The Effects of Small-Dose Ketamine on Propofol Sedation: Respiration, Postoperative Mood, Perception, Cognition, and Pain

We compared the effects of coadministration of propofol and small-dose ketamine to propofol alone on respiration during monitored anesthesia care. In addition, mood, perception, and cognition in the recovery room, and pain after discharge were evaluated. In the Propofol group (n = 20), patients received propofol 38 +/- 24 microg x kg(-1) x min(-1). The Coadministration group (n = 19) received propofol 33 +/- 13 microg x kg(-1) x min(-1) and ketamine 3.7 +/- 1.5 microg x kg(-1) x min(-1). Respiration was assessed by using end-expiratory PCO(2) measurements at nasal prongs. After surgeries, mood, perception, and thought were assessed by using visual analog scales, and cognition was assessed by Mini-Mental State Examination (MMSE). Pain after discharge was assessed by a five-point rating scale in the evening for 5 days. End-expiratory PCO(2) was lower in the Coadministration group (P < 0.0001). Mood and MMSE scores were higher in the Coadministration group (P < 0.004 and P = 0.001, respectively). Pain scores and analgesic consumption after discharge were less in the Coadministration group (P = 0.0004 and P < 0.0001, respectively). We conclude that coadministration of small-dose ketamine attenuates propofol-induced hypoventilation, produces positive mood effects without perceptual changes after surgery, and may provide earlier recovery of cognition.

Oesophageal Doppler monitoring overestimates cardiac output during lumbar epidural anaesthesia

Oesophageal Doppler monitoring (ODM) has been advocated as a non-invasive means of measuring cardiac output (CO). However, its reliance upon blood flow measurement in the descending aorta to estimate CO is susceptible to error if blood flow is redistributed between the upper and lower body. We hypothesize that lumbar epidural anesthesia (LEA), which causes blood flow redistribution, causes errors in CO estimates. We compared ODM with thermodilution (TD) measurements in fourteen patients under general anaesthesia for radical prostatectomy, who had received an epidural catheter at the intervertebral level L2-L3. Coupled measurements of CO by means of the TD and ODM techniques were performed at baseline (general anaesthetic only) and after epidural administration of 10 ml of 0.25% bupivacaine. The two methods were compared using Bland-Altman analysis: before LEA there was a bias of -0.89 litre min(-1) with limits of agreement ranging between -2.67 and +0.88 litre min(-1). Following lumbar sympathetic block, bias became positive (+0.55 litre min(-1)) and limits of agreement increased to -3.21 and +4.30 litre min(-1). ODM measured a greater increase in CO after LEA (delta=+1.71 (1.19) litre min(-1) (mean (SD)) compared with TD (delta=+0.51 (0.70) litre min(-1)). We conclude that following LEA, measurements with the Oesophageal Doppler Monitor II overestimate CO and show unacceptably high variability. Blood flow redistribution may limit the value of ODM.

Influence of sepsis on sevoflurane minimum alveolar concentration in a porcine model

Sevoflurane is widely used in anaesthetic protocols for patients undergoing surgical procedures. However, there are no reports on the influence of sepsis on minimum alveolar concentration of sevoflurane (MAC(SEV)) in animals or in humans. The aim of this study was to test the hypothesis that sepsis could alter the MAC(SEV) in a normotensive septic pig model. Twenty young, healthy pigs were used. After they had received 10 mg kg(-1) of ketamine i.m. for premedication, anaesthesia was established with propofol 3 mg kg(-1) and the trachea was intubated. Sevoflurane was used as the sole anaesthetic agent. Baseline haemodynamic recording included electrocardiography, carotid artery blood pressure and a pulmonary thermodilution catheter. Baseline MAC(SEV) in each pig was evaluated by pinching with a haemostat applied for 1 min to a rear dewclaw. MAC(SEV) was determined using incremental changes in sevoflurane concentration until purposeful movement appeared. Pigs were assigned randomly to two groups: the saline group (n = 10) received a 1-h i.v. infusion of sterile saline solution while the sepsis group (n = 10) received a 1-h i.v. infusion of live Pseudomonas aeruginosa. Epinephrine and hydroxyethylstarch were used to maintain normotensive and normovolemic haemodynamic status. In both groups, MAC(SEV) was evaluated 5 h after infusion. Significant increases in mean artery pulmonary pressure, filling, epinephrine and vascular pulmonary resistances occurred in the sepsis group. MAC(SEV) for the saline group was 2.4% [95% confidence interval (CI) 2.1-2.55%] and the MAC(SEV) for the sepsis group was 1.35% (95% CI 1.2-1.45%, P<0.05). These data indicate that MAC(SEV) is significantly decreased in this normotensive septic pig model.

Monitoring level of sedation with bispectral EEG analysis: comparison between hypothermic and normothermic cardiopulmonary bypass

The level of sedation of 28 patients undergoing elective coronary artery bypass grafting with fentanyl-propofol anaesthesia was monitored with bispectral analysis (BIS), spectral edge frequency, and band power of the electroencephalogram. Fourteen patients underwent hypothermic cardiopulmonary bypass (CPB) (32 degrees C, group H), and 14 normothermic CPB (group N). The level of sedation was measured with Observer's Assessment of Alertness/Sedation Score and with Ramsay Sedation Score. BIS was the only EEG measurement that paralleled the clinical course of the patients' sedation level. Values (median, 95% confidence intervals (CI)) changed significantly over time in both groups (P<0.0001). In group H, BIS decreased from 97 (95, 99) the day before surgery to 48 (44, 52) after tracheal intubation, to 46 (41, 52) before going off CPB, to 91 (85, 97) immediately before extubation. In group N, values were 93 (91, 97) the day before surgery, 53 (47, 59) after tracheal intubation, 48 (43, 53) before going off CPB, and 90 (84, 96) before extubation. During CPB, BIS values were significantly different between the two groups. Group H had a median of 41 (95% CI, 39, 42), and group N had a median of 49 (95% CI, 48, 51, P<0.0001). Peak values of all other processed EEG parameters during anaesthesia and surgery overlapped with values from the day before, when patients had no sedating medication, and these values did not correlate to the patients' course of sedation during the study. There was no explicit recall of the surgery in either group. During the phases of anaesthesia and surgery without CPB, the progression of BIS levels was comparable with previously published data for non-cardiac surgery. During normothermic CPB, the highest BIS values were close to values representing insufficient depth of sedation. It remains to be elucidated whether the much lower BIS values in the hypothermic group were solely a result of brain cooling or if increased serum propofol concentrations, because of slowed pharmacodynamics during hypothermia, also contributed.

[A case of coring on using a 1% Diprivan vial]

We report a case in which two fragments due to coring from the rubbercap of a 50 ml Diprivan vial were detected only immediately before infusion to a patient. The attending anesthesiologist noticed the foreign bodies by chance. The rubbercap was punctured only once, but the two foreign bodies from the syringe were proved to be from the rubbercap by infrared spectrometer analysis. It is difficult to recognize the small fragments in Diprivan which is white unclear emulsion. Therefore, anesthesiologists should be aware of the danger of coring.

[Perioperative management using propofol in a patient with uncontrolled preoperative hyperthyroidism]

There is a risk of thyrotoxic crisis during and after surgery in patients with uncontrolled hyperthyroidism. To avoid this, suppression of sympathetic activity during the perioperative period is important. For this purpose, we used propofol for the anesthetic and the postoperative management in a 19-year-old female with uncontrolled hyperthyroidism. Propofol 6 to 8 mg.kg-1.hr-1 plus 66% of nitrous oxide was not sufficient to obtain hemodynamic stability during the surgery, but propofol 3 mg.kg-1.hr-1 produced optimal sedation in the postoperative period. The results demonstrate that propofol is useful for the anesthetic management of patients with uncontrolled hyperthyroidism.

[A case of pulmonary edema after electroconvulsive therapy under propofol anesthesia]

Electroconvulsive therapy (ECT) was scheduled for a 61-yr-old woman with major depression who had been taking a beta-blocker for hypertension. She underwent the first ECT under thiamylal anesthesia uneventfully. The second ECT was performed under propofol anesthesia on the next day. Immediately after ECT, the heart rate dropped from 56 to 19 beats.min-1, which was remedied by intravenous atropine. Then, the blood pressure increased to 204/108 mmHg but it was controlled by nicardipine. However, the SpO2 decreased to 84-88% under oxygen administration by mask at a rate of 3 l.min-1. The patient complained of chest discomfort and had a bloody secretion from the trachea. A chest X-ray showed a butterfly shadow. The patient was diagnosed as having neurogenic pulmonary edema and was treated in the ICU by artificial ventilation and administration of diuretics and catecholamines. These treatments proved to be successful, and the patient was discharged from the ICU 4 days later uneventfully. This case indicates that hemodynamics should be carefully monitored following ECT and that care should be taken to prevent the occurrence of complications after ECT.

[The effects of conscious sedation by propofol on respiration during abdominal hysterectomy under spinal anesthesia]

The effects of conscious sedation by propofol on respiration were studied in 28 patients undergoing abdominal hysterectomy under spinal anesthesia. The patients were randomly assigned to receive conscious sedation by propofol (Group P, n = 20) or no sedation (Group C, n = 8). After a satisfactory level of analgesia had been achieved, a loading dose of propofol, 0.2 mg.kg-1 was administered every minute in Group P until patients exhibited spontaneous eye closure or nystagmus. Thereafter, the infusion rates were adjusted to maintain conscious sedation. Respiratory rate, SpO2 and nasal PETCO2 were measured every minute during the initial 30 minutes and subsequently at 5-min intervals. The patients were questioned on the 1st postoperative day concerning intraoperative recall and the level of satisfaction. The mean loading dose of propofol was 0.4 mg.kg-1 and the mean mainteinance rate was 1.7 +/- 0.5 mg.kg-1.h-1. Compared with Group C, the respiratory depression was less in Group P; SpO2 was significantly higher at 25 min after spinal tap and PETCO2 was significantly lower at 30 and 50 min after spinal tap in Group P. A score of patient satisfaction was significantly higher in Group P. Conscious sedation by propofol is a safe and useful supplement to spinal anesthesia for abdominal hysterectomy.

Propofol/remifentanil versus propofol alone for bone marrow aspiration in paediatric haemato-oncological patients

BACKGROUND

This prospective randomized study was designed to evaluate the effects of adding remifentanil to the standard propofol-based technique in the setting of paediatric haematology-oncology outpatient clinic.

METHODS

Eighty ASA III paediatric patients treated in the outpatient haematology-oncology clinic requiring bone marrow aspiration were randomly assigned either to the propofol (P) or the propofol/remifentanil (PR) group. The quality of anaesthesia and recovery were evaluated.

RESULTS

The total amount of propofol required to prevent patient movement was lower in the PR group. The time interval to eye opening and to home readiness was significantly lower in the PR group. Adverse respiratory events (RR < 10.min-1 or SpO2 < 90%) occurred significantly more in the propofol/remifentanil group.

CONCLUSIONS

The addition of remifentanil improved the conditions during the procedure and reduced the total amount of propofol, as well as the time to home readiness. However, the addition of remifentanil is associated with an increased risk of respiratory depression.

Activation of interictal spiking in mesiotemporal lobe epilepsy by propofol-induced sleep

The objective of this study was to test whether low-dose propofol increases the number of interictal spikes in patients with mesiotemporal lobe epilepsy, and to determine whether this is the result of intrinsic properties and is restricted to the primary epileptogenic focus. Controlled infusion of propofol in step-up/-down target concentrations of 0, 0.3, 0.6, and 0.8 mg/L was administered to 10 patients during a 3.5-hour daytime EEG registration. The number of spikes were counted and related to propofol concentration and sleep level. Results were compared with a spontaneous, nocturnal first sleep cycle in 9 of 10 patients. All patients entered nonrapid eye movement 1 sleep during propofol administration, and 8 reached nonrapid eye movement 2 sleep. In 7 patients who showed spikes, spikes were related to sleep (P < 0.05) and not to increasing (P = 0.1) or decreasing (P = 0.5) propofol concentration. Six of nine patients showed more spikes during spontaneous (nocturnal) sleep than during propofol-induced sleep. Contralateral spiking was not suppressed selectively. Low-dose propofol is a safe means of increasing spiking in these patients because it induces sleep. There were no signs of an intrinsic epileptogenicity of propofol or a selective effect on ipsilateral spikes. Controlled sleep induction will increase the yield of interictal spikes during short interictal recordings such as in magnetoencephalography.

[Anesthesia for electroconvulsive therapy: propofol versus thiopental]

The anesthesia for sismotherapy is characterized by its briefness and repetitiveness, resulting in several imperatives: anesthesia of short duration, deep narcosis with muscular relaxation and ambulatory character. Thus anesthesic drugs should have a fast onset of action, in order to obtain a rapid and as alert as possible post anesthesia awakening. The objective of this study is to compare two anesthesic drugs: propofol versus thiopentone. We included in this study patients referred to our unit by the psychiatric service for sismotherapy, which was carried on under general anesthesia in the awakening room of the anesthesia department of Ibn Rochd University hospital. 7 of our patients received sismotherapy for schizophrenia, 2 for acute mania and 1 for suicidal depression. A total of 40 sessions of sismotherapy were analyzed, distributed in two groups: group I (n = 20): benefitted of a general anesthesia by thiopentone, the dose was 2 to 3 mg/kg; group II (n = 20): benefitted of general anesthesia by propofol, the dose was 1 to 1.5 mg/kg. Sismotherapy was carried out only once narcosis was considered as deep. To monitor our patients we used electrocardioscope and pulpe oxymeter. We evaluated the quality and especially the time of onset of anesthesia, its duration, the quality of narcosis, the degree of muscular relaxation, respiratory and cardiovascular parameters as well as side effect linked to anesthesia drugs and sismotherapy. Analysis of the results showed that the quality of anesthesia was excellent for both groups. The necessary dose for narcosis was 202 mg for thiopentone and 167 mg for propofol, time of onset of narcosis was 30 seconds for propofol and 45 seconds for thiopentone, anesthesia and the quality of muscular relaxation were considered deep for the two groups. Many authors showed that propofol is the most efficient agent in anesthesia for sismotherapy due to its brief delay of action and faster reversibility. As for thiopentone despite its convulsive properties and poor hemodynamic tolerance, it still is a good hypnotic in anesthesia for sismotherapy when administered at appropriate dose by slow injection. This is due on the one hand to easy administration, lesser incidence of side effects and on the other hand to brief duration of action and low cost. We conclude that thiopentone can be recommended in anesthesia for sismotherapy owing to good properties: deepness of anesthesia, good awakening, tolerance and lower cost.

Does discontinuation of desflurane at the time of neostigmine administration speed recovery from cisatracurium block compared to that with a propofol-based technique?

BACKGROUND

Volatile anaesthetics are known to influence the effect of neostigmine as an antagonist of neuromuscular block. The aim of the present study was to investigate whether discontinuation of desflurane at the time of neostigmine administration shortens reversal time from cisatracurium block, compared to that with a propofol-based anaesthesia.

METHODS

Ten volunteers were studied twice. For one study, anaesthesia was induced with alfentanil and propofol and maintained with nitrous oxide 70% and propofol 150 microg. kg-1. min-1. For the other study, experimental conditions were replicated except that desflurane 6% was administered and the dose of propofol was only 50 microg. kg-1. min-1. The evoked mechanical response of the adductor pollicis to train-of-four (TOF) stimulation was recorded. Neuromuscular block was induced with cisatracurium 0.2 mg. kg-1. When the magnitude of the first TOF response (T1) had recovered to 10%, the block was antagonized with neostigmine 70 microg. kg-1. At this time, propofol was decreased to 50 microg. kg-1. min-1, or the desflurane was discontinued.

RESULTS

There were no significant differences between the two techniques of anaesthesia in the rate of neostigmine-induced recovery of the TOF ratio. The times (mean+/-SD) to achieve TOF ratios of 0.7, 0.8, and 0.9 were (propofol first, desflurane second) 6.1+/-2.2 and 6.5+/-1.6 min; 10.4+/-4.2 and 9.6+/-2.7 min; 17.1+/-6.9 and 21.0+/-13.0 min, respectively.

CONCLUSION

Discontinuing desflurane does not speed neostigmine-induced recovery from cisatracurium neuromuscular block, when compared to that during propofol-based anaesthesia.

[Anesthetic management of a patient with tetanus using epidural anesthesia]

A 75-year-old woman with breast cancer complicated with tetanus was scheduled for mastectomy. Since severe bradycardia (17 beats.min-1) was detected by preoperative Holter monitoring, a temporary pacing catheter was inserted. She underwent mastectomy under general anesthesia using propofol combined with thoracic epidural anesthesia. She also received postoperative thoracic epidural block. Her perioperative heart rate was 80-105 beats.min-1 and the rhythm was sinus. There was no marked perioperative cardiovascular derangement.

A randomized double-blinded multicenter comparison of remifentanil versus fentanyl when combined with isoflurane/propofol for early extubation in coronary artery bypass graft surgery

We compared a fentanyl/isoflurane/propofol regimen with a remifentanil/isoflurane/propofol regimen for fast-track cardiac anesthesia in a prospective, randomized, double-blinded study on patients undergoing elective coronary artery bypass graft surgery. Anesthesia was induced with a 1-min infusion of 0.5 mg/kg propofol followed by 10-mg boluses of propofol every 30 s until loss of consciousness. After 0.2 mg/kg cisatracurium, a blinded continuous infusion of remifentanil at 1 microg. kg(-1). min(-1) or the equivalent volume rate of normal saline was then started. In addition, a blinded bolus syringe of 1 microg/kg remifentanil or 10 microg/kg fentanyl, respectively, was given over 3 min. Blinded remifentanil, 1 microg. kg(-1). min(-1) (or the equivalent volume rate of normal saline), together with 0.5% isoflurane, were used to maintain anesthesia. Significantly more patients (P < 0.01) in the fentanyl regimen experienced hypertension during skin incision and maximum sternal spread compared with patients in the remifentanil regimen. There were no differences between the groups in time until extubation, discharge from the surgical intensive care unit, ST segment and other electrocardiogram changes, catecholamine levels, or cardiac enzymes. The remifentanil-based anesthetic (consisting of a bolus followed by a continuous infusion) resulted in significantly less response to surgical stimulation and less need for anesthetic interventions compared with the fentanyl regimen (consisting of an initial bolus, and followed by subsequent boluses only to treat hemodynamic responses) with both drug regimens allowing early extubation.

IMPLICATIONS

Both fentanyl and the newer opioid remifentanil, when each is combined with isoflurane and propofol, allowed for fast-track cardiac anesthesia. The remifentanil regimen used in this study resulted in significantly less hemodynamic response to surgical stimulation.

[Minimally invasive stereotactic functional surgery using an intravenous anesthetic propofol and applying Image Fusion and AtlasPlan]

Image-guided stereotactic surgery of the ventralis intermedius nucleus of the thalamus, globus pallidus, and subthalamic nucleus is a prevailing modality as a treatment of movement disorders. This technical note describes a method of minimally-invasive stereotactic functional surgery for patients with parkinsonian symptom or various tremors. Patients were administered propofol, an intravenous anesthetic, during placement of a burr hole and a stereotactic frame, but not the period when the patients were necessary to be awake. The intravenous anesthesia was very beneficial to relieve local pain and mental stress of the patients. Radionics ImageFusion and AtlasPlan were used for defining the target localization without an intraoperative ventriculography. ImageFusion efficiently fused high-resolution MR images on CT images. AtlasPlan accurately corrected the localization of the tentative target point after measurements from the midpoint of the anterior commissure-posterior commissure line on the modified MRI, and enabled us to reduce the degree of an intraoperative correction to fix a final target. Stereotactic functional surgery has been thought to be less-invasive, however further modifications of surgical procedure and intraoperative medication can make this type of surgery much more less-invasive.

Auditory information processing during adequate propofol anesthesia monitored by electroencephalogram bispectral index

Memory for intraoperative events may arise from inadequate anesthesia when the hypnotic state is not continuously monitored. Electroencephalogram bispectral index (BIS) enables monitoring of the hypnotic state and titration of anesthesia to an adequate level (BIS 40 to 60). At this level, preserved memory function has been observed in trauma patients. We investigated memory formation in elective surgical outpatients during target-controlled propofol anesthesia supplemented with alfentanil. While BIS remained between 40 and 60, patients listened to a tape with either familiar instances (exemplars) from two categories (Experimental [E] group, n = 41) or bird sounds (Control [C] group, n = 41). After recovery, memory was tested directly and indirectly. BIS during audio presentation was on average (+/- SD) 44 +/- 5 and 46 +/- 5 for Groups E and C, respectively. No patient consciously recalled the intraoperative period, nor were presented words recognized reliably (Group E, 0.9 +/- 0.8 hits; Group C, 0.8 +/- 0.8 hits) (P = 0.7). When asked to generate category exemplars, Group E named 2.10 +/- 1.0 hits versus 1.98 +/- 1.0 in Group C (P = 0.9). We found no explicit or implicit memory effect of familiar words presented during adequate propofol anesthesia at BIS levels between 40 and 60 in elective surgical patients.

IMPLICATIONS

This study suggests that stable levels of adequate hypnosis may prevent information processing and memory formation during general anesthesia and supports the feasibility of electroencephalogram bispectral index as a monitor of adequate anesthesia.

[Anesthetic management of a hyper-obese patient by target-controlled infusion (TCI) of propofol and fentanyl]

We gave total intravenous anesthesia to an over-100% hyper-obese patient using target-controlled infusion (TCI) of propofol and fentanyl. To keep him asleep, we maintained his BIS in a range of 40 to 60 by adjusting the target concentration of propofol. For the target concentration of fentanyl, we chose 2 ng.ml-1 at incision and 1.6 ng.ml-1 during the operation. At the patient's emergence from anesthesia, his estimated blood concentration of propofol was 1.51 micrograms.ml-1 and his BIS was 80. The relationship between BIS value and effect-site concentration of propofol was almost the same as that assessed in ordinary adults of a normal weight. We conclude that the estimated concentration of propofol is a good indicator of the effect of propofol and that TCI is a useful technique in obese patients as well as in ordinary adults.

Bronchoskopische Intubation in Remifentanil-Propofol-Sedierung

OBJECTIVE

Fiberoptic intubation for the management of the difficult airway is usually achieved with the patient under light sedation. The goal of the present study was to evaluate the combination of propofol and remifentanil for sedation during fiberoptic intubation.

METHODS

Plans were made to use fiberoptic intubation in 40 patients with predictably difficult airways. After topical anaesthesia of the pharynx with lidocaine, oxygen was administered via nasal cannula. A capnograph was attached to determine the adequacy of ventilation and an infusion of remifentanil (0.05 microgram/kg/min) and propofol (2 mg/kg/h) was started. After the first signs of sedation, nasal fiberoptic intubation was carried out. The depth of sedation was guided by clinical observation and capnographic data and the remifentanil dose was adjusted as necessary.

RESULTS

All patients, including some with very severe airway anomalies, were uneventfully intubated using the regimen we have described. Nasal capnography made it possible to monitor ventilation in all patients during bronchoscopy and intubation. The onset of hypoventilation was recognized in patients and appropriately treated by adjusting the narcotic dose. No subject became hypoxic or hypercarbic during the procedure. The changes of blood pressure and heart rate exceeded the 30% range in only one patient (a 37% blood pressure increase). Sedation was rated as good to very good in 35 patients. Coughing occurred only in 5 patients and 37 out of 40 patients had no recall that intubation had occurred.

CONCLUSION

Our combination of remifentanil and propofol was shown to be a safe sedation regimen for fiberoptic intubation. Monitoring ventilation via nasal capnography and arterial oxygen saturation via pulse oximetry provided sufficient patient safety.

Propofol vs midazolam for ICU sedation : a Canadian multicenter randomized trial

STUDY OBJECTIVES

To determine whether sedation with propofol would lead to shorter times to tracheal extubation and ICU length of stay than sedation with midazolam.

DESIGN

Multicenter, randomized, open label.

SETTING

Four academic tertiary-care ICUs in Canada.

PATIENTS

Critically ill patients requiring continuous sedation while receiving mechanical ventilation.

INTERVENTIONS

Random allocation by predicted requirement for mechanical ventilation (short sedation stratum, < 24 h; medium sedation stratum, > or = 24 and < 72 h; and long sedation stratum, > or = 72 h) to sedation regimens utilizing propofol or midazolam.

MEASUREMENTS AND RESULTS

Using an intention-to-treat analysis, patients randomized to receive propofol in the short sedation stratum (propofol, 21 patients; midazolam, 26 patients) and the long sedation stratum (propofol, 4 patients; midazolam, 10 patients) were extubated earlier (short sedation stratum: propofol, 5.6 h; midazolam, 11.9 h; long sedation stratum: propofol, 8.4 h; midazolam, 46.8 h; p < 0.05). Pooled results showed that patients treated with propofol (n = 46) were extubated earlier than those treated with midazolam (n = 53) (6.7 vs 24.7 h, respectively; p < 0.05) following discontinuation of the sedation but were not discharged from ICU earlier (94.0 vs 63.7 h, respectively; p = 0.26). Propofol-treated patients spent a larger percentage of time at the target Ramsay sedation level than midazolam-treated patients (60.2% vs 44.0%, respectively; p < 0.05). Using a treatment-received analysis, propofol sedation either did not differ from midazolam sedation in time to tracheal extubation or ICU discharge (sedation duration, < 24 h) or was associated with earlier tracheal extubation but longer time to ICU discharge (sedation duration, > or = 24 h, < 72 h, or > or = 72 h).

CONCLUSIONS

The use of propofol sedation allowed for more rapid tracheal extubation than when midazolam sedation was employed. This did not result in earlier ICU discharge.

Comparison of sevoflurane-nitrous oxide anaesthesia with the conventional intravenous-inhalational technique using bispectral index monitoring

Ninety-one patients were randomly allocated to one of two groups. Group A was induced with a single vital capacity breath of 6% (end-tidal) sevoflurane in nitrous oxide-oxygen (2 : 1 l.min-1), whereas group B was induced with intravenous fentanyl 1 microg.kg-1 + propofol 2 mg.kg-1 followed by nitrous oxide-oxygen (2 : 1 l.min-1) and sevoflurane. Induction was considered to have been achieved when the bispectral index value decreased to below 70. Mean induction time in group A (95.2 s, 95% CI 88.5-101.9 s) was longer than group B (70.3 s, 95% CI 66.3-74.3 s; p < 0.0001). Mild coughing was more common in group A, but relative hypotension was more common in group B. There was no difference in the emergence times. Thirty minutes after emergence, there was no difference in the incidence of adverse effects, with the exception of essentially mild abdominal pain which was more frequent in group A.

[Recovery characteristics of propofol anesthesia in pediatric outpatients; comparison with sevoflurane anesthesia]

We compared recovery characteristics of propofol anesthesia with those of sevoflurane anesthesia in pediatric outpatients. One hundred and four children, 3 months to 6 years of age, ASA physical status 1 or 2, were randomly assigned to following four groups; sevoflurane (group S), propofol (group P), sevoflurane with premedication (group MS), or propofol with premedication (group MP). Midazolam 0.5 mg.kg-1 and famotidine 1 mg.kg-1 were administered orally 30 min before the induction in the MS and MP group. Recovery from anesthesia, agitation, and postoperative pain were evaluated. The time intervals from the end of surgery to extubation and to discharge from the hospital were recorded. The incidence of vomiting and use of analgesic drugs were also checked. The emergence from anesthesia was slower with propofol anesthesia than with sevoflurane anesthesia, but the time to discharge from the hospital was not significantly different among the four groups. Incidence of agitation was higher in S group compared with P group, but there were no differences between MS and MP. Postoperative pain was similar among the four groups. There were no differences in the incidence of vomiting. Propofol anesthesia provided slower emergence and less agitation compared with sevoflurane anesthesia.

[Changes in sedative level during induction of anesthesia using a single volatile anesthetic]

We investigated the changes in sedative level during induction of anesthesia using a single volatile anesthetic, sevoflurane, compared with the changes when propofol and sevoflurane were used. We used a bispectral index (BIS) monitor (Aspect, Newton, USA) to monitor the sedative level. Thirty patients were randomly divided into one group receiving sevoflurane alone (S group, n = 15) and another group receiving propofol and sevoflurane (PS group, n = 15). The S group received 5% sevoflurane with nitrous oxide 6 l.min-1 and oxygen 3 l.min-1 via a face mask, while the PS group received propofol 1.5 mg.kg-1 i.v. followed by step-wise increasing sevoflurane up to 5%. Induction times, as assessed by loss of eyelash reflex, were 32 s in the PS group and 65 s in the S group. The decrease in the BIS value was smooth in the S group, whereas it increased transiently and varied greatly in the PS group. Two patients in the PS group showed body movement during induction of anesthesia, and the BIS values in both cases transiently exceeded 60. BIS monitor is useful for monitoring the sedative level during induction of anesthesia, and induction using a single volatile anesthetic such as sevoflurane is smooth.

Ultra-fast-track anesthetic technique facilitates operating room extubation in patients undergoing off-pump coronary revascularization surgery

OBJECTIVE

To determine if implementation of ultra-fast-track anesthetic (UFTA) technique facilitates operating room extubation in patients undergoing off-pump coronary artery bypass graft (CABG) surgery.

DESIGN

Retrospective review.

SETTING

Referral center for cardiovascular surgery at a university hospital.

PARTICIPANTS

Thirty-seven patients undergoing off-pump CABG surgery.

INTERVENTIONS

Two groups represented UFTA (n = 10) and standard anesthetic (controls, n = 27) techniques. Anesthesia was conducted with propofol, remifentanil, vecuronium, and thoracic epidural analgesia in the UFTA group and thiopental, fentanyl, pancuronium, and isoflurane in the control group. Active temperature control was an integral part of the UFTA technique but not the standard technique. The active temperature control included intravenous fluid warmer, prewarmed skin preparation, humidified inspired gases, a circulating water warming blanket, and a forced-air warmer, along with the maintenance of the operating room temperature at 24 degrees C. The control group was managed with an intravenous fluid warmer, and the ambient temperature remained constant (20 degrees C). Patients who did not satisfy extubation criteria within 30 minutes from the end of surgery were sedated and transferred to the intensive care unit (ICU).

MEASUREMENTS AND MAIN RESULTS

All patients in the UFTA group and 2 in the control group were extubated in the operating room immediately after surgery. None of the patients required reintubation. There was no significant difference in postextubation PaO(2) and PaCO(2) between the groups. Nasopharyngeal temperature decreased from 36.7 +/- 0.4 degrees C to 36.4 +/- 0.3 degrees C in the UFTA group and from 36.6 +/- 0.5 degrees C to 35.6 +/- 0.4 degrees C in the control group (p < 0.0001). Bradycardia occurred significantly more often in the UFTA group but there was no difference in episodes of hypotension. There were no perioperative deaths. Patients who were extubated in the operating room required lower nurse-to-patient acuity ratio (1:2) in the ICU. No difference was found in ICU and hospital length of stay.

CONCLUSIONS

Implementation of UFTA technique provided adequate hemodynamic control and facilitated operating room extubation in all patients. The impact of UFTA on earlier patient discharge and actual cost savings within a fully integrated post-cardiac surgery unit requires further evaluation.