Volume 3, Issue 10 S A M B A T A L K S - PAGE 3 March, 2004

FROM THE LITERATURE: - TOP


ANESTHESIA AND ANALGESIA - TOP

Effective Treatment of Laparoscopic Cholecystectomy Pain with Intravenous Followed by Oral COX-2 Specific Inhibitor
Girish P. Joshi, MBBS MD, Eugene R. Viscusi, MD, Tong J. Gan, MD, Harold Minkowitz, MD, Mark Cippolle, MD PhD, Rienhard Schuller, MSc, Raymond Y. Cheung, BPharm PhD, and John G. Fort, MD
Anesth Analg 2004;98:336-342

In this multicenter, double-blinded, randomized, placebo-controlled study we evaluated the analgesic and opioid-sparing efficacy of a preoperative dose of IV parecoxib followed by oral valdecoxib in treating pain associated with elective laparoscopic cholecystectomy. Patients were randomized to receive a single IV dose of parecoxib 40 mg (n = 134) or placebo (n = 129) 30–45 min before induction of anesthesia. Six to 12 h after the IV dose, the parecoxib group received a single oral dose of valdecoxib 40 mg, followed by valdecoxib 40 mg qd on postoperative days 1–4, then 40 mg qd prn days 5–7. The placebo IV group received oral placebo on an identical schedule. All patients were allowed supplemental IV fentanyl as needed during the first 4 h postoperatively (T0–240 min) followed by hydrocodone 5 mg/acetaminophen 500 mg (Vicodin^®; 1–2 tablets orally every 4–6 h as needed). Patients taking parecoxib used 21% less fentanyl than those receiving placebo (P = 0.011). The mean area under the curve of pain intensity (PI) scores over time from T0–240 min was 55.2 for parecoxib and 61.2 for placebo (P = 0.083). At T180 and T240 min, mean PI score was 7.0 and 7.6 points lower in the parecoxib group, respectively (P < 0.02). Fewer patients on valdecoxib required supplemental analgesics (P < 0.05) after discharge. At T240 min and at day 7, Patient’s and Physician’s/Nurse’s Global Evaluations were significantly better in the parecoxib/valdecoxib group (P < 0.05). Incidences of adverse events, adverse events causing withdrawal, and serious adverse events were less for parecoxib/valdecoxib than for placebo. The authors conclude that preoperative parecoxib is a valuable opioid-sparing adjunct to the standard of care for treating pain after laparoscopic cholecystectomy, and subsequent treatment with oral valdecoxib extends this clinical benefit.
IMPLICATIONS: Parecoxib 40 mg IV, 30–45 min preoperatively followed by oral valdecoxib 40 mg qd reduced opioid requirements and provided superior pain relief as well as improved patient global evaluation after laparoscopic cholecystectomy.

The Incidence of Laryngospasm with a "No Touch" Extubation Technique After Tonsillectomy and Adenoidectomy
Ban C. H. Tsui, MD MSc, FRCP(C), Alese Wagner, BSc, Dominic Cave, MB FRCP(C), Clark Elliott, MD FRCS, Hamdy El-Hakim, MD FRCS(Ed), FRCS(ORL), and Stephan Malherbe, MB ChB, FCA(SA), MMed(Anes)
Anesth Analg 2004;98:327-329

In this case series, we evaluated the incidence of laryngospasm using a clearly defined awake tracheal extubation technique in 20 children undergoing elective tonsillectomy with or without adenoidectomy. This technique required patients to be turned to the recovery position at the end of the procedure before discontinuing the volatile anesthetics. No further stimulation, besides continuous oximetry monitoring, was allowed until the patients spontaneously woke up ("no touch" technique). The incidence of laryngospasm, oxygen saturation, and coughing was recorded. No cases of laryngospasm, oxygen desaturation, or severe coughing occurred in our patient population.
IMPLICATIONS: This study re-emphasizes the importance of a sound anesthetic technique in tracheally extubating pediatric patients

Reducing Venipuncture Pain by a Cough Trick: A Randomized Crossover Volunteer Study
Taras I. Usichenko, MD, Dragan Pavlovic, MD, Sebastian Foellner, and Michael Wendt, MD PhD
Anesth Analg 2004;98:343-345

We tested the effectiveness of the cough trick (CT) as a method of pain relief during peripheral venipuncture (VP) in a crossover study. Twenty healthy volunteers were punctured twice in the same hand vein within an interval of 3 wk, once with the CT procedure and once without it. The intensity of pain, hand withdrawal, palm sweating, blood pressure, heart rate, and serum glucose concentration were recorded. The intensity of pain during VP with the CT procedure was less than without it, whereas the other variables changed insignificantly. The easily performed CT was effective in pain reduction during VP, although the mechanism remains unclear.
IMPLICATIONS: The effectiveness of a cough trick for pain reduction during peripheral venipuncture was tested in a volunteer study in which each subject served as his own control. The easily performed cough-trick procedure was effective for pain reduction, although the mechanism remains unclear.

A Suspected Case of Delayed Onset Malignant Hyperthermia with Desflurane Anesthesia
Thomas J. Papadimos, MD MPH, Mohamad Almasri, MD, James C. Padgett, CRNA BS, and Joanne E. Rush, CRNA MS
Anesth Analg 2004;98:548-549

Desflurane has been identified as a weak triggering anesthetic of malignant hyperthermia that, in the absence of succinylcholine, may produce a delayed onset of symptoms. The prolonged interval after exposure may occur more than 6 h after the induction of anesthesia. The unintended underdosing of this patient with dantrolene and the prompt reversal of symptoms may be an attribute of the genetic expression of a weak triggering volatile anesthetic such as desflurane.
IMPLICATIONS: There are multiple genetic variations for malignant hyperthermia (MH) at the ryanodine receptor. Desflurane, as a sole trigger of MH, is weak, and on two occasions in the literature (including this case), less than optimal doses of dantrolene were given with a good result. There may be possible to engineer the risk of MH out of an anesthetic once the genetics of the ryanodine receptor are better understood.

The Effect of Caudal Analgesia on Emergence Agitation in Children After Sevoflurane Versus Halothane Anesthesia
B. Craig Weldon, MD, Martin Bell, MD, and Thomas Craddock, MD
Anesth Analg 2004;98:321-326

Sevoflurane anesthesia in young children has been associated with an increased incidence of emergence agitation compared with halothane. Postoperative pain may be an etiologic factor. We designed a study to compare the incidence of emergence agitation after halothane and sevoflurane anesthesia in children whose pain was managed with caudal analgesia. Eighty children undergoing inguinal hernia repair between the ages of 12 mo and 6 yr were randomly assigned to receive either halothane or sevoflurane anesthesia. Baseline preoperative anxiety was assessed with the Yale Preoperative Anxiety Scale. The children were sedated with oral midazolam, underwent a mask induction, and had a caudal block placed for postoperative analgesia. After surgery, the children’s behavior was assessed with a four-point agitation scale. At 5 min after arrival in the postanesthesia care unit (PACU), sevoflurane was associated with a greater incidence of emergence agitation than halothane (26% vs 6%; P < 0.05), but not during the remainder of the PACU stay. Higher levels of preoperative anxiety were associated with difficult mask induction, agitation on admission to the PACU, and more severe agitation episodes. Emergence agitation appears to be an early and transient phenomenon after sevoflurane anesthesia in children with effective postoperative analgesia.
IMPLICATIONS: Effective postoperative analgesia may reduce the incidence of emergence agitation reported with sevoflurane anesthesia. The Yale Preoperative Anxiety Scale appears to be helpful in identifying young children who are at risk for developing emergence agitation.

CANADIAN JOURNAL OF ANESTHESIA - TOP

Drinking 300 mL of clear fluid two hours before surgery has no effect on gastric fluid volume and pH in fasting and non-fasting obese patients
J. Roger Maltby, MB FRCA FRCPC, Saul Pytka, MD FRCPC, Neil C. Watson, MB FRCPC, Robert A. McTaggart Cowan, MD FRCPC and Gordon H. Fick, BSc MSc PhD
Canadian Journal of Anesthesia 51:111-115 (2004)

Purpose: To determine whether, in obese [body mass index (BMI) > 30 kg•m²] patients, oral intake of 300 mL clear liquid two hours before elective surgery affects the volume and pH of gastric contents at induction of anesthesia.
Methods: A single-blind, randomized study of 126 adult patients, age 18 yr, ASA physical status I or II, BMI > 30 kg•m² who were scheduled for elective surgery under general anesthesia. Patients were excluded if they had diabetes mellitus, symptoms of gastroesophageal reflux, or had taken medication within 24 hr that affects gastric secretion, gastric fluid pH or gastric emptying. All patients fasted from midnight and were randomly assigned to fasting or fluid group. Two hours before their scheduled time of surgery, all patients drank 10 mL of water containing phenol red 50 mg. Those in the fluid group followed with 300 mL clear liquid of their choice. Immediately following induction of general anesthesia and tracheal intubation, gastric contents were aspirated through a multiorifice Salem sump tube. The fluid volume, pH and phenol red concentration were recorded.
Results: Median (range) values in fasting vs fluid groups were: gastric fluid volume 26 (3–107) mL vs 30 (3–187) mL, pH 1.78 (1.31–7.08) vs 1.77 (1.27–7.34) and phenol red retrieval 0.1 (0–30)% vs 0.2 (0–15)%. Differences between groups were not statistically significant.
Conclusion: Obese patients without comorbid conditions should follow the same fasting guidelines as non-obese patients and be allowed to drink clear liquid until two hours before elective surgery, inasmuch as obesity per se is not considered a risk factor for pulmonary aspiration.

Clear hydro-gel, compared to ointment, provides improved eye comfort after brief surgery
Michaela Smolle, RN, Christian Keller, MD, Germar Pinggera, MD, Martina Deibl, MSc, Josef Rieder, MD and Philipp Lirk, MD
Canadian Journal of Anesthesia 51:126-129 (2004)

Purpose: Anesthesia impairs lid closure and decreases tear secretion and stability. Protection may, in principle, be conveyed by manual eye closure, taping the eyelids closed, and by instillation of protective substances into the conjunctival sac. Both hydro-gels and ointments are used in clinical practice. It was the objective of the present study to compare a transparent clear ocular hydro-gel (Vidisic^®) and a commonly used dexpanthenol and vitamin A (Oleovit^®) based ointment as examples of these classes of ocular lubricants in their capability to provide perioperative eye comfort. Furthermore, their bacteriostatic properties were assessed in vitro.
Methods: Ninety-two consecutive patients undergoing total iv general anesthesia were randomly allocated to receive either ocular dexpanthenol ointment or a clear hydro-gel after induction of anesthesia. Subjects were assessed one hour following termination of anesthesia.
Results: Main findings were an increased incidence of foreign body sensation, adherent eyelashes and disturbance elicited by blurred vision in the ointment group as compared to clear hydro-gel (P < 0.001). Bacterial growth was significantly attenuated by the ocular hydro-gel as compared to ointment.
Discussion: Clear ocular hydro-gel offers improved patient comfort and decreased ocular inflammation as compared to conventional eye ointments. In addition, it decreases bacterial growth. Therefore, the use of clear ocular hydro-gel for perioperative ocular comfort is suggested.

Vein pretreatment with magnesium sulfate to prevent pain on injection of propofol is not justified
Anil Agarwal, MD, Sanjay Dhiraj, MD, Mehdi Raza, MD, Ravinder Pandey, MD, Chandra Kant Pandey, MD, Prabhat K. Singh, MD, Uttam Singh, PhD and Devendra Gupta, MD
Canadian Journal of Anesthesia 51:130-133 (2004)

Purpose: Propofol produces anesthesia with rapid recovery. However, it causes pain or discomfort on injection. A number of techniques have been tried for minimizing propofol-induced pain with variable results. We have compared the efficacy of magnesium and lidocaine for the prevention of propofol induced pain.
Methods: Three hundred ASA I and II adults undergoing elective surgery were randomly assigned into three groups of 100 each. Group I received magnesium sulfate 1 g, Group II received lidocaine 2% (40 mg) and Group III received normal saline, all in a volume of 2 mL and accompanied by venous occlusion for one minute. Induction with propofol 2.5 mg•kg^-1 was accomplished following the release of venous occlusion. Pain was assessed on a four-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain, and 3 = severe pain at the time of pretreatment and propofol injection. Results were analyzed by ‘Z’ test. A P value of < 0.05 was considered as significant.
Results: Pain during iv pretreatment with magnesium was 31% as compared to 2% for both the lidocaine and control groups (P < 0.05). Seventy-six percent of patients in the control group had pain during iv propofol as compared to 32% and 42% in the magnesium and the lidocaine groups respectively (P < 0.05). Lidocaine and magnesium pretreatment were equally effective in attenuating pain during the propofol injection (P > 0.05).
Conclusions: Intravenous magnesium and lidocaine pretreatment are equally effective in attenuating propofol-induced pain. However, magnesium pretreatment itself causes pain. Therefore, there is no justification in the use of magnesium pretreatment for attenuating pain associated with iv propofol.

The Callander laryngoscope blade modification is associated with a decreased risk of dental contact
Jaemin Lee, MD, Jong H. Choi, MD, Yoon K. Lee, MD, Eun S. Kim, MD, Ou K. Kwon, MD and Randolph H. Hastings, MD PhD
Canadian Journal of Anesthesia 51:181-184 (2004)

Purpose: Dental damage may occur with laryngoscopy. The purpose of this study was twofold: to determine whether preoperative examination could predict the risk of contacting the teeth with the laryngoscope and to evaluate the effectiveness of a modified Macintosh blade on reducing dental contact.
Methods: Four hundred and eighty-three patients scheduled for elective surgery requiring general anesthesia with endotracheal tube placement were studied prospectively. Features that might predict difficult intubation were assessed preoperatively. Laryngoscopy was performed twice on each patient, once with a regular Macintosh 3 blade and once with a blade in which the flange was partially removed (Callander modification). The distance between the flange of the blade and the upper incisors at glottic exposure was measured. We calculated correlations between individual airway characteristics and the chance of hitting the upper teeth with the regular Macintosh 3 blade and compared the frequencies of contacting the teeth between the two blades.
Results: The chance of hitting the upper teeth when using the regular Macintosh 3 blade increased significantly with non-parametric scores for Mallampati classification, mandibular subluxation, head and neck movement, interincisor gap, and condition of the upper teeth. (P < 0.01) The frequency of direct contact varied significantly between the two blades: 20.3% vs 4.1% for Macintosh 3 and modified blades, respectively (P < 0.05). Laryngeal views were improved with the modified blade.
Conclusion: Airway characteristics correlate with the risk of hitting the upper teeth during laryngoscopy. The modified Macintosh blade reduces the risk of contacting the teeth.

ACTA ANAESTHESIOLOGICA SCANDINAVICA - TOP

Are there reliable predictors of postoperative pain?
C. Mamie, M. Bernstein, A. Morabia, C. E. Klopfenstein, D. Sloutskis and A. Forster
Acta Anaesthesiologica Scandinavica Volume 48 Issue 2 Page 234

Background: The purpose of this study was to identify the preoperative determinants of severe postoperative pain.
Methods: Potential predictors were assessed using a questionnaire submitted on the day before surgery. Pain at rest, and pain during coughing/mobilization, were measured using visual analog scales on the day of surgery and on the following 2 days. The type of postoperative pain management was not standardized and was prescribed by the anesthesiologist in charge. Multivariate logistic regression models explaining postoperative pain were developed in Group I, comprising 304 consecutive patients undergoing orthopedic or intraperitoneal surgery, and validated in Group II, comprising 145 independent patients.
Results: Of the 62 variables examined by univariate analysis, only five were found to increase the risk of severe postoperative pain in Group I at rest and six factors during cough/mobilization. In the multivariate model for pain at rest, general anesthesia, expectation of postoperative pain, and chronic sleeping difficulties increased the risk of severe postoperative pain. In Group II, only chronic sleeping difficulties remained (OR: 3.97, 95% Cl: 1.69-9.29). In the multivariate model during cough/mobilization, intraperitoneal surgery, fear of postoperative pain, and having a relative with a history of pain increased the risk of severe postoperative pain in Group I. Intraperitoneal surgery OR 2.45 (95% Cl = 1.01-4.50) and having a relative with a history of pain OR 2.06 (95% Cl = 1.005-4.50) remained in Group II.
Conclusion: Of the many factors that may influence postoperative pain, chronic sleeping difficulties emerge in this population of patients as the strongest determinant of pain at rest. Intraperitoneal surgery and having a relative with a history of pain are the strongest determinants of pain during cough/mobilization. These findings make physiological sense and deserve more attention by anesthesiologists.

BRITISH JOURNAL OF ANAESTHESIA - TOP

Unconscious learning during surgery with propofol anaesthesia
C. Deeprose, J. Andrade, S. Varma and N. Edwards
Br J Anaesth 2004; 92: 171–7

Background. Learning during anaesthesia has been demonstrated, but little is known about the circumstances under which it may occur. This study investigated the hypothesis that learning during anaesthesia occurs during, but not before, surgical stimulation.
Methods. Words were played through headphones to 64 day-surgery patients during propofol anaesthesia. Fourteen words were played repeatedly (15 times) for 1 min each either before (n=32) or during (n=32) surgical stimulation. The depth of anaesthesia was estimated using the bispectral index^TM (BIS^TM). Heart rate, ventilatory frequency, mean arterial pressure, end-tidal carbon dioxide concentration, and infusion rate of propofol were recorded at 1 min intervals during word presentation. On recovery, memory was assessed using an auditory word stem completion test and word recognition test.
Results. The mean BIS^TM, arterial pressure, end-tidal carbon dioxide and heart rate during word presentation did not differ between the groups. The infusion rate of propofol and the ventilatory frequency were significantly greater in the during-surgical stimulation group. There was no evidence for explicit recall or recognition, nor of awareness during anaesthesia (median mean-BIS^TM=38 in the before-surgical stimulation group and 42 in the during-surgical stimulation group). Only patients who were played words during surgical stimulation showed significant implicit memory on recovery (mean score=0.08, P<0.02) However, their scores were not significantly higher than those of the before-surgical stimulation group (mean score=0.01).
Conclusions. Learning during anaesthesia seems more likely to occur during rather than before surgical stimulation at comparable anaesthetic depth. We hypothesize that surgical stimulation facilitates learning during anaesthesia, independently of its effects on anaesthetic depth.

Relation between fentanyl dose and predicted EC50 of propofol for laryngeal mask insertion
M. Kodaka, Y. Okamoto, F. Handa, J. Kawasaki and H. Miyao
Br J Anaesth 2004; 92: 238–41

Background. This study sought to determine the effective concentration for 50% of the attempts to secure laryngeal mask insertion (predicted EC_50LMA) of propofol using a target-controlled infusion (Diprifusor^TM) and investigated whether fentanyl influenced these required concentrations, respiratory rate (RR) and bispectral index (BIS).
Methods. Sixty-four elective unpremedicated patients were randomly assigned to four groups (n = 16 for each group) and given saline (control) or fentanyl 0.5, 1 or 2 mcg kg^-1. Propofol target concentration was determined by a modification of Dixon’s up-and-down method. Laryngeal mask airway insertion was attempted without neuromuscular blocking drugs after equilibration had been established for >10 min. Movement was defined as presence of bucking or gross purposeful muscular movement within 1 min after insertion. EC_50LMA values were obtained by calculating the mean of 16 patients in each group.
Results. Predicted EC_50LMA of the control, fentanyl 0.5, 1 and 2 mcg kg^-1 groups were 3.25 (0.20), 2.06 (0.55), 1.69 (0.38) and 1.50 (0.54) mcg ml^-1 respectively; those of all fentanyl groups were significantly lower than that of control. RR was decreased in relation to the fentanyl dose up to 1 mcg kg^-1. BIS values after fentanyl 1 and 2 mcg kg^-1 were significantly greater than in the control and 0.5 mcg kg^-1 groups.
Conclusions. A fentanyl dose of 0.5 mcg kg^-1 is sufficient to decrease predicted EC_50LMA with minimum respiratory depression and without a high BIS value.

Caudal bupivacaine supplemented with caudal or intravenous clonidine in children undergoing hypospadias repair: a double-blind study
T. G. Hansen, S. W. Henneberg, S. Walther-Larsen, J. Lund and M. Hansen
Br J Anaesth 2004; 92: 223–7

Background. Clonidine is used increasingly in paediatric anaesthetic practice to prolong the duration of action of caudal block with a local anaesthetic agent. Which route of administration of clonidine is the most beneficial remains unknown. We compared the effects of caudal and i.v. clonidine on postoperative analgesia produced by caudal bupivacaine after hypospadias repair.
Methods. Forty-six children (ASA I or II) aged 24–104 months received standardized premedication with midazolam, a general anaesthetic and a caudal block with bupivacaine 0.25%, 0.5 ml kg^-1. The children were randomized in a double-blind fashion to two groups: the i.v. group received clonidine 2 µg kg^-1 i.v. and simultaneously the same volume of saline caudally. The caudal group received clonidine 2 µg kg^-1 caudally and a similar volume of saline i.v. After surgery, all children received acetaminophen 20 mg kg^-1 rectally or orally 6-hourly and were given a patient-controlled or nurse-controlled analgesia (PCA/NCA) pump with i.v. morphine (bolus of 25 µg kg^-1 and an 8-min lockout period with no background infusion). Monitoring of scores for pain, sedation, motor block, and postoperative nausea and vomiting was performed by nurses blinded to the study allocations. Time to first activation of the PCA/NCA pump and 0–24 h and 24–48 h morphine consumption were also recorded.
Results. Forty-four children completed the study. Age, weight and duration of anaesthesia and surgery were similar in the two groups. The median (range) time to first activation of the PCA/NCA pump was similar in the two groups: 425 (150–1440) min in the i.v. group and 450 (130–1440) min in the caudal group. The number of children not requiring postoperative morphine was four and seven respectively. Morphine consumption during 0–24 h and 24–48 h was similar between groups.
Conclusions. The analgesic effect of clonidine 2 µg kg^-1 as an adjunct to caudal block with bupivacaine 0.25%, 0.5 ml kg^-1 is similar whether administered i.v. or caudally.

Leg weakness is a complication of ilio-inguinal nerve block in children
A. K. Lipp, J. Woodcock, B. Hensman and K. Wilkinson
Br J Anaesth 2004; 92: 273–4

Background. Ilio-inguinal nerve block is commonly used in children to provide analgesia after surgery in the groin. Several case reports and clinical studies have described leg weakness after this technique and suggest that it may caused by inadvertent femoral nerve block. No prospective studies describing the incidence of this complication have been published.
Methods. We carried out a prospective, observational study to find out how many children had leg weakness after ilio-inguinal nerve block. We studied 200 children having day-case surgery in the groin under a general anaesthetic with an ilio-inguinal nerve block. All children performed a simple leg-raising test with each leg before induction of general anaesthesia with a standardized ilio-inguinal nerve block on the side of surgery. When the child was awake and comfortable after surgery, they repeated the leg-raising test.
Results. Sixteen of 182 children (8.8%) had leg weakness after surgery on the side of the nerve block only, as detected by a leg-raising test.
Conclusions. Leg weakness consistent with a femoral nerve block occurs after ilio-inguinal nerve block in approximately one in nine children.

ANESTHESIOLOGY - TOP

Can We Improve the Assessment of Discharge Readiness?: A Comparative Study of Observational and Objective Measures of Depth of Sedation in Children
Shobha Malviya, M.D.; Terri Voepel-Lewis, M.S., R.N.; Achiau Ludomirsky, M.D.; Janelle Marshall, B.S.; Alan R. Tait, Ph.D.
Anesthesiology 2004; 100(2):218-224

Background: Current recommended discharge criteria might not be rigorous enough to detect residual sedation. This study evaluated the use of the Bispectral Index (BIS® monitor), the University of Michigan Sedation Scale (UMSS; i.e., 0-4 observational scale), and a Modified Maintenance of Wakefulness Test (MMWT; visual observation of the time the child is able to stay awake) in assessing return to baseline status.
Methods: Twenty-nine children sedated for echocardiographic examination were studied. Nurses administered sedatives and monitored and discharged children according to institutional guidelines. Children were monitored with the BIS^® throughout the study. Trained observers assigned UMSS scores every 10-15 min until revised discharge criteria were met (i.e., UMSS score of 0 or 1, MMWT duration ≥ 20 min). The MMWT value was recorded at each observation following the procedure. Subsequently, blinded observers recorded average BIS values for the 5 min before each UMSS observation.
Results: There were moderate correlations between the BIS, MMWT, and UMSS scores (r = 0.68-0.78; P < 0.01). Revised criteria correctly identified children who were awake and alert (BIS value ≥ 90) in 88% of the cases. Only 55% of the children had returned to baseline BIS values when discharged by the nurse, compared with 92% when revised criteria were met (P < 0.05). It took longer to meet revised criteria compared with standard criteria (75.3 ± 76.2 min vs. 16.4 ± 13.1 min; P = 0.001).
Conclusions: The incorporation of specific, objective discharge criteria (i.e., UMSS score of 0 or 1, MMWT duration ≥ 20 min) may ensure a status closer to baseline (BIS value ≥ 90) compared with nursing judgment using standard criteria. However, such assurance may delay the discharge of sedated children

Obesity Decreases Perioperative Tissue Oxygenation
Barbara Kabon, M.D.; Angelika Nagele, R.N.; Dayakar Reddy, M.D. ; Chris Eagon, M.D.; James W. Fleshman, M.D.; Daniel I. Sessler, M.D.; Andrea Kurz, M.D.
Anesthesiology 2004; 100(2):274-280

Background: Obesity is an important risk factor for surgical site infections. The incidence of surgical wound infections is directly related to tissue perfusion and oxygenation. Fat tissue mass expands without a concomitant increase in blood flow per cell, which might result in a relative hypoperfusion with decreased tissue oxygenation. Consequently, the authors tested the hypotheses that perioperative tissue oxygen tension is reduced in obese surgical patients. Furthermore, they compared the effect of supplemental oxygen administration on tissue oxygenation in obese and nonobese patients.
Methods: Forty-six patients undergoing major abdominal surgery were assigned to one of two groups according to their body mass index: body mass index less than 30 kg/m² (nonobese) or 30 kg/m² or greater (obese). Intraoperative oxygen administration was adjusted to arterial oxygen tensions of approximately 150 mmHg and approximately 300 mmHg in random order. Anesthesia technique and perioperative fluid management were standardized. Subcutaneous tissue oxygen tension was measured with a polarographic electrode positioned within a subcutaneous tonometer in the lateral upper arm during surgery, in the recovery room, and on the first postoperative day. Postoperative tissue oxygen was also measured adjacent to the wound. Data were compared with unpaired two-tailed t tests and Wilcoxon rank sum test; P < 0.05 was considered statistically significant.
Results: Intraoperative subcutaneous tissue oxygen tension was significantly less in the obese patients at baseline (36 vs. 57 mmHg; P = 0.002) and with supplemental oxygen administration (47 vs. 76 mmHg; P = 0.014). Immediate postoperative tissue oxygen tension was also significantly less in subcutaneous tissue of the upper arm (43 vs. 54 mmHg; P = 0.011) as well as near the incision (42 vs. 62 mmHg; P = 0.012) in obese patients. In contrast, tissue oxygen tension was comparable in each group on the first postoperative morning.
Conclusion: Wound and tissue hypoxia were common in obese patients in the perioperative period and most pronounced during surgery. Even with supplemental oxygen tissue, oxygen tension in obese patients was reduced to levels that are associated with a substantial increase in infection risk.

Ophthalmic Regional Anesthesia: Medial Canthus Episcleral (Sub-Tenon) Single Injection Block
Emmanuel Nouvellon, M.D.; Joel L'Hermite, M.D.; Arnaud Chaumeron, M.D.; Aba Mahamat, M.D.; Martine Mainemer, M.D.; Pierre Charavel, M.D.; Philippe Mahiou, M.D.; Gérard Dupeyron, M.D.; Bruno Bassoul, M.D.; Stephane Dareau, M.D.; Jean-Jacques Eledjam, M.D., Ph.D.; Jacques Ripart, M.D., Ph.D.
Anesthesiology 2004; 100(2):370-374

Background: The purpose of this study was to evaluate the efficacy and safety of episcleral single-injection anesthesia in a large number of patients.
Methods: Over a period of 5 yr, in four institutions, anesthesiologists involved in this prospective study completed a standardized form to evaluate single-injection medial canthus high-volume episcleral anesthesia. The success rate of the block was rated according to an akinesia score. The study parameters included demographic data, surgical procedure, and anesthetic management. All patients were followed up at least until postoperative day 1, and all complications, pain, and discomfort were noted. Statistical analysis was done to assess the risk factors for complications.
Results: A total of 2,031 patients were included in the study. The most frequent surgical procedures performed were phacoemulsification and posterior chamber artificial lens implantation (91.0%). A total of 66 complications (3.3%) occurred in 60 patients. One patient had a retrobulbar hemorrhage, and 59 had one or two more minor incidents or pain/discomfort with the procedure. The complications consisted of subconjunctival hematoma (1.3%), ocular hypertonia (0.4%), and chemosis (0.30%). Statistical analysis revealed that inexperience in the technique represented a risk factor for complications.
Conclusions: This is the first survey of a large experience in episcleral single-injection anesthesia, a form of anesthesia that does not preclude sharp-needle complications and does require training. Only one complication occurred among 2,031 patients; however, a larger number of patients is needed to definitively evaluate the safety of episcleral single-injection anesthesia.

Infraclavicular Perineural Local Anesthetic Infusion: A Comparison of Three Dosing Regimens for Postoperative Analgesia
Brian M. Ilfeld, M.D.; Timothy E. Morey, M.D.; F. Kayser Enneking, M.D.
Anesthesiology 2004; 100(2):395-402

Background: In this randomized, double-blind study, the authors investigated the efficacy of continuous and patient-controlled ropivacaine infusions via an infraclavicular perineural catheter in ambulatory patients undergoing moderately painful orthopedic surgery at or distal to the elbow.
Methods: Preoperatively, patients (n = 30) received an infraclavicular perineural catheter and nerve block. Postoperatively, patients were discharged home with both oral analgesics and a portable infusion pump delivering 0.2% ropivacaine (500-ml reservoir) in one of three dosing regimens: the basal group (12 ml/h basal, 0.05-ml patient-controlled bolus dose), the basal-bolus group (8 ml/h basal, 4 ml bolus), or the bolus group (0.3 ml/h basal, 9.9 ml bolus). Investigators and patients were blinded to random group assignment.
Results: The basal group (n = 10) required more oral analgesics than the basal-bolus group (P = 0.002) and had a shorter median infusion duration than the other two groups (P < 0.001 for both). The bolus group had the longest median infusion duration (P < 0.001 for both) but experienced an increase in breakthrough pain incidence (P = 0.004) and intensity (P = 0.04 vs. basal-bolus group) as well as sleep disturbances (P < 0.001 for both) compared with the other groups. Overall satisfaction was greatest in the basal-bolus group (9.7 ± 0.5 vs. 7.9 ± 1.7 and 8.1 ± 1.5; P < 0.05 for both).
Conclusions: After moderately painful orthopedic surgery at or distal to the elbow, 0.2% ropivacaine delivered as a continuous infusion combined with patient-controlled bolus doses via an infraclavicular perineural catheter optimizes analgesia while minimizing oral analgesic use compared with basal- or bolus-only dosing regimens.

Quantifying Net Staffing Costs Due to Longer-than-average Surgical Case Durations
Amr E. Abouleish, M.D., M.B.A.; Franklin Dexter, M.D., Ph.D.; Charles W. Whitten, M.D.; Jeffery R. Zavaleta, M.D.; Donald S. Prough, M.D.
Anesthesiology 2004; 100(2):403-412

Background: Anesthesiology departments incur staffing costs that are not covered by revenue because the operating room (OR) time allocation and case scheduling are not done to maximize OR efficiency and because surgical durations are longer than average. The purpose of this article is to demonstrate a method to quantify net anesthesia staffing costs due to longer-than-average surgical durations and evaluate the factors that influence staffing costs.
Methods: Data collected from two anesthesiology departments in academic hospitals for 1 yr included date of surgery, time that patients entered the OR, time that patients exited the OR, surgical service, and the Current Procedural Terminology code for the primary surgical procedure. Anesthesia care performed outside the main surgical suite and services not billed with American Society of Anesthesiologists units were excluded. National average surgical durations were determined from the Current Procedural Terminology code from the Centers for Medicare and Medicaid Services' database. Actual surgical durations were then used to determine staffing solutions to maximize OR efficiency; national average surgical durations were then used to determine a second solution. The difference in staffing costs between these two staffing solutions represented the staffing costs attributable to longer surgical durations. Costs were converted to dollar amounts using compensation values reported in a national compensation survey. The differences in revenue were determined by applying conversion factors to the differences in surgical durations. The annual net cost attributable to longer surgical durations equaled the staffing costs minus the revenue produced by longer durations. Net staffing costs were estimated for two hospitals using median staffing compensation and median payer mix. Net staffing costs were then recalculated by varying the parameters (conversion factors, limits on differences between actual and average surgical duration, levels of compensation, surgical service size of OR allocation).
Results: Using the median compensation of staff and an average conversion factor, the net annual staffing costs attributable to longer surgical durations were $672,100 for the first hospital. However, if staff members were highly compensated and the payer mix was unfavorable, the net staffing costs were $1,688,000. Reducing the difference between actual and average duration resulted in lower staffing costs. Net staffing costs were less in a second hospital studied that had many low-volume surgical services.
Conclusions: Longer-than-average surgical durations can increase net staffing costs for anesthesiology groups. The increase is dependent on factors such as staffing compensation and payer mix.

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The influence of esmolol on the dose of propofol required for induction of anaesthesia
E. S. Wilson, S. McKinlay, J. M. Crawford, H. M. Robb
Anaesthesia Volume 59: Issue 2 Pages 122-126

Cardiac output may be an important determinant of the induction dose of intravenous anaesthetic. Esmolol is known to reduce cardiac output, and we examined its effect on the propofol dose required for induction of anaesthesia. The size of the effect seen with esmolol was compared with midazolam co-induction. Sixty patients were randomly allocated to placebo (saline), esmolol (1mg.kg^-1 bolus, followed by an infusion at 250 µg.kg^-1min^-1) or midazolam (0.04 mg.kg^-1) groups. Induction of anaesthesia commenced 3 min following the administration of the study drug, using a Diprifusor set to achieve plasma propofol concentrations of 10 µg.ml^-1 at 5 min. The primary end point used was the propofol dose per kg at loss of response to command. The mean (SD) propofol dose for each group was 2.38 (0.48) mg.kg^-1 for placebo, 1.79 (0.36) mg.kg^-1 for esmolol and 1.34 (0.35) mg.kg^-1 for midazolam (all means significantly different; p <0.0005). We found that predosing with esmolol reduces the propofol requirements for induction of anaesthesia by 25%.

Patient maintained sedation for colonoscopy using a target controlled infusion of propofol
L. Campbell, G. Imrie, P. Doherty, C. Porteous, K. Millar, G. N. C. Kenny, G. Fletcher
Anaesthesia Volume 59: Issue 2 Pages 127-132

In this study, we evaluated safety and recovery using a patient maintained, target controlled infusion of propofol for sedation in 20 patients undergoing colonoscopy. Using a handset with a two-minute lockout interval, patients could make 0.2 µg.ml^-1 increments to an initial target plasma concentration of 1 µg.ml^-1 up to a maximum 4.5 µg.ml^-1. Four patients became oversedated but required no airway or circulatory interventions. Subjects had a significant reduction in mean (SD) heart rate: 78.7 (15) vs. 69.8 (13.5) (p < 0.001) and in systolic blood pressure 121.1 (13.2) mmHg vs. 96.5 (8.6) mmHg (p < 0.001). Choice reaction time testing 15 min after colonoscopy showed a significant median (IQR [range]) rise of 162 (- 16, 383.3 [-199–859]) ms (p < 0.05). Six patients had faster reaction times postcolonoscopy. All patients denied unpleasant recall and were satisfied with the system. Although oversedation was a problem in this model, we conclude that patient maintained propofol sedation could be possible for colonoscopy.

Acupuncture compared to placebo-acupuncture for postoperative nausea and vomiting prophylaxis: A randomised placebo-controlled patient and observer blind trial
K. Streitberger, M. Diefenbacher, A. Bauer, R. Conradi, H. Bardenheuer, E. Martin, A. Schneider, K. Unnebrink
Anaesthesia Volume 59: Issue 2 Pages 142 - 149

This randomised, placebo-controlled, patient and observer blinded trial was conducted to determine whether acupuncture at the acupuncture point P6 is effective in preventing postoperative nausea and vomiting (PONV) compared to placebo acupuncture. Female patients (n = 220) scheduled for gynaecological or breast surgery were randomly assigned to two groups receiving either acupuncture (n = 109) or placebo acupuncture (n = 111). Each group was stratified for type of surgery and included two subgroups receiving intervention either before or after induction of anaesthesia. The incidence of PONV and/or antiemetic rescue medication within 24 h after surgery was the main outcome measure which showed no statistically significant difference between groups (43.7% acupuncture, 50.9% placebo, p = 0.27). The differences were more pronounced for patients having gynaecological surgery (48.9% acupuncture, 67.6% placebo, p = 0.07) than for those having breast surgery (38.7% acupuncture, 40.3% placebo, p = 0.86). The secondary outcome, vomiting, was significantly reduced by acupuncture from 39.6% to 24.8% (p = 0.03). Subgroup analysis showed no difference between applications of acupuncture before compared to after induction of anaesthesia.

Improving anaesthetists' communication skills
C. Harms, J. R. Young, F. Amsler, C. Zettler, D. Scheidegger, C. H. Kindler
Anaesthesia Volume 59: Issue 2 Pages 166 - 172

The attitude, behaviour and communication skills of specialised doctors are increasingly recognised as important and they have been identified as training requirements. We designed a programme to teach communication skills to doctors in a University Department of Anaesthesia and evaluated its effect on patient outcomes such as satisfaction and anxiety. The 20 h programme was based on videotaped reviews of actual pre-operative visits and role-playing. Effects on patient satisfaction and pre-operative anxiety were assessed using a patient questionnaire. In addition, all participating anaesthetists assessed the training. We provide evidence that the training increased patient satisfaction with the pre-operative anaesthetic visit. Training also decreased anxiety associated with specific aspects of anaesthesia and surgery, but the effect was rather small given the intense programme. The anaesthetists agreed that their interpersonal skills increased and they felt better prepared to understand patients' anxieties. Communication skills training can increase patient satisfaction and decrease specific anxieties. The authors conclude that in order to better demonstrate the efficacy of such a training programme, the particular communication skills of anaesthetists rather than indirect patient outcome parameters should be measured.

Laparoscopic appendectomy in an outpatient setting.
Zinaman MJ, Russell A, Sukhani R, Uhler ML.
J Am Assoc Gynecol Laparosc. 2003 Nov;10(4):478-80.

STUDY OBJECTIVE: To determine the ability to perform laparoscopic appendectomy on an outpatient basis.
DESIGN: Prospective study (Canadian Task Force classification II-2).
SETTING: University ambulatory surgery center.
PATIENTS: Forty-two consecutive patients.
INTERVENTION: Laparoscopic appendectomy.
MEASUREMENTS AND MAIN RESULTS: After performing five laparoscopic appendectomies, three women required hospitalization. Thus a new multimodal protocol was implemented and admission and recovery times were monitored. After the new protocol was implemented, only 1 of 37 patients required hospitalization. Discharge times were similar to those for women undergoing gynecologic laparoscopy without appendectomy.
CONCLUSION: With attention to surgical and anesthetic protocols, appendectomy can be performed at the time of gynecologic laparoscopy in an ambulatory setting without a significant delay in discharge.

Improving ambulatory surgical pain management.
Woodley KS.
Jt Comm J Qual Saf. 2004 Jan;30(1):36-41, 1.

A surgical pain improvement team used an improvement model to standardize pain management at two hospital-based ambulatory surgery facilities.

Comparison of Spinal vs General Anesthesia via Laryngeal Mask Airway in Inguinal Hernia Repair.
Burney RE, Prabhu MA, Greenfield ML, Shanks A, O'Reilly M.
Arch Surg. 2004 Feb;139(2):183-7.

HYPOTHESIS: The use of laryngeal mask airway and propofol in inguinal hernia repair results in shorter operative and recovery room times.
DESIGN: Randomized control trial.
SETTING: University hospital.
PATIENTS: From May 2000 to March 2002, a convenience sample of 79 patients was invited to participate; 34 entered the study. Fifteen patients were randomized to subarachnoid block, and 18 patients were randomized to laryngeal mask airway. No patients withdrew from the study because of adverse effects. All study subjects were followed up for 6 months.
INTERVENTION: General anesthesia via laryngeal mask airway or lidocaine subarachnoid block anesthesia for inguinal hernia repair.
MAIN OUTCOME MEASURES: Operative and recovery room times; surgeon evaluation of the adequacy of the anesthetic technique; 36-Item Short-Form Health Survey scores before and after operation.
RESULTS: Total time from entry into the operating room to discharge home was slightly longer in the subarachnoid block group (285 vs 262 minutes; 95% confidence interval, 251-317 minutes) but this difference was not statistically or clinically significant. Patient satisfaction was high with both techniques; patient-reported outcomes were the same. Surgeons rated muscle relaxation and exposure better with the subarachnoid block.
CONCLUSIONS: We found no differences between short-acting spinal anesthesia and general anesthesia via laryngeal mask airway with intravenous propofol in efficiency or in early or late outcomes after elective inguinal hernia repair. Surgeon and patient preferences appear to be the most important reasons for selecting an anesthetic technique for individual patients undergoing inguinal hernia repair.

Comparative study of the antiemetic efficacy of ondansetron, propofol and midazolam in the early postoperative period.
Unlugenc H, Guler T, Gunes Y, Isik G.
Eur J Anaesthesiol. 2004 Jan;21(1):60-5.

BACKGROUND AND OBJECTIVE: To compare the antiemetic efficacy of ondansetron with two different hypnotic drugs (propofol 15 mg, midazolam 1 and 2 mg) for the treatment of established postoperative nausea and vomiting (PONV).
METHODS: Four-hundred-and-fifty-three patients scheduled for elective gynaecological or abdominal surgery were enrolled. One-hundred-and-twenty patients (26%) experienced postoperative emesis, and when nausea scores reached 2 or greater on a five-point scale, they were randomized to receive intravenously: propofol 15 mg (1.5 mL) in Group P, midazolam 1 mg in Group M1, midazolam 2 mg in Group M2 and ondansetron 4 mg in Group O.
RESULTS: Four patients (13.3%) in Group P, 13 patients (43.3%) in Group M1, five patients (16.6%) in Group M2 and one patient (3.3%) in Group O required a second dose of the study drug. After administration of the study drugs, nausea scores were significantly lower in all groups than before these drugs were given. No patient had a sedation score over 3 (the patients remained awake and/or responded to verbal contact). The sedative effects of midazolam and propofol lasted for a much shorter time than the antiemetic effects of these drugs.
CONCLUSIONS: Propofol and midazolam used in subhypnotic doses were as effective as ondansetron in treating PONV in patients undergoing abdominal or gynaecological surgery without untoward sedative or cardiovascular effects.

General anaesthesia or spinal anaesthesia for outpatient urological surgery
Erhan E., Ugur G., Anadolu O., Saklayan M., Ozyar B.
European Journal of Anaesthesiology. 20(8):647-52, 2003

BACKGROUND AND OBJECTIVE: A variety of drugs and techniques have been introduced into ambulatory anaesthesia. The technique as well as the drugs used may hasten or delay home discharge. We compared recovery profiles and side-effects of spinal anaesthesia and total intravenous anaesthesia.
METHODS: Forty unpremedicated ASA I-II patients (18-65 yr) undergoing varicocele repair were randomly divided into two groups. Spinal anaesthesia (26-G atraumatic needle) with hyperbaric bupivacaine 0.5% 5 mg and fentanyl 25 mcg were given to patients in Group Spinal (n = 20). Patients in Group TIVA (n = 20) received total intravenous anaesthesia with propofol and remifentanil given by continuous infusion; a laryngeal mask was used to secure the airway. The duration of surgery, time to home readiness and side-effects were recorded.
RESULTS: The two groups were comparable with respect to patients' characteristics and duration of surgery. The times to achieve ambulation were similar between groups (Spinal = 78.4 +/- 40.9 min, TIVA = 75.9 +/- 13.8 min). Urinary voiding was a requirement for discharge after spinal anaesthesia and the time for home readiness was longer in Group Spinal (158.0 +/- 40.2 versus 94.9 +/-18.8 min) (P < 0.05). Two patients reported pruritus and one reported postdural puncture headache in Group Spinal, whereas two patients reported nausea in Group TIVA. Patients in Group TIVA had a greater need for analgesia postoperation (P < 0.05).
CONCLUSIONS: In healthy unpremedicated men undergoing minor urological operations, total intravenous anaesthesia with remifentanil and propofol provided as safe and effective anaesthesia as spinal block with the advantage of earlier home readiness.

Aromatherapy with peppermint, isopropyl alcohol, or placebo is equally effective in relieving postoperative nausea.
Anderson LA, Gross JB.
Perianesth Nurs. 2004 Feb;19(1):29-35.

To determine whether aromatherapy can reduce postoperative nausea, the investigators studied 33 ambulatory surgery patients who complained of nausea in the PACU. After indicating the severity of nausea on a 100-mm visual analogue scale (VAS), subjects received randomized aromatherapy with isopropyl alcohol, oil of peppermint, or saline (placebo). The vapors were inhaled deeply through the nose from scented gauze pads held directly beneath the patients' nostrils and exhaled slowly through the mouth. Two and 5 minutes later, the subjects rated their nausea on the VAS. Overall nausea scores decreased from 60.6 +/- 4.3 mm (mean +/- SE) before aromatherapy to 43.1 +/- 4.9 mm 2 minutes after aromatherapy (P <.005), and to 28.0 +/- 4.6 mm 5 minutes after aromatherapy (P < 10(-6)). Nausea scores did not differ between the treatments at any time. Only 52% of the patients required conventional intravenous (IV) antiemetic therapy during their PACU stay. Overall satisfaction with postoperative nausea management was 86.9 +/- 4.1 mm and was independent of the treatment group. Aromatherapy effectively reduced the perceived severity of postoperative nausea. The fact that a saline "placebo" was as effective as alcohol or peppermint suggests that the beneficial effect may be related more to controlled breathing patterns than to the actual aroma inhaled.

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