Emergency airway management in a tertiary trauma centre (AIRMAN): a one-year prospective longitudinal study.

PURPOSE: Emergency airway management can be associated with a range of complications including long-term neurologic injury and death. We studied the first-pass success rate with emergency airway management in a tertiary care trauma centre. Secondary outcomes were to identify factors associated with first-pass success and factors associated with adverse events peri-intubation. METHODS: We performed a single-centre, prospective, observational study of patients ≥ 17 yr old who were intubated in the emergency department (ED), surgical intensive care unit (SICU), medical intensive care unit (MICU), and inpatient wards at our institution. Ethics approval was obtained from the local research ethics board. RESULTS: In a seven-month period, there were 416 emergency intubations and a first-pass success rate of 73.1%. The first-pass success rates were 57.5% on the ward, 66.1% in the intensive care units (ICUs) and 84.3% in the ED. Equipment also varied by location; videolaryngoscopy use was 65.1% in the ED and only 10.6% on wards. A multivariate regression model using the least absolute shrinkage and selection algorithm (LASSO) showed that the odds ratios for factors associated with two or more intubation attempts were location (wards, 1.23; MICU, 1.24; SICU, 1.19; reference group, ED), physiologic instability (1.19), an anatomically difficult airway (1.05), hypoxemia (1.98), lack of neuromuscular blocker use (2.28), and intubator inexperience (1.41). CONCLUSIONS: First-pass success rates varied widely between locations within the hospital and were less than those published from similar institutions, except for the ED. We are revamping ICU protocols to improve the first-pass success rate.

RéSUMé: OBJECTIF: La prise en charge d'urgence des voies aériennes peut être associée à une multitude de complications, y compris des lésions neurologiques à long terme et la mort. Nous avons étudié le taux de réussite à la première tentative lors de la prise en charge d'urgence des voies aériennes dans un centre de traumatologie tertiaire. Les critères d'évaluation secondaires étaient l'identification des facteurs associés à la réussite de la première tentative et des facteurs associés aux événements indésirables péri-intubation. MéTHODE: Nous avons réalisé une étude observationnelle prospective monocentrique sur des patients âgés de 17 ans ou plus qui avaient été intubés à l'urgence, à l'unité de soins intensifs chirurgicaux (USIC), à l'unité de soins intensifs médicaux (USIM) et aux étages dans notre établissement. L'approbation a été obtenue du comité d'éthique de la recherche local. RéSULTATS: Au cours d'une période de sept mois, il y a eu 416 intubations d'urgence et un taux de réussite à la première tentative de 73,1 %. Les taux de réussite à la première tentative étaient de 57,5 % aux étages, de 66,1 % dans les unités de soins intensifs (USI) et de 84,3 % à l'urgence. Le matériel variait également selon l'emplacement; l'utilisation de la vidéolaryngoscopie était de 65,1 % à l'urgence et de seulement 10,6 % aux étages. Un modèle de régression multivariée utilisant l'algorithme LASSO (Least Absolute Shrinkage and Selection Algorithm) a montré que les rapports de cotes pour les facteurs associés à deux tentatives d'intubation ou plus étaient l'emplacement (étages, 1,23; USIM, 1,24; USIC, 1,19; groupe de référence, urgence), l'instabilité physiologique (1,19), des voies aériennes présentant des complications anatomiques (1,05), l'hypoxémie (1,98), la non-utilisation de bloqueurs neuromusculaires (2,28) et l'inexpérience de la personne pratiquant l'intubation (1,41). CONCLUSION: Les taux de réussite à la première tentative variaient considérablement d'un emplacement à l'autre au sein de l'hôpital et étaient inférieurs à ceux publiés par des établissements comparables, à l'exception du service des urgences. Nous retravaillons les protocoles des soins intensifs afin d'améliorer le taux de réussite à la première tentative.

The use of low-osmolar water-soluble contrast in videofluoroscopic swallowing exams.

The selection of the contrast agent used during fluoroscopic exams is an important clinical decision. The purpose of this article is to document the usage of a nonionic, water-soluble contrast (iohexol) and barium contrast in adult patients undergoing fluoroscopic exams of the pharynx and/or esophagus and provide clinical indications for the use of each. For 1 year, data were collected on the use of iohexol and barium during fluoroscopic exams. The contrast agent used was selected by the speech language pathologist (SLP) or the radiologist based on the exam's indications. A total of 1,978 fluoroscopic exams were completed in the 12-month period of documentation. Of these exams, 60.6 % were completed for medical reasons and 39.4 % for surgical reasons. Fifty-five percent of the exams were performed jointly by a SLP and a radiologist and 45 % were performed by a radiologist alone. Aspiration was present in 22 % of the exams, vestibular penetration occurred in 38 %, extraluminal leakage of contrast was observed in 4.6 %, and both aspiration and leakage were seen in 1 % of the exams. In cases with aspiration, iohexol was used alone in 8 %, iohexol and barium were both used in 45 %, and barium was used alone in 47 %. In cases with extraluminal leakage, iohexol was used alone in 58 %, iohexol and barium were both used in 31 %, and barium was used alone in 11 %. No adverse effects were seen with the use of iohexol. When barium was used in cases of aspiration and extraluminal leakage, the amount of aspirated barium was small and the extraluminal barium in the instances of leakage was small. Iohexol is a useful screening contrast agent and can safely provide information, and its use reduces the risk of aspiration and the chance of leakage of large amounts of barium.

Reductions in GABA following a tDCS-language intervention for primary progressive aphasia.

Transcranial direct current stimulation (tDCS) has shown efficacy in augmenting the effects of language therapy in primary progressive aphasia (PPA). The mechanism of action of tDCS is not understood, but preliminary work in healthy adults suggests it modulates γ-aminobutyric acid (GABA) levels to create an environment optimal for learning. It is unknown if this proposed mechanism translates to aging or neurodegenerative conditions. This study tested the hypothesis that tDCS reduces GABA at the stimulated tissue in PPA. We applied GABA-edited magnetic resonance spectroscopy to quantify GABA levels before and after a sham-controlled tDCS intervention with language therapy in PPA. All participants showed improvements but those receiving active tDCS showed significantly greater language improvements compared to sham both immediately after the intervention and at 2-month follow-up. GABA levels in the targeted tissue decreased from baseline after the intervention and remained decreased 2 months after the intervention. This work supports the hypothesis that tDCS modulates GABAergic inhibition to augment learning and is clinically useful for PPA combined with language therapy.

Hypoxic respiratory response during acute stable hypocapnia.

The hypoxic ventilatory response during hypocapnia has been studied with divergent results. We used volume-cycled ventilation in spontaneously breathing normal subjects to study their hypoxic ventilatory response under conditions of stable hypocapnia. Subjects were studied at three different levels of end-tidal (partial) carbon dioxide pressure (PETCO2), eucapnia and 6 and 12 mm Hg below eucapnia (mild and moderate hypocapnia, respectively). The response to hypoxia was assessed by changes in muscle pressure output (Pmus) and respiratory rate. Compared with the Pmus response at eucapnia (0.53 +/- 0.59 cm H2O/percentage oxygen saturation [% O2sat]), the response at mild hypocapnia was attenuated (0.26 +/- 0.33 cm H2O/% O2sat), whereas the response at moderate hypocapnia was negligible (0.003 +/- 0.09 cm H2O/% O2sat). Similar reductions were seen with the respiratory rate (eucapnia, 0.17 +/- 0.2 breaths/minute/% O2sat; mild hypocapnia, 0.11 +/- 0.11 breaths/minute/% O2sat; moderate hypocapnia, 0.01 +/- 0.06 breaths/minute/% O2sat). The Pmus and respiratory rate responses at the three levels of PETCO2 were significantly different (p < 0.05, analysis of variance). The responses at moderate hypocapnia were not significantly different from zero. We conclude that when apnea occurs under conditions in which central PCO2 is well below the CO2 setpoint, subjects are at risk of developing dangerous hypoxemia due to absence of a hypoxic ventilatory response.

Response of ventilator-dependent patients to delayed opening of exhalation valve.

In conventional mechanical ventilation, the inflation cycle often extends into neural expiration (TEN), potentially exacerbating dynamic hyperinflation (DH). We wished to determine the extent to which patients defend against DH when this happens. Such defense may include prolongation of TEN (timing response) and/or expiratory muscle recruitment (neuromuscular response). Fifty patients were ventilated in the Proportional Assist mode, allowing us to infer these responses noninvasively. At random intervals, exhalation of single breaths was delayed by briefly delaying the opening of exhalation valve (occlusion) (T(occ) = 0.78 +/- 0.34 seconds). Timing response was assessed from the change in TEN. Neuromuscular response was assessed from the difference between volume exhaled after release of occlusion and volume exhaled in unoccluded breaths over a similar expiratory flow duration (DeltaV(iso-time)). There was no evidence of an acute neuromuscular response; DeltaV(iso-time) averaged 0.005 +/- 0.023 L (NS). Forty-five of 50 patients significantly lengthened TEN. However, the timing response offset only 36 +/- 20% of the delay in expiration. Because of absent neuromuscular responses and weak timing responses, DH increased in most patients in postocclusion breaths (DeltaDH = 0.10 +/- 0.08 L, p = 2E-10). We conclude that acute compensatory responses to delays in opening of exhalation value are weak in ventilator-dependent patients. As a result, such nonsynchrony tends to exacerbate DH.