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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.

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.

We investigated whether xanthine oxidase (XO) is a major source of oxygen-derived free radicals (oxy-radicals) in the pig and human skeletal muscles. It was observed that xanthine dehydrogenase and XO activities in nonischemic pig latissimus dorsi (LD) and gracilis muscles and human LD and rectus abdominis (RA) muscles were < 0.5 mU/g wet wt. The pig LD muscle hypoxanthine content increased significantly from 0.33 +/- 0.02 to 2.33 +/- 0.44 mumol/g dry wt after 5 h of warm ischemia, but the muscle uric acid content remained unchanged up to 2 h of reperfusion. Similarly, the hypoxanthine content in the human LD and RA muscles increased from 0.33 +/- 0.03 to 0.84 +/- 0.23 mumol/g dry wt after 2.0-3.5 h of warm ischemia, and the muscle uric acid content remained unchanged at the end of 15-90 min of reperfusion. Furthermore, 5 days of allopurinol treatment (25 mg/kg iv twice daily) starting 2 days before ischemia or 3 days of oxypurinol treatment (25 mg/kg iv twice daily) starting 15 min before reperfusion did not attenuate the extent of skeletal muscle necrosis in pig LD muscles subjected to 5 h of ischemia and 48 h of reperfusion. However, deferoxamine treatment (250 mg/kg iv twice daily) starting before or after ischemia, as described above, significantly reduced the extent of pig LD muscle necrosis. Finally, at 2 and 48 h of reperfusion significantly higher muscle neutrophil contents were seen in ischemic than in nonischemic control pig LD muscles. Neutrophil depletion with mechlorethamine (0.75 mg/kg iv) significantly reduced the extent of necrosis in pig LD muscles. These observations indicate that XO is not a major source of oxy-radicals in ischemia/reperfusion injury in the pig gracilis and LD muscles and human RA and LD muscles.

from 9.8% to 5.5% (P ¼ .004), and 1-year major amputation decreased from 25.4% to 18.2% (P < .001), with a corresponding odds ratio of 0.65 (95% CI, 0.517-0.838; P < .0001) as the volume increased. An increase in the chance of a revision surgery (10.6% vs 8.2%, P < .001) was seen with higher volume, with an increased odds ratio of 1.031 (95% CI, 1.005-1.057; P ¼ .018). Comment: Although the 30-day mortality for leg bypass is quite high in this series, this is another bit of evidence that outcomes for open vascular surgical procedures are better in hospitals with higher volumes of such procedures. The data have some limitations because it is unclear whether every procedure analyzed was an additional bypass, followed a failed endovascular procedure, or was a vein or prosthetic bypass. There are some additional oddities in the data, in that 54% of the patients treated with femoral distal bypass were supposedly treated for claudication. Nevertheless, the relationship between increasing volume and favorable outcomes for LEAB seems statistically solid. The data also suggest that benefits for limb salvage may be partly due to increased reintervention rates in higher-volume hospitals with perhaps better resources and willingness to attempt revisions rather than move to amputation.

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.

The present study, performed in nonsedated, conscious lambs, consisted of two parts. In the first part, we 1) examined for the first time whether a respiratory response to pulmonary C-fiber stimulation could be elicited in nonsedated newborns and 2) determined whether this response could be abolished by capsaicin pretreatment. Then, by using capsaicin-desensitized lambs, we studied whether pulmonary C fibers were involved in the sustained, active expiratory upper airway closure previously observed during pulmonary edema. Airflow and thyroarytenoid and inferior pharyngeal constrictor muscle electromyographic activities were recorded. In the first set of experiments, a 5-10 microg/kg capsaicin bolus intravenous injection in seven intact lambs consistently led to a typical pulmonary chemoreflex, showing that C fibers are functionally mature in newborn lambs. In the second series of experiments, eight lambs pretreated with 25-50 mg/kg subcutaneous capsaicin did not exhibit any respiratory response to 10-50 microg/kg intravenous capsaicin injection, implicating C fibers in the response. Finally, in the above capsaicin-desensitized lambs, we observed that halothane-induced high-permeability pulmonary edema did not cause the typical response of sustained expiratory upper airway closure seen in the intact lamb. We conclude that functionally mature C fibers are present and responsible for a pulmonary chemoreflex in response to capsaicin intravenous injection in nonsedated lambs. Capsaicin pretreatment abolishes this reflex. Furthermore, the sustained expiratory upper airway closure observed during halothane-induced pulmonary edema in intact nonsedated lambs appears to be related to a reflex involving stimulation of pulmonary C fibers.

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