Arne O. Budde

The prediction of difficult intubation in obese patients using mirror indirect laryngoscopy: A prospective pilot study.

Background: The incidence of difficult laryngoscopy and intubation in obese patients is higher than in the general population. Classical predictors of difficult laryngoscopy and intubation have been shown to be unreliable. We prospectively evaluated indirect mirror laryngoscopy as a predictor of difficult laryngoscopy in obese patients. Materials and Methods: 60 patients with a body mass index (BMI) greater than 30, scheduled to undergo general anesthesia, were enrolled. Indirect mirror laryngoscopy was performed and was graded 1-4 according to Cormack and Lehane. A view of grade 3-4 was classified as predicting difficult laryngoscopy. Additional assessments for comparison were the Samsoon and Young modification of the Mallampati airway classification, Wilson Risk Sum Score, neck circumference, and BMI. The view obtained upon direct laryngoscopy after induction of general anesthesia was classified according to Cormack and Lehane as grade 1-4. Results: Sixty patients met the inclusion criteria; however, 8 (13.3%) patients had an excessive gag reflex, and examination of the larynx was not possible. 15.4% of patients who underwent direct laryngoscopy had a Cormack and Lehane grade 3 or 4 view and were classified as difficult. Mirror laryngoscopy had a tendency toward statistical significance in predicting difficult laryngoscopy in these patients. Conclusions: This study is consistent with previous studies, which have demonstrated that no one individual traditional test has proven to be adequate in predicting difficult airways in the obese population. However, the new application of an old test - indirect mirror laryngoscopy - could be a useful additional test to predict difficult laryngoscopy in obese patients.

Intradermal sufentanil does not improve lidocaine-induced local anesthesia.

PurposePeripheral opioid receptors may result in antinociceptive effects when occupied by opioids. This study examined intradermally injected sufentanil (S), a highly lipid soluble opioid, administered with and without lidocaine (L), in a thermal pain model.MethodsNine volunteers were instructed on the method of magnitude estimation of pain before undergoing baseline testing with seven seconds thermal stimuli between 44 and 52°C, delivered by a contact thermal stimulator at five cutaneous forearm sites. Then, four sites randomly received injections of equal volumes (0.1 mL) of either normal saline (NS), lidocaine 0.5% (L), sufentanil 0.75 μg (S), lidocaine 0.5% plus sufentanil 0.75 μg (L + S), and one site was not injected and served as reference (REF). Testing was repeated at six, 30, 60, 90, 120, and 150 min following injection. The pain elicited by each stimulus was normalized to the subjects response to the 50°C stimulus at the REF site.ResultsBaseline testing showed small (P = ns) differences in pain scores. At six minutes, the lidocaine sites (L, L + S) had pain scores that were mean 83% (range 78–88%) lower than the other sites (P < 0.05), but there was no difference between the L and L + S sites or between the S and NS or REF sites. At 30 and 60 min these pain scores were mean 38% (29–44%) and 20% (8–30%) less than at the REF NS, and S sites (P = ns). At 90 min and later times, the pain scores had returned to baseline.ConclusionsThese results suggest that intradermal sufentanil alone has no analgesic effect. Further, in combination with lidocaine, sufentanil does neither potentiate nor prolong the analgesic effect of lidocaine.RésuméObjectifLes récepteurs d’opioïdes périphériques peuvent produire des effets nociceptifs quand ils sont occupés par les opioïdes. Notre étude utilise un modèle de douleur thermique et examine le sufentanil (S) en injection intradermique, un opidïde hautement liposoluble, administré avec ou sans lidocaïne (L).MéthodeLa méthode d’estimation du degré de douleur a été expliquée à neuf volontaires avant les tests de base réalisés avec sept stimuli thermiques de sept secondes appliqués entre 44 et 52 °C par un stimulateur thermique à contact sur cinq sites cutanés de l’avantbras. Puis, sur quatre sites choisis au hasard, nous wons procédé à l’injection d’un volume égal (0,1 mL) de solution salée (SS), de lidocaïne à 0,5 % (L), de 0,75 μg de sufentanil (S) ou de lidocaïne à 0,5% plus 0,75 μg de sufentanil (L+S). Un site est demeuré libre comme référence (REF). L’épreuve a été reprise à 6, 30, 60, 90, 120 et 150 min après l’injection. La douleur provoquée par chaque stimulation a été normalisée selon la réponse du sujet au stimulus fait au site REF à 50°C.RésultatsLépreuve de base a montré de faibles différences (P = ns) entre les scores de douleurs. À six minutes, les sites de lidocaïne (L, L+S) ont affiché des scores de douleurs d’une moyenne de 83% (limites de 78–88 %) plus faibles que ceux des autres sites (P < 0,05), mais il n’y avait pas de différence entre les sites L et L+S ou entre les sites S et SS ou REF. À 30 et 60 min, les scores de douleurs présentaient une moyenne de 38 % (29–44 %) et 20 % (8–30 %) de moins qu’aux sites REF, SS et S (P = ns). À 90 min et aux temps de mesure ultérieurs, les scores de douleurs étaient revenus aux mesures de base.ConclusionCes résultats laissent penser que l’administration intradermique de sufentanil seule n’a pas d’effet analgésique. De plus, en combinaison avec la lidocaïne, le sufentanil ne potentialise pas, ou ne prolonge pas, l’effet analgésique de la lidocaïne.

Comparison of 2 techniques of laryngeal tube exchange in a randomized controlled simulation study

BACKGROUND Laryngeal tubes (LT) are often used as rescue airway devices. Among prehospital medical personnel, the success rates are high and significantly faster compared to an endotracheal tube (ETT). Therefore, LTs are increasingly used in the prehospital setting. The exchange of an LT for an ETT may often be desirable. Two fiberoptic bronchoscope-facilitated techniques have been described to exchange an LT for an ETT: an intraluminal technique using an Aintree intubating catheter and an extraluminal technique using a nasal route alongside the LT. In this randomized cross-over mannequin study, we compared the intraluminal with the extraluminal exchange technique. The primary outcome was time to achieve an effective airway through an ETT. We hypothesized that the intraluminal technique would be significantly faster. METHODS Thirty anesthesia providers were recruited to the study. Each participant attempted both techniques in an intubation simulation model. The tube exchange time was recorded from picking up the fiberoptic bronchoscope until confirmation of ventilation with the ETT. RESULTS Four participants in each group had a failed attempt at intubation. Time to establish an endotracheal intubation was significantly shorter with the intraluminal technique vs the extraluminal technique (77.5 vs 140 seconds; P=.03). CONCLUSION Based on the results of our study, we suggest that the intraluminal technique may be a suitable alternative for a fiberoptic-guided rapid exchange of an LT for an ETT to establish an effective airway in a challenging situation.

A method for overcoming the ceiling effect of bounded pain scales

Objective.The Verbal Numerical Scale (VNS) for rating pain isbounded between 0 (= no pain) and 10 (= worst pain imaginable). Wehypothesized that the limitations inherent to this boundary when ratingextremely painful stimuli may be identified by integrating the VNS with anunbounded score such as magnitude estimation of relative change. Methods.Volunteers received stimuli of increasing current via cutaneous electrodesuntil they rated > 5 on the VNS scale. This stimulus, termed S, wasarbitrarily assigned a magnitude estimate of 100%. Then, stimuli of varyingcurrents were delivered; two were 10 mA and 20 mA higher than S(S+10 and S+20), two were 1/2 of the current for the Sstimulus (S1/2), and one was at the original current(Srepeat). The pain elicited by each stimulus was scored inproportion to the S stimulus. The extrapolated VNS score (VNSext)was determined by multiplying this magnitude estimate (%) by the VNS score forS. Main Results.Seventy percent of the stimuli with higher intensitythan S generated a VNSext score above 10. The mean magnitudeestimations for S+10 and S+20 were 186% and 242%: theygenerated mean (median) VNSext values of 12.4 [12] and16.2 [14], respectively (p = 0.019 for the differencebetween them by Wilcoxon signed rank test). Conclusions.The combineduse of VNS and magnitude estimation confirmed that the ceiling of the boundedpain scale may significantly limit a patients ability to describe a newpain stimulus. VNSext may provide a means of overcoming thislimitation.

An Uncommon Complication with a Supraglottic Airway: The King LT.

General anesthesia was administered in an 18-year-old man for removal of hardware from his right knee using a King Laryngeal Tube supraglottic airway. An hour after extubation, he reported inability to swallow with no respiratory distress. Examination showed an edematous uvula, which took 3 days to subside with anti-inflammatory medication. During the positioning of the King Laryngeal Tube, it was pulled back to ensure adequate ventilation. The inflated cuff could have dragged the uvula and folded it on itself, leading to venous congestion and edema.

Rhythmic movement disorder after general anesthesia

Dystonic movements after general anesthesia are very rare. The differential diagnosis includes adverse drug reaction, local anesthetic reaction, emergence delirium, hysterical response, and shivering. We present a case of a 10-year-old, otherwise healthy girl undergoing outpatient foot surgery. Involuntary jerking movements of her arms and torso every time she would drift off to sleep started about 2.5 hours after emergence from general anesthesia. The patient was easily arousable and absolutely unaware of the movements. These movements lasted for several days before they resolved completely. We believe to present the first case of sleep-related rhythmic movement disorder after general anesthesia, considering the nature of the movements in our patient.

Physics of Instrumentation

It is important for the anesthesiologist to be familiar with the physics of instrumentation to be able to effectively use the information provided by various monitors in the operating room. The basic physical principles of some of the commonly used monitors and equipment are explained here.

Anesthesia for Procedures in the Neurointerventional Suite

Procedures in the neurointerventional suite can be divided into opening procedures and closing procedures, such as angioplasty for stroke, embolization for cerebral arterio-venous malformations or coiling for cerebral aneurysm. Different equipment and medications are available for each type of procedure with unique possible side effects and complications.

Emergent airway management in a case of fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva (FOP), or Stone man syndrome, is rare and one of the most disabling genetic conditions of the connective tissue due to progressive extraskeletal ossification. It usually presents in the first decade of life as painful inflammatory swellings, either spontaneously or in response to trauma, which later ossify and lead to severe disability. Progressive spinal deformity including thoracolumbar kyphoscoliosis leads to thoracic insufficiency syndrome, increasing the risk for pneumonia and right sided heart failure. We present the airway management in a 22-year-old male, diagnosed with FOP with severe disability, who required urgent airway intervention as a result of respiratory failure from pnuemonia. Tracheostomy triggers ossification and consequent airway obstruction at the tracheostomy site and laryngoscopy triggers temporomandibular joint ankylosis. Therefore, awake fiber-optic endotracheal intubation is recommended in these patients. Use of an airway endoscopy mask enabled us to simultaneously maintain non-invasive ventilation and intubate the patient in a situation where tracheostomy needed to be avoided.

Combined spinal-epidural anesthesia for cesarean delivery in a patient with capillary pontine telangiectasia.

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