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Propofol exhibits antiepileptic activity in hippocampal pyramidal neurons.

Propofol was reported to exhibit an antiepileptic activity. This study was performed to investigate the effect of propofol on evoked and spontaneous seizure-like activity induced by the convulsant veratridine. Studies were performed on rat brain slices using conventional electrophysiological intracellular techniques. The alteration of sodium channel function by veratridine (0.3 microM) induced an evoked and spontaneous seizure-like activity in the hippocampal CA1 pyramidal neurons. Therapeutic concentrations of propofol (10 microM) were ineffective in inhibiting veratridine-induced seizure-like activity. However, higher concentrations (50-100 microM, n=6) inhibited both evoked and spontaneous bursting, induced by veratridine. The inhibitory effect of propofol (100 microM) was associated with membrane hyperpolarization [after veratridine, -66+/-0.71 mV (mean+/-S.E.M.), and after propofol, -77+/-2.15 mV] and with an increase in input resistance [after veratridine (37.8+/-1.2 MOmega) and after propofol (43+/-1.3 MOmega)]. The drug also produced an increase in current threshold. Results from this study are valuable in solving critical questions regarding the antiepileptic activity of propofol and strengthen the validity of the veratridine model in testing for potential antiepileptic drugs.

Animals↗

Multicenter evaluation of propofol for head-injured patients in Taiwan.

BACKGROUND: The present study was a multicenter, retrospective study which aimed to evaluate the efficacy of propofol, a new choice of pharmacotherapy in head-injured patients. METHODS: Head-injured patients admitted to 3 hospitals during the period from January 2003 to December 2004 were included in this clinical trial. Data on patients' demographics, laboratory data, GCS score, ICP, CPP, concurrent medications, and therapeutic outcomes were collected. RESULTS: Among the 104 patients included, only 44 were given propofol. The average age was 40.8 +/- 22 years for all patients, with 41.91 +/- 20.41 and 43.48 +/- 23.19 years for the propofol group and nonpropofol group, respectively (P=.097). There was no significant difference in baseline GCS score between the 2 groups (5.86 +/- 1.84 vs 5.66 +/- 1.59, P=.729). Mean ICP for the first 3 days in the ICU was 17.23 +/- 9.0 mm Hg in the propofol group and 33.19 +/- 32.56 in the nonpropofol group, respectively (P=.017). Mean CPP for the first 5 days in the ICU was 71.10 +/- 15.32 mm Hg in the propofol group and 43.20 +/- 29.92 mm Hg in the nonpropofol group (P<.001). A higher survival rate was found in the propofol group (81.8% vs 46.7%, P<.001). CONCLUSIONS: The present study demonstrated that propofol improved the outcome in recovery phase of head-injured patients.

Adolescent↗

The use of propofol for electroejaculation in domestic cats.

The objective was to evaluate the use of propofol as an anesthetic drug for electroejaculation in the domestic cat. Cortisol concentrations, heart rates and respiratory rates of 20 male domestic cats were examined. The animals were randomly allocated into three groups. Group A (n = 8), were anesthetized with propofol (10 mg/kg) and underwent electroejaculation. Group B (n = 6), were pre-medicated with buprenorphine (0.01 mg/kg), anesthetized with propofol (5 mg/kg) and underwent electroejaculation. Group C (n = 6), the cats were anesthetized with propofol (10 mg/kg) without electroejaculation (control group). Blood samples were collected at four time points (30 min before propofol administration, immediately after the surgical plane of anesthesia was induced, immediately post-electroejaculation, and at the onset of anesthetic recovery). In the control group, the sampling time coincident with the end of electroejaculation was assigned as 21 min after the induction of anesthesia. The mean (+/- S.E.M.) duration time for electroejaculation was 18 +/- 3 min. The duration of anesthesia did not differ (P > 0.05) among the three groups of cats (26 +/- 2 min). Most of the cats (17/20) recovered smoothly. Pre-anesthetic medication with buprenorphine did not reduce the requirement of propofol for anesthesia. The cortisol concentrations, heart rates and respiratory rates of the three groups of cats did not differ (P > 0.05). A marked decline in cortisol levels was observed immediately post-electroejaculation. Propofol was a useful anesthetic for electroejaculation in felids with rapid onset, optimal duration of anesthesia for performing electroejaculation, and smooth recovery.

Anesthesia↗

Halothane induces oxidative stress and NF-kappaB activation in rat liver: protective effect of propofol.

We investigated the effects of propofol on markers of oxidative stress, nuclear factor kappa B (NF-kappaB) activation and inducible nitric oxide synthase (iNOS) expression in liver of rats treated with halothane under hypoxic conditions. Male Wistar rats received halothane 1%/oxygen 14%, oxygen 14%/propofol 60 mg kg(-1) i.p., or halothane 1%/oxygen 14%/propofol 60 mg kg(-1) i.p. Morphological examination showed complete loss of architecture with massive necrosis of parenchyma in the halothane group, while only minor histological abnormalities were observed in rats receiving halothane plus propofol. The cytosolic concentration of TBARS and the hydroperoxide-initiated chemiluminescence increased significantly in the liver of animals from the halothane group (+62% and +40% versus controls, respectively), and this increase was abolished by propofol administration. Halothane induced a marked activation of NF-kappaB (+180%), and resulted in a significant decrease of the nonphosphorylated form of the inhibitor IkappaBalpha (-53%), while phosphorylated IkappaBalpha protein level was markedly increased (+146%). Propofol administration lowered these effects to +30% (NF-kappaB), -26% (nonphosphorylated IkappaBalpha), and +56% (phosphorylated IkappaBalpha). The increase of iNOS protein level (+59%) induced by halothane was significantly reduced to +22% by additional administration of propofol. Results obtained show that administration of propofol inhibits oxidative stress, NF-kappaB nuclear traslocation and iNOS overexpression in liver of rats receiving halothane. Propofol treatment, by inhibiting the NF-kappaB signal transduction pathway, might block the production of noxious mediators involved in the development of halothane-induced injury.

Anesthetics, Inhalation↗

Propofol modulation of [3H]flunitrazepam binding to GABAA receptors in guinea pig cerebral cortex.

Binding of the radioligand [3H]flunitrazepam to membranes prepared from the cerebral cortex of adult, male guinea pigs under equilibrium and non-equilibrium conditions was used to investigate the allosteric interaction between the intravenous general anesthetic propofol and the benzodiazepine site of the GABAA receptor. Propofol induced a potentiation of [3H]flunitrazepam binding with an EC50 of 9+/-4 microM. Propofol increased the affinity for [3H]flunitrazepam binding with no change in maximal binding. Propofol did not change the rate constant of association for [3H]flunitrazepam binding to cerebral cortical membranes. In contrast, the rate constant for dissociation of [3H]flunitrazepam was significantly decreased in the presence of propofol. These data demonstrate that propofol increases the affinity of the benzodiazepine site of the GABAA receptor via a selective decrease in the rate constant for dissociation, and suggest a mechanism for the allosteric interaction between propofol and benzodiazepines at the GABAA receptor.

Anesthetics, Intravenous↗

Propofol enhances ischemic tolerance of middle-aged rat hearts: effects on 15-F(2t)-isoprostane formation and tissue antioxidant capacity.

OBJECTIVE: Experimental study has shown that myocardial ischemic tolerance is reduced during middle-age. We investigated the effect of propofol on ischemic tolerance of middle-aged rat hearts. METHODS: Hearts of young adult (10 weeks old, Y) and middle-aged rats (20 weeks old, M) were assigned to propofol (P-Y, P-M) and control (C-Y, C-M) groups (n=6 each). Hearts were perfused using a Langendorff preparation with Krebs-Henseleit solution (KH) at constant flow rates. We applied propofol (P-Y, P-M) for 10 min at 12 microg/ml before inducing 40 min global ischemia. During ischemia, saline (C-Y, C-M) or propofol (P-Y, P-M) in saline was perfused through the aorta at 60 microl/min. Propofol in KH was perfused at 12 microg/ml for the first 15 min of reperfusion and subsequently reduced to 5 microg/ml in propofol treatment groups. Coronary effluent was assayed for 15-F(2t)-isoprostane after equilibration, during ischemia (T(1)) and at 0.5 (T(2)) and 5 (T(3)) min of reperfusion. After 90 min of reperfusion (T(4)), hearts were harvested to assess tissue antioxidant capacity. RESULTS: In P-Y, we observed an increased latency to ischemic-contracture and a significantly reduced contracture after 35 min ischemia compared to control groups. No ischemic contracture was observed in P-M. There were significantly lower 15-F(2t)-isoprostane levels in P-M and P-Y than in C-M and C-Y at T(1). At T(4), the recovery of left ventricular developed pressure in P-M was greater than in P-Y (P<0.05); both were greater than in C-M and C-Y. CONCLUSION: Propofol enhanced ischemic tolerance of middle-aged hearts, primarily by inhibiting lipid peroxidation.

Aging↗

Propofol for endoscopic sedation: A protocol for safe and effective administration by the gastroenterologist.

BACKGROUND: There is increasing interest in the use of propofol, an ultrashort-acting hypnotic agent, for sedation during endoscopic examinations. A protocol was developed for administration of propofol, combined with small doses of midazolam and meperidine, for endoscopic sedation under the direction of a gastroenterologist. Initial experience with using this protocol is described. METHODS: A total of 819 consecutive endoscopic examinations under sedation with propofol, midazolam, and meperidine (or fentanyl), in adherence with the sedation protocol, were reviewed retrospectively. RESULTS: There were 638 colonoscopies and 181 EGDs; 89% of patients were classified as American Society of Anesthesiologists (ASA) class I or II. Mean dosages of medications were: propofol 63 (33.5) mg, meperidine 48 (7.2) mg, and midazolam 1 (0.12) mg. The dose of propofol was inversely correlated with age and ASA class, and positively correlated with patient weight and duration of examination. Hypotension (>20 mm Hg decline in either systolic or diastolic blood pressure) developed in 218 (27%) patients, and hypoxemia (oxygen saturation <90%) developed in 75 (9%). All episodes of hypotension and hypoxemia were transient, and no patient required administration of a pharmacologic antagonist or assisted ventilation. The average time for recovery after colonoscopy and after EGD was, respectively, 25 minutes and 28 minutes. All EGDs and 98% of colonoscopies were completed successfully. CONCLUSIONS: On the basis of this initial experience, it is believed that propofol, potentiated by small doses of midazolam and meperidine, can be safely and effectively administered under the direction of a gastroenterologist. Additional research will be necessary to determine whether propofol is superior to the current methods of sedation.

Adolescent↗

Endoscopist administered propofol for upper-GI EUS is safe and effective: a prospective study in 500 patients.

BACKGROUND: The administration of propofol for endoscopic sedation by a qualified person, other than the endoscopist, is safe and effective. The aim of this study was to determine if propofol can be administered safely and effectively by the endoscopist performing the procedure. METHODS: All patients referred for upper-GI EUS were eligible for inclusion in the study. Exclusion criteria included the following: age less than 18 years, American Society of Anesthesiology physical status class greater than 2, a potential for difficulty in airway maintenance, and allergy to propofol constituents. The endoscopist administered propofol as an intravenous bolus followed by a constant infusion. Adverse events, drug dosage, complications, and patient/endoscopist satisfaction were recorded. RESULTS: A total of 500 patients (285 women, 215 men; mean age 53.4 [14.8 years]) were enrolled. Mean propofol dose was 301 mg (range 100-1000 mg). Mean procedure time was 19 minutes (range 3-70 minutes). The required examination was completed in all cases. There was no major adverse event. Oxygen desaturation (oxygen saturation < 95%) occurred in 16 (3%) patients. There were 4 (1%) cases of mild hypoxemia (saturation < 90%) but no case of severe hypoxemia (saturation <85%). The endoscopist rated the 92% of the procedures as "very smooth" or "smooth" and regarded administration of propofol as "easy" for 92%. All patients said they would prefer the same method of sedation if the procedure were repeated. CONCLUSIONS: Endoscopist-administered propofol is safe and effective in selected patients.

Adult↗

The changing landscape of practice patterns regarding unsedated endoscopy and propofol use: a national Web survey.

BACKGROUND: Lower reimbursements for endoscopic procedures and increasing demand for screening endoscopy over the past decade have spurred efforts to increase efficiency in the performance of endoscopic procedures. Two dichotomous approaches have emerged: (1) unsedated endoscopy and (2) propofol sedation. The aim was to determine national practice patterns of unsedated endoscopy and propofol sedation, and to assess endoscopists' attitudes toward unsedated screening with an electronic survey. METHODS: A short survey was developed and then was converted to a Web-based format. All national members of the American Society for Gastrointestinal Endoscopy (ASGE) were invited via electronic mail (e-mail) to participate. Survey data were collected electronically. RESULTS: Two e-mails elicited responses to the Web survey from 18% (724) of national ASGE members contacted, within 2 weeks. Of the respondents, 45% do not routinely offer unsedated EGD and colonoscopy, and only 15% of those respondents plan to incorporate unsedated endoscopy into their practice in the next year. Of the 55% who currently perform unsedated endoscopy, 85% do no more than 25 unsedated procedures per year. Lack of patient acceptance was the most common reason cited for not offering unsedated endoscopy. Most endoscopists felt that the availability of unsedated esophagoscopy or colonoscopy would not significantly increase screening for Barrett's esophagus or colonic polyps/colorectal cancer, respectively. Routine use of propofol sedation for EGD, colonoscopy, and ERCP/EUS was reported by 19%, 22%, and 19%, respectively. Community practitioners were more likely to use propofol than those at academic centers (p < 0.0002 for all). Of those not currently using propofol, 43% plan to incorporate it into their practice within the next year. Over 70% of respondents would themselves choose to be sedated for routine endoscopic procedures. CONCLUSIONS: Electronic surveys allow for rapid distribution and data collection but suffer from a limited response rate. The survey suggests that unsedated endoscopy has limited acceptance in the United States, and, without a major intervention that affects endoscopists' attitudes, its use is not likely to increase significantly. Unsedated endoscopy will not have a great impact on endoscopic screening. In contrast, propofol sedation has already gained acceptance in the community, and the routine use of propofol in endoscopy units will likely increase in the future.

Anesthetics, Intravenous↗

Electropharmacological actions of propofol on calcium current in guinea-pig ventricular myocytes.

Propofol, a widely-used intravenous anesthetic, causes bradycardia, depression in contractility and hypotension. The cellular mechanisms responsible for these cardiac toxicity remain unclear. In this study, we examined the cellular electropharmacological actions of propofol on calcium current in guinea-pig heart. Single ventricular myocytes were freshly isolated from guinea-pig using modified enzymatic method. Whole-cell voltage-clamp technique was applied with one suction pipette. Transmembrane L-type calcium current (ICa(L)) was separated from other ionic currents by voltage-control, ionic channel blockers and ion substitution methods. Our results show that propofol decreased ICa(L) in a concentration-dependent manner (KD = 54.2 microM). Slope conductance of current-voltage relation was decreased by 56 microM propofol. Propofol did not affect the steady-state activation curve, but shifted the inactivation curve to hyperpolarizing direction. Recovery from inactivation was slowed down by propofol. Marked resting block and use-dependent block were noted. In conclusion, our results indicate that propofol inhibits cardiac L-type calcium current mainly by shifting inactivation curve and retarding the recovery from inactivation.

Anesthetics, Intravenous↗

Methionine 286 in transmembrane domain 3 of the GABAA receptor beta subunit controls a binding cavity for propofol and other alkylphenol general anesthetics.

gamma-Aminobutyric acid type A (GABA(A)) receptors are an important target for general anesthetics in the central nervous system. Site-directed mutagenesis techniques have identified amino acid residues that are important for the positive modulation of GABA(A) receptors by general anesthetics. In the present study, we investigate the role of an amino acid residue in transmembrane (TM) domain 3 of the GABA(A) receptor beta(2) subunit for modulation by the general anesthetic 2,6-diisopropylphenol (propofol). Mutation of methionine 286 to tryptophan (M286W) in the beta(2) subunit abolished potentiation of GABA responses by propofol but did not affect direct receptor activation by propofol in the absence of GABA. In contrast, substitution of methionine 286 by alanine, cysteine, glutamate, lysine, phenylalanine, serine, or tyrosine was permissive for potentiation of GABA responses and direct activation by propofol. Using propofol analogs of varying molecular size, we show that the beta(2)(M286W) mutation resulted in a decrease in the 'cut-off' volume for propofol analog molecules to enhance GABA responses at GABA(A) alpha(1)beta(2)gamma(2s) receptors. This suggests that mutation of M286 in the GABA(A) beta(2) subunit alters the dimensions of a 'binding pocket' for propofol and related alkylphenol general anesthetics.

Amino Acid Sequence↗

Propofol versus isoflurane anesthesia under hypothermic conditions: effects on intracranial pressure and local cerebral blood flow after diffuse traumatic brain injury in the rat.

BACKGROUND: The aim of this study was to compare the cerebral protective effects of two known protective anesthetics, isoflurane and propofol, when these were used in combination with moderate hypothermia (33-34 degrees C) after diffuse traumatic brain injury (TBI) in the rat. We assessed cerebral protection by measuring local cerebral blood flow (LCBF), mean arterial blood pressure (MABP), cerebral perfusion pressure (CPP) and intracranial pressure (ICP). METHODS: Sixteen female Wistar rats weighing 275 to 350 g were anesthetized and subjected to an accelerated-impact weight-drop model of diffuse TBI. Hypothermia (33-34 degrees C) was induced 45 minutes after TBI (baseline), and was maintained for 180 minutes. The isoflurane group (n = 8) received 70% N(2)O in O(2), and isoflurane at 0.9 +/- 0.04%. The propofol group (n = 8) received 70% N(2)O in O(2) and a propofol infusion (12 mg/kg/hr). LCBF was measured by laser Doppler flowmeter. MABP, ICP, and brain and rectal temperatures were measured every 15 minutes from baseline through 180 minutes. Blood gas and hematocrit testing was also done at baseline and every 60 minutes thereafter to assess the animals' physiological state. RESULTS: In the isoflurane group, MABP and CPP decreased significantly from baseline to 180 minutes (p < 0.05 and p < 0.01, respectively), and MABP was significantly lower than the pressure in the propofol group from 45 minutes through 180 minutes (p < 0.05, p < 0.01). ICP and LCBF remained unchanged in this group. In the propofol group, from baseline to 180 minutes, CPP increased to maximum 120 +/- 8 mmHg at 75 minutes from 98 +/- 5 mmHg (p < 0.05) and ICP fell from 18 +/- 2 mmHg to 7 +/- 1 mmHg (p < 0.01); and the latter was significantly lower than ICP in the isoflurane group (p < 0.05, p < 0.01, p < 0.001). LCBF in this group was significantly higher than LCBF in the isoflurane group in the last 30 minutes of the experiment (p < 0.05). The propofol group showed no change in MABP over the course of the experiment. CONCLUSION: In the clinical setting, propofol anesthesia may be better for use in combination with hypothermia in cases of traumatic brain injury, as it reduces ICP and increases CPP under these conditions.

Anesthetics, Inhalation↗

Suppression of the hyperpolarization-activated inward current contributes to the inhibitory actions of propofol on rat CA1 and CA3 pyramidal neurons.

Intracellular and field potential recordings were taken from the hippocampal CA1 and CA3 neurons in rat brain slices to investigate the effects of 2,6 di-isopropylphenol (propofol) on the neuronal excitability during GABA(A)-C1 channel blockade by picrotoxin (100 microM). Propofol produced a membrane hyperpolarization and an inhibition of the magnitude of the 'voltage sag' that was mediated by the activation of a hyperpolarization-activated inward current (I(H)). Propofol (>100 microM) decreased the spontaneous discharge rate of epileptiform burst responses in CA1 neurons up to 38+/-6% of the control level. Propofol also markedly reduced the duration of both spontaneous and evoked epileptiform burst responses. A propofol-induced decrease in the spontaneous discharge rate in CA3 neurons was coincident with that in CA1 neurons. The effects of propofol on the membrane potential and spontaneous discharge rate but not on the duration of burst responses were duplicated by ZD7288 (potent selective antagonist for I(H) channels), indicating that the blockade of I(H) significantly contributes to reduction of cell's excitability. The present study suggests that various actions including suppressive effects on I(H) contribute to the anesthetic and anti-convulsant properties of propofol.

Anesthetics, Intravenous↗

Propofol versus isoflurane for endoscopic sinus surgery.

PURPOSE: A previous retrospective study reported that propofol anesthesia decreased bleeding during endoscopic sinus surgery compared with isoflurane. We performed a prospective study to compare the effects of propofol versus isoflurane on measured blood loss and the surgeon's subjective assessment of operating conditions during endoscopic sinus surgery. PATIENTS AND METHODS: After receiving institutional review board approval and written informed consent, 56 patients undergoing endoscopic sinus surgery were randomly assigned to receive propofol (n = 30) or isoflurane (n = 26) supplemented with nitrous oxide-oxygen and alfentanil. Blood loss was calculated from the hemoglobin concentration in suction canisters. One surgeon, who was blinded to the anesthetic agent, performed every procedure and assessed bleeding as follows: 1, no bleeding; 2, modest bleeding; 3, bleeding interfering with operating conditions and cause for an agent switch; and 4, intolerable bleeding requiring a change in surgical plan. Results were compared in the two anesthetic groups using chi-squared test, unpaired t-test, Mann-Whitney Utest, and a permutation test. A P of .05 was considered significant. RESULTS: Mean bleeding scores were less over time (P = .02) with propofol anesthesia, particularly in surgery in the ethmoid and sphenoid sinuses (P = .03), and the proportion of patients with a mean score >2 was less in the propofol group (30% v 54%; P = .033). Time until discharge to home or to a limited stay in a hospital bed was also less in the propofol group (183 v 243 minutes; P = .019). CONCLUSION: In our study, surgical blood loss was the same for both anesthetic agents overall, but propofol appeared to offer an advantage in terms of subjective improvement in operating conditions, particularly in the ethmoid and sphenoid sinuses.

Adult↗

Propofol: an alternative general anesthetic for outpatient oral surgery.

PURPOSE: This study compared propofol with methohexital for use in outpatient general anesthesia for oral surgery procedures. PATIENTS AND METHODS: Fifty American Society of Anesthesia (ASA) class I or II patients undergoing elective minor oral surgery procedures were selected for inclusion in the study. Participants were randomly divided into two groups-propofol-treated and methohexital-treated. All anesthetic agents were titrated in bolus using dosages standardized by weight. After premedication with intravenous midazolam and fentanyl, general anesthesia was induced either by propofol or methohexital. The quality of the anesthesia was subjectively evaluated by the anesthetist, surgeon, and the patient. Also, a standardized battery of tests was developed to quantitatively evaluate recovery from anesthesia. RESULTS: Propofol showed significantly less percentage increase in diastolic blood pressure and heart rate than methohexital. However, at the same time, propofol showed significantly greater percentage lowering of diastolic blood pressure. The mean low heart rate percentage of preoperative baseline were different, but both were greater than 100%. The anesthetist and patient evaluations showed no statistically significant difference in the acceptance of either agent. No patient in either group had any recollection of pain with induction or any recollection of the operation itself. There were no statistically significant effects of group in recovery test performance, although patients tended to recover more quickly in the symbol digit test and object recall test with propofol. No patient complained of any postoperative complications secondary to the anesthetic. CONCLUSIONS: Propofol is a suitable agent for induction and maintenance of general anesthesia for outpatient oral surgery procedures. It provides a smooth induction of anesthesia with few excitatory effects.

Adjuvants, Anesthesia↗

Effects of propofol on the activity of rat glutamate transporter type 3 expressed in Xenopus oocytes: the role of protein kinase C.

We investigated the effects of propofol on one type of glutamate transporter, excitatory amino acid transporter 3 (EAAT3) and the role of protein kinase C (PKC) in mediating these effects. Rat EAAT3 was expressed in Xenopus oocytes. L-glutamate (30 microM)-induced membrane currents were measured. Propofol increased glutamate-induced inward currents significantly at two tested concentrations (30 and 100 microM) but not at other concentrations. Propofol (30 microM) significantly increased V(max), but not K(m) of EAAT3 for glutamate. The combination of phorbol-12-myrisate-13-acetate (PMA, a PKC activator) and propofol did not increase the responses further compared with PMA or propofol alone. Three PKC inhibitors (staurosporine, calphostin C, and chelerythrine) did not affect basal EAAT3 activity but significantly inhibited the propofol-enhanced EAAT3 activity. Our results suggest that propofol enhances EAAT3 activity at clinically relevant concentrations and PKC may mediate these effects.

Amino Acid Transport System X-AG↗

[Prevention of pain on injection with propofol in children: comparison of nitrous oxide with lidocaine].

INTRODUCTION: Injection pain caused by propofol is an important disadvantage, especially in children, incompletely reduced by adding lidocaine intravenously. Nitrous oxide's analgesic effects, well known, have never been evaluated on pain due to propofol. OBJECTIVE: To compare the effects of nitrous oxide with lidocaine on pain on injection caused by propofol in children. STUDY DESIGN: Double blind, randomised, prospective study. PATIENTS AND METHODS: 48 children aged more than 5 were randomly allocated to one of the 2 groups: N2O group, breathed 50% N2O + 50% O2 than received propofol only and Lido group breathed 100% O2 and received a mixture of propofol with lidocaine. The possible pain was scored during injection by a behavioural scale and once again in the recovery room by the child himself with a VAS. RESULTS: There was no significant difference in behavioural pain scores among the 2 groups; pain was assessed as being moderate or severe in 6/24 patients in N2O group and 10/24 in Lido group (behavioural scores > 1). Significantly more children in the N2O group had low VAS scores compared with the Lido group (no child/24 scored a VAS > 4 and 7/23 in the Lido group) demonstrating that N2O amnesic effects would omit the memory of pain caused by propofol. CONCLUSION: The use of nitrous oxide is an easy, cheap and efficient method to reduce the incidence of pain injection of propofol and his amnesic effects can provide real advantages in paediatric anaesthesia.

Analgesics↗

[Recovery after anesthesia with propofol in otorhinolaryngologic surgery of brief duration].

This study was designed to assess recovery from total intravenous anaesthesia with propofol for short ENT procedures. Twenty-six patients (ASA I and II) were assigned to two groups of thirteen: one breathed air (Laser laryngeal microsurgery), the second N2O-O2 (FIO2 : 0.5) (various ENT procedures). The induction sequence was exactly the same for both groups: oral premedication with 10 mg diazepam one hour before surgery, I mg pancuronium bromide, 2 micrograms X kg-1 fentanyl, denitrogenation within 3 min, after which propofol was delivered (2.5 mg X kg-1). When the eye-lash reflex had disappeared (time recorded), 1.5 mg X kg-1 suxamethonium was given and laryngotracheal intubation carried out. A continuous infusion of propofol (9 mg X kg-1 X h-1) was started. Surgery began 5 +/- 2 min after the start of propofol infusion. The durations of anaesthesia, surgery and propofol infusion were similar in both groups. To have good surgical conditions, it was necessary to give repeated doses of propofol for 15 patients. Thus, the total dose of propofol was significatively different between the two groups: 24.5 +/- 6.7 mg X kg-1 X h-1 in group "air" versus 16 +/- 3.6 mg X kg-1 X h-1 in group "N2O-O2" (p less than 0.001). Extubation occurred within 16 +/- 8 min in group "air", being more rapid in group "N2O-O2" (11 +/- 9 min; no significant difference). Recovery was assessed with two psychomotor tests: choice reaction time (CRT) and tracing test (TT).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗