Airway management in the paediatric difficult intubation registry: a propensity score matched analysis of outcomes over time.

Background: The Paediatric Difficult Intubation Collaborative identified multiple attempts and persistence with direct laryngoscopy as risk factors for complications in children with difficult tracheal intubations and subsequently engaged in initiatives to reduce repeated attempts and persistence with direct laryngoscopy in children. We hypothesised these efforts would lead to fewer attempts, fewer direct laryngoscopy attempts and decrease complications. Methods: Paediatric patients less than 18 years of age with difficult direct laryngoscopy were enrolled in the Paediatric Difficult Intubation Registry. We define patients with difficult direct laryngoscopy as those in whom (1) an attending or consultant obtained a Cormack Lehane Grade 3 or 4 view on direct laryngoscopy, (2) limited mouth opening makes direct laryngoscopy impossible, (3) direct laryngoscopy failed in the preceding 6 months, and (4) direct laryngoscopy was deferred due to perceived risk of harm or poor chance of success. We used a 5:1 propensity score match to compare an early cohort from the initial Paediatric Difficult Intubation Registry analysis (August 6, 2012-January 31, 2015, 785 patients, 13 centres) and a current cohort from the Registry (March 4, 2017-March 31, 2023, 3925 patients, 43 centres). The primary outcome was first attempt success rate between cohorts. Success was defined as confirmed endotracheal intubation and assessed by the treating clinician. Secondary outcomes were eventual success rate, number of attempts at intubation, number of attempts with direct laryngoscopy, the incidence of persistence with direct laryngoscopy, use of supplemental oxygen, all complications, and severe complications. Findings: First-attempt success rate was higher in the current cohort (42% vs 32%, OR 1.5 95% CI 1.3-1.8, p < 0.001). In the current cohort, there were fewer attempts (2.2 current vs 2.7 early, regression coefficient -0.5 95% CI -0.6 to -0.4, p < 0.001), fewer attempts with direct laryngoscopy (0.6 current vs 1.0 early, regression coefficient -0.4 95% CI -0.4 to 0.3, p < 0.001), and reduced persistence with direct laryngoscopy beyond two attempts (7.3% current vs 14.1% early, OR 0.5 95% CI 0.4-0.6, p < 0.001). Overall complication rates were similar between cohorts (19% current vs 20% early). Severe complications decreased to 1.8% in the current cohort from 3.2% in the early cohort (OR 0.55 95% CI 0.35-0.87, p = 0.011). Cardiac arrests decreased to 0.8% in the current cohort from 1.8% in the early cohort. We identified persistence with direct laryngoscopy as a potentially modifiable factor associated with severe complications. Interpretation: In the current cohort, children with difficult tracheal intubations underwent fewer intubation attempts, fewer attempts with direct laryngoscopy, and had a nearly 50% reduction in severe complications. As persistence with direct laryngoscopy continues to be associated with severe complications, efforts to limit direct laryngoscopy and promote rapid transition to advanced techniques may enhance patient safety. Funding: None.

A Retrospective Analysis of Neuromuscular Blocking Drug Use and Ventilation Technique on Complications in the Pediatric Difficult Intubation Registry Using Propensity Score Matching.

BACKGROUND: Ventilation is critical in airway management, and failure can be fatal. The optimal ventilation approach for endotracheal intubation in children with difficult airways remains controversial. The Pediatric Difficult Intubation (PeDI) Registry is an international multicenter registry that collects intubation data in difficult to intubate children. The registry captures the initial (at induction) and final ventilation technique (at intubation), the use of neuromuscular blocking drugs (NMBDs), airway reactivity during intubation, and complications. We analyzed data in the PeDI Registry to determine the frequency of use of various ventilation techniques and associated complications. Because spontaneously breathing patients ventilate throughout intubation, we hypothesized that spontaneous ventilation would be associated with fewer complications than other approaches. METHODS: We queried the PeDI Registry for cases entered between September 2012 and February 2016, from 16 children's hospitals. We categorized the attending anesthesiologist's ventilation plan into 3 groups: spontaneous ventilation, controlled ventilation after administering an NMBD, and controlled ventilation without administering an NMBD. Generalized Estimating Equation (GEE) model, with a binomial family distribution and logit link, was used to determine the association between ventilation technique and the risk of complications, as well as to account for within-site clustering. Propensity score matching was further applied to balance pretreatment characteristics of ventilation groups. RESULTS: Of 1289 anticipated difficult intubations, 507 (39%) were managed with spontaneous ventilation, 453 (35%) controlled ventilation with an NMBD, and 329 (26%) controlled ventilation without an NMBD. Complications occurred in 242 (18.8%; 95% confidence interval [CI], 16.6%-20.9%) patients. Of these, 218 (16.9%) were nonsevere, and 24 (1.9%) were severe. The spontaneous ventilation group had 114 (22.5%, standardized residual [Std.Res] = 4.29) nonsevere complications, which was higher than the controlled ventilation with an NMBD 60 (13.3%, Std.Res = -2.58), and controlled ventilation without an NMBD 44 (13.4%, Std.Res = -1.98), P < .001. Nearest neighbor matching with caliper width equal to 0.2 of the standard deviation (SD) of the logit of the propensity score also demonstrated that patients with spontaneous ventilation had greater odds of complications compared to controlled ventilation techniques: odds ratio (OR) = 2.07 (95% CI, 1.36-3.15; P = .001). CONCLUSIONS: Spontaneous ventilation is associated with more nonsevere complications, such as hypoxemia and laryngospasm, than controlled ventilation techniques during intubation of children with difficult airways. Inadequate anesthetic depth may contribute to increased complications.

Videolaryngoscopy versus Fiber-optic Intubation through a Supraglottic Airway in Children with a Difficult Airway: An Analysis from the Multicenter Pediatric Difficult Intubation Registry.

BACKGROUND: The success rates and related complications of various techniques for intubation in children with difficult airways remain unknown. The primary aim of this study is to compare the success rates of fiber-optic intubation via supraglottic airway to videolaryngoscopy in children with difficult airways. Our secondary aim is to compare the complication rates of these techniques. METHODS: Observational data were collected from 14 sites after management of difficult pediatric airways. Patient age, intubation technique, success per attempt, use of continuous ventilation, and complications were recorded for each case. First-attempt success and complications were compared in subjects managed with fiber-optic intubation via supraglottic airway and videolaryngoscopy. RESULTS: Fiber-optic intubation via supraglottic airway and videolaryngoscopy had similar first-attempt success rates (67 of 114, 59% vs. 404 of 786, 51%; odds ratio 1.35; 95% CI, 0.91 to 2.00; P = 0.16). In subjects less than 1 yr old, fiber-optic intubation via supraglottic airway was more successful on the first attempt than videolaryngoscopy (19 of 35, 54% vs. 79 of 220, 36%; odds ratio, 2.12; 95% CI, 1.04 to 4.31; P = 0.042). Complication rates were similar in the two groups (20 vs. 13%; P = 0.096). The incidence of hypoxemia was lower when continuous ventilation through the supraglottic airway was used throughout the fiber-optic intubation attempt. CONCLUSIONS: In this nonrandomized study, first-attempt success rates were similar for fiber-optic intubation via supraglottic airway and videolaryngoscopy. Fiber-optic intubation via supraglottic airway is associated with higher first-attempt success than videolaryngoscopy in infants with difficult airways. Continuous ventilation through the supraglottic airway during fiber-optic intubation attempts may lower the incidence of hypoxemia.

Mechanisms and environmental factors that underlying the intensification of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy)-induced serotonin syndrome in rats.

RATIONALE: Illicit use of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) may cause a mild or severe form of the serotonin syndrome. The syndrome intensity is not just influenced by drug doses but also by environmental factors. OBJECTIVES: Warm environmental temperatures and physical activity are features of raves. The purpose of this study was to assess how these two factors can potentially intensify the syndrome. METHODS: Rats were administered MDMA at doses of 0.3, 1, or 3 mg/kg and examined in the absence or presence of warm temperature and physical activity. The syndrome intensity was estimated by visual scoring for behavioral syndrome and also instrumentally measuring changes in symptoms of the syndrome. RESULTS: Our results showed that MDMA at 3 mg/kg, but not 0.3 or 1 mg/kg, caused a mild serotonin syndrome in rats. Each environmental factor alone moderately intensified the syndrome. When the two factors were combined, the intensification became more severe than each factor alone highlighting a synergistic effect. This intensification was blocked by the 5-HT2A receptor antagonist M100907, competitive N-methyl-D-aspartic acid (NMDA) receptor antagonist CGS19755, autonomic ganglionic blocker hexamethonium, and the benzodiazepine-GABAA receptor agonist midazolam but not by the 5-HT1A receptor antagonist WAY100635 or nicotinic receptor antagonist methyllycaconitine. CONCLUSIONS: Our data suggest that, in the absence of environmental factors, the MDMA-induced syndrome is mainly mediated through the serotonergic transmission (5-hydroxytryptamine (5HT)-dependent mechanism) and therefore is relatively mild. Warm temperature and physical activity facilitate serotonergic and other neural systems such as glutamatergic and autonomic transmissions, resulting in intensification of the syndrome (non-5HT mechanisms).