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.

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.

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.

Vasopressin for treatment of shock following aprotinin administration.

PURPOSE: To describe the utility of vasopressin in the treatment of acute distributive shock clinically compatible with the diagnosis of aprotinin anaphylaxis. CLINICAL FEATURES: A 57-yr-old female patient underwent repeat cardiac surgery to treat prosthetic valve endocarditis. She had received aprotinin during her first surgery 60 days ago. Despite a negative test dose of i.v. aprotinin 20,000 KIU, when aprotinin loading was initiated during the repeat surgery, the patient developed bronchospasm and hypotension secondary to acute distributive shock. Bronchospasm responded to inhaled salbutamol and ipatropium. The hypotension was refractory to high doses of phenylephrine. Two doses of i.v. vasopressin 5 U reversed the vasodilation and reestablished normal blood pressure. CONCLUSION: Vasopressin, in association with alpha-agonists, can reverse acute refractory distributive shock following aprotinin administration.

Ultrasound guidance speeds execution and improves the quality of supraclavicular block.

UNLABELLED: In this prospective study, we assessed the quality, safety, and execution time of supraclavicular block of the brachial plexus using ultrasonic guidance and neurostimulation compared with a supraclavicular technique that used anatomical landmarks and neurostimulation. It was hypothesized that ultrasonic guidance would increase the proportion of successful blocks, decrease block execution time, and reduce the incidence of complications such as pneumothorax and neuropathy. Eighty patients were randomized into two groups of 40, Group US (supraclavicular block guided in real time by a two-dimensional ultrasonic image, with neurostimulator confirmation of correct needle position) and Group NS (supraclavicular block using the subclavian perivascular approach, also with neurostimulator confirmation). Blocks were performed using bupivacaine 0.5% and lidocaine 2% (1:1 vol) with epinephrine 1:200000 as the anesthetic mixture. The onset of motor and sensory block for the musculocutaneous, median, radial, and ulnar nerves was evaluated over a 30 min period. At 30 min 95% of patients in Group US and 85% of patients in Group NS had a partial or complete sensory block of all nerve territories (P = 0.13) and 55% of patients in Group US and 65% of patients in Group NS had a complete block of all nerve territories (P = 0.25). Surgical anesthesia without supplementation was achieved in 85% of patients in Group US and 78% of patients in Group NS (P = 0.28). No patient in Group US and 8% of patients in Group NS required general anesthesia (P = 0.12). The quality of ulnar block was significantly inferior to the quality of block in other nerve territories in Group NS, but not in Group US; the quality of ulnar block was not significantly different between Groups NS and US. The block was performed in an average of 9.8 min in Group NS and 5.0 min in Group US (P = 0.0001). No major complication occurred in either group. We conclude that ultrasound-guided neurostimulator-confirmed supraclavicular block is more rapidly performed and provides a more complete block than supraclavicular block using anatomic landmarks and neurostimulator confirmation. IMPLICATIONS: Ultrasound-guided neurostimulator-confirmed supraclavicular block is more rapidly performed and provides a block of better quality than supraclavicular block using anatomic landmarks and neurostimulator confirmation.

Time course and magnitude of movement-related gating of tactile detection in humans. III. Effect of motor tasks.

This study investigated the relative importance of central and peripheral signals for movement-related gating by comparing the time course and magnitude of movement-related decreases in tactile detection during a reference motor task, active isotonic digit 2 (D2) abduction, with that seen during three test tasks: a comparison with active isometric D2 abduction (movement vs. no movement) evaluated the contribution of peripheral reafference generated by the movement to gating; a comparison with passive D2 abduction (motor command vs. no motor command; movement generated by an external agent) allowed us to evaluate the contribution of the central motor command to tactile gating; and finally, the inclusion of an active "no apparatus," or freehand, D2 abduction task allowed us to evaluate the potential contribution of incidental peripheral reafference generated by the position detecting apparatus to the results (apparatus vs. no apparatus). Weak electrical stimuli (2-ms pulse; intensity, 90% detected at rest) were applied to D2 at different delays before and after movement onset or electromyographic (EMG) activity onset. Significant time-dependent movement-related decreases in detection were obtained with all tasks. When the results obtained during the active isotonic movement task were compared with those obtained in the three test tasks, no significant differences in the functions describing detection performance over time were seen. The results obtained with the isometric D2 abduction task show that actual movement of a body part is not necessary to diminish detection of tactile stimuli in a manner similar to the decrease produced by isotonic, active movement. In the passive test task, the peak decrease in detection clearly preceded the onset of passive movement (by 38 ms) despite the lack of a motor command and, presumably, no movement-related peripheral reafference. A slightly but not significantly earlier decrease was obtained with active movement (49 ms before movement onset). Expectation of movement likely did not contribute to the results because stimulus detection during sham passive movement trials (subjects expected but did not receive a passive movement) was not different from performance at rest (no movement). The results obtained with passive movement are best explained by invoking backward masking of the test stimuli by movement-related reafference and demonstrate that movement-related reafference is sufficient to produce decreases in detection with a time course and amplitude not significantly different from that produced by active movement.