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Query: UMLS:C0278134 (anesthesia)
 110,339 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fentanyl has been shown to increase the overall resistance to inspiratory flow of the ventilatory system (Rmax). Rmax is the sum of the airway resistance (Raw) and of the non-Newtonian resistance (delta R) which may result from the viscoelastic properties of the thoracic tissues, from inequalities of the regional time constants within the lung, or from both. A bronchoconstrictor challenge may increase the magnitude of variation in regional time constants. Thus, in order to describe the effect of fentanyl on the two components of Rmax, this study was performed, with the end-inflation occlusion method, during paralysis and mechanical ventilation in 10 normal men undergoing barbiturate anaesthesia for minor urological procedures. The patients were anaesthetized with methohexitone and paralysed with vecuronium. Before administration of fentanyl, delta R accounted for 56% of Rmax. Fentanyl 5 micrograms kg-1 elicited a significant increase in Rmax (+34.5%; P = 0.005) and a parallel increase in both Raw (+35.2%, P = 0.017) and delta R (+33.5%, P = 0.005). The increase in Raw, but not in delta R, was reversed by atropine, suggesting that the increase in these two components of Rmax was not linked. Thus fentanyl increased both components of Rmax, but the effects of fentanyl on Raw and delta R seemed to depend on different mechanisms.
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PMID:Effect of fentanyl on ventilatory resistances during barbiturate general anaesthesia. 136 57

Whereas the efficacy of flumazenil (Fl) for improving vigilance in the presence of other benzodiazepine agonists (BZA) is undoubted, its effect on BZA- and/or opioid agonists (OA)-induced respiratory depression is the subject of controversies. Some authors describe an improvement of a midazolam (Mi)-induced increase in paCO2, whereas others cannot find any influence on diazepam-induced respiratory depression. In two studies in which Fl was used to antagonize Mi/Fentanyl (Fe) anaesthesia we found even worse oxygen saturation values than with placebo (Pl). All our previous studies indicate a slight intrinsic activity of Fl on respiration in the presence of opioids. We therefore investigated the influence of Fl and Pl on expiratory pCO2 and oxygen saturation (SAT). METHODS. A group of 15 male, healthy volunteers aged 20-30 years gave written informed consent to participate in this double blind study, which was approved by our Institutional Review Board. Each subject received 3 micrograms/kg body wt. Fe + 0.5 mg Fl and 1 week later 3 micrograms/kg body wt. Fe + 5 ml NaCl 0.9% (Pl) i.v., in random order. They were undisturbed and breathed spontaneously. The following parameters were measured: SAT, pCO2 and heart rate (HR) continuously, using a pulse oximeter (SAT, H) and CO2 infrared absorption monitor (Oscar, Messrs., Datex). The blood pressure was recorded before and after a 5-min preinjection period (baseline) and at the end of the procedure (25 min). The data were stored in a microcomputer (Multitalent, Messrs. ZAK) and transmitted to a PC after each trial. STATISTICS. The groups were compared with the Wilcoxon rank sum test. P less than 0.05 is significant. RESULTS. In trials 1 and 2 there was an increase of pCO2 and a drop in SAT. The changes in pCO2 and SAT were more pronounced after Fe+Fl in 12 subjects (80%), as against 1 subject with the opposite result. There were 2 subjects who showed no difference between trials 1 and 2. The combination of Fe and Fl caused significantly higher increases in pCO2 (P = 0.007) and more pronounced decreases in SAT (P = 0.04) than Fe and Pl. DISCUSSION. These results indicate a slight enhancement of Fe-induced respiratory depression by Fl. In a previous study it could be shown that Fl antagonized the respiratory depressive effect of Mi, but baseline paCO2 was not completely recovered. In previous studies respiratory function impaired by Mi+Fe was initially improved by Fl, but rebound effects on SAT were observed, which were more pronounced than those after Pl. Therefore, respiratory function must be closely monitored in Fl-antagonized patients after Mi/Fe anaesthesia.
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PMID:[The action of flumazenil in combination with fentanyl on spontaneous respiration]. 149 27

Cardiovascular physiological studies in anesthetized animals may be confounded by the hemodynamic actions of the anesthetic agents themselves. To identify an anesthetic regimen that does not significantly influence cardiovascular physiology, the hemodynamic responses of 28 dogs were studied. Animals were equally divided among groups with 1) no anesthesia (i.e., trained conscious preparation), 2) pentobarbital sodium, 3) fentanyl citrate, and 4) a combination of morphine sulfate and alpha-chloralose. Anesthesia was maintained for 3 h. Data were acquired with the use of ultrasound imaging of the heart in conjunction with invasive pressure measurements. Left ventricular ejection phase indexes and end-systolic force-velocity relations were used to evaluate the effects of each anesthetic agent on overall systolic performance and myocardial contractility. Compared with the conscious animals, pentobarbital profoundly depressed systolic performance (P less than 0.05 vs. control) because of a reduction in myocardial contractility (P less than 0.01) and an increase in left ventricular afterload (end-systolic wall stress, P less than 0.05). Fentanyl increased myocardial contractility (P less than 0.05) but also tended to increase afterload with the net result that overall systolic performance remained unchanged. Morphine-chloralose did not affect overall ventricular systolic performance or its individual determinants. Pentobarbital and fentanyl also caused progressive time-dependent deteriorations in all parameters of systolic function during prolonged anesthesia. In contrast, cardiac function was stable for greater than or equal to 3 h after induction of morphine-chloralose anesthesia. The hemodynamic profile of dogs anesthetized with morphine-chloralose most closely resembled that of the conscious animals. Morphine-chloralose is recommended when prolonged anesthesia is required for studies of cardiovascular physiology.
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PMID:A time-course study of the effects of pentobarbital, fentanyl, and morphine chloralose on myocardial mechanics. 150 61

In the last two decades, opioid analgesics have assumed an important place in general anesthetic practice in the United States. Part of the reason for this has been the introduction of the potent new agonists fentanyl, sufentanil, and alfentanil. Because of problems with morphine-oxygen anesthesia (incomplete amnesia, occasional histamine-related reaction, marked increases in intra- and postoperative respiratory depression), a suitable alternative was sought but not found among existing opioids. A breakthrough came in 1960, when fentanyl was synthesized, laying the foundation for a better understanding of the structure-activity relationships of narcotic analgesics and stimulating interest in developing compounds with even greater potency and safety margins. Investigators interested in opioid anesthesia began to study fentanyl in animals and then in humans. Fentanyl (50-100 micrograms/kg) with oxygen (100%) was evaluated as an anesthetic in patients undergoing mitral valve and coronary artery surgery. Changes in cardiovascular dynamics with induction doses ranging from 8 to 30 micrograms/kg consisted of small decreases in heart rate and arterial blood pressure. All other cardiovascular variables studied, including cardiac output, remained unchanged, even with additional doses up to 100 micrograms/kg. It was determined that fentanyl had use as a narcotic anesthetic, despite its potential for cardiovascular depression and stimulation, respiratory depression, muscle rigidity, and, occasionally, incomplete anesthesia. Since the introduction of fentanyl, two other potent synthetic opioids have been introduced into clinical practice--sufentanil and alfentanil.
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PMID:The history and development of the fentanyl series. 151 29

Laparoscopic cholecystectomy (LSC) is being performed increasingly often. The carbon dioxide cavity increases end-expiratory carbon dioxide (exCO2), which can be regulated by mechanical ventilation. Because about 20-40% carbon dioxide remains in the patient at the end of surgery, we were interested in its influence on spontaneous respiration. PATIENTS AND METHODS. Fifteen patients classed as ASA 1-2 and undergoing LSC were compared with 15 patients (also ASA 1-2) undergoing laparotomy for cholecystectomy (LAP). All patients had balanced anaesthesia with fentanyl, enflurane, nitrous oxide and vecuronium. After surgery they were extubated when spontaneous respiration and vigilance were adequate. In the next 3 h we continuously determined exCO2 in the expired air through an intranasal catheter, and oxygen saturation (SAT), respiratory rate (RR) and heart rate (HR) using Oscar (Datex) and Ohmeda (Braun) apparatus while the patients were breathing room air. The blood pressure (BP) was determined intermittently. Postoperative pain treatment was standardized. RESULTS. The groups were reduced comparable with respect of the anthropometric data, because the weight was significantly higher in the LAP group. Fentanyl consumption was also significantly higher in the LAP group, reflecting the more pronounced trauma than with LSC. Mean exCO2 was 46 mmHg after LSC and 36 mmHg after LAP (P less than or equal to 0.05), continuously decreasing in the LSC group and increasing in the LAP group to 40 mmHg after 3 h. Mean RR was 18-20.min-1 after LSC and 12-15.min-1 after LAP during this period (P less than or equal to 0.05). There were no differences in SAT (94-96%), HR (75.min-1) and BP (130/80 mmHg). DISCUSSION AND CONCLUSIONS. The remaining carbon dioxide after LSC has important implications for postoperative spontaneous respiration. Probably due to an activation of carbon dioxide receptors, RR is increased to eliminate residual carbon dioxide. This is confirmed by a significantly increased exCO2 compared with that in the LAP group. This effect lasts at least 3 h, exCO2 being comparable in both groups, but RR is still increased after LSC. This different respiratory pattern does not affect SAT, being normal without hypoxic episodes. Cardiovascular parameters were also normal without group differences. We conclude that the carbon dioxide peritoneal cavity has important consequences for postoperative ventilation. Using our anaesthetic technique and postoperative treatment exCO2 reaches normal values after about 3 h due to an increased RR. If other methods, e.g., stronger opioids, which decrease carbon dioxide response are used, this effect may even be prolonged and more pronounced. We are now performing an investigation to evaluate this effect.
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PMID:[The effects of the carbon dioxide pneumoperitoneum in laparoscopic cholecystectomy on postoperative spontaneous respiration]. 848 1

The effectiveness of fentanyl in attenuating the pressor and heart rate response to orotracheal fibreoptic intubation under general anaesthesia was assessed in 60 healthy patients undergoing elective surgery. Patients were randomly assigned to receive either fibreoptic intubation with or without fentanyl 6 micrograms.kg-1 or traditional Macintosh intubation with fentanyl 6 micrograms.kg-1. A standardised general anaesthetic was administered which included temazepam premedication, thiopentone, atracurium, oxygen, nitrous oxide and isoflurane. The pressor response to fibreoptic intubation was suppressed in those patients who received fentanyl and was similar to that seen in the Macintosh-fentanyl group of patients. The heart rate response to fibreoptic intubation was also significantly reduced in the patients who received fentanyl, but, in contrast, was still significantly greater than that in the Macintosh-fentanyl group. Fentanyl 6 micrograms.kg-1 appears to have a useful place in attenuating the cardiovascular effects of fibreoptic intubation under general anaesthesia.
Anaesthesia 1992 Jan
PMID:Effect of fentanyl on the circulatory responses to orotracheal fibreoptic intubation. 153 96

The intraperitoneal injection of anaesthetic agents is a simple and convenient method of anaesthetizing rats. However, all of the anaesthetic combinations in current use which are administered by intraperitoneal injection produce prolonged sedation, and full recovery of consciousness may take several hours. Fentanyl, a mu agonist opioid, and medetomidine, an alpha 2-adrenoceptor agonist were mixed and administered as a single intraperitoneal injection. Combinations of 300 micrograms/300 micrograms/kg and 300 micrograms/200 micrograms/kg of fentanyl/medetomidine were shown to produce surgical anaesthesia in the rat. This anaesthetic regimen produced significant respiratory depression (P less than 0.01) and animals did not regain their righting reflex until 193 +/- 21 min (mean +/- 1 SD) after injection. Administration by intraperitoneal injection of atipamezole, a specific alpha 2-adrenoceptor antagonist (1 mg/kg) mixed with a mu antagonist/k agonist opioid (nalbuphine, 2 mg/kg or butorphanol 0.4 mg/kg), resulted in a rapid (less than 8 min) reversal of anaesthesia and the associated respiratory depression, and apparent full recovery of consciousness.
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PMID:Fentanyl and medetomidine anaesthesia in the rat and its reversal using atipamazole and either nalbuphine or butorphanol. 154 41

Epidural fentanyl is often added to epidural local anaesthetic agents to improve the quality of anaesthesia obtained during Caesarean section. Fentanyl may be given either before or after delivery of the infant. When given before delivery, fentanyl has not been reported to cause neonatal depression, although this remains a concern. A prospective, randomized, double-blind study was undertaken to determine if fentanyl was more effective if given before or after delivery of the baby in 64 women undergoing Caesarean section under lidocaine epidural anaesthesia. Maternal outcome was determined by time to achieve T4 neural blockade, the dose of lidocaine necessary to achieve this block and intraoperative scores for pain, nausea, vomiting, shivering, and sedation. Neonates were assessed by umbilical arterial blood pH and Apgar scores. No differences were detected in either group with respect to maternal or neonatal outcome. We recommend using only epidural local anaesthetic agents before delivery, and giving epidural fentanyl following delivery of the infant.
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PMID:Epidural fentanyl and caesarean section: when should fentanyl be given? 840 64

We measured haemodynamic effects and uptake of enflurane in patients undergoing cardiac surgery utilizing a standard anaesthetic technique of fentanyl 15 mcg/kg nitrous oxide 50%/enflurane 1%. We divided 22 patients preoperatively into two groups according to standard criteria: good and poor myocardial function. Regression lines could be drawn illustrating the relationship of cardiac output and uptake (at 1 minute: r = -0.56, P less than 0.01; at 5 minutes: r = -0.43, P less than 0.05; at 30 minutes: r = -0.31, P = 0.08). Although patients with poor myocardial function had decreased uptake of enflurance (approximately 10-20%), this did not reach statistical significance. Fentanyl/nitrous oxide/enflurane anaesthesia provided stable haemodynamics, even in patients with poor myocardial function. Both groups had a shunt fraction of approximately 10% and an arterial: end-tidal carbon dioxide difference of approximately 3-4 mmHg.
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PMID:Haemodynamic effects and uptake of enflurane in patients undergoing cardiac surgery: good versus poor myocardial function. 160 36

Fentanyl is commonly used as an adjunct to general anaesthesia for day-surgery procedures. We have prospectively studied the effect of this practice on postoperative analgesia in 304 day-surgery patients, 164 undergoing termination of pregnancy and 140 having various other minor gynaecological procedures. Approximately half the patients received fentanyl, the mean dose being 50 mcg. Fentanyl given during anaesthesia had no effect during recovery on analgesic requirements or on nausea or vomiting in either pregnant or non-pregnant patients.
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PMID:Is fentanyl effective for postoperative analgesia in day-surgery? 160 39


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