Performance and impact of an airway management team launched during the COVID-19 pandemic.

PURPOSE: To determine the performance and impact of an airway management team (AMT) assembled during the COVID-19 pandemic. METHODS: We conducted a retrospective cohort review of all adult patients who had received airway management services from the AMT (n = 269) and administered a survey questionnaire targeting physicians who had the option to activate the AMT (n = 77). The retrospective review determined the performance of the AMT, and the physicians' survey evaluated the impact of the AMT. The study was conducted at a large Canadian health centre (1,133 beds) from 28 March to 30 June 2020. We included patients in the cohort review who were ≥18 yr of age, whose chart showed that the AMT was activated, and whose airway was managed outside the operating room. We reviewed both electronic medical records and paper chart documentation. Outcomes included intubation success, number of intubation attempts, intubation time, team response time, patient contact time, intubation complications, and breaches of personal protective equipment (PPE) protocol. The physicians' survey evaluated the relevance, performance, reasonableness, and clinical utility of the AMT. RESULTS: The AMT intubated 231 patients. Charts showed that 91% of intubations were accomplished on first attempt. The mean (standard deviation) intubation time was 2.1 (0.2) min. The complication rate was minimal. The incidence of breaching PPE protocol items was less than 6%. No AMT members reported COVID-19 symptoms. The response rate for the physician's survey was 36%. The consensus among the participants was that the AMT had considerable clinical utility during the COVID-19 pandemic. CONCLUSION: An AMT assembled during the COVID-19 pandemic showed high competency and effectiveness, and had favourable impact on the main responsible physicians who activated the team.

RéSUMé: OBJECTIF: Déterminer la performance et l'impact d'une équipe de prise en charge des voies aériennes (AMT - Airway Management Team) assemblée pendant la pandémie de COVID-19. MéTHODE: Nous avons réalisé une revue de cohorte rétrospective de tous les patients adultes qui avaient bénéficié des services de prise en charge des voies aériennes par l'AMT (n = 269) et avons soumis un questionnaire aux médecins qui avaient eu la possibilité de faire appel à l'AMT (n = 77). La revue rétrospective a permis de déterminer la performance de l'AMT, et le sondage auprès des médecins a évalué l'impact de cette équipe dédiée. L'étude a été réalisée dans un grand centre de santé canadien (1133 lits) du 28 mars au 30 juin 2020. Dans la revue de cohorte, nous avons inclus des patients âgés de ≥18 ans, dans le dossier médical desquels il était fait mention de l'activation de l'AMT et dont les voies aériennes avaient été prises en charge à l'extérieur de la salle d'opération. Nous avons passé en revue à la fois la documentation des dossiers médicaux informatisés et des dossiers papier. Les résultats mesurés comprenaient le succès de l'intubation, le nombre de tentatives d'intubation, le temps pour intubation, le temps de réponse de l'équipe, le temps de contact avec le patient, les complications de l'intubation et les violations du protocole relatif aux équipements de protection individuelle (EPI). Le sondage auprès des médecins a évalué la pertinence, la performance, le caractère raisonnable et l'utilité clinique de l'AMT. RéSULTATS: L'AMT a intubé 231 patients. Les dossiers ont montré que 91 % des intubations ont réussi à la première tentative. Le temps moyen (écart type) d'intubation était de 2,1 (0,2) min. Le taux de complications était minime. L'incidence d'infractions aux articles du protocole pour les EPI était inférieure à 6 %. Aucun membre de l'AMT n'a rapporté de symptômes de COVID-19. Le taux de réponse au sondage auprès des médecins était de 36 %. Le consensus parmi les participants était que l'AMT était d'une utilité clinique considérable pendant la pandémie de COVID-19. CONCLUSION: Une équipe de prise en charge des voies aériennes assemblée pendant la pandémie de COVID-19 a démontré une compétence et une efficacité élevées et a eu un impact favorable sur les principaux médecins en charge qui ont fait appel à l'équipe.

Pre-operative biomarkers and imaging tests as predictors of post-operative delirium in non-cardiac surgical patients: a systematic review.

BACKGROUND: Post-operative delirium (POD) is a common post-operative complication in elderly individuals and imposes a significant health and financial burden. Identifying predictive biomarkers may help understand the pathophysiology of POD. Our objective is to summarize the evidence of pre-operative biomarkers and imaging tests to predict POD in patients undergoing non-cardiac surgery. METHODS: A systematic search of English language articles in MEDLINE, EMBASE, Cochrane Database, PsychINFO, PubMed and ClinicalTrials. Gov up to January 2018 was performed. Studies that used biomarkers or imaging tests to predict POD and a validated POD assessment tool were included. Animal studies, paediatric, cardiac and intracranial surgery were excluded. Risk of bias was assessed using the Quality In Prognosis Study tool. RESULTS: Thirty-four prospective cohort studies involving 4424 patients were included. Nineteen studies described serum tests [Interleukin-6, Insulin-like Growth Factor 1, C-Reactive Protein (CRP), cholinesterases, apolipoprotein-E genotype, leptin, hypovitaminosis, hypoalbuminaemia, gamma-amino butyric acid], 10 described cerebral-spinal fluid tests (monoamine precursor, melatonin, acute phase proteins, S100B and neurofibrillary tangles), and 5 described imaging tests. Two studies had high risk of bias due to unclear outcome measurement and study participation. CRP was significantly associated with POD in 5 studies. Other biomarkers were either examined by only a single study or two or more studies with conflicting results. CONCLUSION: CRP is the most promising biomarker associated with POD. However, we are still in the early stages in identifying biomarkers and imaging tests that may further understanding of the pathophysiology of POD.

The effects of adding local infiltration analgesia of the knee to a multimodal pain protocol for total arthroplasty: A matched pair retrospective study.

Background: We hypothesize that the addition of local infiltration analgesia (LIA) to a multimodal pain protocol will reduce the total amount of opioids consumed for acute pain control post total knee arthrolplasty (TKA). Methods: This study was a retrospective, matched pair study including patients who had primary TKA. All patients included in the analysis had preoperative oral celecoxib and acetaminophen, had single-dose spinal anesthetic with intrathecal morphine, and had intravenous patient-controlled analgesia with an opioid agent in addition to gabapentin and celecoxib in the first 48 h. Patients whose charts were excluded from the study had revision TKA, received opioid therapy prior to the surgery, were classified as American Society of Anesthesiology (ASA) IV, and had general anesthesia. Fifty patients who underwent TKA and had LIA were matched for age, body mass index (BMI), and gender with patients who did not receive LIA. The primary outcome measures were total doses of opioids consumed post TKA. Results: Patients receiving LIA consumed on average significantly less intravenous (IV) morphine equivalents than patients not receiving LIA, with a mean difference (±SD) of 88.9 ± 15.6 mg IV morphine equivalents. Furthermore, pain control was better in the LIA group. The incidences of nausea and vomiting, pruritis, and excessive sedation were higher in the non-LIA group compared to the LIA group. There was no difference in the hospital length of stay between both groups. Conclusions: The addition of LIA to our multimodal pain protocol for TKA was associated with a reduction in total opioid consumption.

Contexte: Nous émettons l'hypothèse que l'ajout d'une analgésie locale par infiltration à un protocole de prise en charge de la douleur multimodal réduira la quantité totale d'opioïdes consommée pour maitriser la douleur aigue après une arthroplastie totale du genou (ATG).Méthodes: Cette étude était une étude rétrospective appariée ont les participants étaient des patients ayant subi une ATG primaire. Tous les patients inclus dans l'analyse s'étaient vus administrer du célécoxib et de l'acétaminophène en période préopératoire, une dose unique d'anasthésiant rachidien sous forme de morphine intrathécale et un analgésique intraveineux contrôlé par le patient comprenant un agent opioïde, en plus de la gabapentine et de l'acélécoxib au cours des premières 48 heures. Les patients dont les dossiers ont été exclus de l'étude avaient subi une ATG de reprise, avaient consommé des opioïdes avant la chirurgie, étaient classés ASA IV et avaient subi une anesthésie générale. Cinquante patients ayant subi une ATG et une analgésie locale par infiltration ont été appariés selon l'âge, l'IMC et le genre avec des patients qui n'avaient pas reçu d'analgésie locale par infiltration. Les résultats primaires ont été mesurés par les doses totales d'opioïdes consommées après l'ATG.Résultats: En moyenne, les patients ayant reçu une analgésie locale par infiltration ont consommé significativement moins d'équivalents morphine IV que les patients qui n'avaient pas reçu d'analgésie locale par infiltration, avec une différence moyenne (± É.-T.) de 88,9 ± 15,6 mg d'équivalents morphine IV. De plus, la douleur était mieux maitrisée dans le groupe ayant reçu une analgésie locale par infiltration. L'incidence des vomissments, du prurit et de la sédation excessive était plus élevée dans le groupe n'ayant pas reçu d'analgésie locale par infiltration que dans le groupe ayant reçu une analgésie locale par infiltration. Il n'y avait pas de différence entre les deux groupes en ce qui concerne la durée du séjour à l'hôpital.Conclusions: L'ajout d'une analgésie locale par infiltration à notre protocole douleur multimodal pour l'arthroplastie totale du genou était associé à une réduction dans la consommation totale d'opioïdes.

Tranexamic acid administration to older patients undergoing primary total hip arthroplasty conserves hemoglobin and reduces blood loss.

BACKGROUND: Tranexamic acid effects in older people are difficult to predict. This study investigated the following research questions: 1) Is tranexamic acid effective in older patients undergoing primary total hip arthroplasty (THA)? and 2) Is there a difference in the effect of tranexamic acid between younger and older patients? METHODS: This was a 2-phase retrospective matched-pair study of patients who underwent THA in 2007-2013. All procedures were performed by surgeons with at least 10 years' experience as senior consultant. In the first phase, 58 patients aged 65 years or more who received tranexamic acid were matched 1:1 with patients who did not receive tranexamic acid for age, sex, American Society of Anesthesiologists (ASA) classification and body mass index. In the second phase, 58 patients aged 65 years or more who received tranexamic acid were matched 1:1 with patients less than 65 years of age who received tranexamic acid for sex, ASA classification and body mass index. The primary outcome measures were percent maximum decrease in hemoglobin level and estimated blood loss after surgery. RESULTS: In the first phase, patients who received tranexamic acid conserved postoperative hemoglobin by a mean of 10.26 g/L (standard deviation [SD] 9.89 g/L) compared to the control group (p < 0.001). The mean difference in the estimated perioperative blood loss between the 2 groups was 410 mL (SD 376 mL) (p < 0.001), which indicated less bleeding in the treatment group. In the second phase, there was no difference between the younger (mean age 55.1 [SD 7.28] yr) and older (mean age 75.6 [SD 6.35] yr) groups in mean lowest postoperative hemoglobin level or percent decrease in hemoglobin level. CONCLUSION: Tranexamic acid reduced the postoperative decrease in hemoglobin level and blood loss in older patients. Moreover, the significant hemoglobin-sparing effect of tranexamic acid in older patients was similar to that observed in younger patients.

CONTEXTE: Les effets de l'acide tranexamique sont difficiles à prévoir chez les personnes âgées. Avec cette étude, nous avons voulu répondre aux 2 questions suivantes : 1) L'acide tranexamique est-il efficace chez les patients âgés soumis à une intervention chirurgicale primaire pour prothèse totale de la hanche (PTH)?, et 2) L'acide tranexamique produit-il un effet différent selon que les patients sont jeunes ou âgés? MÉTHODES: Cette étude rétrospective en 2 phases sur des paires appariées a regroupé des patients soumis à une intervention pour PTH entre 2007 et 2013. Toutes les interventions ont été effectuées par des chirurgiens détenant au moins 10 ans d'expérience à titre de consultants principaux. Au cours de la première phase, 58 patients de 65 ans ou plus ayant reçu de l'acide tranexamique ont été assortis (rapport 1:1), selon l'âge, le sexe, la classification ASA (American Society of Anesthesiologists) et l'indice de masse corporelle, à des patients n'en ayant pas reçu. Au cours de la deuxième phase, 58 patients de 65 ans ou plus ayant reçu de l'acide tranexamique ont été assortis (rapport 1:1), selon le sexe, la classification ASA et l'indice de masse corporelle, à des patients de moins de 65 ans ayant aussi reçu de l'acide tranexamique. Les paramètres principaux étaient la diminution maximale en pourcentage du taux d'hémoglobine et la perte sanguine estimée après l'intervention chirurgicale. RÉSULTATS: Pour la première phase, les patients qui ont reçu l'acide tranexamique ont maintenu une hémoglobine postopératoire moyenne à 10,26 g/L (écart-type [É.-T.] 9,89 g/L) comparativement au groupe témoin (p < 0,001). La différence moyenne entre les 2 groupes pour ce qui est des pertes sanguines periopératoires a été de 410 mL (É.-T. 376 mL) (p < 0,001), indiquant de ce fait une perte sanguine moindre dans le groupe traité. Pour la deuxième phase, on n'a noté aucune différence entre le groupe plus jeune (âge moyen 55,1 ans [É.-T. 7,28 ans]) et le groupe plus âgé (âge moyen 75,6 ans [É.-T. 6,35 ans]) pour ce qui est du taux d'hémoglobine postopératoire moyen le plus bas ou le pourcentage de baisse du taux d'hémoglobine. CONCLUSION: L'acide tranexamique a permis d'atténuer la baisse postopératoire de l'hémoglobine et les pertes sanguines chez les patients âgés. De plus, l'effet significatif de l'acide tranexamique sur le maintien de l'hémoglobine chez les patients âgés a été similaire à ce qui s'observe chez les patients plus jeunes.

Ultrasound guided transversus abdominis plane vs surgeon administered intraoperative regional field infiltration with bupivacaine for early postoperative pain control in children undergoing open pyeloplasty.

PURPOSE: Regional analgesic techniques are commonly used in pediatric urology. Ultrasound guided transversus abdominis plane block has recently gained popularity. However, there is a paucity of information supporting a benefit over regional field infiltration. We present a parallel group, randomized, controlled trial evaluating ultrasound guided transversus abdominis plane block superiority over surgeon delivered regional field infiltration for children undergoing open pyeloplasty at a tertiary referral center. MATERIALS AND METHODS: Following ethics board approval and registration, children 0 to 6 years old were recruited and randomized to undergo perioperative transversus abdominis plane block or regional field infiltration for early post-pyeloplasty pain control. General anesthetic delivery, surgical technique and postoperative analgesics were standardized. A blinded assessor regularly captured pain scores in the recovery room using the FLACC (Face, Legs, Activity, Cry, Consolability) scale. The primary outcome was the need for rescue morphine administration based on a FLACC score of 3 or higher. RESULTS: Two pediatric urologists performed 57 pyeloplasties during a 2.5-year period, enrolling 32 children (16 in each group, balanced for age and weight). There were statistically significant differences in the number of children requiring rescue morphine administration (13 of 16 receiving transversus abdominis plane block and 6 of 16 receiving regional field infiltration, p = 0.011), mean ± SD total morphine consumption (0.066 ± 0.051 vs 0.028 ± 0.040 mg/kg, p = 0.021) and mean ± SD pain scores (5 ± 5 vs 2 ± 3, p = 0.043) in the recovery room, in favor of surgeon administered regional field infiltration. No local anesthetic specific adverse events were noted. CONCLUSIONS: Ultrasound guided transversus abdominis plane block is not superior to regional field infiltration with bupivacaine as a strategy to minimize early opioid requirements following open pyeloplasty in children. Instead, our data suggest that surgeon delivered regional field infiltration provides better pain control.

Effects of aging and propofol on the cardiovascular component of the autonomic nervous system.

STUDY OBJECTIVES: To determine the combined effects of aging and propofol on autonomic nervous system activity using heart rate variability (HRV) analysis. DESIGN: Prospective, two-parallel group, repeated-measures study. SETTING: Operating room of an academic hospital. PATIENTS: ASA physical status 1, 2, and 3 patients, including 14 young (< 65 yrs) and 14 elderly (> 65 yrs) patients. All patients were scheduled for general surgical procedures with general anesthesia. INTERVENTIONS: Each patient received two successive propofol doses during induction (0.5 mg/kg and 1.5 mg/kg) with a time interval allowing the return of Bispectral Index (BIS) to awake values. MEASUREMENTS: Primary outcomes were HRV parameters, which included normalized power spectral density at low frequency (LFnorm) and high frequency (HFnorm) bands and the ratio LF/HF. Secondary outcomes were BIS values, blood pressure, heart rate, respiratory rate, and body temperature. MAIN RESULTS: The interaction of age and propofol dose level was significant [multivariate analysis of variance, F (3,74) = 4.72, P = 0.005], representing a combined effect of age and propofol dose level on the mean HRV parameters. Propofol induction decreased the HFnorm component and enhanced LFnorm and LF/HF in the younger group, but had no significant effect in the older group. Such an effect was not associated with a significant difference in systolic blood pressure (SBP) decrements between the younger and older groups. Within each group, propofol caused significant decreases in SBP compared with preinduction values. Heart rate did not change significantly during propofol administration between groups or within groups. CONCLUSIONS: Propofol and aging act in synergy to depress the activity of the cardiovascular component of the autonomic nervous system. However, a compensatory increase in sympathetic outflow was seen in young patients. Such counterbalance was not observed in the older group.

Continuous infraclavicular brachial plexus blockade: effect on survival of replanted digits.

In replantation surgery, the use of continuous brachial plexus blockade (CBPB) is popular as it improves postoperative analgesia and vascular flow. The aim of our study was to determine whether CBPB may affect the odds of survivability of replanted digit(s). A four-year retrospective chart review was performed and various parameters affecting replant survival were examined. Outcome was recorded as successful if the transplanted digit(s) survived six months after discharge. All the independent variables were forced into a regression model without using a specific variable selection algorithm. The data for 146 patients was obtained from our chart review. The success rate of replanted digits in the patients reviewed was 65.8%. The logistic regression model showed a relation between the number of digits injured and replanted digit(s) survival. Our study showed that CBPB has no effect on the survivability of the replanted digit(s) till six months after hospital discharge.

Can ultrasound of the tibial nerve detect diabetic peripheral neuropathy? A cross-sectional study.

OBJECTIVE: Peripheral nerve imaging by portable ultrasound (US) may serve as a noninvasive and lower-cost alternative to nerve conduction studies (NCS) for diagnosis and staging of diabetic sensorimotor polyneuropathy (DSP). We aimed to examine the association between the size of the posterior tibial nerve (PTN) and the presence and severity of DSP. RESEARCH DESIGN AND METHODS: We performed a cross-sectional study of 98 consecutive diabetic patients classified by NCS as subjects with DSP or control subjects. Severity was determined using the Toronto Clinical Neuropathy Score. A masked expert sonographer measured the cross-sectional area (CSA) of the PTN at 1, 3, and 5 cm proximal to the medial malleolus. RESULTS: Fifty-five patients had DSP. The mean CSA of the PTN in DSP compared with control subjects at distances of 1 (23.03 vs. 17.72 mm(2); P = 0.004), 3 (22.59 vs. 17.69 mm(2); P < 0.0001), and 5 cm (22.05 vs. 17.25 mm(2); P = 0.0005) proximal to the medial malleolus was significantly larger. Although the area under the curve (AUC) for CSA measurements at all three anatomical levels was similar, the CSA measured at 3 cm above the medial malleolus had an optimal threshold value for identification of DSP (19.01 mm(2)) with a sensitivity of 0.69 and a specificity of 0.77 by AUC analysis. CONCLUSIONS: This large study of diabetic patients confirms that the CSA of the PTN is larger in patients with DSP than in control subjects, and US is a promising point-of-care screening tool for DSP.

Protecting the brain during neurosurgical procedures: strategies that can work.

PURPOSE OF REVIEW: The quest for neuroprotection strategies during periods of neuronal vulnerability persists despite decades of basic and clinical research. This review will focus on the latest developments in the area of clinical brain protection with the major emphasis on strategies that can be beneficial during neurosurgical procedures. RECENT FINDINGS: Brain protection in neurosurgical patients may be achieved by nonpharmacological and pharmacological strategies. Pharmacological neuroprotection including anaesthetic administration have not been recently shown to be successful. Alternatively, nonpharmacological strategies including maintenance of cerebral perfusion by adequate control of mean arterial pressure (≥80 mmHg), liberal normoglycaemia (7.8-10 mmol/l), adequate haemoglobin levels (preoperative ≥120 g/l and intraoperative ≥90 g/l) and induction of hypertension (20-40% of preoperative values) in certain neurosurgical situations can be beneficial as neuroprotectants during neurosurgery. Mild hypothermia (32-35°C) failed to achieve neuroprotective effects in several situations of brain injury. SUMMARY: The findings of this review suggest that the anaesthesiologist is compelled to use nonpharmacological strategies sometimes based on empiric evidence to protect the brain during neurosurgical procedures. These strategies are simple, have high benefit/risk ratios and are inexpensive. Rigorous controlled clinical studies are needed to investigate the neuroprotective efficacy of these commonly used nonpharmacological methods.

Topical Tranexamic Acid to Reduce Postoperative Blood Loss in Total Knee Arthroplasty.

INTRODUCTION: Total knee arthroplasty alleviates pain and restores function in patients with osteoarthritis of the knee, but it is associated with postoperative blood loss resulting in anemia and allogeneic blood transfusion in 10% to 38% of patients. STEP 1 PREPARE SOLUTION: Prepare tranexamic acid solution using aseptic technique. STEP 2 APPLY SOLUTION: Apply tranexamic acid solution to the open joint and soft-tissue surfaces. STEP 3 REMOVE SOLUTION AND CLOSE: Remove tranexamic acid, keeping the tourniquet inflated until the wound is closed and the dressing is applied. RESULTS & PREOP/POSTOP IMAGES: We showed, in a prospective, double-blinded, placebo-controlled randomized trial, that topical application of tranexamic acid directly into the surgical wound prior to closure at the end of a total knee arthroplasty reduces postoperative bleeding by 20% to 25%, or 300 to 400 mL. WHAT TO WATCH FOR: IndicationsContraindicationsPitfalls & Challenges.

Spectral features of electroencephalogram in characterizing various brain states under anesthesia.

The administration of the anesthetic agents is known to alter the electroencephalogram (EEG) signal significantly with the brain being their primary target. In this study, we analyzed the EEG recorded from six ASA I/II patients undergoing a 1-2 hour surgery. The EEG was collected before and during induction, maintenance and recovery of anesthesia using the 10/20 lead-system. A combination of fentanyl and propofol (± rocuronium) was used for induction and a Sevoflurane in air/O(2) mixture was administered through an endotracheal tube to achieve the steady minimum alveolar concentration (MAC). This study showed that 0 to 4 Hz signal power was most sensitive to the changes associated with induction of anesthesia whereas the 4 to 12 Hz power was important in classifying states during maintenance of anesthesia. Anesthesia also promoted heightened phase coherence in 8 to 16 Hz and 16 to 30 Hz ranges during maintenance and induction of anesthesia, respectively. Additionally, strong cross-frequency coupling between 7 to 20 Hz and 10 to 40 Hz was observed during anesthesia suggesting alteration of neural coding.

Topical application of tranexamic acid reduces postoperative blood loss in total knee arthroplasty: a randomized, controlled trial.

BACKGROUND: Topical application of tranexamic acid to bleeding wound surfaces reduces blood loss in patients undergoing some major surgeries, without systemic complications. The objective of the present trial was to assess the efficacy and safety of the topical application of tranexamic acid on postoperative blood loss in patients undergoing primary unilateral total knee arthroplasty with cement. METHODS: In a prospective, double-blind, placebo-controlled trial, 124 patients were randomized to receive 1.5 or 3.0 g of tranexamic acid in 100 mL of normal saline solution or an equivalent volume of placebo (normal saline solution) applied into the joint for five minutes at the end of surgery. The primary outcome was blood loss calculated from the difference between the preoperative hemoglobin level and the corresponding lowest postoperative value or hemoglobin level prior to transfusion. The safety outcomes included Doppler ultrasound in all patients and measurement of plasma levels of tranexamic acid one hour after release of the tourniquet. RESULTS: Twenty-five patients were withdrawn for various reasons; therefore, ninety-nine patients were included in the intention-to-treat analysis. The postoperative blood loss was reduced in the 1.5 and 3-g tranexamic acid groups (1295 mL [95% confidence interval, 1167 to 1422 mL] and 1208 mL [95% confidence interval, 1078 to 1339 mL], respectively) in comparison with the placebo group (1610 mL [95% confidence interval, 1480 to 1738 mL]) (p < 0.017). The postoperative hemoglobin levels were higher in the 1.5 and 3.0-g tranexamic acid groups (10.0 g/dL [95% confidence interval, 9.5 to 10.4 g/dL] and 10.1 g/dL [95% confidence interval, 9.8 to 10.5 g/dL], respectively) in comparison with the placebo group (8.6 g/dL [95% confidence interval, 8.2 to 9 g/dL]) (p < 0.017). With the numbers studied, there was no difference in the rates of deep-vein thrombosis or pulmonary embolism between the three groups. Minimal systemic absorption of tranexamic acid was observed. CONCLUSIONS: At the conclusion of a total knee arthroplasty with cement, topical application of tranexamic acid directly into the surgical wound reduced postoperative bleeding by 20% to 25%, or 300 to 400 mL, resulting in 16% to 17% higher postoperative hemoglobin levels compared with placebo, with no clinically important increase in complications being identified in the treatment groups.

Nerve expansion seen on ultrasound predicts histologic but not functional nerve injury after intraneural injection in pigs.

BACKGROUND AND OBJECTIVES: Intraneural injection can be seen as nerve expansion during ultrasound-guided regional anesthesia. The purpose of this animal study was to determine if nerve expansion seen on ultrasound during intraneural injection results in nerve injury. METHODS: Ten pigs underwent general anesthesia for this randomized control study. After skin incision, the right and left median nerves for each animal were randomly assigned to the local anesthetic (LA) side or control side. For the LA side, a needle was placed intraneurally under direct vision. Nerve expansion seen on ultrasound was produced by injecting up to 20 mL lidocaine 2% with epinephrine intraneurally. For the control side, no needle puncture or injection was administered. The primary outcome was histologic evidence of nerve injury (axonal retraction balls) on the seventh postoperative day after intraneural injection seen as nerve expansion on ultrasound. Correlation coefficients were calculated between the maximum volume injected, maximum injection pressure, degree of nerve expansion, and histologic and functional nerve injury. RESULTS: Six nerves from the LA side and none from the control side had histologic evidence of injury (P < 0.01). All 10 nerves from the LA side exhibited histologic evidence of inflammation compared with 3 from the control side (P < 0.005). No pigs exhibited functional nerve injury. We were unable to demonstrate any correlation between the maximum volume injected or pressure generated and the relative increase in nerve cross-sectional area or the graded presence of any histologic markers of inflammation or injury. CONCLUSIONS: This animal study suggests that nerve expansion seen on ultrasound during intraneural injection of clinically relevant volumes of LA results in histologic but not functional nerve injury.

Improved esophageal patency when inserting the ProSeal laryngeal mask airway with an Eschmann tracheal tube introducer.

PURPOSE: We hypothesized that a more accurate alignment of the tip of the drain tube with the upper esophageal opening would be achieved in adult patients, as confirmed by fibreoptic bronchoscopy, by placing the ProSeal laryngeal mask airway (PLMA) by means of guiding it over an Eschmann tracheal tube introducer, commonly know as a gum elastic bougie (GEB), that was previously inserted into the esophagus, rather than by placing the PLMA with a curved metal introducer (IT). METHODS: Seventy-five adult elective surgery patients, whose airway management involved a PLMA, were randomly allocated to either the GEB- or IT-guided techniques. After inserting the PLMA, alignment of the tip of the drain tube relative to the esophageal opening was verified by a fibrescope introduced through the drain tube. Placing the fibrescope through the PLMA identified the glottic structures. The primary endpoint indicating the proper alignment of the tip of the drain tube of the PLMA with the upper esophageal opening was the ability to pass the fibrescope into the esophagus through the drain tube by a distance >35 cm without obstruction and the ability to simultaneously visualize the esophageal mucosa. RESULTS: The overall success rates of PLMA insertion were similar in the GEB and IT groups. However, the mean airway insertion times were longer with the GEB than with the IT-PLMA. The GEB group achieved proper alignment of the drain tube and the upper esophageal opening more frequently than the IT group (97% confidence interval (CI(95)) 91.5-100% vs 81% CI(95) 68.5-93.5% of subjects, respectively; P = 0.027). When the GEB was used to place the PLMA, the patients' vocal cords were visualized more frequently than when the IT technique was used (100% vs 73% CI(95) 58.9-87.1% of subjects, respectively; P = 0.003). CONCLUSION: Fibreoptic bronchoscopy confirmed that GEB is superior to the IT technique in ensuring precise alignment of the tip of the drain tube of the PLMA with the upper esophageal opening. Accurate positioning may better preserve gastroesophageal drainage function of the PLMA.

Minimum effective volume of local anesthetic for ultrasound-guided supraclavicular brachial plexus block.

BACKGROUND AND OBJECTIVES: The aim of this study was to determine the minimum effective anesthetic volume required to produce an effective supraclavicular block for surgical anesthesia using an ultrasound (US)-guided technique. METHODS: Twenty-one adults undergoing elective upper limb surgery received a US-guided supraclavicular block. The initial volume of local anesthetic (LA; 50:50 mixture of lidocaine 2% and bupivacaine 0.5% with epinephrine) injected was 30 mL, which was subsequently varied by 5 mL for each consecutive patient according to the response of the previous patient. The minimum effective anesthetic volume in 50% of patients was determined using the Dixon and Massey up-and-down method. The effective volume in 95% of patients (ED95) was calculated using probit transformation and logistic regression. RESULTS: The minimum effective anesthetic volume in 50% and calculated effective volume in 95% of patients were 23 mL (95% confidence interval, 13-39 mL) and 42 mL (95% confidence interval, 19-65 mL), respectively. Seven patients received supplemental LA, with no patient requiring a general anesthetic. CONCLUSION: In this study, the minimum volume required for US-guided supraclavicular block in 50% of patients was 23 mL, and in 95% of patients was 42 mL. Under the present study conditions, the calculated volume of LA required for US-guided supraclavicular block does not seem to differ from the conventionally recommended volume required for supraclavicular blocks using non-US-based nerve localization techniques.

Tranexamic Acid reduces perioperative blood loss in adult patients having spinal fusion surgery.

BACKGROUND: Spinal reconstructive surgery in adults can be associated with significant blood loss, often requiring allogeneic blood transfusion. The objective of this randomized, prospective, double-blind, multicenter study was to evaluate the efficacy of tranexamic acid (TXA) in reducing perioperative blood loss and transfusion in adult patients having elective posterior thoracic/lumbar instrumented spinal fusion surgery. METHODS: One hundred fifty-one adult patients were randomized to receive either a bolus of 10 mg/kg IV of TXA after induction followed by a maintenance infusion of 1 mg/kg/hr of TXA, or an equivalent volume of placebo (normal saline). The primary outcome was the total perioperative estimated and calculated blood loss intraoperatively and 24 h postoperatively. Secondary outcomes were incidence of allogeneic blood exposure, and duration of hospital stay. RESULTS: Four patients were withdrawn for identifiable surgical bleeding, therefore 147 patients were included in the analysis. The total estimated and calculated perioperative blood loss was approximately 25% and 30% lower in patients given TXA versus placebo (1592 +/- 1315 mL vs 2138 +/- 1607 mL, P = 0.026; 3079 +/- 2558 vs 4363 +/- 3030, P = 0.017), respectively. There was no difference in the amounts of blood products transfused, and length of stay between the two groups. TXA, surgical duration, and number of vertebrae fused were independent factors related to perioperative blood loss. Predictors for the need for allogeneic red blood cell transfusion were ASA classification, surgical duration and number of levels fused. CONCLUSIONS: TXA significantly reduced the estimated and calculated total amount of perioperative blood loss in adult patients having elective posterior thoracic/lumbar instrumented spinal fusion surgery.

Practice patterns related to block selection, nerve localization and risk disclosure: a survey of the American Society of Regional Anesthesia and Pain Medicine.

BACKGROUND AND OBJECTIVES: We aimed to identify current clinical practice patterns among members of the American Society of Regional Anesthesia and Pain Medicine (ASRA) members that relate to complications of regional anesthesia (RA). METHODS: Invitations were posted to the 3,732 ASRA members, to participate in our survey. Members were asked to report the types and numbers of blocks performed annually, preferred nerve localization techniques, and routine risk disclosure practices prior to common neuraxial (NAB) and peripheral nerve (PNB) block techniques. RESULTS: The number of respondents was 801 (response rate: 21.7%). Approximately half of the respondents perform >100 spinal and epidural blocks but <50 of each listed PNB annually. With the exception of axillary block, nerve stimulation is the overwhelmingly preferred nerve localization technique for PNB. Five hundred twenty-nine respondents (66.2%) disclose of RA primarily to allow patients to make an informed choice, while 227 (28.4%) disclose for medicolegal reasons. For NAB, the most commonly disclosed risks are headache and local pain/discomfort. Neurological complications following NAB such as permanent neuropathy and paralysis are inconsistently disclosed. For PNB, the most commonly disclosed risks are local pain/discomfort and transient neuropathy. The least commonly disclosed risks for both NAB and PNB include seizures, respiratory failure, cardiac arrest, and death. With the exception of headache following spinal anesthesia (1:100) and Horner's syndrome following interscalene block (1:10), there is little consensus regarding the perceived incidence of complications. CONCLUSIONS: Based on a 22% response rate, our survey suggests that the risks of RA most commonly disclosed to patients by ASRA members are benign while severe complications of RA are far less commonly disclosed. There is little agreement among ASRA members regarding their perceived incidence of complications following RA.

Evolution of ultrasound guided axillary brachial plexus blockade: retrospective analysis of 662 blocks.

PURPOSE: Ultrasound (US) is being used increasingly to guide needle placement during axillary brachial plexus blockade (AXB). This retrospective study investigated whether US guidance can increase the success rate, decrease block onset time, and reduce local anesthetic (LA) volume for AXB compared to a traditional (TRAD) approach, namely, peripheral nerve stimulation (PNS) and transarterial (TA) techniques. METHODS: The anesthetic records, operative reports, discharge summaries, and surgical consultation notes of all patients who had undergone AXB for surgical anesthesia at the Toronto Western Hospital, between October 2003 and November 2006 were, retrospectively reviewed for evidence of block success and associated complications. Block success was defined as the achievement of surgical anesthesia without additional LA supplementation. RESULTS: Among the 662 patients, 535 patients underwent AXB using US guidance (US group), and 127 using TRAD techniques (TRAD group), namely, 56 using PNS (PNS subgroup) and 71 using the TA technique (TA subgroup). The block success rate was higher in the US group compared to the TRAD group (91.6% vs 81.9%, P = 0.003). The LA volume used for AXB was less in the US group compared to the TRAD group (39.8 +/- 6.4 mL vs 46.7 +/- 17.1 mL, P < 0.0001). Ultrasound group patients spent less time in the block procedure room than those in the TRAD group (30.6 +/- 14.2 min vs 40.1 +/- 27.3 min, P < 0.0001). When analyzed by subgroup, the US group demonstrated significantly greater success and shorter duration in the block room compared to the PNS subgroup, but not the TA subgroup. Complications (inadvertent intravenous LA injection, and transient neuropathy) were lower in the US group compared to the TRAD group (0.37% vs 3.15%, P = 0.014). CONCLUSIONS: Our results suggest that US-guided AXB may improve block success, reduce the local anesthetic volume used, and shorten the time spent in the block room compared to traditional nerve localization techniques.

Mechanisms of morphine enhancement of spontaneous seizure activity.

BACKGROUND: High-dose opioid therapy can precipitate seizures; however, the mechanism of such a dangerous adverse effect remains poorly understood. The aim of our study was to determine whether the neuroexcitatory activity of high-dose morphine is mediated by selective stimulation of opioid receptors. METHODS: Mice hippocampi were resected intact and bathed in low magnesium artificial cerebrospinal fluid to induce spontaneous seizure-like events recorded from CA1 neurons. RESULTS: Application of morphine had a biphasic effect on the recorded spontaneous seizure-like events. In a low concentration (10 microM), morphine depressed electrographic seizure activity. Higher morphine concentrations (30 and 100 microM) enhanced seizure activity in an apparent dose-dependent manner. Naloxone, a nonselective opiate antagonist blocked the proconvulsant action of morphine. Selective mu and kappa opiate receptor agonists and antagonists enhanced and suppressed the spontaneous seizure activity, respectively. On the contrary, delta opioid receptor ligands did not have an effect. CONCLUSIONS: The proseizure effect of morphine is mediated through selective stimulation of mu and kappa opiate receptors but not the activation of the delta receptor system. The observed dose-dependent mechanism of morphine neuroexcitation underscores careful adjustment and individualized opioid dosing in the clinical setting.

Management of the airway in patients undergoing cervical spine surgery.

The perioperative management of the airway in patients with cervical spine disease requires careful consideration. In an observational prospective cohort study, we assessed the preoperative factors that may have influenced the anesthesiologists' choice for the technique of intubation and the incidence of postoperative airway complications. We recorded information from 327 patients: mean (+/-SD) age 51+/-15 year, 138 females and 189 males, for anterior surgical approach (n=195) and posterior (n=132). The technique of intubation used was awake fiberoptic bronchoscopy (FOB) in 39% (n=128), asleep FOB 32% (n=103), asleep laryngoscopy 22% (n=72), and other asleep 7% (n=24). Awake FOB was predominately chosen for intubating patients with myelopathy (45%), unstable/fractured spine (73%), and spinal stenosis (55%) but patients with radiculopathy had more asleep FOB (49%) (P<0.001). There was no association between method of intubation and postoperative airway complications. Acute postoperative airway obstruction occurred in 4 (1.2%) patients requiring reintubation. The technique of management of the airway for cervical spine surgery varied considerably among the anesthesiologists, although the choice was not associated with postoperative airway complications.