manual infusion systems.

Continuous infusion of intravenous anesthetics can be achieved either by a manually controlled infusion (MCI) pump, or by a computer-assisted continuous infusion (CACI) pharmacokinetic model-driven infusion system. Randomized double-blind comparisons of the two infusion systems for general anesthesia were performed in 24 patients undergoing coronary artery bypass grafting. Patients were allocated to receive continuous infusions of midazolam and fentanyl by either a MCI device or CACI.

Congenital diaphragmatic hernia: long-term outcome in neonates treated with extracorporeal membrane oxygenation.

As more infants with congenital diaphragmatic hernia (CDH) survive with extracorporeal membrane oxygenation (ECMO), it seems prudent to detail the longterm outcome in these medically complex infants. Eighteen children with CDH-treated with postoperative ECMO were recruited for participation in this study. The mean duration of ECMO was 193 hours (range 82 to 493 hours), mean time to extubation after ECMO was 142 hours (range 34 to 312 hours), and median duration of hospitalization was 46 days (range 30 to 181 days).

Isoflurane minimum alveolar concentration reduction by fentanyl.

Background: Isoflurane is commonly combined with fentanyl during anesthesia. Because of hysteresis between plasma and effect site, bolus administration of fentanyl does not accurately describe the interaction between these drugs. The purpose of this study was to determine the MAC reduction of isoflurane by fentanyl when both drugs had reached steady biophase concentrations.

Plasma concentration of fentanyl, with 70% nitrous oxide, to prevent movement at skin incision.

Background: The Cp50 (minimal steady state plasma concentration of an intravenous analgesic/anesthetic required to prevent a somatic response in 50% of patients following skin incision) and the Cp50-BAR (minimal plasma concentration of an analgesic/anesthetic required to prevent either a somatic, hemodynamic, or autonomic response in 50% of patients following skin incision) have been recently proposed as a measure, like minimum alveolar concentration (MAC; and MAC-BAR), to establish the relative potency of intravenous analgesics. This study was conducted to establish the Cp50 for fentanyl.

Methods: Unpremedicated patients were administered fentanyl (in the presence of 70% N2O) via computer-assisted continuous infusion, a pharmacokinetic model-driven infusion device.

A-3665, a new short-acting opioid: a comparison with alfentanil.

A-3665 is a new short-acting synthetic opioid of the piperidine class. We conducted a double-blind, escalating dose comparison of A-3665 to alfentanil and placebo. Analgesic efficacy was assessed after the administration of A-3665 in increasing intravenous doses (0.

Fentanyl does not alter the "sleep" plasma concentration of thiopental.

Thiopental and fentanyl are commonly combined for induction of anesthesia. The effect of an analgesic concentration of fentanyl on the plasma concentration of thiopental to induce sleep was studied in 46 unpremedicated patients. As a measure of drug effect, sleep (the lack of response to open eyes to a verbal command) was used.

Mortality and morbidity rates among lower birth weight infants (2000 to 2500 grams) treated with extracorporeal membrane oxygenation.

To assess the validity of the currently accepted lower weight limit of 2 kg for treatment of neonates with extracorporeal membrane oxygenation (ECMO), we reviewed the outcome of lower birth weight (2.0 to 2.5 kg, n = 29) and higher birth weight (n = 235) for infants treated with venoarterial ECMO at our institution from 1984 through 1990.

Context-sensitive half-time in multicompartment pharmacokinetic models for intravenous anesthetic drugs.

Elimination half-life is the pharmacokinetic parameter used most commonly to describe duration of pharmacologic action, including that expected of intravenous anesthetic drugs administered by continuous infusion. Little consideration has been given, however, to the relevance of elimination half-life in describing plasma (central compartment) drug concentrations in the context of relevant infusion durations. Therefore, simulations were performed with multicompartment pharmacokinetic models for six intravenous anesthetic drugs.

Use of patient-controlled analgesia to compare the efficacy of epidural to intravenous fentanyl administration.

Fentanyl, unlike morphine, is highly lipophilic and rapidly diffuses out of the epidural space. Respiratory depression is, therefore, unlikely when fentanyl is given epidurally. However, much of fentanyl's analgesic effect is mediated by systemic rather than spinal receptor binding.

Quantitative analysis of regional wall thickening by transesophageal echocardiography.

To develop a method for quantitative analysis of regional left ventricular function from transesophageal two-dimensional echocardiograms, we conducted studies 10 and 20 minutes after induction of anesthesia in 16 patients with normal hearts who were undergoing minor orthopedic operations. Wall thickening was measured with the centerwall method along 100 chords drawn perpendicular to a line constructed around the center of the ventricular wall, midway between the endocardial and epicardial contours. Thickening, either normalized by the length of the end-diastolic perimeter or expressed as a percentage of the end-diastolic wall thickness at each chord, was compared with measurements of endocardial motion.

Reduction of the MAC of desflurane with fentanyl.

Opioids are known to affect the MAC of inhalational anesthetics. We have determined the interaction between fentanyl and desflurane, following a bolus injection of fentanyl at induction in 134 adult patients. Five groups of patients were studied.

Posterior fossa intracranial hemorrhage in infants treated with extracorporeal membrane oxygenation: sonographic findings.

Posterior fossa hemorrhage was documented by autopsy in five infants who had been treated with extracorporeal membrane oxygenation over a 5-year-period. In all five cases, the diagnosis was made prospectively by cranial sonography. Sonographic findings were compared with those in a control group of 15 infants with normal posterior fossae at autopsy.

Clinical responses to ORG 9426 during isoflurane anesthesia.

To determine average dose requirements and pharmacodynamic characteristics before general clinical use, the dose-response curve, onset time, and recovery time for the neuromuscular relaxant ORG 9426 were determined in 72 adult patients given doses of 120, 160, 200, or 240 micrograms/kg after establishment of a steady-state expired isoflurane concentration of approximately 1%. Neuromuscular blockade was continuously recorded using the ulnar evoked electromyogram. Using the log probit method, ED95 was 268 micrograms/kg, ED90 was 251 micrograms/kg, and ED50 was 144 micrograms/kg.

Pharmacokinetic model-driven infusion of fentanyl: assessment of accuracy.

Computer-assisted continuous infusion (CACI) is a pharmacokinetic model-driven infusion device that enables physicians to administer intravenous (iv) drugs in a quantitative fashion, specifying a theoretical blood or plasma concentration. This study evaluated the accuracy of CACI administration of fentanyl using a newly developed CACI device programmed with a well-known set of pharmacokinetic parameters for fentanyl. Patients received diazepam 1 or 2 h before surgery.

Depression of ventilatory responses to hypoxia and hypercapnia after pentamorphone.

Pentamorphone is a novel, potent opiate with rapid onset and short duration of action that has been reported to produce analgesia with limited depression of ventilation. We quantified the effects of pentamorphone (0.08, 0.