Effect of aminophylline on bispectral index

BACKGROUND: The aim of the present study was to investigate the effects of aminophylline on BIS as well as clinical recovery in patients anesthetized with sevoflurane. METHODS: Sixty patients with status of ASA I-II scheduled for elective surgery were enrolled in this study. Anesthesia was induced by 2 mg kg(-1) of propofol and 0.5 mg kg(-1) of atracurium, maintained with 1:1 ratio of oxygen and nitrous oxide and 2-2.5% sevoflurane, keeping BIS values at 50 +/- 5. During the last 30 min of the operation no muscle relaxant was given and anesthesia was continued without decreasing anesthetic concentration. After sevoflurane discontinuation, saline was given to Group P, and 5 mg kg(-1) of aminophylline was given to Group A. Bispectral index values, heart rate, blood pressure and oxygen saturation were determined in all the patients before and every min after injection of the test drug for 15 min. The following variables were measured in both groups: eye opening, extubation time, response to command, Aldrete scores, and performing three simple arithmetic calculations. RESULTS: Between groups there was no statistically significant difference in mean arterial blood pressure, SpO2 and anesthesia time. Heart rate was found to be statistically higher (P < 0.001) at 2 to 6 min in Group A when compared with group P. Eye opening, verbal response, extubation and arithmetic calculation times were significantly shorter (P < 0.001) in Group A. Bispectral index scores were significantly higher in Group A at 1 to 12 min after aminophylline injection when compared with placebo (P < 0.001). Conclusion: Recovery from sevoflurane anesthesia and BIS scores are improved in early period when aminophylline is given at emerging from anesthesia.     

Doxapram and aminophylline on bispectral index under sevoflurane anaesthesia: a comparative study

BACKGROUND AND OBJECTIVE: To evaluate and compare the effect of two clinically available central nervous system stimulants, namely doxapram and aminophylline on arousal from sevoflurane anaesthesia and bispectral index. METHODS: This randomized, double-blind, placebo-controlled, prospective study was conducted in 90 adult females, ASA I-II, scheduled for elective lower abdominal surgeries at Taipei Medical University Hospital. At 5 min before the completion of surgery, under sevoflurane anaesthesia, patients were divided into three groups to receive doxapram 1 mg kg(-1), aminophylline 2 mg kg(-1) or saline placebo intravenous. Standard vital signs, end-tidal CO(2), end-expiratory sevoflurane concentration, bispectral index and neuromuscular blockade were measured plus clinical parameters of recovery from general anaesthesia. RESULTS: Compared with the control group, patients receiving doxapram or aminophylline showed a similarly faster recovery from sevoflurane anaesthesia correlated with increase in bispectral index. CONCLUSION: Intravenous administration of doxapram 1 mg kg(-1) or aminophylline 2 mg kg(-1) hastened the early recovery from sevoflurane anaesthesia. The arousal effect of aminophylline and doxapram appears to be similar.     

The effects of aminophylline on bispectral index during inhalational and total intravenous anaesthesia

Aminophylline is usually used during anaesthesia to treat bronchospasm but recent findings suggest that it can also be used to shorten recovery time after general anaesthesia. However, it is unclear whether aminophylline shows similar properties during a steady-state phase of deep surgical anaesthesia. We therefore wanted to test the hypothesis that the administration of aminophylline leads to an increase in bispectral index as a surrogate parameter suggesting a lighter plane of anaesthesia. The study was designed as a double-blind, randomised, controlled trial with two main groups (aminophylline and placebo) and two subgroups (sevoflurane and propofol). We studied 60 patients. The injection of aminophylline 3 mg x kg(-1) was associated with significant increases in bispectral index up to 10 min after its injection, while heart rate and blood pressure did not change. It appears that aminophylline has the ability to partially antagonise the sedative effects of general anaesthetics.     

Effects of propofol on hepatic venous oxygen saturation--a comparison with isoflurane or sevoflurane anesthesia

BACKGROUND: We performed a comparative study of propofol versus isoflurane and sevoflurane using continuous monitoring of hepatic venous oxygen saturation (ShvO2) during upper abdominal surgery in 26 patients. METHODS: Anesthesia was induced with propofol 2-2.5 mg x kg(-1) and vecuronium 0.1 mg x kg(-1). Thereafter, Swan Ganz catheters were inserted into the pulmonary artery and hepatic vein. Group P (n=26) patients received continuous propofol infusion and epidural mepivacaine injection for maintenance, while Group I (n=17) received isoflurane and Group S (n=9) received sevoflurane. Systemic oxygen extraction ratio (OERsys) and hepato-splanchnic oxygen extraction ratio (OERspl) were calculated. RESULTS: Heart rate, mean arterial pressure and cardiac index were unchanged after propofol infusion, and isoflurane or sevoflurane inhalation. Propofol at 8 and 10 mg x kg(-1) x h(-1) significantly decreased ShvO2 and increased OERspl, although isoflurane and sevoflurane did not change them. Mixed venous saturation and OERsys were within normal ranges during the studies. CONCLUSIONS: The results suggest that propofol increases the metabolism and oxygen consumption in the liver.     

Intraoperative fetal oxygen saturation during Caesarean section: general anaesthesia using sevoflurane with either 100% oxygen or 50% nitrous oxide in oxygen

BACKGROUND AND OBJECTIVE: The study was designed to evaluate whether the administration of sevoflurane in 100% oxygen for anaesthesia during Caesarean section would improve fetal and neonatal oxygenation compared with the administration of sevoflurane with 50% nitrous oxide in oxygen. METHODS: The randomized, single-blind controlled study examined 24 mothers, ASA I-II, at term undergoing Caesarean section who were allocated to receive sevoflurane in either 100% oxygen (n = 13) or 50% nitrous oxide in oxygen (n= 11). General anaesthesia was induced in both groups with thiopental 4-5 mg kg(-1) followed by succinylcholine 1.5 mg kg(-1) to facilitate tracheal intubation. Parturients received sevoflurane given either in 100% O2 or in a 50:50 nitrous oxide and oxygen mixture, using 0.5-1.0% progressive incremental dosing up to 1.5-2.0 MAC. Non-invasive fetal oxygen saturation was measured between induction to delivery, and umbilical artery and vein PaO2 were evaluated at birth. RESULTS: Intraoperative fetal oxygen saturation increased in all patients after maternal 100% oxygen administration (P < 0.01). Maternal hyperoxygenation significantly increased the umbilical vein and umbilical artery PaO2 and the umbilical artery SaO2 at birth (P < 0.0001). CONCLUSIONS: Maternal hyperoxygenation significantly improves fetal as well as neonatal oxygenation.     

Quality of recovery in children: sevoflurane versus propofol

BACKGROUND: Sevoflurane, with its low pungency and low blood and tissue solubility, is an attractive anaesthetic in paediatric outpatient surgery. Propofol-anaesthesia is recognised for its rapid and clear-headed emergence. This study was designed to compare emergence and recovery characteristics of sevoflurane and propofol anaesthesia for tonsillectomy in children. METHODS: Children aged 3-10 years, undergoing elective tonsillectomy, were randomly assigned to receive propofol (n=25, induction with 3 mg x kg(-1), maintenance with 100-250 microg x kg(-1) min(-1)) or sevoflurane anaesthesia (n=25, induction 7 vol.%, maintenance 2-3 vol.%). Tracheal intubation was performed with alfentanil 20 microg x kg(-1) and atracurium 0.5 mg x kg(-1). Ventilation was controlled to maintain normocapnia and all patients received N2O/O2 (60:40 vol.%) for induction and maintenance of anaesthesia. At the end of surgery infiltration of the operative sites with bupivacaine 2 mg x kg(-1) was provided for postoperative analgesia. Emergence, recovery, discharge times, and incidence of side effects were compared between the two groups. RESULTS: Time to extubation (14 vs 15 min), time to response to simple verbal command (21 vs 21 min) and time to discharge from the recovery room (45 vs 50 min) were similar in the sevoflurane and propofol groups, respectively. There was a significantly greater incidence of postoperative agitation in the sevoflurane group (46%) compared with the propofol group (9%) (P=0.008). This did not, however, delay discharge from the recovery room. The incidence of nausea and vomiting was not significantly different (8% vs 0%; P=0.49). CONCLUSION: In children, recovery from anaesthesia with sevoflurane results in a higher incidence of agitation compared with propofol.     

Sevoflurane versus propofol for induction and maintenance of anaesthesia with the laryngeal mask airway in children

We compared patient outcomes for propofol vs sevoflurane with the laryngeal mask airway (LMA) using either spontaneous breathing (SB) or pressure controlled ventilation (PCV). One hundred and twenty children undergoing minor surgery below the umbilicus were randomly assigned to receive either (1) propofol 3 mg.kg-1 followed by a maintenance infusion of 5 mg.kg-1.h-1, or (2) induction with sevoflurane 7% followed by maintenance with 1.7%. Following LMA insertion, patients were given atracurium and underwent PCV if surgery was expected to last > or = 30 min. The following assessments were made: time to LMA insertion/removal, airway problems, cardiorespiratory effects and recovery characteristics. The first time insertion success rates were similar, but insertion time was shorter with sevoflurane (115 +/- 67 s vs 252 +/- 107 s, P < 0.0001). One patient coughed during placement, but there were no other problems during any phase of anaesthesia in any group. Heart rate was higher in the sevoflurane group following insertion, during maintenance and emergence (all P < 0.03). There were no differences in blood pressure and oxygen saturation among groups PECO2 in the SB group was unaffected by the agent used. Emergence was more rapid (232 +/- 104 s vs 348 +/- 127 s, P < 0.0001) and postoperative agitation more common (15% vs 0%, P = 0.02) with sevoflurane. There were no differences in the Aldrete scores among groups. Patient outcome was similar for the SB and PCV groups. We concluded that the techniques described here using propofol and sevoflurane are equally suitable for induction and maintenance of anaesthesia with the LMA in children undergoing minor surgery below the umbilicus. Emergence is more rapid, but postoperative agitation more common with sevoflurane.     

Cost-reduction analysis of propofol versus sevoflurane: maintenance of anaesthesia for gynaecological surgery using the bispectral index

BACKGROUND AND OBJECTIVE: The study was designed to compare the costs of propofol versus sevoflurane for the maintenance of the hypnotic component of anaesthesia during general anaesthesia, guided by the bispectral index, for gynaecological laparoscopic surgery. METHODS: Forty ASA Grade I-II female patients scheduled for gynaecological laparoscopy were randomly allocated to two groups. All patients received a continuous infusion of remifentanil (0.25 microg kg(-1) min(-1)) for 2 min. Then anaesthesia was induced with propofol 1% at 300 mL h(-1) until loss of consciousness. To guide the bispectral index between 40 and 60, Group 1 patients received propofol 10 mg kg(-1) h(-1) initially, which was increased or decreased by 2 mg kg(-1) h(-1) steps; Group 2 patients received sevoflurane, initially set at 2 vol.% and adjusted with steps of 0.2-0.4%. The time and quality of anaesthesia and recovery were assessed in two postoperative standardized interviews. RESULTS: Patient characteristics, the propofol induction dose, the bispectral index and the haemodynamic profiles during induction of anaesthesia, and its duration, were similar between the groups. In Group 1, 7.55 +/- 1.75 mg kg(-1) h(-1) propofol and in Group 2, 0.20 +/- 0.09 mL kg(-1) h(-1) liquid sevoflurane were used for maintenance. The cost for maintenance, including wasted drugs, was higher when using propofol (Euro 25.14 +/- 10.69) than sevoflurane (Euro 12.80 +/- 2.67). Postoperatively, recovery profiles tended to be better with propofol; however, the day after discharge no differences were found. CONCLUSIONS: When applying the bispectral index to guide the administration of hypnotic anaesthetic drugs, propofol-based maintenance of anaesthesia was associated with the highest cost. A trend towards a better recovery profile was obtained with propofol. However, on the day after discharge, no differences in quality were observed.     

TIVA mit Propofol/Remifentanil oder balancierte Anästhesie mit Sevofluran/Fentanyl bei laparoskopischen Operationen

OBJECTIVE: This study was designed to investigate the differences between TIVA with propofol/remifentanil (P/R) and balanced anaesthesia with sevoflurane/fentanyl (S/F) in gynaecological laparoscopic surgery. Emphasis was put on haemodynamic reaction, recovery profile, postoperative side effects and patient satisfaction. METHODS: Sixty patients were randomly assigned to receive either total intravenous anaesthesia with propofol/remifentanil or anaesthesia with sevoflurane/fentanyl. After premedication (midazolam) and induction of anesthesia (propofol, atracurium) in both groups, either 1 microgram/kg fentanyl (S/F) or 1 microgram/kg remifentanil (P/R) was injected. Anaesthesia was maintained with 0.5 microgram/kg/min remifentanil (reduced to 50% after 5 min) and 0.06 microgram/kg/min propofol (P/R) or 1.7 vol % sevoflurane (S/F). Both groups were mechanically ventilated with 30% oxygen in air. The administration of sevoflurane and the infusion of the anaesthetics were adjusted to maintain a surgical depth of anaesthesia. For postoperative analgesia 1 g paracetamol was administered rectally prior to surgery. After recovery 20 mg/kg metamizol was given intravenously. At the end of surgery the anaesthetics were discontinued and haemodynamics, early emergence from anaesthesia, pain level, frequency of analgesic demand, incidence of PONV, shivering and patient satisfaction were assessed. Parameters were recorded for 24 h postoperatively. RESULTS: Recovery time after propofol-remifentanil anaesthesia was significantly shorter than after administration of sevoflurane and fentanyl (spontaneous ventilation 4.1 vs. 6.3 min, extubation 4.3 vs. 9.3 min, eye opening 4.4 vs 8.2 min, stating name 5.3 vs. 13.2 min, stating date of birth 5.4 vs. 13.3 min). There were no significant differences between the groups in shivering, pain score, analgesic demand and PONV. The S/F group responded to tracheal intubation with significantly higher blood pressure than the P/R group. During maintenance of anaesthesia heart rate in patients with S/F was significantly higher (P/R:HR max +16/-10; S/F:HR max +24/-0.). Measured on a scale (S/F 62%). CONCLUSION: Compared with patients given balanced anaesthesia with sevoflurane and fentanyl, TIVA with propofol and remifentanil proved to be particularly suited for gynaecological laparoscopic surgery. Its major advantages are haemodynamic stability, significantly shorter times of emergence, and the exceptional acceptance by the patients.     

Pressure support ventilation during inhalational induction with sevoflurane and remifentanil in adults

BACKGROUND AND OBJECTIVE: The purpose of this prospective randomized study was to assess the value of pressure support ventilation during inhalational induction with sevoflurane in adult patients. METHODS: Thirty-five adult patients, ASA I-II and scheduled for ear nose throat surgery were studied. Vital capacity induction with 8% sevoflurane in 8 L min-1 oxygen was performed. Pressure support ventilation was used in Group 1 with pressure set at 15 cmH2O. In Group 2, patients breathed spontaneously. After 2 min, sevoflurane was set to 3% and remifentanil 1 microg kg(-1) was injected over 2 min followed by an infusion of 0.1 microg kg(-1) min(-1). Two minutes after the end of the bolus, intubation was performed. Bispectral index, oxygen saturation, respiratory rate, end-tidal carbon dioxide, expired tidal volume and expired sevoflurane concentration were recorded every minute. RESULTS: Eighteen patients were included in Group 1 and 17 in Group 2. Saturation, respiratory rate and end-tidal carbon dioxide were similar in the two groups. Expired tidal volume was significantly higher and bispectral index values significantly lower in Group 1. Intubating conditions were better in Group 1. CONCLUSIONS: Pressure support ventilation provides both better ventilation and deeper level of anaesthesia during inhalation induction with sevoflurane.     

Low flow desflurane and sevoflurane anaesthesia in children

BACKGROUND AND OBJECTIVE: Low flow desflurane and sevoflurane anaesthesia were administered to children and compared for haemodynamic response, renal and hepatic function, recovery time and postoperative nausea and vomiting. METHODS: Eighty ASA I-II patients aged 5-15 yr were included in the study. Midazolam was given for premedication. Anaesthesia induction was performed with fentanyl, propofol and atracurium. After intubation, the first group received desflurane, oxygen and nitrous oxide at 6 L min(-1) and the second sevoflurane, oxygen and nitrous oxide at 6L min(-1). Ten minutes after induction the flow was decreased to 1 L min(-1) in both groups. Haemodynamic parameters, preoperative and postoperative renal and hepatic function, the times of operation and anaesthesia, and early recovery data were recorded. Modified Aldrete scores were noted at the 10th and 30th minutes postoperatively and postoperative nausea, and vomiting were assessed. RESULTS: There were no significant differences in haemodynamic parameters, renal and hepatic functions, postoperative recovery and postoperative nausea and vomiting between groups. The recovery time was shorter in the desflurane group compared to the sevoflurane group. CONCLUSION: Low flow desflurane and sevoflurane anaesthesia do not adversely affect haemodynamic parameters, hepatic and renal function in children. Desflurane may be preferred when early recovery from anaesthesia is warranted.     

The effects of magnesium sulphate on sevoflurane minimum alveolar concentrations and haemodynamic responses

BACKGROUND AND OBJECTIVE: Magnesium administered before anaesthesia induction results in a significant reduction in intravenous anaesthetic consumption. The purpose of this study was to evaluate whether the dose of intravenous magnesium sulphate reduces the minimum alveolar anaesthetic concentration of sevoflurane for endotracheal intubation (MACEI) and skin incision (MAC), and attenuates haemodynamic responses. METHODS: We studied 60 patients who were scheduled for elective surgery. Patients were not premedicated before induction of anaesthesia and were randomly assigned to receive intravenous saline 0.9% (Group I, n = 20) or magnesium sulphate 30 mg kg(-1) bolus + 10 mg kg(-1) h(-1) continuous infusion (Group II, n = 20) or 50 mg kg(-1) bolus + 10 mg kg(-1) h(-1) continuous infusion (Group III, n = 20). RESULTS: Median and 95% confidence limits for sevoflurane MACEI were 2.68 (2.48-2.85), 2.88 (2.70-3.06) and 2.96 (2.70-3.16), and for sevoflurane MAC were 2.08 (1.76-2.40), 2.26 (2.08-2.47) and 2.40 (2.19-2.68) in Groups I, II and III, respectively. The differences in MACEI and MAC among groups were not statistically significant, except Group III in MAC study (P < 0.05). Mean arterial pressures and heart rate did not increase in Groups II and III after endotracheal intubation and skin incision. CONCLUSIONS: Magnesium sulphate administered before induction of anaesthesia increases MAC of sevoflurane and reduces cardiovascular responses to intubation.     

Rocuronium duration of action under sevoflurane, desflurane or propofol anaesthesia

BACKGROUND AND OBJECTIVE: We conducted a prospective randomized study to evaluate whether the duration of action of a single bolus dose of rocuronium is influenced by maintenance of anaesthesia with sevoflurane, desflurane or propofol infusion. METHODS: Fifty-seven ASA I-II patients undergoing elective abdominal surgery were enrolled in this study. Anaesthesia was induced with thiopental 3-5 mg kg(-1) or propofol 2.5 mg kg(-1) and fentanyl 5 microg kg(-1) and tracheal intubation was facilitated with rocuronium 0.9 mg kg(-1). Thereafter patients were randomly allocated to three different groups to receive sevoflurane, desflurane or propofol for maintenance of anaesthesia. Recovery of neuromuscular function was monitored by single twitch stimulation of the ulnar nerve and by recording the adductor pollicis response using accelerometry. Intergroup recovery times to 5% of control value of single twitch were analysed using analysis of variance with Bonferroni correction. RESULTS: The mean (95% confidence interval) recovery time to 5% of control value of single twitch during desflurane anaesthesia was 90.18 (86.11-94.25) min. Significantly shorter recovery times were observed during sevoflurane or propofol anaesthesia, 58.86 (54.73-62.99) min and 51.11 (45.47-56.74) min, respectively (P < 0.001). There were also significant differences in the recovery time between groups receiving desflurane vs. sevoflurane (P < 0.001) and desflurane vs. propofol (P < 0.001). CONCLUSIONS: Desflurane anaesthesia significantly prolongs the duration of action of rocuronium at 0.9 mg kg(-1) single bolus dose, compared to sevoflurane or propofol anaesthesia maintenance regimens.     

Atracurium: neuromuscular blockade in repeated administration

The neuromuscular blocking action of repeated injections of atracurium and vecuronium was studied in 74 surgical patients during balanced anaesthesia (methohexitone or etomidate, intubation after suxamethonium, fentanyl, droperidol, N2O). The initial bolus dose (ID) of atracurium was 0.25 mg/kg and of vecuronium 0.05 mg/kg followed by repeated increments (RD) of atracurium 0.1 mg/kg and vecuronium 0.0125 mg/kg when neuromuscular function (EMG) had recovered to about 30% of pre-relaxant control. Dose-response relationships revealed atracurium to be about 1/5 as potent as vecuronium; the ED50 of atracurium was 0.13 +/- 0.03 mg/kg and of vecuronium 0.023 +/- 0.007 mg/kg. The ID of both relaxants produced a neuromuscular blockade of about 90% within 4 min. The duration from the time of injection to 30% recovery was slightly longer in atracurium 26 +/- 9 min. In all patients the RD produced within 3.5 min satisfactory muscle relaxation with a neuromuscular block of about 85%. The mean duration of atracurium (18 min) was 5-10 min longer than of vecuronium (12 min). To maintain good surgical relaxation (more than 70% blockade) atracurium 0.32 mg/kg X h and vecuronium 0.056 mg/kg X h were required. No cumulation could be measured after repeated injections. The recovery time of atracurium and vecuronium at the end of anaesthesia was 10-12 min. Neither cardiovascular side-effects nor signs of histamine release were observed after both relaxants in our particular dose range. It is concluded, that atracurium is a favourable blocker for anaesthetic practice: The time of onset is approximately the same compared with vecuronium. The duration of action, however, is slightly longer but still truly intermediate long.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of aminophylline or physostigmine on recovery from nitrous oxide-enflurane anaesthesia

If facilities for recovery are limited, shortening the recovery time from general anaesthesia is important. A comparative study on the effect of 3 mg.kg-1 aminophylline or 0.04 mg.kg-1 physostigmine on duration and quality of the recovery time from nitrous oxide-enflurane anaesthesia is presented. Three groups of 35 patients were observed, placebo being included for comparison in this double-blind study. Without treatment, recovery from nitrous oxide-enflurane inhalation anaesthesia lasted 18.8 +/- 5.80 min. Aminophylline considerably shortened the recovery time (12.06 +/- 3.52 min), whereas physostigmine did not (18.97 +/- 9.18 min). In the physostigmine group, however, a remarkably calm recovery and early return of protective reflexes was observed. Although aminophylline shortens the recovery time, due to earlier incidence of pain and other disturbances, it cannot be recommended for general improvement of recovery, whereas physostigmine clearly improves the quality of recovery from nitrous oxide-enflurane anaesthesia.     

Effects of fentanyl on the incidence of emergence agitation in children receiving desflurane or sevoflurane anaesthesia

BACKGROUND AND OBJECTIVE: In children, emergence agitation frequently complicates sevoflurane and desflurane anaesthesia. The effect of intravenous fentanyl 2.5 microg kg(-1) was examined on the incidence of emergence agitation in children who received desflurane or sevoflurane after midazolam premedication and intravenous thiopental induction. METHODS: One hundred and twenty children (2-7 yr) undergoing adenoidectomy or tonsillectomy, or both, were studied. All children were premedicated orally with midazolam 0.5 mg kg(-1). After intravenous induction with thiopental and atracurium to facilitate endotracheal intubation, patients were randomly assigned to one of four groups: Patients in Groups 1 and 3 received physiological saline solution, whereas patients in Groups 2 and 4 received intravenous fentanyl 2.5 microg kg(-1) during induction. Anaesthesia was maintained with sevoflurane in Groups 1 and 2 and with desflurane in Groups 3 and 4. After discontinuation of the volatile anaesthetic, the times to tracheal extubation and response to verbal stimuli (emergence time), and emergence behaviours were recorded. RESULTS: The time to tracheal extubation was significantly shorter in Groups 3 (5.2+/-1.7 min) and (6.4+/-2.1 min) than in Groups 1 (8.1+/-2.1 min) (P = 0.0001 and 0.006, respectively) and 2 (8.8+/-1.9 min) (P = 0.0001). The emergence time was significantly shorter in Group 3 (10.0+/-3.9 min) than in Groups 1 (13.8+/-4.9 min) (P = 0.017) and 2 (14.9+/-4.1 min) (P = 0.003). The incidence rate of severe agitation was 13% in Groups 1 and 3, and 7 and 10% in Groups 2 and 4, respectively (P > 0.05). CONCLUSIONS: After midazolam premedication and intravenous induction of anaesthesia with thiopental administration of intravenous fentanyl 2.5 microg kg(-1) did not provide any clinically significant benefit on emer gence agitation in children who receive sevoflurane or desflurane anaesthesia.     

Effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing non-ophthalmic surgery

BACKGROUND AND OBJECTIVE: To compare the effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing elective non-ophthalmic surgery. METHODS: Thirty-two patients (ASA I-II) were randomized into two groups to receive either a continuous infusion of remifentanil (0.25-0.5 microg kg(-1) min(-1), n =16, Group R) or an intermittent bolus of fentanyl (2-5 microg kg(-1), n = 16, Group F) during the maintenance of anaesthesia. For the induction of anaesthesia, Group R received remifentanil 1 microg kg(-1) and Group F received fentanyl 2 microg kg(-1); both groups then received propofol 2 mg kg(-1) with vecuronium 0.1 mg kg(-1). Anaesthesia in both groups was maintained with a continuous infusion of propofol 4-8 mg kg(-1) h(-1). Ventilation of the lungs was controlled to a constant end-tidal PCO2 of 4.7-5.4 kPa. Blood pressure, electrocardiography, heart rate and oxygen saturation were monitored throughout anaesthesia. Intraocular pressure was determined before surgery, during the maintenance of anaesthesia, 2 min after emergence and in the recovery room using a Perkins hand-held applanation tonometer by an ophthalmologist blinded to the anaesthetic technique. RESULTS: After induction of anaesthesia, a significant decrease in intraocular pressure in the remifentanil group from 13.6 +/- 2.6 to 7.1 +/- 3.1 mmHg (P < 0.001) and in the fentanyl group from 13.7 +/- 2.2 to 9.7 +/- 3.4 mmHg (P < 0.001) was observed and maintained during anaesthesia. Thirty minutes after the end of anaesthesia, intraocular pressure returned to baseline values in both groups (remifentanil: 13.9 +/- 2.8 mmHg, P = 0.28; fentanyl: 13.6 +/- 2.3 mmHg, P = 0.59). The intraocular pressure and haemodynamic variables did not differ significantly between the two groups (intraocular pressure, P = 0.7327; blood pressure, P = 0.1295; heart rate, P = 0.8601). CONCLUSIONS: Remifentanil maintains intraocular pressure at an equally reduced level compared with fentanyl.     

Neuromuskuläre Blockade nach Atracurium und Alcuronium unter dem Einfluß von Propofol und Thiopental

Does propofol or thiopentone enhance the effect of nondepolarizing muscle relaxants? We evaluated the effects of propofol and thiopentone on the pharmacodynamics of atracurium and alcuronium in 43 surgical patients (ASA I and II) under general anaesthesia. Methods. The patients were randomized into five groups, A–E. Anaesthesia was induced in all patients with fentanyl 4?μg/kg i.v. Patients in groups A and C patients received thiopentone 7?mg/kg i.v., and relaxation was achieved with alcuronium 0.25?mg/kg (group A) and atracurium 0.5?mg/kg (group C). Electromyography (train of four, TOF) was used to determine the time of onset of relaxation (AZ) and the maximum degree of blockade (T%). The recovery times to 25%, 50% and 75% of baseline muscle strength were recorded. Additionally, the TOF ratio T4:T1 was calculated, indicating the probable end of relaxation at a ratio of 0.7. At the beginning of the recovery phase (T1=15%) propofol 1% 3?mg/kg was given, and the effect on the TOF was measured. Patients in groups B and D patients received total intravenous anaesthesia (TIVA) with propofol 1% 6–12?mg/kg per hour continuously after induction with 3?mg/kg. The action profile of alcuronium 0.25?mg/kg (group B) and atracurium 0.5?mg/kg (group D) were recorded. Group E patients received thiopentone (10?mg/kg per hour) under the use of atracurium 0.5?mg/kg. Ventilation was performed with 30%/70% oxygen and N₂O. The results were analyzed for significance using the Mann-Whitney U-test (P=0.019). Results. A slight difference in AZ was noted for alcuronium under the use of TIVA between propofol and thiopentone: 13?min and 5?min, respectively. Otherwise, the pharmacodynamics (T% and recovery of neuromuscular function) of the two relaxants exhibited no major differences related to thiopentone, propofol or their combination. The TOF was not influenced under additional propofol application. Noteworthy were the wide distribution of the time course of action (up to 3?h) and the magnitude of T% depression under alcuronium. Conclusion. Propofol and thiopentone have no potentiating influence on the time course of action and the magnitude of relaxation with alcuronium and atracurium. Pharmacodynamics of nondepolarizing muscle relaxants do not seem to be influenced by these two hypnotics.     

The intubating laryngeal mask airway in severe ankylosing spondylitis

PURPOSE: To evaluate the use of inhalational induction followed by intubation through the intubating laryngeal mask (ILM) for patients with severe ankylosing spondylitis undergoing elective surgery who prefer airway management under anesthesia. METHODS: Nine patients undergoing a total of 11 procedures were enrolled in the study. Fentanyl 2 microg*kg(-1), midazolam 0.035 mg*kg(-1) and sevoflurane in oxygen 100% were used for induction. The ILM was inserted when the end-tidal sevoflurane concentration reached 3%. After an effective airway was established, atracurium 0.5 mg*kg(-1) was given. A polyvinyl chloride tube in the reversed position using a blind technique was used to intubate the trachea. RESULTS: The ILM provided an effective airway on 11/11 occasions at the first attempt. Intubation was successful at the first attempt on 7/11 occasions, at the second attempt on 2/11 and at the third attempt in 1/11. Intubation failed in one patient. The mean (range) minimal oxygen saturation was 99.4% (97-100%). There were no problems with ILM removal. CONCLUSION: Inhalational induction followed by ILM insertion and blind intubation is a reasonable option in patients with severe ankylosing spondylitis undergoing elective surgery who prefer airway management under anesthesia.     

Sevoflurane vs isoflurane anaesthesia: a study of postoperative mental concentration and fine motor movements

Ambulatory anaesthesia is a challenging specialty. Often locoregional techniques are preferred due to the speedy recovery and short hospital stay. However a reasonable number of day-case surgery are performed under general anaesthesia where the recovery of cognitive functions are delayed. Therefore we conducted this study in order to assess the postoperative mental concentration and fine motor movements following isoflurane versus sevoflurane anaesthesia. Twenty adult patients were enrolled in the study. They were ASA 1, age 33 +/- 10 yr and weight 68 +/- 7 kg. They were divided into two groups A and B for isoflurane and sevoflurane respectively. After routine monitoring, induction for both groups was achieved with propofol, endotracheal intubation was facilitated with atracurium and maintenance with either isoflurane or sevoflurane 1 MAC with 50% nitrous oxide in oxygen. During the recovery period the cognitive functions were assessed using the tracing test equipment where the time error product (TEP) was used as a test score. In both groups 30 min after anaesthesia the TEP was 10,000 sec. Thirty minutes later the median TEP was 6,316 sec and 10,000 sec in groups A and B respectively. Another thirty minutes later, the TEP median was 4,052 sec and 1,209 sec for groups A and B respectively. Five hours after anaesthesia the TEP in both groups became identical but still significantly higher compared with the preoperative values. In the present study the TEP was reduced in the sevoflurane group 2 hr after anaesthesia from 10,000 sec to nearly 1,000 sec where in the isoflurane group it was reduced from 10,000 sec to 4,000 sec. In conclusion, sevoflurane anaesthesia resulted in superior recovery of the early TEP scores compared to isoflurane but in both groups the late TEP scores were identical. We believe that following general anaesthesia in day-case set up the patients should refrain from any kind of work that necessitates fine motor movement and mental concentration for at least 24 hr postoperatively.