Anesthesia In Adult Patients Research Articles

Bispectral index in pediatrics: fashion or a new tool?

The bispectral index (BIS, Aspect Medical Systems, Inc. Newton, MA) is becoming the gold standard for assessing depth of anesthesia in adult patients. Indeed, BIS values are highly correlated with the concentration of hypnotic drugs such as propofol or sevoflurane (1–8). The BIS is derived from a large database of EEG traces obtained in adult patients under various conditions of anesthesia (9). This database is regularly updated and the corresponding software is changed accordingly. The calculation of BIS is kept secret, but the elements included into the algorithm are known. Basically, the value displayed takes into account the frequency of EEG signal (the proportion of rapid to slow waves decreases with increasing hypnotic concentration), the synchronization of the waveforms (from virtually no synchronization in awake patient to higher degree of synchronization with increasing depth of anesthesia), and the percentage of burst suppression (the latter being observed at very deep level of anesthesia). The BIS is displayed as a dimensionless number between 0 (deep anesthesia) and 100 (awake), with 40–60 being suitable for surgical anesthesia (10). The BIS has well-known limitations. First, the BIS is more or less insensitive to narcotics, thus it reflects the hypnotic state which is only one component of anesthesia. Therefore it is not surprising that the specificity of BIS for predicting the response to noxious stimuli (such as surgical incision or laryngoscopy) under balanced anesthesia is low. Second, the BIS algorithm was validated mainly against propofol or volatile agents currently in use (isoflurane, desflurane and sevoflurane). BIS values are not correlated with ketamine plasma concentrations and are much higher at a given MAC values of halothane compared with sevoflurane (11). The latter drawbacks are not surprising as EEG traces obtained with these agents are very different from those integrated in the database (i.e. propofol and more recent volatile agents) (12–14). The BIS monitor was developed to assess depth of anesthesia and to decrease the incidence of awareness. The latter objective is achieved (15). Indeed, the B-Aware randomized controlled trial demonstrated that BISguided anesthesia reduces the risk of awareness in at-risk adult surgical patients undergoing relaxant general anesthesia. Other potential benefits in adults include decreased drug consumption, decreased postoperative incidence of nausea and vomiting (16) and quicker recovery time compared with non BIS-guided anesthesia (17). Having said that, one can understand easily that the BIS was conceived as an adult tool, not a pediatric one. Thus, the preliminary questions are: does it work in pediatric patients and if the answer is positive, what could be the interest of this device in pediatric patients? As indicated above, the BIS is only derived from adult EEG traces while EEG traces in young children differ from adult traces. Roughly, from infancy to adulthood, the amplitude of EEG decreases and dominant frequency increases (in other words, EEG becomes composed of faster waves of smaller amplitude with increasing age). However, the effects of anesthetic agents on EEG tracings are comparable throughout life. BIS values recorded in pediatric patients are inversely correlated with endtidal sevoflurane (18–20) and isoflurane concentrations (21) as in adults. BIS values are better Correspondence to: Pr Isabelle Murat, Service d’Anesthesie-Reanimation, Hopital d’enfants Armand Trousseau, 26 avenue du Dr Arnold Netter, 75571 Paris cedex 12, France (email: isabelle. murat@trs.aphp.fr). Pediatric Anesthesia 2005 15: 177–180 doi:10.1111/j.1460-9592.2004.01564.x

Two Reports of Propofol Anesthesia Associated with Metabolic Acidosis in Adults

Two Reports of Propofol Anesthesia Associated with Metabolic Acidosis in Adults

Outpatient urethrocutaneous fistula repair with local anesthesia in adult patients.

The aim of this prospective study was to demonstrate that urethrocutaneous fistulas could be repaired under local anesthesia in adult patients without catheters. Between 1998 and 2000, 32 patients with urethrocutaneous fistulas were repaired under local anesthesia. The patients were divided into two groups in terms of whether they did or did not have catheters. The catheterized group (group I) included 15 patients and the uncatheterized group (group II) included 17 patients. Although the uncatheterized patients were discharged the same day as their operation, catheterized patients were discharged 4 to 6 days postoperatively. Patients were reevaluated on postoperative day 7 and month 3 in terms of wound infection, urethral stricture, and recurrence of fistula. All patients tolerated the fistula repair under local anesthesia. The success rate of fistula repair was 93.3% and 94.1% in the catheterized and uncatheterized groups, respectively. During postoperative days 1 through 7, wound infection was seen in 2 patients in group I but was not noted in the uncatheterized group. Fistulas recurred in one patient from each group (6.6% and 5.8%, respectively) after 3 months postoperatively. As a result, the authors suggest that catheterless fistula repair with local anesthesia in the adult age group is an effective, safe, and inexpensive procedure.

Daily General Anaesthesia for Radiotherapy in Unco-operative Patients: Ingredients for Successful Management

An unco-operative patient requiring daily radiation therapy presents a difficult clinical problem. After reviewing the paediatric oncology literature addressing the use of general anaesthesia for short medical procedures, we have developed checklists of procedural guidelines and monitoring equipment for the safe use of daily anaesthesia in adult patients who require a fractionated course of radiation therapy. We illustrate this by describing the successful treatment of a woman with autism and Hodgkin's disease who required daily general anaesthesia for immobilization during a 4–week course of radiation therapy. Propofol was used as the primary drug and was not associated with any adverse side-effects. There was no development of tolerance.

Regional anaesthesia for limb surgery--before or after general anaesthesia. A survey of anaesthetists in the Oxford region.

We conducted a postal survey of 221 anaesthetists in the Oxford region to determine their views and actual clinical practice regarding regional anaesthesia in adult patients undergoing limb surgery, when a combined regional and general anaesthetic was planned. Of the 162 respondents (73.3%), 142 (87.6%) regularly practised regional blocks for limb surgery in adult patients. For all the regional anaesthetic techniques in question, more anaesthetists felt it was safer to perform these blocks before induction of general anaesthesia than after induction. However, their actual practice varied markedly from their views, with more anaesthetists performing these blocks after general anaesthesia. Overall, trainees performed blocks before induction of general anaesthesia more often than consultants (p = 0.047).

Sevoflurane vs. propofol both combined with epidural anaesthesia in adult patients during major abdominal surgery

Sevoflurane vs. propofol both combined with epidural anaesthesia in adult patients during major abdominal surgery

Comparison of Intubating Conditions After Rapacuronium (Org 9487) and Succinylcholine Following Rapid Sequence Induction in Adult Patients

We have assessed intubating conditions provided by rapacuronium (Org 9487) and succinylcholine after rapid sequence induction of anaesthesia in adult patients undergoing elective surgery. We studied 335 patients, ASA I and II, in five centres. Two hundred and thirty-four subjects with normal body weight and 101 obese subjects were allocated randomly to one of four treatment groups differing in the neuromuscular blocking drug administered (rapacuronium 1.5 mg kg-1 or succinylcholine 1 mg kg-1) and in the technique used for induction of anaesthesia (fentanyl 2-3 micrograms kg-1 with thiopental 3-6 mg kg-1 or alfentanil 20 micrograms kg-1 with propofol 1.5-2 mg kg-1). Intubation was started at 50 s by an anaesthetist blinded to the drugs used. Intubating conditions were clinically acceptable (excellent or good) in 89.4% of patients after rapacuronium and in 97.4% after succinylcholine (P = 0.004), the estimated difference being 8.1% (95% confidence interval (CI) 2.0-14.1%). Neither anaesthetic technique nor subject group had an influence on intubating conditions. After intubation, the maximum increase in heart rate averaged 23.1 (SD 25.4%) and 9.4 (26.1%) after rapacuronium and succinylcholine, respectively (P

Comparison of intubating conditions after rapacuronium (Org 9487) and succinylcholine following rapid sequence induction in adult patients

We have assessed intubating conditions provided by rapacuronium (Org 9487) and succinylcholine after rapid sequence induction of anaesthesia in adult patients undergoing elective surgery. We studied 335 patients, ASA I and II, in five centres. Two hundred and thirty-four subjects with normal body weight and 101 obese subjects were allocated randomly to one of four treatment groups differing in the neuromuscular blocking drug administered (rapacuronium 1.5 mg kg-1 or succinylcholine 1 mg kg-1) and in the technique used for induction of anaesthesia (fentanyl 2-3 micrograms kg-1 with thiopental 3-6 mg kg-1 or alfentanil 20 micrograms kg-1 with propofol 1.5-2 mg kg-1). Intubation was started at 50 s by an anaesthetist blinded to the drugs used. Intubating conditions were clinically acceptable (excellent or good) in 89.4% of patients after rapacuronium and in 97.4% after succinylcholine (P = 0.004), the estimated difference being 8.1% (95% confidence interval (CI) 2.0-14.1%). Neither anaesthetic technique nor subject group had an influence on intubating conditions. After intubation, the maximum increase in heart rate averaged 23.1 (SD 25.4%) and 9.4 (26.1%) after rapacuronium and succinylcholine, respectively (P < 0.001). Pulmonary side effects (bronchospasm and increased airway pressure) were observed in 10.7% (95% CI 5.8-17%) and 4.1% (95% CI 1.3-8.8%) of patients given rapacuronium and succinylcholine, respectively (P = 0.021). We conclude that after rapid sequence induction of anaesthesia in adults, clinically acceptable intubating conditions were achieved less frequently after rapacuronium 1.5 mg kg-1 than after succinylcholine.

Arterial baroreflex function in humans anaesthetized with sevoflurane

Volatile anaesthetic agents attenuate arterial baroreflex function, while noxious stimuli may modify baroreflex-induced circulatory responses during anaesthesia. We have examined baroreflex control of heart rate during the entire course of sevoflurane anaesthesia in adult patients undergoing surgical procedures. Baroreflex sensitivity was assessed in nine healthy patients undergoing general anaesthesia with sevoflurane. After an 8-10-h fast and no premedication, measurements of R-R intervals were made at conscious baseline (awake), during 2% end-tidal sevoflurane and 67% nitrous oxide before incision (anaesthesia), during surgery at 2% end-tidal sevoflurane and 67% nitrous oxide (surgery) and 20 min after extubation (recovery). Baroreflex responses were triggered by bolus i.v. injections of phenylephrine 50-100 micrograms and nitroprusside 100-200 micrograms to increase and decrease systolic arterial pressure by 20-30 mm Hg, respectively. Baroreflex sensitivities to both pressor and depressor tests were significantly depressed during anaesthesia, surgery and the recovery periods compared with awake values. Pressor test sensitivity during recovery increased significantly from that during surgery (mean 6.16 (SD 2.95) vs 4.42 (3.19) ms mm Hg-1; P < 0.05), but was still significantly less than the awake value (22.50 (17.02) ms mm Hg-1). No improvement in the depressor test sensitivity was seen during the recovery period.

The Efficacy of Epinephrine Test Doses during Combined Spinal-Epidural Anesthesia in Adult Patients

The Efficacy of Epinephrine Test Doses during Combined Spinal-Epidural Anesthesia in Adult Patients

Etomidate: Applications in Pediatric Anesthesia and Critical Care

Etomidate is a rapidly acting, intravenous anesthetic agent. Because of its limited effects on cardiovascular function, it has generally been used for the induction of anesthesia in adult patients with compromised cardiorespiratory function. There is limited information concerning its use in children. The author presents three cases and reviews the possible applications of etomidate in the pediatric population.

Endopyelotomy: experience with 320 cases.

We were the first to initiate endopyelotomy in Hungary (in 1986) and in Yemen and Pakistan (in 1993). Through the end of 1995, 320 cases of ureteropelvic junction (UPJ) stenosis have been operated upon. The procedure was performed under local anesthesia in adult patients and general anesthesia in children. The minimum age of the patient was 4 years, while the oldest patient was 80 years of age. The UPJ was incised longitudinally at the posterolateral aspect until the perinephric fat was seen, and a drain of 8F to 12F was inserted transrenally into the ureter through a nephroscope. Patients soon left the hospital and were able to start working in 5 days (average). The drain was removed after 6 weeks. During the follow-up period, ultrasonic examination was performed each 3 months. The success rate (mean of three centers) came out to be 87%. Open pyeloplasty was performed in cases where the symptoms of pyelectasia were persisting and caused complaints and stenosis was present even after 6 months. In our opinion, endopyelotomy should be the procedure of first choice for UPJ stenosis, because it is less troublesome for the patient than open pyeloplasty, and the results are real encouraging.

The Comparative Effects of Sevoflurane Versus Propofol in the Induction and Maintenance of Anesthesia in Adult Patients

A randomized, prospective study was performed at four institutions to compare anesthetic induction, maintenance, and recovery characteristics between sevoflurane- and propofol-based anesthesia in 186 ASA physical status I and 11 patients undergoing elective surgical procedures of 1-3 h. Group 1 (n = 93) patients received sevoflurane-nitrous oxide for both induction and maintenance of anesthesia while Group 2 (n = 93) received propofol-nitrous oxide anesthesia. Induction of anesthesia and tracheal intubation times were significantly shorter with propofol (2.21 +/- 0.2 min, 5.11 +/- 0.3 min, respectively) than with sevoflurane (3.11 +/- 0.2 min, 7.21 +/- 0.3 min, respectively). Emergence times after sevoflurane (8.81 +/- 1.2 min) were significantly shorter than with propofol (13.21 +/- 1.2 min). Overall frequency of complication-free induction, maintenance, and emergence did not differ between the two anesthetic groups. However, side effects involving airway excitement were more prevalent during mask induction with sevoflurane as compared to propofol. Patients in the sevoflurane group were oriented and required postoperative analgesia much earlier than those who received propofol. Both groups were hemodynamically stable throughout the study period. The incidence of postoperative nausea, vomiting, and pain-discomfort scores were similar between the two groups. Urinary specific gravity decreased in the sevoflurane-treated group while serum creatinine and urinary pH were unchanged from preoperative values in both groups. Sevoflurane compared favorably with propofol when used for anesthesia for elective procedures of 1-3 h duration.

Oral clonidine reduces thiamylal requirement for induction of anesthesia in adult patients

Although preanesthetic clonidine, an α-2 agonist, is known to reduce anesthetic requirements, the effect of preanesthetic oral clonidine medication per se on the requirement of thiamylal in adult humans has not yet been examined. One hundred and sixty-one adult patients (14-78 years of age) were randomly assigned to groups that received oral clonidine (5μg·kg(-1) (n=51), 2.5μg·kg(-1) (n=55), or none (n=55)) in addition to 20mg oral famotidine 90min before anesthesia induction. Thiamylal was injected at the rate of 25mg every 15 s until the eyelash reflex disappeared, while blood pressure and heart rate were recorded at 30-s intervals from the start of the induction. Thiamylal requirements were significantly less in both clonidine groups (2.95±0.09 and 3.14±0.10 mg·kg(-1) (mean±SE) for patients receiving 5μg·kg(-1) and 2.5μg·kg(-1) clonidine, respectively) than in the control group (3.81±0.11 mg·kg(-1),P<0.05); however, no difference was found between the two clonidine groups. Although mean blood pressure and heart rate during the study period were significantly lower in both clonidine groups than in the control group, no profound hypotension or marked bradycardia were noted in the clonidine groups.

The Comparative Effects of Sevoflurane Versus Propofol in the Induction and Maintenance of Anesthesia in Adult Patients

The Comparative Effects of Sevoflurane Versus Propofol in the Induction and Maintenance of Anesthesia in Adult Patients

Oral clonidine reduces thiamylal requirement for induction of anesthesia in adult patients

Oral clonidine reduces thiamylal requirement for induction of anesthesia in adult patients

Lansoprazole in the prophylaxis of acid aspiration during elective surgery

We have assessed the efficacy of a single dose of lansoprazole in increasing the pH and decreasing the volume of gastric residue at induction of anaesthesia in adult patients undergoing elective orthopaedic surgery. We studied 66 ASAI-II patients, allocated to one of three groups to receive either placebo (group 1), lansoprazole 30 mg (group 2) or lansoprazole 60 mg (group 3), 8-12 h before induction of anaesthesia. Volume and pH of gastric contents were measured after induction of anaesthesia by aspiration via a 16-French gauge gastric tube. Patients who received lansoprazole had a significantly higher pH than the placebo group (P < 0.01) but there was no difference between the two lansoprazole groups. The volume of gastric residue was significantly smaller (P < 0.01) in both lansoprazole groups compared with the placebo group: 28% of those in group 3 had a pH of gastric residue < 2.5 and volume > 25 ml compared with 30% in group 2 and 63% in group 1, respectively.

Pharmacokinetics of clonidine after rectal administration in children.

alpha 2 Agonists have been shown to produce desirable effects when used as premedication or as an adjunct to general anesthesia in adult patients. Several of these beneficial effects (e.g., reduced anesthetic requirements and analgesia without respiratory depression) would be of great benefit in pediatric anesthesia. Information regarding the use of alpha 2 agonists in children is largely lacking. The aim of this study was to investigate the pharmacokinetics of clonidine after rectal administration in children. Ten ASA physical status 1 pediatric patients (age 14-48 months, weight 10-20 kg) received 2.5 micrograms.kg-1 of clonidine by the rectal route. Blood samples were taken during a 24-h period after the administration. Plasma levels of clonidine were analyzed by radioimmunoassay and subjected to a computer-aided curve-fitting program (PC Nonlin). To estimate the bioavailability of clonidine the results from the current study were compared with data from a previous study in which the same dose of clonidine was given to a similar patient population by the intravenous route. Maximum plasma concentration was 0.77 ng.ml-1 (0.62-0.88), time to maximum plasma concentration 51 min (29-70), terminal half-life 12.5 h (8.7-19.5), and bioavailability 95% (73-119) (medians [95% confidence interval]). Plasma concentrations within the adult clinically effective range (0.2-2.0 ng.ml-1) were obtained within 10 min of administration. Rectal administration of 2.5 micrograms.kg-1 of clonidine in children, approximately 20 min before induction of anesthesia, achieves plasma concentrations within the range known to be clinically effective in adults.

Comparison of Rocuronium, Succinylcholine, and Vecuronium for Rapid-sequence Induction of Anesthesia in Adult Patients

Succinylcholine has been the agent of choice when clinical conditions require emergency airway protection during a rapid-sequence induction of anesthesia. Rocuronium, a new nondepolarizing muscle relaxant with a brief onset of action, but devoid of the adverse reactions associated with succinylcholine, may be an alternative to succinylcholine. To test this hypothesis, the authors compared rocuronium with succinylcholine and vecuronium for rapid-sequence induction of anesthesia. Fifty patients, ASA 1-3, were randomly designated to receive one of three intravenous doses of rocuronium (0.6, 0.9, and 1.2 mg/kg), vecuronium (0.1 mg/kg), or succinylcholine (1.0 mg/kg). Patients were premedicated with midazolam and fentanyl, and received 2-7 mg/kg thiopental for induction of anesthesia. Sixty seconds after receiving a muscle relaxant, intubation of the trachea was attempted by a clinician who was blinded to the muscle relaxant administered. Neuromuscular monitoring was established before administration of the muscle relaxant. The time from injection of muscle relaxant until complete ablation of T1 (onset) and recovery of T1 to 25% (duration) were recorded. Tracheal intubating conditions were evaluated, and the presence or absence of fasciculations was noted. Onset times for patients receiving 0.9 mg/kg (75 +/- 28 s) and 1.2 mg/kg rocuronium (55 +/- 14 s), and succinylcholine (50 +/- 17 s) were similar. Onset times for the groups given 0.6 mg/kg rocuronium (89 +/- 33 s) and vecuronium (144 +/- 39 s) were significantly longer. Clinical duration of action was longest with 1.2 mg/kg rocuronium, similar with 0.6 and 0.9 mg/kg rocuronium, and vecuronium, and least with succinylcholine. There is a dose-dependent decrease in onset time with rocuronium. The onset times for the two larger doses of rocuronium were similar to that for succinylcholine, but clinical duration of action with rocuronium was significantly longer. The brief onset time achieved with rocuronium indicates that administration of 0.9-1.2 mg/kg is an acceptable alternative to succinylcholine for rapid-sequence induction of anesthesia.

Intraocular Pressure during Enflurane and Neurolept Anesthesia in Adult Patients undergoing Ophthalmic Surgery

The effects of neurolept and enflurane anesthesia on intraocular pressure (IOP) were studied in 20 patients undergoing elective ophthalmic surgery. Ten received neurolept and ten enflurane anesthesia. Continuous EEG tracings recorded the level of anesthesia. IOP was measured before and at intervals during anesthesia at varying concentrations of enflurane and incremental doses of fentanyl. During level I neurolept anesthesia IOP increased from control values of 18.10 +/- 0.93 mm Hg (mean +/- SEM) to 19.50 +/- 1.65 mm Hg, but decreased to 14.55 +/- 0.84 mm Hg during level II and to 12.29 +/- 1.13 mm Hg during level III anesthesia. During enflurane anesthesia IOP decreased from control values of 19.00 +/- 1.44 mm Hg (mean +/- SEM) to 14.50 +/- 1.60 mm Hg during level, I, 14.10 +/- 1.04 mm Hg during level II, and 11.60 +/- 1.46 mm Hg during level III anesthesia. The increase in IOP during neurolept level I anesthesia was not statistically significant but the decreases in IOP from control values during levels II and III anesthesia were statistically significant. Decreases in IOP from control values were statistically significant at all levels of enflurance anesthesia. There was, however, no statistical significance between the differences in IOP values during levels II and III neurolept anesthesia, nor between levels I, II, and III enflurane anesthesia. The differences in the mean IOP values between neurolept and enflurane anesthesia were statistically significant only during EEG level I anesthesia.