[Climate crisis and carbon-neutral anesthesia]. / Urgence climatique et anesthésie carboneutre.

In the context of climate crisis, health care systems need to reduce their own carbon footprint. An accumulating amount of data shows how anesthesia can drastically reduce direct emissions of powerful greenhouse gases (GHG), like inhaled volatile anesthetics and nitrous oxyde (N2O). This synthesis exposes why anesthesia is a carbon hotspot and how practical strategies can reduce direct GHG emissions without compromising quality of care.

Dans le contexte de la crise climatique, les systèmes de santé doivent se mobiliser pour diminuer leur propre empreinte carbone. Les évidences actuelles mettent en lumière les progrès qui peuvent être faits dans des domaines émettant directement des gaz à effet de serre (GES) comme en anesthésie, utilisant des gaz halogénés et du protoxyde d'azote (N2O), puissants GES. Cet article synthétise la problématique des émissions de GES directes en anesthésie et l'impact de quatre stratégies durables et concrètes pouvant être instaurées dans nos institutions pour réduire considérablement ces GES, sans compromis pour la qualité des soins.

Efficacy of a propofol bolus against placebo to prevent cough at emergence from general anesthesia with desflurane: a randomized controlled trial.

PURPOSE: Emergence from anesthesia is a critical period and cough can result in adverse effects. Propofol inhibits airway reflexes and when infused it reduces cough more than inhalation anesthesia does. We evaluated the effect of a propofol bolus given at emergence on the incidence of coughing following a desflurane-based anesthesia. METHODS: One hundred and fifty-four patients scheduled for elective surgery were prospectively randomized to propofol (0.5 mg·kg-1) or normal saline (NS) administered at the end of the surgery at 1 minimum alveolar concentration (MAC) of desflurane. A "no touch" emergence technique was used until extubation. The primary outcome was the incidence of cough at the discontinuation of desflurane (T0) and reaching a MAC adjusted for age (MACage) of 0.15. Secondary outcomes included incidence and severity of cough until five minutes postextubation (T0-T5), time to extubation, nausea and vomiting, sedation, hemodynamic variations, postoperative hypoventilation, hypoxemia, and sore throat. RESULTS: We could not draw inferences on the incidence of cough between T0 and MACage of 0.15 because only 27/68 (40%) patients in the NS group and 13/73 (18%) patients in the propofol group regained consciousness before reaching a MACage of 0.15. There were no significant differences between the groups in coughing incidence and severity between T0 and T5 (NS group, 57/68 [84%] vs propofol group, 70/73 [96%] ). The mean time to extubation in the propofol group was prolonged by 3 min 27 sec (95% confidence interval, 1 min 7 sec to 4 min 47 sec; P < 0.001) and more vasopressors were used at emergence (P = 0.02). The incidence of respiratory complications, nausea and vomiting, agitation, and sedation were not different between groups. CONCLUSION: In the present trial, a propofol bolus administered at emergence did not reduce the incidence of cough occurring between T0 and T5 following a desflurane-based general anesthesia compared with placebo. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02932397); registered 13 October 2016.

RéSUMé: OBJECTIF: L'émergence de l'anesthésie est une période critique et la toux peut entraîner des effets indésirables. Le propofol inhibe les réflexes des voies aériennes et, lorsqu'il est perfusé, il est plus efficace pour réduire la toux que l'anesthésie inhalée. Nous avons évalué l'effet d'un bolus de propofol administré à l'émergence sur l'incidence de toux après une anesthésie à base de desflurane. MéTHODE: Cent cinquante-quatre patients devant bénéficier d'une chirurgie non urgente ont été randomisés prospectivement à recevoir du propofol (0,5 mg·kg−1) ou une solution physiologique de sérum salé (NS) administrée à la fin de la chirurgie lorsque la concentration alvéolaire minimale (MAC) de desflurane était de 1. Une technique d'émergence « sans contact ¼ a été utilisée jusqu'à l'extubation. Le critère d'évaluation principal était l'incidence de toux à l'arrêt du desflurane (T0) et à l'atteinte d'une MAC ajustée en fonction de l'âge (MACâge) de 0,15. Les critères d'évaluation secondaires comprenaient l'incidence et la gravité de la toux jusqu'à cinq minutes après l'extubation (T0-T5), le délai d'extubation, les nausées et vomissements, la sédation, les variations hémodynamiques, l'hypoventilation postopératoire, l'hypoxémie et les maux de gorge. RéSULTATS: Nous n'avons pas pu tirer de conclusions sur l'incidence de toux entre T0 et à une MACâge de 0,15 parce que seulement 27/68 (40 %) patients du groupe NS et 13/73 (18 %) patients du groupe propofol ont repris conscience avant d'atteindre une MACâge de 0,15. Il n'y avait aucune différence significative entre les groupes dans l'incidence et la gravité de la toux entre T0 et T5 (groupe NS, 57/68 [84 %] vs groupe propofol, 70/73 [96 %]). Le temps moyen d'extubation dans le groupe propofol a été prolongé de 3 min 27 sec (intervalle de confiance à 95 %, 1 min 7 sec à 4 min 47 sec; P < 0,001) et une plus grande quantité de vasopresseurs a été utilisée à l'émergence (P = 0,02). L'incidence de complications respiratoires, de nausées et vomissements, d'agitation, et de sédation n'était pas différente entre les groupes. CONCLUSION: Dans la présente étude, un bolus de propofol administré à l'émergence n'a pas réduit l'incidence de toux survenant entre T0 et T5 après une anesthésie générale à base de desflurane par rapport au placebo. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT02932397); enregistrée le 13 octobre 2016.

Peak plasma concentration of total and free bupivacaine after erector spinae plane and pectointercostal fascial plane blocks.

PURPOSE: Erector spinae plane blocks (ESPB) and pectointercostal fascial (PIFB) plane blocks are novel interfascial blocks for which local anesthetic (LA) doses and concentrations necessary to achieve safe and effective analgesia are unknown. The goal of this prospective observational study was to provide the timing (Tmax) and concentration (Cmax) of maximum total and free plasma bupivacaine after ESPB in breast surgery and after PIFB in cardiac surgery patients. METHODS: Erector spinae plane blocks or PIFBs (18 patients per block; total, 36 patients) were performed with 2 mg⋅kg-1 of bupivacaine with epinephrine 5 µg⋅mL-1. Our principal outcomes were the mean or median Cmax of total and free plasma bupivacaine measured 10, 20, 30, 45, 60, 90, 180, and 240 min after LA injection using liquid chromatography with tandem mass spectrometry. RESULTS: For ESPB, the mean (standard deviation [SD]) total bupivacaine Cmax was 0.37 (0.12) µg⋅mL-1 (range, 0.19 to 0.64), and the median [interquartile range (IQR)] Tmax was 30 [50] min (range, 10-180). For ESPB, the mean (SD) free bupivacaine Cmax was 0.015 (0.017) µg⋅mL-1 (range, 0.003-0.067), and the median [IQR] Tmax was 30 [20] min (range, 10-120). After PIFB, mean plasma concentrations plateaued at 60-240 min. For PIFB, the mean (SD) total bupivacaine Cmax was 0.32 (0.21) µg⋅mL-1 (range, 0.14-0.95), with a median [IQR] Tmax of 120 [150] min (range, 30-240). For PIFB, the mean (SD) free bupivacaine Cmax was 0.019 (0.010) µg⋅mL-1 (range, 0.005-0.048), and the median [IQR] Tmax was 180 [120] min (range, 30-240). For both ESPB and PIFB, we observed no correlations between pharmacokinetic and demographic parameters. CONCLUSION: Total and free bupivacaine Cmax observed after ESPB and PIFB with 2 mg⋅kg-1 of bupivacaine with epinephrine 5 µg⋅mL-1 were five to twenty times lower than levels considered toxic in the literature.

RéSUMé: OBJECTIF: Les blocs des muscles érecteurs du rachis (ESP) et les blocs des plans fasciaux pecto-intercostaux (PIFB) sont de nouveaux blocs interfasciaux pour lesquels les doses et les concentrations d'anesthésique local (AL) nécessaires à obtenir une analgésie sécuritaire et efficace sont inconnues. L'objectif de cette étude observationnelle prospective était de déterminer le moment d'administration (Tmax) et la concentration (Cmax) de bupivacaïne plasmatique totale et plasmatique libre maximale après un bloc ESP pour chirurgie mammaire et après un PIFB chez les patients en chirurgie cardiaque. MéTHODE: Des blocs ESP ou PIFB (18 patients par bloc; total, 36 patients) ont été réalisés avec 2 mg⋅kg-1 de bupivacaïne et 5 µg⋅mL-1 d'épinéphrine. Nos principaux critères d'évaluation étaient la Cmax moyenne ou médiane de bupivacaïne plasmatique totale et libre mesurée 10, 20, 30, 45, 60, 90, 180 et 240 min après l'injection d'AL par chromatographie liquide avec spectrométrie de masse en tandem. RéSULTATS: Pour le bloc ESP, la Cmax de bupivacaïne totale moyenne (écart type [ET]) était de 0,37 (0,12) µg⋅mL-1 (plage, 0,19 à 0,64), et le Tmax médian [écart interquartile (ÉIQ)] était de 30 [50] min (intervalle, 10­180). Pour le bloc ESP, la Cmax de bupivacaïne libre moyenne (ET) était de 0,015 (0,017) µg⋅mL-1 (plage, 0,003­0,067), et le Tmax médian [ÉIQ] était de 30 [20] min (intervalle, 10­120). Après un PIFB, les concentrations plasmatiques moyennes ont plafonné à 60­240 min. Pour le bloc PIFB, la Cmax de bupivacaïne totale moyenne (ET) était de 0,32 (0,21) µg⋅mL-1 (plage, 0,14­0,95), et le Tmax médian [ÉIQ] était de 120 [150] min (intervalle, 30­240). Pour le bloc PIFB, la Cmax de bupivacaïne libre moyenne (ET) était de 0,019 (0,010) µg⋅mL-1 (plage, 0,005­0,048), et le Tmax médian [ÉIQ] était de 180 [120] min (intervalle, 30­240). Pour le bloc ESP et le PIFB, nous n'avons observé aucune corrélation entre les paramètres pharmacocinétiques et démographiques. CONCLUSION:  : Les Cmax de bupivacaïne totale et libre observées après un bloc ESP et PIFB avec 2 mg⋅kg-1 de bupivacaïne avec 5 µg⋅mL-1 d'épinéphrine étaient cinq à vingt fois plus faibles que les niveaux considérés comme toxiques dans la littérature.

Patient factors associated with difficult flexible bronchoscopic intubation under general anesthesia: a prospective observational study.

PURPOSE: Patient characteristics associated with difficult tracheal intubation using a flexible bronchoscope (FB) under general anesthesia have not been prospectively evaluated. This observational study aimed to identify demographic and morphologic factors associated with difficult FB intubation. METHODS: We recruited 420 adult elective surgery patients undergoing tracheal intubation during general anesthesia. Patients characteristics were recorded including age, sex, weight, height, body mass index, American Society of Anesthesiologists physical status, history of snoring, obstructive sleep apnea, Mallampati score, upper lip bite test score, neck circumference and skinfold thickness, maximal neck flexion and extension angles, absence of teeth, Cormack and Lehane grade, presence of blood or secretions during intubation, as well as the inter-incisor, thyromental, sternothyroid, and manubriomental distances. The time (duration) needed to complete intubation (primary endpoint) and the number of attempts needed were correlated with these patient characteristics in a multivariable analysis. RESULTS: Intubation was successful on the first attempt in 409/420 patients (97%). Seven patients (1.7%) needed more than one attempt. Failure to intubate with the FB occurred in four patients (1%). A correlation was found between intubation duration and visibility impaired by secretions or blood (P < 0.001), higher neck skinfold thickness (P < 0.001), and larger endotracheal tube diameter (relative to a constant 5.5 mm FB; P < 0.001). CONCLUSIONS: The presence of secretions or blood that impair FB glottic visualization, a larger diameter endotracheal tube on the same size FB, as well as higher neck skinfold thickness may prolong the duration of FB intubation under general anesthesia. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT02769819); registered 5 May, 2016.

RéSUMé: OBJECTIF: Les caractéristiques des patients associées à une intubation trachéale difficile avec un bronchoscope flexible sous anesthésie générale n'ont pas été évaluées de façon prospective. Cette étude observationnelle avait pour but d'identifier les facteurs démographiques et morphologiques associés aux intubations difficiles avec un bronchoscope flexible. MéTHODES: Nous avons recruté 420 patients adultes devant subir une intubation trachéale au cours d'une anesthésie générale pour une chirurgie élective. Les caractéristiques suivantes des patients ont été consignées : âge, sexe, poids, taille, indice de masse corporelle, score de l'American Society of Anesthesiologists, antécédents de ronflements et de syndrome d'apnée-hypopnée du sommeil, score de Mallampati, score du test de morsure de la lèvre supérieure, circonférence du cou et épaisseur du pli cutané cervical, angles maximums de flexion et extension du cou, absence de dents, grade de la classification de Cormack et Lehane, présence de sang ou de sécrétions pendant l'intubation, ainsi que les distances inter-incisives, menton-cartilage thyroïde, sterno-thyroïdienne et menton-manubrium. Le temps nécessaire pour compléter l'intubation (critère d'évaluation principal) et le nombre de tentatives nécessaires ont été corrélés aux caractéristiques des patients dans une analyse multifactorielle. RéSULTATS: L'intubation a été réussie dès la première tentative chez 409 patients sur 420 (97 %). Pour 7 patients (1,7 %, il a fallu plus d'une tentative. Un échec de l'intubation avec bronchoscope flexible est survenu chez 4 patients (1 %). Une corrélation a été trouvée entre la durée de l'intubation et une mauvaise visualisation due à des sécrétions ou du sang (P < 0,001), un pli cutané cervical plus épais (P < 0,001), et un plus grand diamètre du tube endotrachéal (par rapport à un fibroscope souple constant de 5,5 mm; P < 0,001). CONCLUSIONS: La présence de sang ou de sécrétions gênant la visualisation de la glotte, un diamètre du tube endotrachéal augmenté par rapport à celui du fibroscope flexible ainsi qu'une plus grande épaisseur du pli cutané cervical peuvent prolonger le temps d'intubation avec endoscope flexible sous anesthésie générale. ENREGISTREMENT DE L'ESSAI CLINIQUE: www.clinicaltrials.gov (NCT02769819); enregistré le 5 mai 2016.

Effect of Intravenous Dexamethasone on the Regression of Isobaric Bupivacaine Spinal Anesthesia: A Randomized Controlled Trial.

The effect of intravenous dexamethasone on the regression of sensory and motor block after isobaric bupivacaine spinal anesthesia is unknown. We conducted a prospective, double-blind, randomized controlled trial on 60 patients who received intravenously either placebo (group P) or 8-mg dexamethasone (group D) during the intrathecal injection of 12-mg isobaric bupivacaine 0.5%. Primary outcome was the time from bupivacaine injection to regression of 2 dermatomes in relation to the highest dermatome blocked by the spinal local anesthetic. Time to 2-dermatome regression was 85 minutes (74-96 minutes) in group P versus 87 minutes (76-98 minutes) in group D (P = .79).

The Effect of Adductor Canal Block on Knee Extensor Muscle Strength 6 Weeks After Total Knee Arthroplasty: A Randomized, Controlled Trial.

BACKGROUND: Total knee arthroplasty (TKA) reduces knee extensor muscle strength (KES) in the operated limb for several months after the surgery. Immediately after TKA, compared to either inguinal femoral nerve block or placebo, adductor canal block (ACB) better preserves KES. Whether this short-term increase in KES is maintained several weeks after surgery remains unknown. We hypothesized that 48 hours of continuous ACB immediately after TKA would improve KES 6 weeks after TKA, compared to placebo. METHODS: Patients scheduled for primary unilateral TKA were randomized to receive either a continuous ACB (group ACB) or a sham block (group SHAM) for 48 hours after surgery. Primary outcome was the difference in maximal KES 6 weeks postoperatively, measured with a dynamometer during maximum voluntary isometric contraction. Secondary outcomes included postoperative day 1 (POD1) and day 2 (POD2) KES, pain scores at rest and peak effort, and opioid consumption; variation at 6 weeks of Knee Osteoarthritis Outcome Score, patient satisfaction, and length of hospital stay. RESULTS: Sixty-three subjects were randomized and 58 completed the study. Patients in group ACB had less pain at rest during POD1 and during peak effort on POD1 and POD2, consumed less opioids on POD1 and POD2, and had higher median KES on POD1. There was no significant difference between groups for median KES on POD2, variation of Knee Osteoarthritis Outcome Score, patient satisfaction, and length of stay. There was no difference between groups in median KES 6 weeks after surgery (52 Nm [31-89 Nm] for group ACB vs 47 Nm [30-78 Nm] for group SHAM, P= .147). CONCLUSIONS: Continuous ACB provides better analgesia and KES for 24-48 hours after surgery, but does not affect KES 6 weeks after TKA. Further research could evaluate whether standardized and optimized rehabilitation over the long term would allow early KES improvements with ACB to be maintained over a period of weeks or months.

Alkalinized Lidocaine Preloaded Endotracheal Tube Cuffs Reduce Emergence Cough After Brief Surgery: A Prospective Randomized Trial.

BACKGROUND: Alkalinized lidocaine in the endotracheal tube (ETT) cuff decreases the incidence of cough and throat pain on emergence after surgery lasting more than 2 hours. However, alkalinized lidocaine needs 60-120 minutes to cross the ETT cuff membrane; therefore, its usefulness in shorter duration surgery is unknown. This prospective double-blind randomized controlled trial tested the hypothesis that alkalinized lidocaine would reduce the incidence of emergence cough after surgeries lasting <120 minutes. METHODS: After local ethics board approval, American Society of Anesthesiologists I-III patients consented to be randomized into 1 of 2 groups receiving either alkalinized lidocaine (group AL) or saline (group S) to inflate the ETT cuff. Cuffs were prefilled >90 minutes before intubation with either 2 mL of 2% lidocaine and 8 mL of 8.4% bicarbonate (group AL) or 10 mL of normal saline (group S). Cuffs were emptied immediately before intubation. After intubation, either 2 mL of 2% lidocaine (AL) or 2 mL of saline (S) were injected into the cuff. Additional 8.4% bicarbonate (AL) or saline (S) was injected into the cuff until there was no air leak. Anesthesia was maintained using desflurane, rocuronium, and either fentanyl or sufentanil to maintain vital signs within 20% of baseline values. Opioids administered in prophylaxis of extubation cough were proscribed. A standardized "no touch" emergence technique was used. A blinded assessor noted any cough above 0.2 minimum alveolar concentration (MAC) of expired desflurane. At 0.2 MAC, once every 30 seconds, the patient was instructed to open his eyes and extubation occurred once a directed response was noted. RESULTS: A total of 213 patients were randomized and 100 patients in each group completed the experimental protocol. The incidence of extubation cough in group AL was 12%, significantly lower (1-sided P = .045) than the 22% incidence in group S. The 1-tailed risk ratio for cough in group AL was 0.55 (0-0.94, P = .045). Total amount of opioids administered (P = .194), ETT cuff preloading times (P = .259), and extubation times (P = .331) were not significantly different between groups. The average duration of surgery was 59 ± 28 minutes in group AL and 52 ± 29 minutes in group S (P = .057). CONCLUSIONS: Alkalinized lidocaine in the ETT cuff significantly decreased general anesthesia emergence cough after surgeries with an average duration of slightly <1 hour.

Predictors of Difficult Intubation with the Bonfils Rigid Fiberscope.

BACKGROUND: Endotracheal intubation is commonly performed via direct laryngoscopy (DL). However, in certain patients, DL may be difficult or impossible. The Bonfils Rigid Fiberscope® (BRF) is an alternative intubation device, the design of which raises the question of whether factors that predict difficult DL also predict difficult BRF. We undertook this study to determine which demographic, morphologic, and morphometric factors predict difficult intubation with the BRF. METHODS: Four hundred adult patients scheduled for elective surgery were recruited. Patients were excluded if awake intubation, rapid sequence induction, or induction without neuromuscular blocking agents was planned. Data were recorded, including age, sex, weight, height, American Society of Anesthesiologist classification, history of snoring and sleep apnea, Mallampati class, upper lip bite test score, interincisor, thyromental and sternothyroid distances, manubriomental distances in flexion and extension, neck circumference, maximal neck flexion and extension, neck skinfold thickness at the cricoid cartilage, and Cormack and Lehane grade obtained via DL after paralysis was confirmed. Quality of glottic visualization (good or poor), as well as the number of intubation attempts and time to successful intubation with the BRF, was noted. Univariate analyses were performed to evaluate the association between patient characteristics and time required for intubation. Variables that exhibited a significant correlation were included in a multivariate analysis using a standard least squares model. A P < 0.05 was considered significant. RESULTS: Glottic visualization with the BRF was good in 396 of 400 (99%) cases. On the first attempt, 390 patients were successfully intubated with the BRF; 6 patients required >1 attempt; 4 patients could not be intubated by using the BRF alone. These 4 patients were intubated by using a combination of DL and BRF (2 patients), DL and a Frova bougie (1 patient), and DL and an endotracheal tube shaped with a semirigid stylet (1 patient). Mean time for successful intubation was 26 ± 13 seconds. Multivariate analysis showed that decreased mouth opening (P = 0.008), increased body mass index (P = 0.011), and higher Cormack and Lehane grade (P = 0.038) predicted longer intubation times, whereas shorter thyromental distance predicted slightly shorter intubation times (P < 0.0001). CONCLUSIONS: Mouth opening, body mass index, and high Cormack and Lehane grade predict longer intubation times, as with DL. Decreasing thyromental distance predicts slightly shorter intubation times with the BRF, possibly because of a design initially optimized for a pediatric population with receding chins. These findings, along with the high success rate of BRF in this study, and the possibility of further increasing success rates by combining BRF with DL, help define the role of BRF intubation in contemporary airway management.

Impact of thoracic epidural catheter threading distance on analgesia during the first 24 hours following thoracotomy: a randomized controlled trial.

PURPOSE: The purpose of this prospective randomized controlled trial was to determine the impact of thoracic epidural catheter threading distance on analgesia quality after thoracotomy. METHODS: We randomly assigned 120 elective thoracotomy patients to a thoracic epidural catheter threading distance of 3, 5, or 7 cm (groups 3CM, 5CM, and 7CM, respectively). Epidural bupivacaine 0.1% with fentanyl 2 µg·mL(-1) was administered according to a standardized protocol. Epidural analgesia quality was assessed at 60 min and 24 hr postoperatively for four measures: incidence of non-functioning epidurals; numerical rating score (NRS) < 4 at rest, while coughing, and during wound palpation; cold perception at the wound site; and cumulative dose of analgesic medication used. Our primary hypothesis was that, compared to threading distances of 3 and 5 cm, a threading distance of 7 cm was not inferior at providing an NRS < 4 while coughing at 60 min postoperatively, with a non-inferiority margin of 25% (absolute value) being significant. RESULTS: The incidence of NRS < 4 while coughing at 60 min was 74% (29/39) in group 7CM compared with 68% (54/80) in the combined 3CM and 5CM groups (absolute difference 7%; 95% confidence interval -11 to 23; P = 0.29). At both 60 min and 24 hr, differences between groups were similar regarding the number of non-functioning epidurals, NRS < 4, and suppressed cold sensation. Analgesic doses were similar in the three groups. CONCLUSIONS: This study found that a thoracic epidural catheter threading distance of 7 cm in the epidural space was not inferior to distances of 3 cm and 5 cm with respect to pain scores at 60 min postoperatively. This study was not powered to examine differences that could have clinical significance that were less than our a priori 25% non-inferiority margin.

A comparison of cervical spine motion during orotracheal intubation with the trachlight(r) or the flexible fiberoptic bronchoscope.

BACKGROUND: Tracheal intubation of an unstable cervical spine (c-spine) patient with the flexible fiberoptic bronchoscope (FOB) is thought to minimize c-spine movement but may be technically difficult in certain patients. Intubation using a luminous stylet, such as the Trachlight(R) (TL), also produces minimal motion of the c-spine and may be an interesting alternative technique for patients with an unstable c-spine. In this study, we compared the cervical motion caused by the TL and the FOB during intubation. METHODS: Twenty patients with a normal c-spine undergoing general anesthesia, including neuromuscular blockade, for a neuroradiologic intervention were included in a prospective, randomized, controlled, nonblinded, crossover trial. Each patient was tracheally intubated sequentially with the TL and the FOB in a randomized order. Manual in-line stabilization was applied by an assistant during intubation. The motions produced by intubation from the occiput (C0) to C5 were recorded in the sagittal plane using continuous cinefluoroscopy. For movement analysis, the recordings were divided into four stages: "baseline" before intubation began; "introduction" of the intubation device; "intubation" (passage of the tube through the vocal cords); and "removal" of the device. For each intubating device, the average maximal segmental motion observed in every patient at any stage or cervical segment was calculated and compared using Student's t-test. The time required to intubate with each device was also compared. RESULTS: There was no significant difference in the mean maximum segmental motion produced during intubation with the TL versus the FOB (12 degrees +/- 6 degrees vs 11 degrees +/- 5 degrees ; P = 0.5). Segmental movements occurred predominantly at the C0-1 and C1-2 levels, and maximal movements were observed during the introduction stage in 18/20 patients for both devices. Intubation took less time with the TL (34 +/- 17 vs 60 +/- 15 s, P < 0.001). CONCLUSION: In patients under general anesthesia with neuromuscular blockade and manual in-line stabilization, we found no difference in the segmental c-spine motion produced during endotracheal intubation using the FOB and the TL.

Poor visualization during direct laryngoscopy and high upper lip bite test score are predictors of difficult intubation with the GlideScope videolaryngoscope.

BACKGROUND: The GlideScope videolaryngoscope allows equal or superior glottic visualization compared with direct laryngoscopy, but predictive features for difficult GlideScope intubation have not been identified. We undertook this prospective study to identify patient characteristics associated with difficult GlideScope intubation. METHODS: Demographic and morphometric factors were recorded preoperatively for 400 patients undergoing anesthesia with endotracheal intubation. After induction, direct laryngoscopy was performed in all patients to assess the Cormack and Lehane grade of glottic visualization followed by GlideScope intubation. The number of attempts and time needed for intubation were recorded. Univariate and multivariate analyses were performed to identify the characteristics associated with difficult GlideScope intubation. RESULTS: Intubation required 1, 2, and 3 attempts in 342, 48, and 9 participants, respectively, with one failure. Mean time for intubation was 21 +/- 14 s. After univariate analysis, the following characteristics were significantly correlated (P < 0.05) with longer time to intubate and/or multiple attempts: older age, male sex, history of snoring, high Mallampati class, small mouth opening, short sternothyroid and manubriomental distances, large neck circumference, high upper lip bite test score, and high Cormack and Lehane grade during direct laryngoscopy. However, after introducing these variables in nominal logistic and proportional hazard multiple regression models, only high Cormack and Lehane grade during direct laryngoscopy, high upper lip bite test score, and short sternothyroid distance were significantly associated with multiple attempts or lengthier intubations. CONCLUSION: Despite a high success rate, intubation with the GlideScope is likely to be more challenging in patients with high Cormack and Lehane grade during direct laryngoscopy, high upper lip bite test score, or short sternothyroid distance.

Perioperative interscalene block versus intra-articular injection of local anesthetics for postoperative analgesia in shoulder surgery.

BACKGROUND AND OBJECTIVES: Up to 70% of patients report moderate to severe pain after shoulder surgery, which can compromise early rehabilitation and functional recuperation. Postoperative shoulder pain control is improved with both interscalene block and intra-articular local anesthetic injection. The present study hypothesized that perioperative interscalene analgesia would offer pain control superior to perioperative intra-articular local anesthetics over the first 24 hours after surgery. METHODS: Sixty patients undergoing shoulder surgery were randomly assigned to 1 of 2 groups: group IS had interscalene block with catheter installation, while group IA received intra-articular local anesthetic, also with catheter installation. All patients received 3 local anesthetic injections: 0.25 mL/kg of 2% lidocaine with epinephrine 2.5 microg/mL immediately before and after surgery, and 0.25 mL/kg of 0.5% bupivacaine with epinephrine 2.5 microg/mL 1 hour after the end of surgery, after which the catheters were removed, and no further local anesthetics were administered. Postoperative pain at rest was evaluated in the postanesthesia care unit (PACU), 3 hours, 6 hours and 24 hours after surgery. The area under the 24 hour pain over time curve was calculated. Hydromorphone consumption in the PACU and over 24 hours was recorded. RESULTS: Pain scores (IS: 0.4 +/- 2 vs. IA: 4 +/- 3, P < .0001) and opioid consumption (IS: 0.7 mg +/- 1.4 vs. IA: 1.5 mg +/- 1.2, P = .02) were significantly higher in the PACU for group IA. However, neither the mean pain scores over the first day after surgery (IS: 5 +/- 2 vs. IA: 5 +/- 3; P = .4) nor 24-hour opioid consumption (IS: 4.4 mg +/- 2.8 vs. IA: 4.2 mg +/- 2.6; P = .4) were significantly higher in group IA. CONCLUSIONS: PACU measurements of immediate postoperative pain and narcotic consumption favor perioperative interscalene analgesia over intra-articular analgesia. This benefit does not translate into lower overall pain for the first 24 hours after surgery.

Cervical spine motion during tracheal intubation with manual in-line stabilization: direct laryngoscopy versus GlideScope videolaryngoscopy.

BACKGROUND: The optimal tracheal intubation technique for patients with potential cervical (C) spine injury remains controversial. Using continuous cinefluoroscopy, we conducted a prospective study comparing C-spine movement during intubation using direct laryngoscopy (DL) or GlideScope videolaryngoscopy (GVL), with uninterrupted manual in-line stabilization of the head by an assistant. METHODS: Twenty patients without C-spine pathology were studied. After induction of general anesthesia with neuromuscular blockade, both DL and GVL were performed on every patient in random order. Cinefluoroscopic images of C-spine movement during GVL and DL were acquired and divided into four stages: a baseline image before airway manipulation, glottic visualization, insertion of the endotracheal tube into the glottis, and tracheal intubation. Peak segmental motion from the occiput to C5 was measured offline for each patient and each stage, averages were calculated, and movements induced by each instrument were compared using a two-way ANOVA. Also studied were the proportion of patients with occiput-C1 rotation exceeding 10, 15, or 20 degrees, and the quality of glottic visualization. RESULTS: No significant difference was found between DL and GVL regarding average segmental spine movement at any level (P values between 0.22 and 0.70). During both techniques, motion was mainly an extension concentrated in the rostral C-spine and occurred predominantly during glottic visualization. The proportion of patients with occiput-C1 extension of more than 10, 15, or 20 degrees was not significantly different. Glottic visualization was significantly better with GVL compared with DL. CONCLUSION: During intubation under general anesthesia with neuromuscular blockade and manual in-line stabilization, the use of GVL produced better glottic visualization, but did not significantly decrease movement of the nonpathologic C-spine when compared with DL.

Preliminary evaluation of infraclavicular catheters inserted using ultrasound guidance: through-the-catheter anesthesia is not inferior to through-the-needle blocks.

BACKGROUND AND OBJECTIVES: This prospective study compared the initial block quality and surgical anesthesia rates of ultrasound-guided infraclavicular blocks with local-anesthetic injected through a catheter versus through a needle. We hypothesized that positioning of the catheter immediately posterior to the axillary artery would produce through-the-catheter (TTC) anesthesia with rates of complete block not inferior to through-the-needle (TTN) injection. METHODS: Eighty patients undergoing hand or forearm surgery extensive enough to require regional anesthesia were randomized into 2 groups of 40. In group TTN, local anesthetic was deposited posterior, lateral, and medial to the axillary artery using as few injections as necessary. In group TTC, a 20-gauge, multiorifice catheter was positioned between the posterior wall of the axillary artery and the posterior cord of the brachial plexus. All blocks were performed by use of ultrasound visualization with a 6-MHz to 10-MHz 38-mm linear probe. Local-anesthetic solution consisted of 0.5 mL/kg lidocaine 2% with epinephrine. Sensory and motor blocks, as well as supplementation rates, were evaluated for the musculocutaneous, median, radial, and ulnar nerves. RESULTS: Complete sensory block of all nerve territories was achieved in 92% of patients in group TTN and 90% in group TTC (P = .51). In group TTN, 90% of patients had satisfactory anesthesia for surgery (no discomfort and no need for anesthetic supplementation of any type) compared with 92% in group TTC (P = .51). CONCLUSION: Ultrasound-guided TTC infraclavicular block produced perioperative anesthesia that was not inferior to a TTN technique.

Neurostimulation in ultrasound-guided infraclavicular block: a prospective randomized trial.

Ultrasound guidance (USG) for infraclavicular blocks provides real time visualization of the advancing needle and local anesthetic distribution. Whether visualization of local anesthetic spread can supplant neurostimulation as the end point for local anesthetic injection during USG block has never been formally evaluated. Therefore, for this prospective randomized study, we recruited 72 patients scheduled for hand or forearm surgery and compared the speed of execution and quality of USG infraclavicular block with either USG alone (Group U) or USG combined with neurostimulation (Group S). In Group U, local anesthetic was deposited in a U-shaped distribution posterior and to each side of the axillary artery using as few injections as possible (1, 2, and 3 injections in 29, 6, and 3 patients, respectively). In Group S, a single injection was made after obtaining a distal motor response with a stimulating current between 0.3 and 0.6 mA. The anesthetic solution consisted of 0.5 mL/kg of lidocaine 1.5%, bupivacaine 0.125%, and epinephrine 1:200 000 (final concentrations). Procedure times were significantly shorter in Group U compared with Group S (3.1 +/- 1.6 min and 5.2 +/- 4.7 min, respectively; P = 0.006). In Group S, anesthetic spread was mainly anterior to the axillary artery in 37% of patients and mainly posterior in 63% of patients. Thirty minutes after the injection, 86% of patients in Group U had complete sensory block in the musculocutaneous, median, radial, and ulnar nerve territories compared with 57% in Group S (P = 0.007). Patients blocked in Group U with a single injection had the same rate of complete block (86%) as those blocked with more than one injection (86%). Block supplementation rates were 8% in Group U versus 26% in Group S (P = 0.049). Block failure occurred in one patient in Group S because of an inability to obtain a distal stimulation after 20 min. We conclude that USG infraclavicular block is more rapidly performed and yields a higher success rate when visualization of local anesthetic spread is used as the end point for injection. Posterolateral spread of local anesthetic around the axillary artery predicts successful block, circumventing the need for direct nerve visualization.

Ultrasound-guided infraclavicular versus supraclavicular block.

In this prospective study we compared ultrasound-guided (USG) infraclavicular and supraclavicular blocks for performance time and quality of block. We hypothesized that the infraclavicular approach would result in shorter performance times with a quality of block similar to that of the supraclavicular approach. Eighty patients were randomized into two equal groups: Group I (infraclavicular) and Group S (supraclavicular). All blocks were performed using ultrasound visualization with a 7.5-MHz linear probe and neurostimulation. The anesthetic mixture consisted of 0.5 mL/kg of bupivacaine 0.5% and lidocaine hydrocarbonate 2% (1:3 vol.) with epinephrine 1:200,000. Sensory block, motor block, and supplementation rates were evaluated for the musculocutaneous, median, radial, and ulnar nerves. Surgical anesthesia without supplementation was achieved in 80% of patients in group I compared with 87% in Group S (P = 0.39). Supplementation rates were significantly different only for the radial territory: 18% in Group I versus 0% in group S (P = 0.006). Block performance times were not different between groups (4.0 min in Group I versus 4.65 min in Group S; P = 0.43). Technique-related pain scores were not different between groups (I: 2.0; S: 2.0; P = 1.00). We conclude that USG infraclavicular block is at least as rapidly executed as USG supraclavicular block and produces a similar degree of surgical anesthesia without supplementation.