Injury and Liability Associated with Monitored Anesthesia Care: A Closed Claims Analysis.
Bhananker, Sanjay M. M.D., F.R.C.A.; Posner, Karen L. Ph.D. ; Cheney, Frederick W. M.D. ; Caplan, Robert A. M.D. ; Lee, Lorri A. M.D. ; Domino, Karen B. M.D., M.P.H.
Anesthesiology. 104(2):228-234, February 2006.

Background: To assess the patterns of injury and liability associated with monitored anesthesia care (MAC) compared with general and regional anesthesia, the authors reviewed closed malpractice claims in the American Society of Anesthesiologists Closed Claims Database since 1990.
Methods: All surgical anesthesia claims associated with MAC (n = 121) were compared with those associated with general (n = 1,519) and regional (n = 312) anesthesia. A detailed analysis of MAC claims was performed to identify causative mechanisms and liability patterns.
Results: MAC claims involved older and sicker patients compared with general anesthesia claims (P < 0.025), often undergoing elective eye surgery (21%) or facial plastic surgery (26%). More than 40% of claims associated with MAC involved death or permanent brain damage, similar to general anesthesia claims. In contrast, the proportion of regional anesthesia claims with death or permanent brain damage was less (P < 0.01). Respiratory depression, after absolute or relative overdose of sedative or opioid drugs, was the most common (21%, n = 25) specific damaging mechanism in MAC claims. Nearly half of these claims were judged as preventable by better monitoring, including capnography, improved vigilance, or audible alarms. On-the-patient operating room fires, from the use of electrocautery, in the presence of supplemental oxygen during facial surgery, resulted in burn injuries in 20 MAC claims (17%).
Conclusions: Oversedation leading to respiratory depression was an important mechanism of patient injuries during MAC. Appropriate use of monitoring, vigilance, and early resuscitation could have prevented many of these injuries. Awareness and avoidance of the fire triad (oxidizer, fuel, and ignition source) is essential to prevent on-the-patient fires.


Intrapatient Reproducibility of the BISxp(R) Monitor.
Niedhart, Dagmar J. M.D. ; Kaiser, Heiko A. M.D. ; Jacobsohn, Eric M.B.Ch.B., M.H.P.E., F.R.C.P.C. ; Hantler, Charles B. M.D. ; Evers, Alex S. M.D. ; Avidan, Michael S. M.B.B.Ch., F.C.A.S.A. 
Anesthesiology. 104(2):242-248, February 2006.
 
Background: The Bispectral Index (BIS) reportedly reflects anesthetic depth. It is recommended that anesthetic agents should be titrated to maintain the BIS between 40 and 60 arbitrary BIS units during anesthesia. For anesthesia providers to follow this recommendation, the monitor should be predictably affected by different anesthetic agents and have good interpatient and intrapatient reproducibility. The authors hypothesized that when two BISxp(R) devices (Aspect Medical Systems, Newton, MA) are placed concurrently on the same patient, their readings are concordant throughout the anesthetic period.
Methods: Simultaneous BIS recordings from two BISxp(R) monitors were obtained during anesthesia at 5-s intervals from 12 participants.
Results: In total 22,860 concurrent paired BIS readings were obtained. For 10.7% of the time, there were sustained periods of 30 s or greater where the readings suggested a different depth of anesthesia. For 6% of the time, there were sustained periods of 30 s or greater where the readings differed by 10 or more arbitrary BIS units. The regression coefficient (R2) for the two devices was 0.65 (range, 0.35-0.92). There was zero bias between the devices, and the 95% limits of agreement ranged between -18 and +17.
Conclusion: A conflicting anesthetic management was suggested by the simultaneous BIS readings 10.7% of the time. These results suggest that BISxp(R) does not always provide a reproducible single number. Anesthesia providers should not rely exclusively on the BIS reading when assessing depth of anesthesia.

Lightwand Tracheal Intubation with and without Muscle Relaxation.
Masso, Eva M.D., Ph.D. ; Sabate, Sergi M.D. ; Hinojosa, Marta M.D. ; Vila, Pere M.D., Ph.D.; Canet, Jaume M.D., Ph.D. ; Langeron, Olivier M.D., Ph.D.
Anesthesiology. 104(2):249-254, February 2006.

Background: Lightwand tracheal intubation is a suitable technique for patients who are difficult to intubate but who are receiving effective ventilation. The effect of muscle relaxants on the efficacy of lightwand intubation has not yet been evaluated. The authors conducted a prospective, double-blind, placebo-controlled study to assess the effectiveness and incidence of complications of lightwand tracheal intubation performed during general anesthesia with and without the use of a muscle relaxant in patients with apparently normal airway anatomy.
Methods: One hundred seventy-six patients who required orotracheal intubation were prospectively included. Anesthesia was administered using propofol (2 mg/kg, then 3 mg [middle dot] kg^-1 [middle dot] h-1) and remifentanil (1 [mu]g/kg, then 0.3 [mu]g [middle dot] kg^-1 [middle dot] min^-1). Patients were randomly assigned to one of two groups (n = 88 for each) to receive rocuronium 0.6 mg/kg or saline intravenously. Lightwand orotracheal intubation (Trachlight(R); Laerdal Medical Inc., Armonk, NY) was attempted after 3 min. The authors recorded the number of successful intubations, the number of attempts and their duration, and events during the procedure.
Results: The failure rate of lightwand intubation was 12% in the placebo group and 2% in the rocuronium group (P = 0.021). Patients in the placebo group received more multiple intubation attempts (P < 0.001), required a greater intubation time (77 +/- 65 vs. 52 +/- 31 s; P = 0.002) and experienced a greater incidence of events during intubation (61 vs. 0%; P < 0.001) than patients in the rocuronium group.
Conclusions: The use of muscle relaxants in patients with apparently normal airways is associated with a lower failure rate, decreased intubation time, and fewer attempts when performing lightwand orotracheal intubation.

Ultrasound Examination and Localization of the Sciatic Nerve: A Volunteer Study.
Chan, Vincent W. S. M.D. ; Nova, Hugo M.D. ; Abbas, Sherif M.D. ; McCartney, Colin J. L. M.B.Ch.B., F.R.C.A. ; Perlas, Anahi M.D. ; Quan Xu, Da M.B. M.Sc. 
Anesthesiology. 104(2):309-314, February 2006.

Background: Few studies have examined the use of ultrasound for sciatic nerve localization. The authors evaluated the usefulness of low-frequency ultrasound in identifying the sciatic nerve at three locations in the lower extremity and in guiding needle advancement to target before nerve stimulation.
Methods: In this prospective observational study, 15 volunteers underwent sciatic nerve examination using a curved ultrasound probe in the range of 2-5 MHz and a Philips-ATL 5000 unit (ATL Ultrasound, Bothell, WA) in the gluteal, infragluteal, and proximal thigh regions. Thereafter, an insulated block needle was advanced inline with the ultrasound beam to reach the nerve target, which was further confirmed by electrical stimulation. The quality of sciatic nerve images, ease of needle to nerve contact, threshold stimulating current, and resultant motor response were recorded.
Results: The sciatic nerve was successfully identified in the transverse view as a solitary predominantly hyperechoic structure on ultrasound in all of the three regions examined. The target nerve was visualized easily in 87% and localized within two needle attempts in all patients. Nerve stimulation was successful in 100% after two attempts with a threshold current of 0.42 +/- 0.12 (mean +/- SD) eliciting foot plantarflexion or dorsiflexion.
Conclusions: These preliminary data show that a curved 2- to 5-MHz ultrasound probe provides good quality sciatic nerve imaging in the gluteal, infragluteal, and proximal thigh locations. Ultrasound-assisted sciatic nerve localization is potentially valuable for clinical sciatic nerve blocks.

Reduction of Verbal Pain Scores after Anterior Cruciate Ligament Reconstruction with 2-Day Continuous Femoral Nerve Block: A Randomized Clinical Trial.
Williams, Brian A. M.D., M.B.A. ; Kentor, Michael L. M.D. ; Vogt, Molly T. Ph.D., Dr.P.H. ; Irrgang, James J. Ph.D., P.T., A.T.C. ; Bottegal, Matthew T. B.S. ; West, Robin V. M.D. ; Harner, Christopher D. M.D. ; Fu, Freddie H. M.D., D.Sc.(Hon), D.Ps.(Hon) ; Williams, John P. M.D. 
Anesthesiology. 104(2):315-327, February 2006.

Background: Single-injection femoral nerve block analgesia and spinal anesthesia have been associated with fewer postoperative nursing interventions and successful same-day discharge after anterior cruciate ligament reconstruction. In the current study, the authors prospectively determined the effect of continuous femoral nerve block on a numeric rating scale (NRS) of pain intensity with movement for 7 postoperative days.
Methods: Patients undergoing this surgery with no history of previous invasive surgery on the same knee were recruited for this study. After standardized spinal anesthesia, intravenous sedation, and perioperative multimodal analgesia, patients received a femoral nerve catheter with (1) saline bolus (30 ml) plus saline infusion (270 ml at 5 ml/h, placebo group); (2) levobupivacaine (0.25%) bolus with saline infusion (group I), or (3) levobupivacaine (0.25%) bolus and infusion (group II). Patients were surveyed preoperatively and on postoperative days 1-4 and 7 to determine NRS scores (scale 0-10).
Results: Data from 233 participants were analyzed. On days 1-2, 50% of placebo patients had NRS scores of 5 or above, whereas among group II patients, only 25% had scores of 5 or above (P < 0.001). In regression models for NRS scores during days 1-4, group II was the only factor predicting lower pain scores (odds ratios, 0.3-0.5; P = 0.001-0.03). Overall, patients with preoperative NRS scores greater than 2 were likely to report higher NRS scores during days 1-7 (odds ratios, 3.3-5.2; P < 0.001).
Conclusions: Femoral nerve block catheters reliably keep NRS scores below the moderate-to-severe pain threshold for the first 4 days after anterior cruciate ligament reconstruction.

Perioperative Abstinence from Cigarettes: Physiologic and Clinical Consequences.
Warner, David O. M.D. 
Anesthesiology. 104(2):356-367, February 2006.

Chronic exposure to cigarette smoke produces profound changes in physiology that may alter responses to perioperative interventions and contribute to perioperative morbidity. Because of smoke-free policies in healthcare facilities, all smokers undergoing surgery are abstinent from cigarettes for at least some period of time so that all are in various stages of recovery from the effects of smoke. Understanding this recovery process will help perioperative physicians better treat these patients. This review examines current knowledge regarding how both short-term (duration ranging from hours to weeks) and long-term smoking cessation affects selected physiology and pathophysiology of particular relevance to perioperative outcomes and how these changes affect perioperative risk. It will also consider current evidence regarding how nicotine replacement therapy, a valuable adjunct to help patients maintain abstinence, may affect perioperative physiology.

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Analgesic efficacy of parenteral paracetamol (propacetamol) and diclofenac in post-operative orthopaedic pain
D. Hynes, M. McCarroll and O. Hiesse-Provost
Volume 50 Page 374  - March 2006

Background: Propacetamol is an injectable pro-drug of paracetamol (acetaminophen) with analgesic and antipyretic activities, especially used in the post-operative period. The aim of this study was to assess the analgesic efficacy and safety of intravenous paracetamol, administered as propacetamol, in comparison with placebo and intramuscular diclofenac in patients with post-operative pain.
Methods: This was a randomized, double-blind, double-dummy study. One hundred and twenty patients with moderate to severe pain following total hip arthroplasty received either two administrations of propacetamol 2 g intravenously, 5 h apart (n = 40), one single administration of diclofenac 75 mg intramuscularly (n = 40) or placebo (n = 40). Efficacy measures were assessed before each drug administration, for the 5 h following each study treatment administration and for the total study duration of 10 h. Safety was assessed by reporting adverse events and changes in vital signs, electrocardiogram (ECG) and biochemical investigations before and 24 h after dosing.
Results: Both active treatments were effective and statistically superior to placebo over the whole study period, as indicated by the total pain relief score. No significant differences were found between propacetamol and diclofenac for any measures of analgesic activity. Only minor and common adverse events were reported, with no overall differences between the groups.
Conclusion: Both active treatments were superior to placebo, and the overall efficacy of two intravenous infusions of propacetamol 2 g (equivalent to 1 g of paracetamol), 5 h apart, was not statistically different from that provided by a single intramuscular injection of diclofenac 75 mg over the first 5 h post-dose and over the total 10-h study period. The safety was good.

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The LMA CTrach^TM, a new laryngeal mask airway for endotracheal intubation under vision: evaluation in 100 patients
E. H. C. Liu, R. W. L. Goy and F. G. Chen
British Journal of Anaesthesia 2006 96(3):396-400

Background. The LMA CTrach^TM is a new laryngeal mask system consisting of an LMA CTrach^TM Airway with integrated fibreoptic channels, and a detachable LMA CTrach^TM Viewer. This system enables viewing of the larynx and aids endotracheal intubation through a laryngeal mask airway.
Method. We used and evaluated this system in 100 adult patients undergoing general anaesthesia for elective surgery. Our primary outcomes were the success rates of LMA CTrach^TM Airway insertion and endotracheal intubation with this system.
Results. We were able to insert the LMA CTrach^TM Airway in and to ventilate all 100 patients. We were successful in endotracheal intubation, either under vision or blind, in 96 patients. We were able to view the larynx in 84 patients, but the quality of the best view obtained was very variable. The median (inter quartile range) time for the complete intubation process was 166 (114–233) s. The system allowed nearly continuous ventilation and oxygenation during the process.
Conclusions. The LMA CTrach^TM system has potential advantages over the LMA FastrachTM system, including the ability to align the LMA outlet with the larynx and a high first intubation attempt success rate. However, it was difficult to view the larynx with the LMA CTrach^TM compared with direct laryngoscopy, and expectations must be moderated.

The Narcotrend ‘depth of anaesthesia’ monitor cannot reliably detect consciousness during general anaesthesia: an investigation using the isolated forearm technique
I. F. Russell
British Journal of Anaesthesia 2006 96(3):346-352

Background. During general anaesthesia in the presence of neuromuscular blocking drugs clinical criteria cannot detect the presence of consciousness. Various ‘depth of anaesthesia’ monitors are available which claim to prevent consciousness and/or reduce anaesthetic drug use. This study uses the Narcotrend anaesthesia brain monitor to guide anaesthetic administration but at the same time checks for the presence of intra-operative consciousness by using the ‘isolated forearm’ technique throughout the whole surgical/anaesthetic procedure.
Methods. Twelve women presenting for major gynaecological surgery under general anaesthesia, which included the use of neuromuscular blocking drugs, had a target controlled infusion of propofol adjusted according to the anaesthetic ‘stage’ indicated by a Narcotrend ‘Depth of Anaesthesia Monitor’. Throughout surgery the isolated forearm technique was used to detect for the presence of consciousness at 1 min intervals.
Results. Isolated forearm responses to commands occurred in all 12 patients at some time during surgery, frequently in the absence of any significant changes in the usually monitored clinical variables. Overall, the 12 patients responded a total of 92 times during surgery. Only 41 (45%) responses were associated with an increase in the Narcotrend stage to a level suggesting consciousness (above stage C0). For the remaining responses, either there was no significant increase in the Narcotrend stage (above C0) or there was no change at all in the Narcotrend stage before, during, or after the patient responded to the taped command.
Conclusions. The Narcotrend was unable to differentiate reliably between conscious and unconscious patients during general anaesthesia when neuromuscular blocking agents were used.

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Similar incidence of hypotension with combined spinal-epidural or epidural alone for knee arthroplasty
Tiberiu Ezri, MD, Islam Zahalka, MD, Deeb Zabeeda, MD, Zeev Feldbrin, MD, Alexander Eidelman, MD, Reuven Zimlichman, MD, Benjamin Medalion, MD and Shmuel Evron, MD
Canadian Journal of Anesthesia 53:139-145 (2006)

Background: We hypothesized that the incidence of hypotension during total knee replacement (TKR) surgery is lower in patients given combined spinal-epidural (CSE) anesthesia vs those receiving epidural anesthesia alone.
Methods: In a prospective study, 80 American Society of Anesthesiologists I–II patients (aged 40–80 yr), undergoing elective TKR surgery were randomly assigned to either CSE anesthesia (CSE, n = 40) or epidural anesthesia alone (Epidural, n = 40). Hemodynamic measurements included oscillometric mean arterial blood pressure (MAP), heart rate (HR), and cardiac index (CI) as determined by thoracic bioimpedance; systemic vascular resistance (SVR) was calculated. Our primary endpoint (outcome) was the number of hypotension episodes (defined as MAP < 70 mmHg).
Results: Using univariate analysis, we found no differences between the groups in regards to MAP, HR, CI, or SVR during the perioperative period. The incidence of hypotension was similar in both groups (two patients in each group), as was the incidence of bradycardia (12 patients in CSE, 7 in Epidural; P = 0.2). There were no differences between groups in other hemodynamic measurements including CI and calculated SVR. Analgesia supplementation with fentanyl was more frequently required in the Epidural group (20 vs 6 patients; P = 0.03).
Conclusion: Combined spinal-epidural anesthesia and epidural anesthesia alone during TKR surgery are associated with the same incidence of hypotension with statistically and clinically similar hemodynamic responses.

Lack of a pre-emptive effect of low-dose ketamine on postoperative pain following oral surgery
Thierry Lebrun, MD, Alain C. Van Elstraete, MD, Ignace Sandefo, MD, Bruno Polin, MD and Luc Pierre-Louis, MD
Canadian Journal of Anesthesia 53:146-152 (2006)

Purpose: The aim of this study was to assess the effect of pre- vs postincisional low-dose iv ketamine on postoperative pain in outpatients scheduled for oral surgery under general anesthesia.
Methods: Eighty-four patients were randomly assigned to receive intravenously saline before and after surgery in Group 1, ketamine 300 µg·kg–1 iv before and saline after surgery in Group 2, saline before and ketamine 300 µg·kg–1 iv after surgery in Group 3. Postoperative analgesia consisted of iv proparacetamol and ketoprofen. Rescue analgesia consisted of nalbuphine 200 µg·kg–1 iv. Analgesia at home consisted of oral ketoprofen, and acetaminophen with codeine as rescue analgesia. A telephone interview was conducted on the first and second postoperative days.
Results: There were no significant differences between groups with respect to pain scores, the number of patients requiring nalbuphine in the postanesthesia care unit (PACU), (36.7%, 38.7%, and 39.5% for Groups 1, 2, and 3 respectively), or nalbuphine consumption in the PACU (66.5 µg·kg–1 ± 16.8, 75.9 µg·kg–1 ± 17.5, 66.7 µg·kg–1 ± 21.6 for Groups 1, 2, and 3 respectively). The number of rescue analgesic tablets taken at home, and time to first request for rescue analgesia, sedation scores, or side-effects were similar amongst groups. No patient required nalbuphine in the ambulatory care unit.
Conclusions: There was no benefit to pre-emptive administration of ketamine 300 µg·kg–1 iv whether administered pre- or postoperatively.

Advantages of ProSealTM and SLIPATM airways over tracheal tubes for gynecological laparoscopies
Donald M. Miller, FFA SA PhD and Luigi Camporota, MD MRCP
Canadian Journal of Anesthesia 53:188-193 (2006)

Purpose: To compare the efficacy of the ProSeal LMATM and SLIPATM supralaryngeal airways (SLA) with the standard tracheal tube (TT) in 150 consecutive day-case laparoscopic gynecological surgery procedures requiring general anesthesia.
Methods: One hundred and fifty patients were randomized into three groups. An identical general anesthesia technique was used in all patients apart from the addition of muscle relaxants and reversal drugs in the TT group. Patients were excluded if there were risk factors for gastroesophageal reflux. Ease of use, quality of seal, ventilation, systolic pressure, response to intubation, side effects and operating room time were assessed.
Results: Both ProSeal LMATM and SLIPATM were easy to insert (100% success) and ventilate with respective mean (standard deviation) maximum sealing pressures of 31 (4.6) and 30 (5.2) cmH2O (P = 0.4) with no muscle relaxants. The seal quality in both ProSeal LMATM and SLIPATM permitted the use of low flows, 485 (291) and 539 (344) mL·min–1 (P = 0.2) respectively, although in the TT group significantly lower flows [377 (124) mL·min–1], (P < 0.01) were achieved. Systolic pressure in the SLA groups was more stable in response to insertion than in the TT. With ProSealTM there was a lower incidence of sore throats than with TT (30% vs 57%), (P < 0.05), but there was a lesser difference as compared with SLIPATM (30% vs 49%), (P > 0.05). With both SLAs, there was a significant reduction in operating room time (> three minutes), (P < 0.001).
Conclusions: These results suggest that the ProSeal LMATM (reusable) and SLIPATM (single-use) SLAs were easy to use without requiring muscle relaxants, and reduce operating room time compared to the TT technique in day case laparoscopies.


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Informing parents about anaesthesia for children’s surgery: a critical literature review
Linda S. Francka, Caroline Spencer
Patient Education and Counseling 59 (2005) 117–125

This review critically analysed the published research literature on providing information about children’s anaesthesia to parents. An extensive search of the biomedical literature yielded 11 studies: 6 descriptive and 5 intervention studies. Standardised instruments for
measuring parental knowledge, need for information and anxiety about children’s anaesthetic care showed preliminary validity and reliability. The intervention studies tested different methods of providing information, including verbal, video or written modalities and showed some improvements in knowledge, anxiety and satisfaction. Parents want detailed information about the specifics of anaesthetic procedures, risks, and personnel roles and this information should be incorporated into the routine pre-surgical anaesthesia assessment clinic visits. Until further research determines the most effective methods, mode of delivery should be based on feasibility so that parents consistently receive more information. Audits of parental satisfaction with information should be performed and used to continuously improve the content and delivery of information.

Preanesthesia Considerations for the Nurse Practitioner
Jamie Reddinger, Kathleen Oft  & Katrina Geier
J Pediatr Health Care. (2005) 19, 374-379

With increases in pediatric ambulatory surgery, primary health care providers such as nurse practitioners are being called upon to provide input about patients preoperatively or prior to other procedures requiring anesthesia. Because the anesthesia team may not meet the patient and family until the day of surgery; a thorough evaluation done by the primary care provider can supply the anesthesia team with the information required for optimal care. Such information includes a detailed history, including the patient’s birth history, medical diagnoses, medications, allergies, recent laboratory test values, and the results of a recent physical examination. The purpose of this article is to provide primary care nurse practitioners with guidelines and information to consider when seeing their patient for a preprocedural visit. 

How painful are shockwave lithotripsy and endoscopic procedures performed at outpatient urology clinics?
Byong Chang Jeong,  Hyoung Keun Park, Cheol Kwak,  Seong-June Oh, Hyeon Hoe Kim
Urol Res (2005) 33: 291–296

Our aim was to investigate the subjective pain felt by patients during shockwave lithotripsy (SWL) and endoscopic procedures such as cystoscopy, retrograde ureteral stenting, retrograde pyelography (RGP), andureteroscopic lithotripsy performed in an outpatient clinic, and to identify how severe pain during such procedures is. We estimated subjective pain in 984 patients after SWL (186), cystoscopy (489), retrograde ureteral stenting (127), RGP (97), and ureteroscopic lithotripsy (85) performed by a single expert in an outpatient clinic using a prospective questionnaire with a ten point visual analog scale between January 2001 and December 2003. There was no premedication in any procedure except ureteroscopic lithotripsy for which an intramuscular injection of analgesics (pethidine HCl 50 mg) was used. The pain scale score in SWL was 6.62±2.27, the highest among the procedures (P<0.05).

Pain scores for endoscopies were 4.48±2.07 in retrograde ureteral stenting, 3.81±2.06 in ureteroscopic lithotripsy, 3.72±1.75 in RGP, and 3.08±1.95 in cystoscopy. In this study, we observed that patients feel most pain in SWL without anesthesia, and that pain during ureteroscopic lithotripsy under local anesthesia is not high, compared with other endoscopic procedures.

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