Volume 4, Issue 6 S A M B A T A L K S - PAGE 3 November, 2004

FROM THE LITERATURE: - TOP


ANESTHESIA AND ANALGESIA - TOP

Propofol-induced injection pain: comparison of a modified propofol emulsion to standard propofol with premixed lidocaine.
Adam S, Van Bommel J, Pelka M, Dirckx M, Jonsson D, Klein J.
Anesth Analg. 2004 Oct;99(4):1076-9.

Propofol is well known for its association with pain on injection. The most frequently used method to reduce this pain is premixture with lidocaine. Recently, a modified lipid emulsion of propofol containing medium-chain triglycerides (MCT) with long-chain triglycerides (LCT), in contrast to the usual LCT formulation, has been advocated to alleviate pain. In a randomized, prospective, controlled, double-blind study on 222 surgical patients, we compared the effect of the two solutions on the incidence and intensity of injection pain. Patients were randomly allocated to receive either propofol MCT/LCT (group M; n = 109) or standard propofol LCT with the addition of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of propofol (group L; n = 113). Pain scores were assessed using a verbal analog scale (VAS) ranging from 0-10. Group L was found to have significantly less pain on the injection of propofol (mean VAS, 2.5 +/- 2.9) (mean +/- sd) than group M (mean VAS, 3.8 +/- 3.2; P = 0.002). Regarding postoperative recall of pain on injection, patients in group L indicated significantly less pain (mean VAS, 2.2 +/- 2.4) than patients in group M (mean VAS, 3.0 +/- 2.7; P = 0.02). Premixing of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of standard propofol LCT causes less pain on injection than propofol MCT/LCT and thus increases patient comfort.
IMPLICATIONS: Premixing of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of standard propofol containing long-chain triglycerides (LCT) causes less pain on injection than propofol containing both medium-chain triglycerides (MCT) and LCT and thus increases patient comfort.

A randomized controlled comparison of electro-acupoint stimulation or ondansetron versus placebo for the prevention of postoperative nausea and vomiting.
Gan TJ, Jiao KR, Zenn M, Georgiade G.
Anesth Analg. 2004 Oct;99(4):1070-5.

In this study we evaluated the efficacy of electro-acupoint stimulation, ondansetron versus placebo for the prevention of postoperative nausea and vomiting (PONV). Patients undergoing major breast surgery under general anesthesia were randomized into active electro-acupoint stimulation (A), ondansetron 4 mg IV (O), or sham control (placement of electrodes without electro-acupoint stimulation; placebo [P]). The anesthetic regimen was standardized. The incidence of nausea, vomiting, rescue antiemetic use, pain, and patient satisfaction with management of PONV were assessed at 0, 30, 60, 90, 120 min, and at 24 h. The complete response (no nausea, vomiting, or use of rescue antiemetic) was significantly more frequent in the active treatment groups compared with placebo both at 2 h (A/O/P = 77%/64%/42%, respectively; P = 0.01) and 24 h postoperatively (A/O/P = 73%/52%/38%, respectively; P = 0.006). The need for rescue antiemetic was less in the treatment groups (A/O/P = 19%/28%/54%; P = 0.04). Specifically, the incidence and severity of nausea were significantly less in the A group compared with the other groups, and in the O group compared with the P group (A/O/P = 19%/40%/79%, respectively). The A group experienced less pain in the postanesthesia care unit, compared with the O and P groups. Patients in the treatment groups were more satisfied with their management of PONV compared with placebo. When used for the prevention of PONV, electro-acupoint stimulation or ondansetron was more effective than placebo with greater degree of patient satisfaction, but electro-acupoint stimulation seems to be more effective in controlling nausea, compared with ondansetron. Stimulation at P6 also has analgesic effects.
IMPLICATIONS: Electro-acupoint stimulation or ondansetron is more effective than placebo for the prevention of postoperative nausea and vomiting but electro-acupoint stimulation is more effective in controlling nausea. Stimulation at P6 has analgesic effects.

The Effects of Cisatracurium on Morbidly Obese Women
Yigal Leykin, MD MSc, Tommaso Pellis, MD, Mariella Lucca, MD, Giacomina Lomangino, MD, Bernardo Marzano, MD, and Antonino Gullo, MD
Anesth Analg 2004;99:1090-1094

There is conflicting evidence on the duration of action of atracurium in obese patients. Cisatracurium is one of the stereoisomers of atracurium. We investigated the neuromuscular effects of cisatracurium in morbidly obese patients. Twenty obese female patients (body mass index >40) were randomized in two groups. Group I (n = 10) received 0.2 mg/kg of cisatracurium on the basis of real body weight (RBW), whereas in Group II (n = 10) the dose was calculated on ideal body weight (IBW). In a control group of 10 normal weight female patients (body mass index 20–24), the dose of cisatracurium was based on RBW. Neuromuscular transmission was monitored using acceleromyography of the adductor pollicis, and anesthesia was induced and maintained with remifentanil and propofol. Onset time was comparable between Group I and the control group (132 s versus 135 s; P = ns). The duration 25% was longer in Group I than in the control group (74.6 min versus 59.1 min; P = 0.01) and in the control group compared with Group II (45.0 min; P = 0.016). In conclusion, the duration of action of cisatracurium was prolonged in morbidly obese patients when dosed according to RBW compared with a control group of normal weight patients. Duration was also prolonged in the control group patients compared with morbidly obese patients to whom the drug was administered on the basis of IBW.
IMPLICATIONS: We investigated the effects of cisatracurium, one of the stereoisomers of atracurium, on morbidly obese patients, prompted by the conflicting evidence reported for atracurium. We concluded that the duration of action of cisatracurium is prolonged when dosed according to real body weight in morbidly obese patients.

Laryngotracheal Topicalization with Lidocaine Before Intubation Decreases the Incidence of Coughing on Emergence from General Anesthesia
Sean C. Minogue, FCARCSI, James Ralph, FRCA, and Martin J. Lampa, FRCPC
Anesth Analg 2004;99:1253-1257

Coughing on emergence can result in a number of undesirable side effects, including hypertension, tachycardia, tachyarrhythmias, increased intracranial pressure, and increased intraocular pressure. The efficacy of endotracheal spraying with lidocaine at the time of intubation in preventing coughing on emergence is unknown. In a double-blind placebo-controlled study, we randomized 50 ASA physical status I and II patients presenting for elective gynecological surgery <2 h duration to receive either endotracheal lidocaine 160 mg or placebo before intubation. Both groups were comparable in terms of demographics and intraoperative conditions. The incidence of coughing before tracheal extubation was less frequent in the lidocaine group (26%) than in the placebo group (66%, P < 0.01), as was the incidence after tracheal extubation (4% versus 30%, P = 0.022). This study supports the use of endotracheal lidocaine before intubation in patients undergoing general anesthesia for surgery <2 h duration where coughing on emergence is undesirable.
IMPLICATIONS: We studied the effect of laryngotracheal spraying with lidocaine before intubation on the incidence of coughing on emergence from general anesthesia in cases <2 h duration and found its use to be associated with a significantly decreased incidence of coughing on emergence.

Perioperative Plasma Concentrations of Stable Nitric Oxide Products Are Predictive of Cognitive Dysfunction After Laparoscopic Cholecystectomy
G. Iohom, FCARCSI, S. Szarvas, MD DEEA, V. Larney, FCARCSI, J. O’Brien, FCARCSI, E. Buckley, FCARCSI, M. Butler, MSc, and G. Shorten, PhD
Anesth Analg 2004;99:1245-1252

In this study our objectives were to determine the incidence of postoperative cognitive dysfunction (POCD) after laparoscopic cholecystectomy under sevoflurane anesthesia in patients aged >40 and <85 yr and to examine the associations between plasma concentrations of i) S-100ß protein and ii) stable nitric oxide (NO) products and POCD in this clinical setting. Neuropsychological tests were performed on 42 ASA physical status I–II patients the day before, and 4 days and 6 wk after surgery. Patient spouses (n = 13) were studied as controls. Cognitive dysfunction was defined as deficit in one or more cognitive domain(s). Serial measurements of serum concentrations of S-100ß protein and plasma concentrations of stable NO products (nitrate/nitrite, NOx) were performed perioperatively. Four days after surgery, new cognitive deficit was present in 16 (40%) patients and in 1 (7%) control subject (P = 0.01). Six weeks postoperatively, new cognitive deficit was present in 21 (53%) patients and 3 (23%) control subjects (P = 0.03). Compared with the "no deficit" group, patients who demonstrated a new cognitive deficit 4 days postoperatively had larger plasma NOx at each perioperative time point (P < 0.05 for each time point). Serum S-100ß protein concentrations were similar in the 2 groups. In conclusion, preoperative (and postoperative) plasma concentrations of stable NO products (but not S-100ß) are associated with early POCD. The former represents a potential biochemical predictor of POCD.
IMPLICATIONS: The results of this prospective observational study suggest that preoperative (and postoperative) plasma concentrations of stable nitric oxide products (but not S-100ß) are associated with early postoperative cognitive dysfunction. The former represents a potential biochemical predictor of postoperative cognitive dysfunction.

ANESTHESIOLOGY - TOP

Severe Neurological Complications after Central Neuraxial Blockades in Sweden 1990-1999.
Moen, Vibeke M.D.; Dahlgren, Nils M.D., Ph.D.; Irestedt, Lars M.D., Ph.D.
Anesthesiology. 101(4):950-959, October 2004.

Background: Central neuraxial blockades find widespread applications. Severe complications are believed to be extremely rare, but the incidence is probably underestimated.
Methods: A retrospective study of severe neurologic complications after central neuraxial blockades in Sweden 1990-1999 was performed. Information was obtained from a postal survey and administrative files in the health care system. During the study period approximately 1,260,000 spinal blockades and 450,000 epidural blockades were administered, including 200,000 epidural blockades for pain relief in labor.
Results: The 127 complications found included spinal hematoma (33), cauda equina syndrome (32), meningitis (29), epidural abscess (13), and miscellaneous (20). Permanent neurologic damage was observed in 85 patients. Incidence of complications after spinal blockade was within 1:20-30,000 in all patient groups. Incidence after obstetric epidural blockade was 1:25,000; in the remaining patients it was 1:3600 (P < 0.0001). Spinal hematoma after obstetric epidural blockade carried the incidence 1:200,000, significantly lower than the incidence 1:3,600 females subject to knee arthroplasty (P < 0.0001).
Conclusions: More complications than expected were found, probably as a result of the comprehensive study design. Half of the complications were retrieved exclusively from administrative files. Complications occur significantly more often after epidural blockade than after spinal blockade, and the complications are different. Obstetric patients carry significantly lower incidence of complications. Osteoporosis is proposed as a previously neglected risk factor. Close surveillance after central neuraxial blockade is mandatory for safe practice.

ACTA ANAESTHESIOLOGICA SCANDINAVICA - TOP

Electromyographic assessment of blink reflexes correlates with a clinical scale of depth of sedation/anaesthesia and BIS during propofol administration
J. Mourisse, J. Lerou, M. Zwarts and L. Booij
Acta Anaesthesiologica Scandinavica 2004; 48: 1174-79

Background:  General anaesthesia is characterized by loss of consciousness, amnesia and obtundation of reflex responses to noxious stimuli. Quantifying the blink reflex may reflect the depression of reflex arches induced by anaesthetics and thus being informative on the anaesthetic state.
Methods:  The relation between the electrically evoked blink reflexes and the depth of sedation and anaesthesia induced with intravenous propofol was investigated. Twenty patients received propofol by target-controlled infusion to create a stepwise deepening of sedation and anaesthesia. Depth of anaesthesia was assessed using the observer's assessment of anaesthesia and sedation (OAAS) scale, and by bispectral EEG analysis (BIS). Probit analysis was used to estimate the predicted propofol effect site concentrations producing unconsciousness, no response to noxious stimulation, and loss of blink reflex components.
Results: Latency of the first (R1) and second (R2) blink component increased, whereas duration and area decreased with increasing depth of sedation and anaesthesia. A reasonably strong correlation between OAAS and the areas of R1 and R2 components was found (Spearman's p = 0.92 and 0.89). The areas of R1 and R2 and the OAAS also correlated with BIS (Spearman's p = 0.91, 0.88 and 0.90). EC50 and EC95 for loss of R1 were 2.8 (95% CI: 2.5-3.2) µg/ml and 4.6 (95% CI: 4.1-5.5) µg/ml, respectively.
Conclusions:  Our results suggest that the differential sensitivity of the components of the blink reflex could be useful in monitoring depth of sedation and light levels of anaesthesia during the administration of propofol. Both OAAS and BIS correlate similarly with the blink reflex components.

Comparison of BIS and AAI as measures of anaesthetic drug effect during desflurane-remifentanil anaesthesia
S. Kreuer, J. Bruhn, R. Larsen, C. Bauer and W. Wilhelm
Acta Anaesthesiologica Scandinavica 2004; 48: 1168-73

Background:  Autoregressive modelling with exogenous input of the middle-latency auditory evoked potential has been developed for monitoring of anaesthetic depth. This study was designed to investigate the dose-response relationship between endtidal desflurane concentrations and the Alaris Autoregressive Index (AAI, Alaris Medical, Hampshire, UK, version 1.4) or the bispectral index (Aspect Medical Systems, Newton, MA, USA, version XP).
Methods:  Twenty-one patients scheduled for radical prostatectomy were investigated. After premedication and induction of anaesthesia with propofol und remifentanil all patients received atracurium and a remifentanil background infusion at a constant rate of 0.1 µg kg^-1 min^-1. During dissection of the prostate, desflurane endtidal concentrations were varied between 3 and 9 vol%. Both AAI and BIS were determined and compared with the respective endtidal desflurane concentration.
Results:  None of the patients showed a significant change of AAI values while changing the desflurane concentrations between 3 and 9 vol%. The dose-response of BIS values and desflurane concentrations was not uniform: two patients showed increasing BIS values with increasing desflurane concentrations, while in three patients BIS values remained unchanged. In 16 patients decreasing BIS values adequately reflected an increase in desflurane concentrations.
Conclusion:  Changes of desflurane concentrations during deep anaesthesia were adequately displayed only in 16 of 21 cases by BIS but in none of the cases by AAI monitoring.
 

Nitrous oxide diffusion into tracheal tube cuffs: comparison of five different tracheal tube cuffs
A. Dullenkopf, A. C. Gerber and M. Weiss
Acta Anaesthesiologica Scandinavica 2004; 48: 1180 - 84

Background:  The aim of this study was to investigate cuff compliance and cuff pressure during nitrous oxide exposure in the recently introduced Microcuff tracheal tube with a polyurethane cuff (Microcuff GmbH, Weinheim, Germany), and to compare it to conventional tracheal tubes with PVC cuffs.
Methods: In an in vitro set up, five cuffed tracheal tubes (ID 7.0 mm) from different manufacturers (Microcuff HVLP, Portex Profile Soft Seal, Mallinckrodt HiLo, Rüsch Super Safety Clear and Sheridan CF) were studied. Pressure-volume curves were assessed and changes of cuff pressure during exposure to nitrous oxide (for 60 min; 66% N₂O in oxygen) were recorded without and with restriction of the cuff in a trachea model. Each experiment was performed four times using two exemplars of each tube twice. Sixty-minute values of the Microcuff group were compared with the other groups using the Mann- Whitney test (P < 0.05).
Results: The Microcuff polyurethane cuff demonstrated an intermediate cuff compliance but the highest cuff pressure increase during nitrous oxide exposure under unrestricted conditions. When inflated within the artificial trachea its cuff compliance became the highest of all tested tracheal tubes. However, exposure to N₂O, again led to a rapid increase in cuff pressure.
Conclusion: The ultra-thin polyurethane tube cuff demonstrated higher permeability for nitrous oxide than conventional PVC cuffs and led to a rapid cuff pressure increase when exposed to N₂O. Routinely checking of cuff-pressure or filling the cuff with nitrous oxide are more important than the brand of tube used.

Postoperative cognitive dysfunction: true deterioration versus random variation
L. S. Rasmussen, V. D. Siersma and the ispocd group
Acta Anaesthesiologica Scandinavica 2004; 48: 1137- 43

Background:  Postoperative cognitive dysfunction (POCD) is a common complication, especially in the elderly. The aim of this study was to describe how variability in neuropsychological testing could lead to the detection of cognitive improvement and poor consistency of POCD between postoperative test sessions.
Methods:  In four published studies performed by the ISPOCD group, we included 2536 patients and 359 healthy controls. Cognitive function was assessed using neuropsychological tests preoperatively and at 7 days and 3 months thereafter, comparing the changes between those at baseline with those after surgery. Postoperative cognitive dysfunction was defined as a Z score greater than 2, and we also defined a corresponding improvement as a Z score less than 2. Consistency of POCD between postoperative test sessions was analyzed and we also assessed test-retest variability using data from healthy control subjects.
Results:  Improvement in cognitive function was found in 4.2-8.7% of patients after 1 week and in 5.0-7.8% after 3 months. The ratio between incidence of dysfunction and improvement varied in patients between 3.3 and 6.2 early after major surgery. Of those patients who displayed POCD at the 3-month test, 30-48% also had POCD at the previous test at 1 week. The test-retest reliability was between 0.56 and 0.90, except for the error score in Concept Shifting Test, where the values were 0.20 and 0.37.
Conclusion:  Variability in neuropsychological test data contributes to a low consistency between postoperative test sessions but it does not explain the detection of cognitive dysfunction after major surgery.

BRITISH JOURNAL OF ANAESTHESIA - TOP

Structured assessment tool to evaluate patient suitability for cataract surgery under local anaesthesia R. MacPherson
British Journal of Anaesthesia 2004 93(4):521-524

Introduction. Cataract extraction and intraocular lens implantation is a common surgical procedure. While the vast majority of these operations are performed under local anaesthesia (LA), this is not an appropriate technique for every patient. Likewise it is time-consuming to assess all patients fitness for general anaesthesia when most will not need it.
Methods. We developed an eight-item questionnaire that can be administered before admission to assess patient suitability for surgery under LA. In a prospective study over a 9-month period, 128 patients were seen in a pre-admission clinic, and according to the responses to the questionnaire administered by junior medical staff, 123 were deemed suitable for surgery under LA, and five under general anaesthetic (GA).
Results. All 123 patients went on to have surgery successfully performed under LA. A further two patients from the GA group were determined by the attending anaesthetist to be suitable for surgery under LA.
Conclusion. This assessment instrument has been shown to be a highly specific means of selecting patients for surgery under LA, and can be administered by medical or nursing staff.

Comparison of the LMA-ProSeal^TM and LMA-Classic^TM in children
H. Shimbori, K. Ono, T. Miwa, N. Morimura, M. Noguchi and K. Hiroki
British Journal of Anaesthesia 2004 93(4):528-531

Background. The LMA-ProSeal^TM is a new laryngeal mask airway with a rear cuff and drainage tube that allows a higher seal pressure than the LMA-Classic^TM for the same intra-cuff pressure, and it permits drainage of gastric secretions and access to the alimentary tract. The LMA-ProSeal can be used in children but it does not have a rear cuff. This study compared the LMA-ProSeal and the LMA-Classic in children for ease of insertion, airway sealing pressure and fibre-optic visualization.
Methods. Sixty ASA I–II children undergoing herniorrhaphy, orchiopexy or myringotomy were included. The patients were randomly assigned to size 2 LMA-Classic^TM or size 2 LMA-ProSeal groups for airway management. We assessed success rates at first attempt of insertion, airway sealing pressure, fibre-optic position, success rates of gastric tube placement and postoperative blood staining of the device, tongue–lip–dental trauma and hoarseness.
Results. There was no statistical difference between the two groups for the success rates at first attempt of insertion, airway sealing pressure and fibre-optic position. Gastric tube insertion was successful in 90% of cases in the LMA-ProSeal group. The LMA-Classic had a higher rate of postoperative blood staining, but there was no tongue–lip–dental trauma or hoarseness in either group.
Conclusion. We conclude that ease of insertion and airway sealing pressure are similar between the LMA-ProSeal and the LMA-Classic in children.

Aspiration and the laryngeal mask airway: three cases and a review of the literature (ACCOMPANIED BY EDITORIAL SHOWN BELOW)
C. Keller, J. Brimacombe, J. Bittersohl, P. Lirk and A. von Goedecke
British Journal of Anaesthesia 2004 93(4):579-582

The primary limitation of the laryngeal mask airway (LMA^®) is that it does not reliably protect the lungs from regurgitated stomach content. We describe three cases of aspiration associated with the LMA, including the first brain injury, the first death, and the first associated with the intubating LMA, and review the 20 specific case reports of aspiration associated with the LMA that we were able to find described in the literature. 

Who is at increased risk of pulmonary aspiration? (EDITORIAL)
T. Asai
Br. J. Anaesth. 2004 93: 497-500

No abstract available.

CANADIAN JOURNAL OF ANESTHESIA - TOP

Increased body mass index and ASA physical status IV are risk factors for block failure in ambulatory surgery - an analysis of 9,342 blocks
Cotter JT, Nielsen KC, Guller U, Steele SM, Klein SM, Greengrass RA, Pietrobon R.
Can J Anaesth. 2004 Oct;51(8):810-6

PURPOSE: Regional anesthesia can be the technique of choice for selected ambulatory surgery procedures, but in spite of its benefits, it has an inherent failure rate even in experienced hands. We examine the efficacy and factors associated with failure of ambulatory regional anesthesia techniques.
METHODS: This study included 9,342 blocks performed on 7,160 patients at the Duke University Ambulatory Surgery Center. Blocks were classified as interscalene, supraclavicular, axillary, lumbar plexus, femoral, sciatic, ankle, paravertebral, spinal, and other (frequency less than 100). A block was considered surgical if a single attempt at placing the block resulted in a complete sensory, motor, and sympathetic nerve block. Multiple logistic regression analyses were used to assess the risk-adjusted association between patient characteristics and block failure.
RESULTS: Paravertebral blocks and those considered in the "other" category had significantly higher failure rates (P < 0.001), while spinal and lumbar plexus blocks had lower than average rates of failure (P < 0.001 and P = 0.03, respectively).In multiple logistic regression analyses excluding paravertebral blocks, body mass index (BMI) scores greater than 25 (P values: BMI 25-29: < 0.001; BMI 30-34: P < 0.001; BMI 35: P < 0.001) and ASA physical status IV (P < 0.001) were significantly associated with higher block failure rates.
CONCLUSION: High BMI and ASA IV are independent risk factors for block failure in ambulatory surgery patients.  

Patient selection in ambulatory anesthesia - An evidence-based review: part I. Bryson GL, Chung F, Finegan BA, Friedman Z, Miller DR, van Vlymen J, Cox RG, CroweMJ, Fuller J, Henderson C.
Can J Anaesth. 2004 Oct;51(8):768-81

PURPOSE: To identify and characterize the evidence supporting decisions made in the care of patients with selected medical conditions undergoing ambulatory anesthesia and surgery. Conditions highlighted in this review include: the elderly, heart transplantation, hyper-reactive airway disease, coronary artery disease, and obstructive sleep apnea.
SOURCE: A structured search of MEDLINE (1966-2003) was performed using keywords for ambulatory surgery and patient condition. Selected articles were assigned a level of evidence using Centre for Evidence Based Medicine (CEBM) criteria. Recommendations were also graded using CEBM criteria.
PRINCIPAL FINDINGS: The elderly may safely undergo ambulatory surgery but are at increased risk for hemodynamic variation in the operating room. The heart transplant recipient is at increased risk of coronary artery disease and renal insufficiency and should undergo careful preoperative evaluation. The patient with reactive airway disease is at increased risk of minor respiratory complications and should be encouraged to quit smoking. The patient with coronary artery disease and recent myocardial infarction may undergo ambulatory surgery without stress testing if functional capacity is adequate. The patient with obstructive sleep apnea is at increased risk of difficult tracheal intubation but the likelihood of airway obstruction and apnea following ambulatory surgery is unknown.
CONCLUSION: Ambulatory anesthesia is infrequently associated with adverse outcomes, however, knowledge regarding specific patient conditions is of generally low quality. Few prospective trials are available to guide management decisions.

Patient selection in ambulatory anesthesia - An evidence-based review: part II Bryson GL, Chung F, Cox RG, Crowe MJ, Fuller J, Henderson C, Finegan BA, Friedman Z, Miller DR, van Vlymen J.
Can J Anaesth. 2004 Oct;51(8):782-94

PURPOSE: This is the second of two reviews evaluating the management of patients with selected medical conditions undergoing ambulatory anesthesia and surgery. Conditions highlighted in this review include: diabetes mellitus; morbid obesity; the ex-premature infant; the child with an upper respiratory infection; malignant hyperthermia; and the use of monoamine oxidase inhibitors.
SOURCE: Medline search strategies and the framework for the evaluation of clinical evidence are presented in Part I.
PRINCIPAL FINDINGS: Diabetes mellitus has not been linked with adverse events following ambulatory surgery. The morbidly obese patient is at an increased risk for minor respiratory complications in the perioperative period but these events do not increase unanticipated admissions. The ex-premature infant may be considered for ambulatory surgery if post-conceptual age is > 60 weeks and hematocrit is > 30%. The child with a recent upper respiratory tract infection is at an increased risk for perioperative respiratory complications, particularly if endotracheal intubation is required. Patients with malignant hyperthermia may undergo outpatient surgery but require four hours of postoperative temperature monitoring. Sporadic cases of drug interactions have been reported when meperidine and indirect-acting catecholamines are administered in the presence of monamine oxidase inhibitors. Ambulatory anesthesia and surgery is safe if these combinations of drugs are avoided.
CONCLUSION: Ambulatory anesthesia can be performed in, and is being offered to, a variety of patients with significant coexistent disease. In many cases there is little evidence documenting the outcomes expected in such patients. Prospective observational and interventional trials are required to better define perioperative management.

Patient satisfaction with anesthesia care: information alone does not lead to improvement
Thomas Heidegger, MD, Matthias Nuebling, PhD, Reinhard Germann, MD, Hans Borg, MD, Katrin Flückiger, MD, Trinidad Coi and Yvonne Husemann, LIC PHIL
Canadian Journal of Anesthesia 51:801-805 (2004)

Purpose: To evaluate if information campaigns and introduction of information leaflets lead to an improvement in patient satisfaction with anesthesia care.
Methods: In 2000, we carried out an assessment of patient satisfaction with anesthesia care. "Information/involvement in decision making" was identified as the worst problem area. The three hospitals involved in this study introduced strategies to improve this dimension of patient satisfaction by launching information campaigns, producing or improving information brochures (particularly in hospitals A and C), and by expanding the preanesthetic care unit (hospital B). In 2002, a second survey was carried out. Each of the hospitals sent questionnaires to 600 elective surgery patients after discharge. We compared the total problem scores (the percentage of patients who responded that a problem was present) and the problem scores for the dimension ‘information/involvement in decision making’ between 2000 and 2002.
Results: The total problem score (mean in %, 95% confidence interval) for all three hospitals together remained unchanged [19% (1)], as well as the problem scores for each hospital [hospital A 16% (1), hospital B 21% (1), hospital C 20% (1)]. The problem score for ‘information/involvement in decision making’ remained unchanged also: 31% (29–33) in 2000 compared to 28% (26–30) in 2002.
Conclusion: Information campaigns and the introduction of information leaflets alone do not improve patient satisfaction with anesthesia care.

PUB MED - TOP

Hearing loss does not occur in young patients undergoing spinal anesthesia.
Ok G, Tok D, Erbuyun K, Aslan A, Tekin I.
Reg Anesth Pain Med. 2004 Sep-Oct;29(5):430-3

Background and objectives: Although uncommon, hearing loss after spinal anesthesia has been described. Vestibulocochlear dysfunction after spinal anesthesia in which 22-gauge and 25-gauge Quincke needles were used was investigated to determine if needle size affected hearing.
Methods: Patients with American Society of Anesthesiologists physical status I and II, aged 20 to 40 years, who were undergoing lower extremity surgery under spinal anesthesia were randomized into 2 groups. After intravenous hydration, 3 mL of 0.5% bupivacaine was administered for spinal anesthesia, which was performed with a 22-gauge Quincke needle in group I (n = 30) patients and a 25-gauge Quincke needle in group II (n = 30) patients. Before surgery and 2 days after surgery, pure-tone audiometry and tympanometry were performed. Preoperative and postoperative hearing data were obtained in the right and left ears for every frequency. Headache, nausea, and vomiting and cranial nerve III, IV, V, VI, VII, and VIII function were assessed on postoperative day 2.
Results: Demographic data were not different between the groups. No hypoacousis was noted at any frequency during the entire testing period in either group. Two patients from group I experienced postdural puncture headache on postoperative day 3, and neither had hearing loss. No patient had cranial nerve dysfunction.
Conclusions: We were unable to induce hearing loss in young patients undergoing spinal anesthesia by injecting the anesthetic with a 22-gauge or a 25-gauge Quincke needle.

Early intravenous cannulation in children during sevoflurane induction.
Schwartz D, Connelly NR, Gutta S, Freeman K, Gibson C.
Paediatr Anaesth. 2004 Oct;14(10):820-4

Summary Background: It has been shown that early placement of an intravenous line in children anesthetized with halothane is equally safe compared with later placement. Whether this is true of sevoflurane is not known.
Methods: Pediatric patients, age 1-18 years, undergoing elective general anesthesia via an inhalation induction were randomized to intravenous placement either 30 or 120 s following loss of lid reflex. Movement on intravenous placement and incidence of laryngospasm were determined. Difficulty with intravenous placement was recorded.
Results: Movement on intravenous placement was more prevalent in the early group than in the late group (P < 0.0001). There was no laryngospasm in the late group and eight cases in the early group (P < 0.004). Children who had laryngospasm were older (P < 0.02) and weighed more (P < 0.04). Older children in the early group were more likely to have significant movement.
Conclusion: Following an inhalation induction with sevoflurane in children, movement with intravenous placement was greater, and the incidence of laryngospasm was higher, when the intravenous access was attempted 30 s rather than 120 s following loss of lid reflex. We recommend waiting two min following the loss of lid reflex before attempting intravenous placement in children receiving an inhalation induction with sevoflurane.

Postoperative behavioral changes following anesthesia with sevoflurane.
Keaney A, Diviney D, Harte S, Lyons B.
Paediatr Anaesth. 2004 Oct;14(10):866-70

Summary Background: Behavioral disturbance following hospitalization is a relatively frequent event, some children still having negative behavioral changes (NBC) 1 month following their operation. Sevoflurane has a propensity to induce 'excitement' during induction of anaesthesia, and delirium in the immediate postoperative phase. The aim of this study was to evaluate whether this translates into prolonged behavioral change.
Methods: A total of 120 children presenting for daycase surgical procedures under anesthesia were included in the study. Children were randomized to induction and maintenance of anesthesia with sevoflurane or halothane. No additional sedative drugs were administered. Postoperative behavioral change was assessed using the Post-Hospital Behavior Questionnaire (PHBQ) on postoperative days 1, 7 and 30.
Results: The Sevoflurane group (n = 63) were more distressed on emergence of anesthesia than the Halothane group (n = 57) (P < 0.05). About 58.3, 46.8 and 38.3% of all children exhibited NBC on postoperative days 1, 7 and 30, respectively. There was no association between anesthetic agent and behavior. There was a significant relationship between decreasing age and NBC (P < 0.005).
Conclusions: Children anesthetized with sevoflurane exhibit more immediate postoperative distress than those anesthetized with halothane. This difference is not carried over into the longer posthospital period. Negative behavioral changes occur more frequently with decreasing age.

Adverse events associated with the intraoperative injection of isosulfan blue.
Daley MD, Norman PH, Leak JA, Nguyen DT, Bui TP, Kowalski AM, Srejic U, Popat K, Arens JF, Gershenwald JE, Hunt KK, Kuerer HM.
J Clin Anesth. 2004 Aug;16(5):332-41

STUDY OBJECTIVE: To describe the adverse events associated with the intraoperative injection of isosulfan blue in a large group of patients having a wide range of surgical procedures, and to identify risk factors for these events.
DESIGN: Retrospective chart review.
SETTING: University-affiliated institution specializing in malignancies
PATIENTS: 1835 patients representing a total of 1852 surgical procedures.
MEASUREMENTS: Incidence, type, severity, onset time, duration, management, and the presence of potential risk factors for adverse events. Events were considered "major" if potentially life-threatening hypotension occurred.
MAIN RESULTS: Adverse events occurred in 28 procedures (1.5%) and 14 of these adverse events (0.75%) were classified as major. The types of events were: skin reactions in 21 patients, hypotension in 14 patients, edema in 1 patients, and unspecified in 1 patient. The time of onset for adverse events was 42.2 +/- 53.9 minutes (median, 17.5; range, 1 to 180 min) after isosulfan blue injection, and was significantly longer for minor reactions compared with major events (p = 0.015). The longest adverse event lasted at least 21 hours. Treatment was successful with usual antiallergy/antianaphylaxis medications. Ten patients received diphenhydramine alone, and four patients received intravenous epinephrine infusions. Factors associated with a significantly increased incidence of adverse events were isosulfan blue injection in the vulvar area (p = 0.000038), and the chronic preoperative use of angiotensin-converting enzyme inhibitors or angiotensin receptor-blocking agents (p = 0.043). Trends toward an increased risk of an adverse event were noted with isosulfan blue injection in the breast area (p = 0.19), and having more than one surgical procedure with isosulfan blue (p = 0.14).
CONCLUSIONS: Although the most frequent adverse event associated with injection of isosulfan blue was a skin reaction, potentially life-threatening hypotension occurred in 0.75% of all procedures. Anesthesiologists must be aware of the variable onset time and potentially prolonged duration of the adverse events. They should recognize the need for extra vigilance in patients with potential risk factors, and have the usual antiallergy/antianaphylaxis medications available for administration if necessary.

Propofol: a gastroenterologist's perspective. (REVIEW)
Vargo JJ.
Gastrointest Endosc Clin N Am. 2004 Apr;14(2):313-23

The use of propofol for GI endoscopy has left the realm of experimentation and is now a viable alternative to standard sedation and analgesia. In the hands of appropriately trained gastroenterologists and registered nurses, propofol has been shown to be superior to standard sedation and analgesia in terms of patient satisfaction and comfort and shorter recovery parameters. Comparative studies have found it to be as safe as the regimens that are used for standard sedation and analgesia. Its narrow therapeutic window demands that specially trained personnel who are not directly involved in the endoscopic procedure administer it. Cost-effectiveness data suggest that propofol is superior to conventional sedation and analgesia, even with the use of added personnel.The importance of pre-procedural assessment and appropriate monitoring cannot be overemphasized. The endoscopist must have a thorough knowledge of the pharmacology of the agents used for sedation and the training necessary to recognize and manage over sedation. Numerous regulatory groups are carefully scrutinizing the practice of sedation and analgesia. It seems that ventilatory monitoring will be required for at least a subset of patients. Although hypercapnia and apnea can be reliably measured, the most important questions to be answered are if such monitoring affects patient outcomes and which patients are at risk for apnea and alveolar hypoventilation.

Local anesthesia use for laparoscopic cholecystectomy.
Inan A, Sen M, Dener C.
World J Surg. 2004 Aug;28(8):741-4

This study aimed to investigate the effects and timing of local anesthesia during laparoscopic surgery in terms of postoperative pain, nausea, and the need for opioids and antiemetics. This prospective study was carried out on 142 patients who underwent laparoscopic cholecystectomy. Peroperative local anesthesia was not administered to 53 patients (group A). The skin, subcutis, fascia, and parietal peritoneum were infiltrated with 0.5% bupivacaine HCl at trocar sites before trocar insertion in 46 patients (group B). Local anesthesia was given to 43 patients in equal doses at the same sites and the same manner at the end of surgery (group C). The higher requirement for analgesics in group A patients was statistically significant when compared with that in group B and C patients. The mean doses of analgesics postoperatively were significantly higher in group B than in group C. The time delay to the first antiemetics was significantly shorter in group A than in group C. Applying local anesthesia to the skin, subcutis, fascia, and parietal peritoneum through trocar sites reduces the postoperative analgesic requirement and pain intensity. This approach is more effective when applied at the end of an operation than at the start.

Strategies for outpatient anaesthesia. (REVIEW)
Gupta A.
Best Pract Res Clin Anaesthesiol. 2004 Dec;18(4):675-92

With the expansion of ambulatory surgery in the Western world over the last 10 years, it has become increasingly important to identify patients at risk of perioperative complications and to use appropriate methods to decrease these risks. The confidential enquiry into perioperative deaths was one of the first national programmes instituted to identify patients at risk after the operation. Although the focus for this initial enquiry was on perioperative mortality, recent developments have increasingly focused on identification of perioperative morbid events. The first large prospective study on outpatients found a very low incidence of death after ambulatory surgery, but with the acceptance of high-risk patients for ambulatory surgery in recent years it is likely that perioperative morbidity will increase in the future. Therefore, identification of the patient at risk is important in order to apply known strategies to decrease these risks. We first need to know what tools are available to detect these 'at-risk' patients. Unfortunately, many of the tools used are very subjective and lack both sensitivity and specificity. In this chapter, an attempt has been made to outline the risks related to surgery, anaesthesia, the patient and the procedure, and finally the role of the establishment. Later, strategies are discussed which could reduce the perioperative general and cardiorespiratory risks in the ambulatory surgical patient. Many of these strategies are derived from the inpatient since appropriate data in outpatients are lacking. Future studies should thus focus on data derived from outpatients and prospective, randomized, double-blind studies in a large population of patients in order to first identify the patient at risk and subsequently to use drugs and techniques that reduce these perioperative risks.

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