Dominique Dorion

Cognitive skills analysis, kinesiology, and mental imagery in the acquisition of surgical skills.

GOAL Isolate and evaluate the impact of mental imagery on the acquisition of an emergency surgical technique. METHOD We studied 44 first-year medical students performing a cricothyrotomy on a mannequin to determine the impact of teaching using mental imagery (MI) and/or kinesiology (KG) compared to the standard Advandec Trauma Life Support (ATLS) approach. Students were randomly assigned to one of three groups: MI and KG, KG alone or control (ATLS). Two weeks after the one-hour teaching session, they were evaluated with an OSCE testing the performance of the different steps of the technique, the time required and its fluidity. RESULTS Total results (maximum: 25 marks) are as follows: KG + MI = 20.3 +/- 1.5 ; KG = 19.3 +/- 2.9 ; ATLS = 18.2 +/- 2.5. The only statistically significant difference for total results was in the use of MI and KG compared to the control group. Kinesiology alone or with mental imagery improved the fluidity of the performance. CONCLUSION Many factors influence the acquisition of a surgical technique. This study showed that acquisition and performance of an emergency procedure (cricothyrotomy) was improved when mental imagery and kinesiology were combined to teach it.

Radiotelemetry system for apnea study in lambs.

Neonatal apneas are being studied in the laboratory using polysomnographic recordings in lambs. Standard equipment, requiring animal restraint, disrupts sleep and prevents development of spontaneous apneas. The aim of the current work was to develop and validate a wireless recording equipment to study freely moving lambs. Firstly, a radiotelemetry equipment composed of a multichannel FM transmitter and a receiver was developed. Secondly, to test the telemetry equipment, each biopotential - [electroencephalogram (EEG), electrooculogram (EOG), electrocardiogram (ECG), electromyograms (EMGs), nasal airflow] - was recorded simultaneously by standard equipment and by telemetry (5 lambs). The results indicated an excellent concordance between signals obtained by both systems. Finally, the 8-channel telemetry prototype was tested for polysomnographic recordings (16 lambs). Results obtained confirmed the possibility of recording frequent REM sleep periods and spontaneous apneas. In conclusion, this radiotelemetry polysomnographic equipment brings new possibilities for research on neonatal apneas.

Obstructive sleep disordered breathing in children: beyond adenotonsillectomy.

Traditionally, adenotonsillectomy (AT) has long been the treatment of choice for obstructive sleep disordered breathing (SDB) in children. AT is usually considered a safe procedure, which cures 80% of children with SDB. Accumulated data have however challenged this overly simplistic view. Indeed, AT is invariably associated with significant morbidity, post‐operative pain, and a mortality rate which, though low, cannot be ignored. In addition, aside from a recurrence of SDB at adolescence in an unknown percentage of cases, some recent results suggest that complete SDB cure is not achieved in as much as 75% of cases after AT. Interestingly, several treatment options have been recently proposed for replacing or complementing AT. Continuous positive airway pressure (CPAP) is now suggested in children with remaining SDB after AT; however, compliance and suitability of equipment remain important hurdles, especially in small children and infants. Anti‐inflammatory treatments, including nasal glucocorticoids and/or the anti‐leukotriene montelukast, appear to hold great promise. Finally, orthodontic treatments are an appealing option, with recent results in children suggesting that it is possible to improve or perhaps even cure SDB in a durable manner by enlarging the nasal passages and/or the oropharyngeal airspace. In conclusion, while we are currently in the midst of an exciting time with several new treatments being developed for childhood SDB, randomized controlled trials are urgently needed to delineate their indications. In the meantime, it appears that systematic detection of orthodontic anomalies and better collaboration with maxillofacial specialists, including orthodontists and/or dentists, is needed for deciding the best treatment options for childhood SDB. Pediatr Pulmonol. 2008; 43:837–843.

Mechanisms of active laryngeal closure during noninvasive intermittent positive pressure ventilation in nonsedated lambs

The present study stems from our recent demonstration (Moreau-Bussiere F, Samson N, St-Hilaire M, Reix P, Lafond JR, Nsegbe E, Praud JP. J Appl Physiol 102: 2149-2157, 2007) that a progressive increase in nasal intermittent positive pressure ventilation (nIPPV) leads to active glottal closure in nonsedated, newborn lambs. The aim of the study was to determine whether the mechanisms involved in this glottal narrowing during nIPPV originate from upper airway receptors and/or from bronchopulmonary receptors. Two groups of newborn lambs were chronically instrumented for polysomnographic recording: the first group of five lambs underwent a two-step bilateral thoracic vagotomy using video-assisted thoracoscopic surgery (bilateral vagotomy group), while the second group, composed of six lambs, underwent chronic laryngotracheal separation (isolated upper airway group). A few days later, polysomnographic recordings were performed to assess glottal muscle electromyography during step increases in nIPPV (volume control mode). Results show that active glottal narrowing does not develop when nIPPV is applied on the upper airways only, and that this narrowing is prevented by bilateral vagotomy when nIPPV is applied on intact airways. In conclusion, active glottal narrowing in response to increasing nIPPV originates from bronchopulmonary receptors.

Do Micropauses Prevent Surgeon's Fatigue and Loss of Accuracy Associated With Prolonged Surgery? An Experimental Prospective Study

Objective: This prospective experimental study evaluates the effectiveness of micropauses (MPs) to prevent muscular fatigue and its deleterious effect on surgeons during prolonged surgical procedures. Background: Operating is a hazard for surgeons health. Beyond acute injuries and blood-borne infections, back and neck pain is a poorly recognized factor causing chronic ailment in more than half the surgeons surveyed. MP, a 20-second break every 20 minutes, is an accepted strategy used widely in the workplace. Methods: We designed a crossover experimental study. Sixteen surgeons were tested 3 times: once in a control situation before any surgery (CTL) and twice after a prolonged, reproducible operation (at least 2 hours), 1 of these with formal MP (WMP) the other without (WOMP). Muscular fatigue was tested by holding a 2.5-kg weight as long as possible with a stretched arm. Accuracy was evaluated with a device, measuring the mistakes made when following a predetermined path on a board. Finally, discomfort was measured by visual analog scale. Results: We found a statistically and more importantly clinically significant difference between the CTL and WOMP groups in all 3 tests. MPs prevented completely or almost completely the effects of fatigue associated with surgery [accuracy (No. errors) CTL: 1.1, WOMP: 7.7, WMP: 1.7; fatigue (seconds) CTL: 137, WOMP: 92, WMP: 142]. Conclusions: Surgical procedures are associated with significant muscular fatigue that can be measured simply and which has a direct effect on comfort and surgical accuracy. More important, this effect is completely or almost completely prevented by MPs.

Effects of C fiber blockade on cardiorespiratory responses to laryngeal stimulation in concious lambs

The primary aim of the study was to explore cardiorespiratory reflexes originating from laryngeal C fiber endings in the neonatal period. Seventeen lambs were instrumented for recording glottal adductor and diaphragm EMG, heart rate, systemic arterial pressure and respiratory movements. C fiber blockade was induced in eight lambs by 30 mg/kg capsaicin, the remaining nine lambs serving as controls. Cardiorespiratory reflexes were induced in non-sedated lambs by flowing air, menthol or 13% CO2, or by injecting water or 50 microg capsaicin in the laryngeal inlet through an endoscope. Responses to all stimuli but capsaicin were similar between the two groups. While cardiorespiratory responses were induced by capsaicin in control lambs, the responses were significantly inhibited in lambs with C fiber blockade. We conclude that laryngeal C fiber endings are functional and responsible for laryngeal chemoreflexes in newborn lambs.

Active glottal closure during anoxic gasping in lambs

The present study was aimed at assessing laryngeal dynamics and their consequences during anoxic gasping in ketamine-sedated lambs. We first verified that the glottis was closed between gasps during anoxic gasping in seven chronically instrumented lambs, aged 11-15 days. Recording of glottal constrictor muscle electrical activity, subglottal pressure and lung volume, together with endoscopic observation, confirmed the presence of active glottal closure with maintenance of a high lung volume between gasps. Secondly, we tested whether maintenance of a high lung volume between gasps improved autoresuscitation efficiency. Six sedated lambs aged 8-11 days underwent two anoxic runs, including one with an open tracheostomy to prevent maintenance of a high lung volume. Access back to air was allowed for gasping. No significant difference was found in time to eupnea resumption, hemodynamic parameters or arterial blood gases. We conclude that a high lung volume is actively maintained by glottal closure between anoxic gasps in sedated lambs. Further studies are however needed to define the importance of laryngeal dynamics during gasping.

The Larynx and Neonatal Apneas

OBJECTIVE We sought to review the current literature on the role of the larynx in neonatal apneas. STUDY DESIGN We conducted a literature search and analysis of the published and other available information on the topic. RESULTS Publications on this topic in otolaryngology journals are rare, although more basic sciences-oriented journals have published interesting results from animal studies during the past 20 years. The scarce data on human neonates are also presented. CONCLUSIONS The authors follow the phylogenetic and oncogenetic pathways to explain the active role of the larynx in neonatal apneas. Although most of these results are derived from animal studies, they certainly improve our understanding of human neonatal apneas.

Quality of life following surgical treatment of oculopharyngeal syndrome

Oculopharyngeal syndrome is a hereditary disease mostly affecting French Canadians. Cricopharyngeal myotomy and blepharoplasty are commonly performed on these patients. We reviewed the files of 20 patients who underwent these procedures between June 1986 and June 1999. The average perioperative stay was 4.7 days. The nine patients still alive were contacted and answered a telephone survey on their quality of life. None reported postoperative complications. Myotomy significantly improved the medical domain of their quality of life as confirmed by improvement in the dysphagia for solids, food incarceration, duration of meals, and choking during meals. The psychological domain also improved, namely, appetite and interest in food. The effects of blepharoplasty were also notable. Long-term satisfaction is reported by the majority of patients up to a maximum of 10 years postoperatively. In conclusion, simple procedures such as blepharoplasty and cricopharyngeal myotomy greatly improved the quality of life of these patients. We therefore recommend early interventions.

Vocal cord adduction causing obstructive sleep apnea from vagal nerve stimulation: case report.

A recognized complication of vagal nerve stimulation is new or worsening sleep apnea. Its pathophysiology is not clearly understood. We report a patient with obstructive sleep apnea that was directly associated with vagal nerve stimulation causing recurring vocal cord adduction. Adjusting the stimulator settings resolved the problem.