Michael J. Bishop

Early clinical experience with a new videolaryngoscope (GlideScope) in 728 patients.

PurposeTo evaluate a new videolaryngoscope and assess its ability to provide laryngeal exposure and facilitate intubation.MethodsFive centres, involving 133 operators and a total of 728 consecutive patients, participated in the evaluation of a new videolaryngoscope [GlideScope® (GS)]. Many operators had limited or no previous GS experience. We collected information about patient demographics and airway characteristics, Cormack-Lehane (C/L) views and the ease of intubation using the GS. Failure was defined as abandonment of the technique.ResultsData from six patients were incomplete and were excluded. Excellent (C/L 1) or good (C/L 2) laryngeal exposure was obtained in 92% and 7% of patients respectively. In all 133 patients in whom both GS and direct laryngoscopy (DL) were performed, GS resulted in a comparable or superior view. Among the 35 patients with C/L grade 3 or 4 views by DL, the view improved to a C/L 1 view in 24 and a C/L 2 view in three patients. Intubation with the GS was successful in 96.3% of patients. The majority of the failures occurred despite a good or excellent glottic view.ConclusionsGS laryngoscopy consistently yielded a comparable or superior glottic view compared with DL despite the limited or lack of prior experience with the device. Successful intubation was generally achieved even when DL was predicted to be moderately or considerably difficult. GS was abandoned in 3.7% of patients. This may reflect the lack of a formal protocol defining failure, limited prior experience or difficulty manipulating the endotracheal tube while viewing a monitor.RésuméObjectifÉvaluer un nouveau vidéolaryngoscope et tester sa capacité à fournir une exposition du larynx et à faciliter l’intubation.MéthodeCinq centres, impliquant 133 opérateurs et 728 patients consécutifs, ont participé à l’évaluation du nouveau vidéolaryngoscope [GlideScope® (GS)]. De nombreux opérateurs avaient une expérience nulle ou limitée du GS. Nous avons noté les données démographiques et les caractéristiques des voies aériennes, la classification Cormack-Lehane (C/L) des visualisations et la facilité à intuber avec le GS. Un échec était défini comme un abandon de la technique. Résultats: Six patients ont été exclus à cause de données incomplètes. Une excellente (C/L 1) ou une bonne (C/L 2) exposition du larynx a été obtenue chez 92 % et 7 % des patients respectivement. Chez les 133 patients soumis aux deux tests avec le GS et à la laryngoscopie directe (LD), le GS a donné des résultats comparables ou une vue supérieure. Parmi les 35 patients avec un grade 3 ou 4 de C/L par LD, la visualisation s’est améliorée à 1 C/L chez 24 patients et à 2 C/L chez trois patients. L’intubation avec le GS a été réussie chez 96,3 % des patients. La majorité des échecs sont survenus malgré une bonne ou une excellente visualisation glottique.ConclusionLa laryngoscopie avec le GS fournit toujours une vision glottique comparable ou supérieure à la LD malgré l’expérience nulle ou limitée avec l’appareil. L’intubation a été généralement réussie même lorsqu’on prévoyait une difficulté modérée ou importante de la LD. Le GS a été abandonné chez 3,7 % des patients. Cela pourrait correspondre au manque de protocole formel définissant l’échec, à l’expérience antérieure limitée ou à la difficulté de manipuler le tube endotrachéal tout en surveillant l’écran.

Correlation of Endotracheal Tube Size with Sore Throat and Hoarseness Following General Anesthesia

Correlation of Endotracheal Tube Size with Sore Throat and Hoarseness Following General Anesthesia DAVID STOUT;MICHAEL BISHOP;JOCHEN DWERSTEC;BRUCE CULLEN; Anesthesiology

The effect of isoflurane, halothane, sevoflurane, and thiopental/nitrous oxide on respiratory system resistance after tracheal intubation

Background: After tracheal intubation, lung resistance and therefore respiratory system resistance (Rrs) routinely increase, sometimes to the point of clinical bronchospasm. Volatile anesthetics generally have been considered to be effective bronchodilators, although there are few human data comparing the efficacy of available agents. This study compared the bronchodilating efficacy of four anesthetic maintenance regimens: 1.1 minimum alveolar concentration (MAC) end‐tidal sevoflurane, isoflurane or halothane, and thiopental/nitrous oxide. Methods: Sixty‐six patients underwent tracheal intubation after administration of 2 micro gram/kg fentanyl, 5 mg/kg thiopental, and 1 mg/kg succinylcholine. Vecuronium or pancuronium (0.1 mg/kg) was then given to ensure paralysis during the rest of the study. Postintubation R sub rs was measured using the isovolume technique. Maintenance anesthesia was then randomized to thiopental 0.25 mg [center dot] kg sup ‐1 [center dot] min sup ‐1 plus 50% nitrous oxide, or 1.1 MAC end‐tidal isoflurane, halothane, or sevoflurane. The Rrs was measured after 5 and 10 min of maintenance anesthesia. Data were expressed as means +/‐ SD. Results: Maintenance with thiopental/nitrous oxide failed to decrease Rrs, whereas all three volatile anesthetics significantly decreased Rrs at 5 min with little further improvement at 10 min. Sevoflurane decreased Rrs more than either halothane or isoflurane (P < 0.05; 58 +/‐ 14% of the postintubation Rrs vs. 69 +/‐ 20% and 75 +/‐ 13%, respectively). Conclusions: After tracheal intubation in persons without asthma, sevoflurane decreased Rrs as much or more than isoflurane or halothane did during a 10‐min exposure at 1.1 MAC.

Comparison of the Effects of Etomidate, Propofol, and Thiopental on Respiratory Resistance after Tracheal Intubation

Background Tracheal intubation frequently results in reversible bronchoconstriction. Propofol has been reported to minimize this response in healthy patients and in asthma patients, but may be unsuitable for hemodynamically unstable patients for whom etomidate may be preferable. The current study examined respiratory resistance after tracheal intubation after induction with either thiopental, etomidate, or propofol. A supratherapeutic dose of etomidate was used to test the hypothesis that the bronchoconstrictive response could be minimized by deep intravenous anesthesia. Methods Seventy‐seven studies were conducted in 75 patients. Anesthesia was induced with either 2.5 mg/kg propofol, 0.4 mg/kg etomidate, or 5 mg/kg thiopental. Respiratory resistance was measured at 2 min after induction. Results Respiratory resistance at 2 min was 8.1+/‐3.4 cmH sub 2 O *symbol* l sup ‐1 *symbol* s (mean+/‐SD) for patients receiving propofol versus 11.3+/‐5.3 for patients receiving etomidate and 12.3+/‐7.9 for patients receiving thiopental (P less than or equal to 0.05 for propofol vs. either etomidate or thiopental). Conclusions Respiratory resistance after tracheal intubation is lower after induction with propofol than after induction with thiopental or after induction with high‐dose etomidate.

The attributable risk of smoking on surgical complications.

Objective:This study aimed to assess the attributable risk and potential benefit of smoking cessation on surgical outcomes. Summary Background Data:Risk reduction with the implementation of surgical care improvement project process measures has been the primary focus for improving surgical outcomes. Little emphasis has been placed on preoperative risk factor recognition and intervention. Methods:A retrospective cohort analysis of elective operations from 2002 to 2008 in the Veterans Affairs Surgical Quality Improvement Program for all surgical specialties was performed. Patients were stratified by current, prior, and never smokers. Adjusted risk of complication and death was calculated using multilevel, multivariable logistic regression. Results:Of 393,794 patients, 135,741 (34.5%) were current, 71,421 (18.1%) prior, and 186,632 (47.4%) never smokers. A total of 6225 pneumonias, 11,431 deep and superficial surgical-site infections, 2040 thromboembolic events, 1338 myocardial infarctions, and 4792 deaths occurred within 30 days of surgery. Compared with both never and prior smokers individually and controlled for patient and procedure risk factors, current smokers had significantly more postoperative pneumonia, surgical-site infection, and deaths (P < 0.001 for all). There was a dose-dependent increase in pulmonary complications based on pack-year exposure with greater than 20 pack years leading to a significant increase in smoking-related surgical complications. Conclusions:This is the first study to assess the risk of current versus prior smoking on surgical outcomes. Despite being younger and healthier, current smokers had more adverse perioperative events, particularly respiratory complications. Smoking cessation interventions could potentially reduce the occurrence and costs of adverse perioperative events.

Laryngeal Effects of Prolonged Intubation

Improved care for acute respiratory failure requires prolonged placement of an endotracheal tube. Whether a tracheotomy or a translaryngeal endotracheal tube is the better choice remains controversial. With the use of high-volume low-pressure cuffs, both routes of intubation have similar low rates of cuff-induced complications. Complications of the alternatives include problems that occur above the cuff, at the larynx during translaryngeal intubation, or the stoma in patients with a tracheotomy. The complications of tracheotomy are well-documented and will be touched on only briefly in this paper, which will review the consequences to the larynx of using translaryngeal intubation for prolonged maintenance of an airway. The issues to be considered are how and why injury to the larynx occurs, what immediate postextubation problems can be expected, and what long-term sequelae may occur.

Delivery efficiency of metered dose aerosols given via endotracheal tubes.

The authors studied the efficiency of delivery of the inhaled bronchodilator metaproterenol when delivered via an endotracheal tube (ETT) using a metered dose inhaler (MDI). They found that the percentage of drug exiting the ETT varied with tube size, ranging from 3.0 +/- 1.9 for a 6.0 mm ETT to 6.5 +/- 4.4 for a 9.0 mm ETT (mean +/- SEM, P less than 0.05). The efficiency of delivery was also affected by whether the MDI was activated before or after initiation of gas flow through the ETT, with activation into a flowing stream significantly more efficient. The authors conclude that an MDI can deliver a dose of drug to the trachea, but delivery efficiency is lower than reported for MDI delivery in spontaneously breathing patients.

Elective surgical case cancellation in the Veterans Health Administration system: identifying areas for improvement

BACKGROUND This study evaluated elective surgical case cancellation (CC) rates, reasons for these cancellations, and identified areas for improvement within the Veterans Health Administration (VA) system. METHODS CC data for 2006 were collected from the scheduling software for 123 VA facilities. Surveys were distributed to 40 facilities (10 highest and 10 lowest CC rates for high- and low-volume facilities). CC reasons were standardized and piloted at 5 facilities. RESULTS Of 329,784 cases scheduled by 9 surgical specialties, 40,988 (12.4%) were cancelled. CC reasons (9,528) were placed into 6 broad categories: patient (35%), work-up/medical condition change (28%), facility (20%), surgeon (8%), anesthesia (1%), and miscellaneous (8%). Survey results show areas for improvement at the facility level and a standardized list of 28 CC reasons was comprehensive. CONCLUSIONS Interventions that decrease cancellations caused by patient factors, inadequate work-up, and facility factors are needed to reduce overall elective surgical case cancellations.

Smoking as a risk factor for short-term outcomes following primary total hip and total knee replacement in veterans.

To assess the effect of smoking on postoperative complications following elective primary total hip replacement (THR) or primary total knee replacement (TKR).

Laryngeal Injury in a Dog Model of Prolonged Endotracheal Intubation

Using a dog model of prolonged translaryngeal intubation, the authors studied laryngeal injury. Segments of 10.7 mm diameter endotracheal tube were sutured in place in the larynges of anesthetized animals, and the animals were allowed to awaken and the tubes left in place for periods of 24 h to 84 days in a total of 13 dogs. Each animals larynx was studied endoscopically at weekly intervals and at the time of death. Both endoscopic and postmortem examination revealed erythematous laryngeal mucosa at 24 h and severe mucosal ulceration by 1 week. Microscopic examination revealed mucosal inflammation at 24 h with loss of mucosal architecture by 1 week. In several animals intubated 1 week or longer, inflammatory infiltrates were present in the arytenoid cartilage. While damage was generally severe by 1 week, it did not tend to become more severe after that time. Between week 1 and week 12, there was no significant correlation of the severity of laryngeal injury with the duration of endotracheal intubation. The results suggest that duration alone may not be a factor in laryngeal injury after the first week of intubation.