Jonathan J. Gamble

Tension pneumothorax during flexible bronchoscopy in a nonintubated infant

We describe the case of a tension pneumothorax occurring during flexible bronchoscopy in a nonintubated infant. The pneumothorax likely occurred secondary to wall source oxygen insufflation via the bronchoscope without sufficient gas egress. The use of wall source oxygen via the bronchoscope working channel is inherently dangerous and should be avoided.

Three‐finger tracheal palpation to guide endotracheal tube depth in children

Accurate endotracheal tube (ETT) depth is critical, especially in children. The current tools used to guide appropriate ETT depth have significant limitations.

Stimulating thoracic epidural placement via a lumbar approach causes significant spinal cord damage in a porcine model

AbstractBackground Continuous thoracic epidural analgesia is a valuable and common technique for analgesia but involves risk to the spinal cord. There is significant pediatric experience safely placing thoracic epidurals via a caudal approach. The use of a stimulating catheter offers the advantage of real-time confirmation of appropriate catheter placement. We hypothesize that the tip of a stimulating epidural catheter can be reliably advanced to the thoracic epidural space with lumbar insertion in a porcine model.MethodsThis prospective experimental porcine study evaluated the feasibility of placing the tip of a stimulating epidural catheter to a predefined thoracic epidural location after percutaneous lumbar epidural access in six live pigs. After the lumbar epidural space was accessed, a stimulating epidural catheter was advanced until the targeted thoracic myotome was stimulated. The final position of the catheter in relation to the targeted location was determined by fluoroscopy. All animals were euthanized at the end of the experiment, necropsy and spinal cord histology were then performed to assess the extent of spinal cord damage.ResultsIn all animals the epidural catheter tip could be accurately advanced to the targeted thoracic myotome. Gross subdural bleeding occurred in three of the six animals and deep spinal damage was observed in two of the six animals. In one animal, the catheter was placed in the subarachnoid space.ConclusionsAccurate access to the thoracic epidural space is possible via a lumbar approach using a stimulating epidural catheter. Based on gross and histopathological examination, this technique resulted in frequent complications, including subdural hemorrhage, deep spinal cord damage, and subarachnoid catheter placement.RésuméContexteL’analgésie péridurale thoracique continue est une technique analgésique précieuse et répandue, mais elle peut endommager la moelle épinière. Il existe de nombreuses données soutenant le positionnement sécuritaire de péridurales thoraciques par approche caudale chez l’enfant. L’utilisation d’un cathéter stimulant offre l’avantage de confirmer en temps réel le bon positionnement du cathéter. Nous avons émis l’hypothèse que l’extrémité d’un cathéter péridural stimulant pouvait être avancée de façon fiable dans l’espace péridural thoracique par insertion lombaire chez un modèle porcin.MéthodeCette étude prospective expérimentale sur un modèle porcin a évalué la faisabilité de positionner l’extrémité d’un cathéter péridural stimulant à un emplacement péridural thoracique prédéterminé après avoir obtenu un accès péridural lombaire percutané chez six porcs vivants. Une fois l’accès à l’espace péridural lombaire obtenu, un cathéter péridural stimulant a été poussé jusqu’à ce que le myotome thoracique ciblé soit stimulé. La position finale du cathéter par rapport à l’emplacement cible a été déterminée par fluoroscopie. Tous les animaux ont été euthanasiés à la fin de l’expérience; ensuite, une autopsie et une histologie de la moelle épinière ont été réalisées afin d’évaluer l’étendue des lésions à la moelle épinière.RésultatsChez tous les animaux, l’extrémité du cathéter péridural a pu être avancée avec précision jusqu’au myotome thoracique ciblé, alors que d’importants saignements sous-duraux sont survenus chez trois des six animaux, et des lésions profondes à la moelle épinière ont été observées chez deux des six animaux. Le cathéter a été placé dans l’espace sous-arachnoïdien chez un animal.ConclusionIl est possible d’accéder précisément à l’espace péridural thoracique par une approche lombaire à l’aide d’un cathéter péridural stimulant. En se fondant sur l’examen grossier et histopathologique, cette technique a provoqué des complications fréquentes, notamment une hémorragie sous-durale, des lésions profondes à la moelle épinière et un placement du cathéter dans l’espace sous-arachnoïdien.

Positive-pressure ventilation during transport: a randomized crossover study of self-inflating and flow-inflating resuscitators in a simulation model.

Positive‐pressure ventilation during transport of intubated patients is generally delivered via a hand‐pressurized device. Of these devices, self‐inflating resuscitators (SIR) and flow‐inflating resuscitators (FIR) constitute the two major types used. Selection of a particular device for transport, however, remains largely an institutional practice.

Artificial ventilation during transport: A randomized crossover study of manual resuscitators with comparison to mechanical ventilators in a simulation model

Positive‐pressure ventilation in critically ill patients is commonly administered via a manual resuscitation device or a mechanical ventilator during transport. Our group previously compared delivered ventilation parameters between a self‐inflating resuscitator and a flow‐inflating resuscitator during simulated in‐hospital pediatric transport. However, unequal group access to inline pressure manometry may have biased our results. In this study, we examined the performance of the self‐inflating resuscitator and the flow‐inflating resuscitator, both equipped with inline manometry, and several mechanical ventilators to deliver prescribed ventilation parameters during simulated pediatric transport.

In reply: Should we ever stop clinical trials for efficacy?

To the Editor, We thank Mr. Fergusson and Dr. Griesdale for presenting a well-reasoned discussion of the consequences of stopping a trial such as ours early. We generally agree that effect overestimation and lack of precision are unfortunate by-products of stopping a trial early. Nevertheless, we disagree with their suggestion that clinical trials should be stopped only ‘‘when it is obvious that clinical equipoise no longer exists.’’ The existence of different stopping rules indicates that deciding whether to stop or continue a trial is neither straightforward nor trivial. While P values are what lie on the surface, there are ethical reckonings involved. It requires weighing the current patients’ good against the potential benefit to society. Each physician is required to balance the duty of care with the search for truth. Each patient desires the most effective treatment for themselves, not to serve an abstract scientific goal. To reconcile these interests, the power to stop or continue is rightfully vested with an institutional review board (IRB). Though IRBs follow the principle of equipoise, this equipoise depends on what evidence is available at a given time. The editorial by Andrade (and the majority of its supporting references) summarizing the inconsistent results in ketamine trials was unavailable during our interim analysis. Instead, the evidence with respect to our primary and many important secondary clinical outcomes significantly favoured ketamine over propofol. Together with findings from a paper published around the same time, our results may have led the IRB to conclude that equipoise no longer held. A larger sample number could give results that show either a greater or a lesser effect size, and would likely be a better estimate of the true treatment effect of our own study intervention. Nevertheless, IRBs are not required to stop or continue trials based on effect size, but rather on whether there is an effect at all. We are aware that our trial’s small size and single-site nature are unlikely to change practice. We do believe that our results contribute to the scientific evidence and warrant a larger multi-centre trial.

Malignant Hyperthermia in a Morbidly Obese Patient Depletes Community Dantrolene Resources: A Case Report

During resection of a duodenal carcinoid tumor, a 28-year-old morbidly obese woman developed suspected malignant hyperthermia. This hypermetabolic state posed a diagnostic challenge given the similar intraoperative presentation of carcinoid crisis and malignant hyperthermia. The patients weight posed therapeutic challenges as massive doses and prolonged administration of dantrolene were required that quickly depleted the available supply. Current dantrolene dosing recommendations are based on actual body weight despite a paucity of literature in obese patients. We speculate that the prolonged need for dantrolene redosing was from the continuous release of the volatile anesthetic from the patients adipose tissue.

Reply to Ideno, Satoshi; Seki, Hiroyuki; Morisaki, Hiroshi, regarding their comment ‘Consider an additional pressure-relief port before we abandon the use of the wall oxygen through a bronchoscope'

as visualization of the diaphragm using a traditional method of scanning through the acoustic windows of the liver (right side) and spleen (left side) is notoriously difficult without sufficient practice and thorough knowledge of the relevant anatomy. We recently published a novel method of ultrasound diaphragm assessment (see Figure 1 for ABCDE method) (2) based on landmarking using recognizable features and measurement of diaphragm thickening. Briefly, a high-frequency, linear probe is placed on the anterior axillary line just below the nipple level; lung sliding can be visualized between the ribs upon ventilation of the lungs. As the probe is moved in a caudal direction along the axillary line, the diaphragm can be visualized as it is no longer obscured by the pleura. Compared to traditional approaches, we believe that this simple method possesses a smaller learning curve for ultrasound novices and anesthesiologists who may not be familiar with identification of the diaphragm using ultrasound. Although our original observations using the ABCDE method were made using adult models, we have since used the method successfully on pediatric patients to assess diaphragm movement. As shown in the Figure 1, typical ultrasound images demonstrate real-time observation of bilateral lung sliding and diaphragm muscles in a 3.0 kg child after proper positive bilateral ventilation via mid-tracheal intubation (also see Videos S1 and S2). In a small infant, use of a linear probe (e.g., L38e; SonoSite, Bothell, WA, USA) allows the operator to view multiple rib levels at once. The sliding movement of the pleura into the zone of apposition above the diaphragm muscle can also be seen easily and clearly, all in a single ultrasound screen. In summary, we believe that the ABCDE method of ultrasound diaphragm scanning is a simple and quick method for diaphragm evaluation in pediatric as well as adult patients. The method avoids the challenges associated with conventional methods, such as difficulty visualizing through acoustic windows, movement artifacts caused by heart pulsations, and the need to reposition the patient to optimize scanning.

Modified pediatric Magill forceps effect on nasal intubation time

SIR—Pediatric anesthesiologists commonly use Magill forceps during nasotracheal intubation yet often have difficultly advancing the nasotracheal tube into the trachea. (1) This problem is frequently caused by the nasotracheal tube abutting the anterior trachea once past the vocal cords. (1) Differences in pediatric airway anatomy including a cephalad larynx and a posterior angled trachea relative to adults are thought to contribute to this problem. (2) Advancing the nasotracheal tube requires the tip to be redirected caudo-dorsally. Troubleshooting techniques such as neck flexion and tube rotation on its axis have been successfully used to accomplish this redirection. (1) We hypothesized that a + 45° angulation of the pediatric Magill forceps tip in a direction away from the handle will allow downward posterior bending of the nasotracheal tube tip after grasping the tube, facilitating tube passage, preventing it from getting caught on the anterior trachea (Figure 1). There have been previous modifications to the Magill forceps to aid its use in foreign body removal and oral intubation of a difficult airway. (3,4) Liberman modified the forceps to allow grasping of the nasotracheal tube in an anteroposterior fashion as opposed to side by side, allowing a firmer grasp and easier downward manipulation. (5) Our modification’s purpose is similar to Liberman’s modification with an added +45° bend at the distal tip. This retains the Magill forceps ability to enter the side of the mouth optimizing visualization of pharyngeal structures while maintaining the benefits of anteroposterior grasping with easy downward manipulation. Following local research ethics board approval, we conducted a randomized control trial enrolling 100 patients undergoing dental surgery between ages 2 and 12 with an American Society of Anesthesiology classification of I or II. Parental consent and patient assent (if >8 years old) was obtained on the day of surgery prior to enrollment. Patients with aspiration risk, known upper airway abnormalities, and difficult airway were excluded. Subjects were randomized using a coin toss to nasal intubation assisted with altered Magill forceps or conventional Magill forceps. The primary outcome was intubation time. Secondary outcomes included number of attempts, hypoxia, pharyngeal trauma, and need for corkscrewing. Only attending anesthesiologists participated in the study. They were given a hands-on demonstration of how to use the altered Magill forceps with the aid of a model pediatric airway, followed by two untimed trial attempts. Data from 52 patients in the altered Magill forceps group and 48 in the conventional Magill forceps group were analyzed. Median intubation time and interquartile ranges for the altered Magill forceps and Magill forceps group were not significantly different at 10.5 s (7.1 s–14.3 s) and 8.9 s (6.5 s–12.5 s) (P = 0.23). Total nasal intubation attempts between the groups was comparable with a median of 1 (IQR 1–3) (P = 0.90). Incidence of hypoxemia on induction, lip lacerations, and pharyngeal bleeding was similar in the two groups. The frequency of corkscrew technique used to aid intubation was not reduced in the altered Magill forceps group (25% vs 21%). Perhaps, the bending maneuver was not enough to overcome the nasotracheal tube abutting the trachea. Another explanation could be incorrect use of the altered Magill forceps from insufficient experience. It was thought at the time of designing the experiment that two trial attempts would provide adequate training. However, it was a

A Practice of Anesthesia for Infants and Children – Fifth Edition

It has been four years since the fourth edition of the premiere textbook of pediatric anesthesia was published. At first glance, the fifth edition distinguishes itself from previous editions in both form and content. The ten wellorganized sections of this text of 1,142 pages and 53 chapters are colour coded for easy and efficient searching, and the pages are printed on a tactile appealing glossy paper. The text contains in excess of 1,000 well-placed high-quality figures and images that add greatly to the content of the text. Additionally, the extensive online content enhances this already excellent book. Brian Anderson replaces David Todres as a co-author in this edition. Dr. Anderson is recognized for his expertise and contributes additional international flavour and know-how to this publication. With close to 2,000 references, Dr. Anderson’s chapter, ‘‘Pharmacokinetics and Pharmacology of Drugs Used in Children’’, is an impressive example of his world-class knowledge of the subject matter. Drs. Coté and Lerman continue to impact this edition with their expertise, their extensive contribution to content, and their editorial oversight. In addition to the editors, the more than 100 contributors are the ‘‘Who’s Who’’ of pediatric anesthesia. These contributors represent ten countries and six continents, giving the book an extensive multinational viewpoint. This edition retains most of its familiar section and chapter arrangement; furthermore, all chapters have been significantly revised and updated and feature many new contributors. Andreas Loepke and Andrew Davidson, two world experts in the field, write a notable new chapter, ‘‘Surgery, Anesthesia, and the Immature Brain’’. This is a very timely addition, as the possible deleterious effects of anesthetic agents on the developing brain are gaining prominence not only in the medical literature but also in the lay news. The chapter offers an excellent discussion on the background of the topic, a synthesis of the available literature, and a frank discussion on the limitations of the science. Given the growing emphasis on simulation as an integral part of medical training, the chapter, ‘‘Simulation in Pediatric Anesthesia’’, written by simulation researchers and educators, Drs. Christine Mai, Demian Szyld, and Jeffrey Cooper, is also an opportune addition. These authors provide an excellent overview of medical simulation with emphasis on its role in pediatric anesthesia. The other chapters continue to offer well-organized, in depth, current, and well-referenced discussions on all aspects of pediatric anesthesia from basic science to cutting-edge practice. Except for the obvious focus on pediatrics, the ten sections are organized in a sequence similar to most other standard textbooks on anesthesia. The written word has provided effective information transfer for millennia. Sophisticated online technology and the near ubiquitous access to the internet with its availability and platforms make this medium vastly superior to the traditional textbook. In addition to the already improved printed content, this edition embraces online content with superb results. Easy access to the content is provided via www.expertconsult.com, an online application used for many medical textbooks. The website states, ‘‘Access Expert Consult from any device via the internet: desktop, laptop, tablet, or smartphone’’. The author was able to access the content seamlessly through one manufacturer’s smartphone, tablet, and laptop and did not require Adobe Flash Player to view. The entire printed text is available online with the added advantage of a search feature with user-defined keywords. In addition, all references are available in the online text (not all references are included in J. Gamble, MD (&) University of Saskatchewan, Saskatoon, SK, Canada e-mail: j_gamble@yahoo.com