Hirabayashi Y

Use of the Pentax-AWS in 293 patients with difficult airways.

Background:Several case reports have shown that the Pentax-AWS® (Hoya Corporation, Tokyo, Japan), a new video laryngoscope, is useful in patients with difficult airways. Methods:We assessed the effectiveness of the Pentax-AWS® in two groups. Group 1 included 270 patients in whom direct laryngoscopy using a Macintosh laryngoscope had been difficult. Group 2 included 23 patients with predicted difficult intubation and difficult mask ventilation without previous use of the Macintosh laryngoscope. Results:In group 1, the view of the glottis with the Macintosh laryngoscope was Cormack and Lehane grade 2 in 14 patients, grade 3 in 208 patients, and grade 4 in 48 patients. In 256 patients in whom the grade was 3 or 4 with the Macintosh laryngoscope, the view with the Pentax-AWS® was either grade 1 or 2 in 255 patients (99.6%; 95% confidence intervals 97.8–100%). Tracheal intubation was successful with the Pentax-AWS® in 268 of 270 patients (99.3%; 95% confidence interval 97.4–100%), and it failed (after two attempts) in two patients. In group 2, tracheal intubation was successful in 22 of 23 patients, and it failed in one patient. The reasons for failed intubation using the Pentax-AWS® were failure to position the blade toward the glottic side of the epiglottis, inability to maneuver the endotracheal tube away from the arytenoids and into the trachea, and bleeding and swelling of the oropharynx. Conclusion:The success rate of tracheal intubation using the Pentax-AWS® was high in patients with difficult laryngoscopy with a Macintosh laryngoscope and in patients with predicted difficult intubation.

The fiberscopic findings of the epidural space in pregnant women

Background The spread of epidural analgesia is facilitated by pregnancy. Changes in the epidural structure during pregnancy may affect the spread of analgesia in pregnant women. To investigate the changes in the epidural space produced by pregnancy, the authors performed epiduroscopy in pregnant women. Methods Using a flexible fiberscope, the authors evaluated the epidural space in 73 women undergoing lumbar epidural anesthesia. Patients were classified into three groups: a nonpregnant group (n = 21), a first trimester pregnant group (8–13 weeks, n = 23), and a third-trimester pregnant group (27–39 weeks, n = 29). A 17-gauge Tuohy needle was inserted using the paramedian technique and the loss-of-resistance method with 5 ml air. The epiduroscope was introduced into the lumbar epidural space via the Tuohy needle and was advanced approximately 10 cm in a cephalad direction from the needle tip within the epidural space. The differences in the epidural space among the three groups then was evaluated. Results The epiduroscopy showed that the epidural pneumatic space, after injection of a given amount of air, was narrower and the density of the vascular network greater in the third-trimester group than in the other two groups. The amount of engorged blood vessels was greater in the third and first trimester groups than in the nonpregnant group. The amount of bleeding at the needle tip and the amount of fatty and fibrous connective tissue did not differ among the three groups. Conclusions Epidural blood vessels become engorged in the first trimester; the density of the vascular networks increase in the third trimester. These changes in the epidural space during pregnancy may affect the spread of epidural analgesia in pregnant women.

Airway Scope: early clinical experience in 405 patients

The Airway Scope (Pentax, Tokyo, Japan) is a new device used for tracheal intubation. It allows visualization of the glottis through a non-line-of sight view. The aim of the present study was to evaluate the suitability of this device for the tracheal intubation of surgical patients. In this prospective study, the Airway Scope was used for the endotracheal intubation of 405 patients by 74 airway operators. The Airway Scope allowed visualization of the glottis in all 405 patients, including those with a Cormack-Lehane view of grade III (n = 15) or grade IV (n = 1) on Macintosh laryngoscopy. All tracheal intubations using the Airway Scope were successful. The mean time to complete tracheal intubation was 42.4 ± 19.7 s (±SD; range, 13–192 s). No dental damage was encountered, though minor mucosal injury caused by the blade was experienced in 2 patients. The Airway Scope consistently permitted a better intubation environment. With its potential advantages, the Airway Scope could be an effective aid to airway management in surgical patients.

Sevoflurane is equivalent to isoflurane for attenuating bupivacaine-induced arrhythmias and seizures in rats

The effects of sevoflurane on bupivacaine toxicity have not been defined.The purpose of this study was to investigate the effects of sevoflurane and isoflurane on bupivacaine-induced arrhythmias and seizures in rats. Thirty-seven Sprague-Dawley rats received bupivacaine intravenously at a constant rate of 2 mg centered dot kg (-1) centered dot min-1 until both arrhythmias and seizures occurred while electrocardiogram (ECG) and electroencephalogram (EEG) recordings were made. The cumulative doses of bupivacaine inducing arrhythmias and seizures were determined in the presence of 1 minimum alveolar anesthetic concentration (MAC) of sevoflurane (sevoflurane group, n = 14) or isoflurane (isoflurane group, n = 10) and in the absence of anesthetic (control group, n = 13). The cumulative doses of bupivacaine inducing arrhythmias and seizures were larger in the sevoflurane and isoflurane groups than in the control group and were similar in the sevoflurane and isoflurane groups. These results indicate that sevoflurane and isoflurane attenuate bupivacaine-induced arrhythmias and seizures in rats. (Anesth Analg 1996;83:570-3)

Pharyngeal Injury Related to Glidescope Videolaryngoscope

Dear Dr Rosenfeld: Your excellent editorial entitled Quality stayed with me. I thought two more ideas might properly be considered on this topic. I increasingly have that sense of seeing the same idea return in new guise—without attribution. A quick survey of the references in that issue, as in all current journals, demonstrates the virtual absence of any references to literature before about 1960. It is as though our specialty emerged fully formed in the 1960s. The root cause of this silence about the past is reliance on computerized search tools. In its current form, this invaluable technique seems inadvertently to have cut us off from our distinguished past. We should push to digitize the entire body of ENT literature, journal by journal, editorial by editorial, letter by letter, all the way back to the 19th century. Much patient suffering is embedded in that database, as is much compassionate reflection and ingenious thought. I believe that many quantum jumps in understanding and management will be found, which current technology can bring to practice. In many cases, we need not reinvent the wheel. We just have to build one. Linked to the idea of “data mining” our past literature— and exemplified in one article in the same issue—is the almost inevitable absence of the concept of “natural history” in considering the effects of one treatment or another. Too many articles compare treatment A with treatment B without referring to what happens if no treatment is given at all. Placebo or blinded studies are often difficult for ethical or technical reasons to be sure. I am confident that, in the history of the nostrums employed in times past, is the actual natural history of many of the diseases we treat. It is a shame to waste all that information.

Stress hormone responses to major intra-abdominal surgery during and immediately after sevoflurane-nitrous oxide anaesthesia in elderly patients

We studied the responses of plasma epinephrine, norepinephrine, adrenocorticotropic hormone (ACTH), cortisol, and antidiuretic hormone (ADH) during and immediately after sevoflurane-nitrous oxide anaesthesia supplemented with vecuronium in seven elderly patients (mean 76.6 ± 1.7 SEM) who underwent major intra-abdominal surgery. The plasma concentrations of norepinephrine, ACTH, cortisol, and ADH increased in response to surgical procedures (P <0.05). The plasma concentration of ADH increased to a peak concentration of 189.1 ± 20.7 pg · ml−1 30 min after skin incision (P < 0.05). the plasma concentrations of epinephrine, norepinephrine, ACTH, and cortisol increased to peak concentrations of 408.6 ± 135.5 pg · ml−1, 635.7 ± 167.8 pg · ml−1, 222.6 ± 48.0 pg · ml−1, and 113.6 ± 67.5 μg · dI−1, respectively immediately after tracheal extubation (P <0.05). We conclude that, in the elderly patients, the responses of stress hormones to major intraabdominal surgery were preserved during sevoflurane-nitrous oxide anaesthesia sufficient to prevent increases in arterial pressure and heart rate. The strongest responses of epinephrine, norepinephrine, ACTH, and cortisol were elicited immediately after treacheal extubation.RésuméCette étude porte sur les réponses de l’épinephrine, de la norépinéphrine, de ACTH, du cortisol, et de l’ADH pendant et immédiatement après l’anesthésie au sévoflurane-protoxyde d’azote supplémentée par du vécuronium chez sept patients avancés en âge (moyenne 76,6 ± 1,7 SEM) opérés pour une chirurgie viscérale majeure. Les concentrations plasmatiques de norépinephrine, d’ACTH, de cortisol, et d’ADH augmentent en réponse à la chirurgie (P < 0,05). La concentration plasmatique d’ADH atteint un maximum de 189,1 ± 20,7 pg · ml−1 après l’incision (P < 0,05). La concentration plasmatique de l’epinéphrine, de la norépinéphrine, de l’ACTH et du cortisol atteignent respectivement un maximum de 408,6 ± 135,5 pg · dl−1, 635,7 ± 167,8 pg · ml−1, 222,6 ± 48,0 pg · ml−1, et de 113,6 ± 67,5 μg · dl−1 immédiatement après l’intubation (P < 0,05). En conclusion, la réponse des hormones de stress à une chirurgie viscérale majeur chez le sujet âgé est conservées pendant une anesthésie au sévoflurane-protoxyde d’azote suffisamment profonde pour prévenir une montée de la pression artérielle et de la fréquence cardiaque. Les réponses les plus internes de l’épinéphrine, de la norépinéphrine, de l’ACTH et du cortisol sont survenues immédiatement après l’intubation de la trachée.

Tracheal intubation by non-anesthesia residents using the Pentax-AWS airway scope and Macintosh laryngoscope

STUDY OBJECTIVE To evaluate the performance of the Pentax-AWS airway scope for tracheal intubation compared with the Macintosh laryngoscope by non-anesthesia residents. DESIGN Prospective, randomized, cohort study. SETTING University-affiliated hospital. PATIENTS 520 patients who underwent tracheal intubation for general anesthesia. INTERVENTIONS 48 non-anesthesia residents performed tracheal intubation using either the Pentax-AWS or the Macintosh laryngoscope. MEASUREMENTS Time to complete tracheal intubation, number of attempts until successful intubation, and number of intubations of the esophagus were recorded. RESULTS Time to secure the airway (sec; mean +/- SD) was shorter with the Pentax-AWS than with the Macintosh laryngoscope (44 +/- 19 vs. 71 +/- 44 sec; P < 0.001). Of the 264 tracheal intubations with the Pentax-AWS, 239 (91%) were completed within 60 seconds, while only 148 (58%) of the 256 tracheal intubations performed with the Macintosh laryngoscope were completed within the same period. The rate of successful intubations on the first attempt was higher with the Pentax-AWS than the Macintosh laryngoscope (P < 0.001). No esophageal intubation was experienced with the Pentax-AWS approach, while 18 occurred with the Macintosh laryngoscope (P < 0.001). CONCLUSION The Pentax-AWS appears to require less operator skill than the Macintosh laryngoscope. Use of the Pentax-AWS may reduce the time to secure the airway and the incidence of failed tracheal intubation by non-anesthesia residents.

Tracheal intubation by non-anaesthetist physicians using the Airway Scope.

Objective: To evaluate the performance of the Airway Scope for tracheal intubation by non-anaesthetist physicians. Methods: Under supervision by staff anaesthetists, non-anaesthesia residents performed tracheal intubation using either the Airway Scope (n = 100) or Macintosh laryngoscope (n = 100). The time required for airway instrumentation and the success rate at first attempt were investigated. Results: The time to secure the airway was shorter with the Airway Scope than with the Macintosh laryngoscope (p<0.001). The success rate at first attempt was higher with the Airway Scope than with the Macintosh laryngoscope (p<0.001). Conclusion: The Airway Scope may reduce the time to secure the airway and the incidence of failed tracheal intubation in novice laryngoscopists.

Airtraq optical laryngoscope: tracheal intubation by novice laryngoscopists

Objective: To evaluate the performance of the Airtraq optical laryngoscope for tracheal intubation by novice laryngoscopists, compared with that of the Macintosh laryngoscope. Methods: Under supervision by staff anaesthetists, non-anaesthesia physicians performed tracheal intubation using either the Airtraq optical laryngoscope (n  =  100) or the Macintosh laryngoscope (n  =  100). The time required for airway instrumentation, the number of attempts until successful intubation and erroneous oesophageal intubation were investigated. Results: The time to secure the airway was shorter with the Airtraq optical laryngoscope than with the Macintosh laryngoscope (p<0.001). The number of attempts until successful intubation was smaller with the Airtraq optical laryngoscope than with the Macintosh laryngoscope (p<0.001). Erroneous oesophageal intubation was less with the Airtraq optical laryngoscope than with the Macintosh laryngoscope (p<0.01). Conclusion: The Airtraq optical laryngoscope reduces the time to secure the airway and the incidence of failed tracheal intubation by novice laryngoscopists.

The effects of sevoflurane and isoflurane anesthesia on renal tubular function in patients with moderately impaired renal function.

Increasing evidence indicates that sevoflurane anesthesia does not impair renal function in healthy patients despite higher concentrations of plasma inorganic fluoride.However, whether sevoflurane further affects renal tubular function in patients with impaired renal function is not known. We compared the effect of sevoflurane anesthesia with that of isoflurane anesthesia on renal tubular function in patients with moderately impaired renal function. Fourteen patients with creatinine clearance between 10 and 55 mL/min were anesthetized with either sevoflurane or isoflurane using a semiclosed circuit system. Plasma inorganic fluoride concentrations and urine N-acetyl-beta-D-glucosaminidase (NAG), gamma-glutamyltranspeptidase (gamma-GTP), and beta2-microglobulin (beta2 MG) excretions were measured up to postanesthetic day 14. Although both the peak plasma inorganic fluoride concentrations and the areas under the curve of plasma inorganic fluoride concentration versus time were significantly greater in the sevoflurane group than in the isoflurane group, urine NAG, gamma-GTP, and beta2 MG excretions per day did not differ between the two groups. These results indicate that sevoflurane and isoflurane may have similar effects on the renal tubules in patients with moderately impaired renal function. (Anesth Analg 1996;82:909-13)