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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To establish anesthesia with minimal respiratory and cardiovascular depression using propofol, the effects of varying the rate of delivery on anesthetic induction dose requirements and hemodynamic changes were studied in four groups of 20 patients each undergoing body surface surgery. All patients were premedicated with temazepam and received 1.5 micrograms/kg fentanyl 5 min before induction. Propofol was delivered at 50, 100, or 200 mg/min by the Ohmeda 9000 infusion pump (groups 1, 2, and 3, respectively) or by bolus of 2 mg/kg (group 4) until loss of verbal contact. Anesthesia was maintained thereafter with propofol infused at 6 mg.kg-1.h-1. Using slower infusion rates, induction took significantly longer (124, 92, 62, and 32 s in groups 1, 2, 3, and 4, respectively) and was achieved with significantly smaller doses of propofol (1.40, 1.96, 2.61, and 2.15 mg/kg in groups 1, 2, 3, and 4, respectively). Slow infusion (groups 1 and 2) caused less depression of systolic and diastolic blood pressure than rapid infusion (groups 3 and 4), but the differences were not statistically significant. Patients in groups 3 and 4 had significantly greater decreases in pulse rate and a greater incidence of apnea than did patients in group 1. There was no correlation between the size of the induction dose and subsequent maintenance requirements of propofol. The finding that the sleep dose of propofol is reduced at slower infusion rates has important practical and theoretical implications when considering the relative potencies of intravenous anesthetics.
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PMID:Rate-dependent induction phenomena with propofol: implications for the relative potency of intravenous anesthetics. 173 65

We have investigated the effects of propofol anaesthesia on the metabolic activity pattern of 35 regions of the rat brain and cervical spinal cord using the 14C-2-deoxyglucose technique. Anaesthesia was produced by an i.v. bolus of the commercial preparation of the drug (8 mg kg-1) and maintained with successive bolus administrations of 6 mg kg-1. Functional activity values (expressed as rates of local utilization of glucose) were reduced in 31 grey matter and two white matter structures in a propofol group relative both to saline-injected and vehicle-injected (aqueous emulsion containing 10% soya bean oil, 1.2% egg phosphatide and 2.25% glycerol) controls. Values from the two control groups did not differ significantly. Propofol-induced depression of metabolic activity was present in central nervous system regions belonging to sensory (auditory, visual and somatosensory), motor and limbic systems, including spinal cord grey matter. Mean percentage decreases ranged from 40% (vestibular nuclei) to 76% (cingulate cortex). Although these values may be slightly overestimated because of the modest increase in PaCo2 in the anaesthetized group, propofol appeared to elicit generalized reduction of central nervous system functional activity.
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PMID:Brain and spinal cord metabolic activity during propofol anaesthesia. 202 77

Propofol is a new intravenous anaesthetic agent chemically unrelated to barbiturate, steroid, imidazole, or eugenol agents. It is available as 1% solution in an aqueous solution of 10% soya bean oil, 2.25% glycerol and 1.2% purified egg phosphatide. The desirable features of the drug are rapid, clear emergence from anaesthesia, lack of cumulation, lack of effect on adrenal steroidogenesis, and has no adverse effect on liver and renal function. In emulsion form, it does not release histamine, nor has it been associated with anaphylactoid reactions. Although, it causes pain on injection, it infrequently results in phlebitis or thrombosis. It causes hypotension and respiratory depression during induction. The induction dose in healthy adults is 2-2.5 mg/kg. Older or debilitated individuals require less propofol for induction.
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PMID:Pharmacology of propofol. 202 66

Isolated rat liver mitochondria have been incubated in the presence of the general anesthetic 2,6-diisopropylphenol (0-100 microM) and the efficiency of oxidative phosphorylation has been evaluated by measuring the respiratory rates, the rates of ATP synthesis or hydrolysis and the magnitude of the transmembrane electrical potential. The results obtained indicate that: (a) in mitochondria energized either by succinate or by ATP, 2,6-diisopropylphenol decreased the transmembrane electrical potential and increased the rates of either electron transfer or ATP hydrolysis; (b) in succinate-energized mitochondria 2,6-diisopropylphenol, at concentrations causing substantial depression of the transmembrane electrical potential, did not modify either the rate of phosphorylation of added ADP or the rate of ADP-stimulated respiration: (c) in succinate-energized mitochondria 2,6-diisopropylphenol caused a concentration-dependent inhibition of the uncoupler-stimulated rate of succinate oxidation. These findings suggest that under the experimental conditions reported 2,6-diisopropylphenol affected the generation and/or maintenance of the transmembrane electrical potential while leaving unchanged the coupling between the electron flow in the respiratory chain and the synthesis of ATP.
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PMID:Influence of the anesthetic 2,6-diisopropylphenol on the oxidative phosphorylation of isolated rat liver mitochondria. 206

Propofol (Diprivan), a modern intravenous hypnotic, produces a reduction in both cardiac index (CI) and mean arterial pressure (MAP). Ketamine (Ketanest), a potent analgesic, in contrast, causes an increase in MAP and CI. The aim of the present study was to investigate whether the combination of propofol and ketamine can give better hemodynamic stability during the induction and maintenance of general anesthesia than propofol used with fentanyl, whose cardiodepressant actions may cumulate. METHODS. For induction of general anesthesia 10 patients (ASA I and II) each received 3-5 boluses of propofol (0.5 mg.kg-1 during 35 s until predetermined level of anesthesia was reached (stage D2/E0 according to [20]) followed by a continuous propofol infusion (0.120 mg.kg-1.min). Fentanyl 0.1 mg was administered to each patient in group A for induction of anesthesia and again if evident pain was present. In group B ketamine was given following a pharmacokinetic model based on computer-simulated calculation. After an initial bolus of 38 mg injected within 2 min further doses of 42 mg, 35 mg, 32 mg and 28 mg ketamine were administered over 30 min at a time. Signs of evident pain were treated by means of supplementary doses of 0.5 mg.kg-1. RESULTS. In both groups a moderate drop of MAP was observed after the induction of general anesthesia. Two patients in each group showed a distinct decrease in MAP (-32%). The heart rate dropped slightly (-9%) in group A, but did not change in group B. Following intubation the MAP rose by less in group A (+8%) than in group B (+21%). After the beginning of the operation the group treated with propofol/fentanyl showed major hemodynamic changes; in particular, bradycardia with less than 40 bpm was observed in more patients than in the propofol/ketamine group. Postoperatively, fewer patients in group B required rescue doses of analgesics (1 of 10) than these in group A (7 of 10), though vigilance was better in group B. DISCUSSION. The dose of ketamine administered during the induction of general anesthesia may have been not high enough to neutralize the cardiodepressant effect of propofol. But during the maintenance of anesthesia there was in fact better hemodynamic stability in group B than in group A as a result of the neutralization of opposing actions. Fentanyl even intensified the fall in MAP after propofol. Patients in group B showed better vigilance as well as better pain relief postoperatively. The population of the fentanyl group was obviously more deeply sedated and analgesia was still inadequate. In our study general intravenous anesthesia with propofol and ketamine offered the advantages of better analgesia, a higher state of vigilance and the absence of respiratory depression during the postoperative phase compared with the combination of propofol and fentanyl.
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PMID:[The effect of propofol-ketamine anesthesia on hemodynamics and analgesia in comparison with propofol-fentanyl]. 207 45

Anaesthesia for elective direct current cardioversion (DCC) was induced with propofol (Diprivan) 1.2 mg/kg in 28 patients and with 0.2 mg/kg etomidate (Hypnomidate) in 20 patients. These mostly high risk patients (NYHA class II to III) were successfully treated with defibrillation. Blood pressure and heart rate were recorded before and after induction and at 2 minutes intervals up to 20 minutes after DCC. Both anaesthetic agents caused mild hypotension. Heart rate did not change significantly after induction but fell significantly after DCC from the mean value of 124 +/- 26 bpm and 122 +/- 37 bpm to 94 +/- 19 bpm and to 91 +/- 19 bpm in propofol and etomidate treated patients respectively. Four patients became apnoeic necessitating assisted ventilation for approximately four minutes. All propofol treated patients had rapid recovery times and opened eyes on command within 5.6 +/- 1.9 minutes after induction, and were fully orientated about 4 minutes later also. Complete amnesia was observed in all patients in this group. In contrast etomidate induced anaesthesia did not cause respiratory depression, but the recovery time was longer. Four patients of this group complained of recall of DCC. In 7 patients due to involuntary movements or myoclonus, after induction with etomidate reliable EKG monitoring appeared to be difficult.
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PMID:[Anesthesia for cardioversion. A comparison of propofol and etomidate]. 220 24

The anaesthetic propofol was investigated in domestic pigeons (Columba livia). The agent was administrated intravenously, in one group of birds as an adjunct to ketamine hydrochloride, and careful monitoring was performed. The dose of 14 mg kg-1 of propofol was based on allometric scaling for its use as a sole agent. Propofol anaesthesia was characterised by smooth rapid induction and good muscle relaxation but was only of short duration, ranging from two to seven minutes, and seemed to cause a marked respiratory depression. Indeed, a very narrow safety margin for propofol was observed in pigeons when ventilation was not assisted. The agent may have applications in avian anaesthesia but these are likely to be limited.
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PMID:Preliminary studies on the use of propofol in the domestic pigeon (Columba livia). 226 24

The effect of the intravenous (i.v.) short-acting anesthetic propofol on baroreflex control of heart rate (HR) was examined in normotensive rats. Propofol was infused at a fixed rate of 9 mg/kg.h immediately after a bolus dose of 10 mg/kg. Blood pressure (BP) was maintained with a plasma substitute. Conscious rats were used for comparisons. Reflex HR response were recorded after i.v. doses of the pressor agent phenylephrine and the depressor agent sodium nitroprusside. Baroreceptor reflex parameters were determined by sigmoidal computerized curve-fitting. Propofol produced tachycardia at rest and atropine increased HR only moderately. In addition, a limitation in the bradycardiac response to artificial BP increases (lower plateau) was shown. This set of data indicated a vagal depression. The sympathetic component of the baroreflex was equally affected, since the maximal tachycardia resulting from artificial BP decreases (higher plateau) was shifted toward lower values. A marked diminution of the baroreflex gain resulted from the reduced activity of both vagal and sympathetic components. The mechanism for this decrease in the baroreflex-dependent total autonomic effector output (HR range) probably reflects the interaction of propofol with the baroreceptor pathways.
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PMID:Attenuation of the baroreceptor reflex by propofol anesthesia in the rat. 247 77

The clinical effects of a propofol-alfentanil association were studied in fifteen patients ASA II (mean age 50.1 +/- 14.1) anaesthetized for E.N.T. endoscopy after informed consent. All the patients received an intramuscular premedication with 0.10 to 0.15 mg.kg-1 midazolam. Propofol 2.5 mg.kg-1 was injected in a peripheral venous line with alfentanil 10 micrograms.kg-1, followed by continuous automatic injection of propofol at a dose of 5 to 10 mg.kg.h-1 and alfentanil 5 micrograms.kg-1 given just before suspension. After induction and during maintenance of anaesthesia, the patients were allowed to breathe oxygen spontaneously O2 assisted when apneic. The following variables were studied before induction (to), after induction (t1), during suspension (t2) and when stopping the infusion (t3): haemodynamic parameters using an invasive method and blood gases. Statistical analysis was performed using the Student's test for paired samples. Surgical conditions and anaesthetic quality were good with early recovery of consciousness and return of all reflexes. After an initial period of cardio vascular depression, the haemodynamic parameters did not vary much during the anaesthesia and propofol-alfentanil appeared to limit considerably the hypertension due to laryngoscopy. However, there was a moderate degree of hypercapnia (p less than 0.001) in most patients, giving evidence of some respiratory depression and possibly a greater depth of anaesthesia than desirable. Indeed, the doses of alfentanil required seemed to be more important with propofol because of a probably interference between the two drugs; the doses of these drugs should therefore be modified according to the length of surgery.
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PMID:[Circulatory and respiratory repercussions to direct suspension laryngoscopy in the adult: value of a propofol-alfentanil combination]. 249 72

Thirty-two patients (14 women and 18 men) whose age ranged between 15 and 76 were admitted on an emergency and anesthetized with propofol in view of various surgical interventions (9 appendectomies, 9 fractures, 5 wound healing, 6 abscess incisions, 2 corneal grafts and one complex trauma surgery) undergone 24 hours after their admission. Premedication included hydroxyzine 1.5 mg.kg-1, atropine sulfate 0.5 to 0.75 mg and pethidine 1 mg.kg-1 according to pain intensity and initial pathology. Narcosis was induced by 2.5 mg.kg-1 propofol injected intravenously. Propofol was then administered continuously at a dose of 9 mg.kg-1 in the first hour and of 4.5 mg.kg-1.h-1 in the following hours for 28 of the patients. Four patients undergoing short operations were given additional injections of one third of the initial dose. Analgesia and myorelaxation were obtained with fentanyl (0.16 +/- 0.06 mg) and vecuronium (9.3 +/- 4 mg). Narcosis proved to be very efficient. The side effects observed (13% myoclonia, 6% rash, 6% bradycardia, 0.3% pains at the time of injection) were similar to those quoted in the literature. Blood pressure stabilized after a short slight depression (13% to 18% of the standard values). Pulse remained regular. We can thus say that propofol is a good hypnotic drug for emergency anesthesia provided that its contra-indications especially shocks of cardiac or septic origin and hypovolemia, are carefully respected.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Propofol in emergency anesthesia]. 278 40


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