Jürg Hammer

Objective: Understanding driving pressure is of general interest in lung mechanics, especially in ventilated neonatal and pediatric patients. The aim of this study was to investigate the effects of endotracheal tube size (ETT) and bi-directional linear flow resistors mimicking different degrees of tube and airway obstruction on tracheal pressure (P_tr) during ventilation with decelerating flow. Methods: A mechanical lung simulator with unchanged respiratory mechanics like the mimicked compliance and resistance, three ETTs (inner diameters of 7.5 mm, 5.5 mm, and 3.5 mm), and four different linear flow resistors were alternatively connected to a commercial ventilator operating in pressure-controlled mode. Four resistors mimicking various degrees of ETT obstructions were placed consecutively between the Y-piece and the ETT. Varying sequentially ETT size, resistance, and ventilator settings resulted in 90 sets of measurements. Data acquisition, signal processing, and data analysis were performed using Python. Results: The results clarify that decreasing ETT sizes and increasing flow resistances cause an increase in the time necessary to reach zero-flow conditions both during in- and expiration. This results in a decrease of P_tr at the end of inspiration and an increase of P_tr at the end of expiration, if inspiratory and expiratory times remain unchanged. Conclusion: The degree to which peak inspiratory pressure overestimates P_tr (or plateau pressure) in decelerating flow can be substantial and increases with increasing flow resistance. This highlights the importance of measuring plateau pressure or P_tr to understand pressure dynamics delivered to the lung.

Background: Acute bronchiolitis (AB) is the most common viral lower respiratory tract infection in the first year of life. Despite international guidelines and numerous Cochrane reviews which emphasize that drugs do not alter the natural course of AB, still many drugs are prescribed. A questionnaire on treatment of AB was sent to all Swiss paediatricians before (2001) and after (2006) introducing national guidelines in 2004. The aim of this study was to evaluate the current management of AB in Switzerland and the long-term impact of national guidelines. Methods: An online questionnaire was sent to all Swiss paediatricians to assess their current prescribing practice for AB. Results: From a total of 2040 questionnaires (1644 registered paediatricians, 396 trainees), 1079 were returned (overall response rate 53%). Of the respondents, 908 (44%) treated children with AB. Up to 89% of the registered paediatricians are still prescribing bronchodilators for outpatients and 58% for inpatients, but mostly not on a regular basis (see table). Steroids were less prescribed (37% in outpatients, 23% in inpatients), also not on a regular basis. The use of salbutamol and steroids was much lower compared to 2006 (see table). Most paediatrician (55%) are using SpO2 of ≤90% as a cut-off to apply oxygen, 36% use ≤92%, and 10% use ≤88%. Conclusion: Bronchodilators and steroids are still widely prescribed for the treatment of AB in Switzerland, however much less compared to the survey in 2006. National guidelines and regular information can have a long-term impact on prescribing patterns.

The 10-year-old European syllabus for paediatric respiratory medicine (PRM; also known as paediatric pulmonology) was updated by a consensus-based method using an expert task force for redrafting, and a subsequent Delphi process to achieve consensus. There was a high degree of consensus for the final syllabus, which has been streamlined and made more relevant to current practice. All modules are now mandatory apart from the undertaking of research projects, which is optional. Although there are still a number of countries in Europe which do not recognise PRM as a separate subspecialty, there are paediatric respiratory physicians practising in every country in Europe, and a current and harmonised European syllabus in the subspecialty remains important for defining the training and areas of practice of PRM practitioners.

Background: Laryngeal clefts (LC) are uncommon but important causes of stridor in infants. Direct laryngoscopy is the recommended method for the detection of LC because LC may be missed by flexible endoscopy. As laryngomalacia by far outnumbers any other cause of stridor in this age group flexible bronchoscopy is usually the preferred method for the evaluation of significant infantile stridor. The aim is to illustrate how the application of CPAP assists the detection of LC during flexible endoscopy.Method: Continuous positive airway pressure (CPAP) is applied via endoscopy mask during flexible endoscopy, titrated to open the upper esophageal sphincter, and to spread the inter‐arytenoid folds.Results: The application of CPAP of 10‐15 cmH₂O resulted in visual unmasking of otherwise obscured LC in four young children assessed for congenital stridor.Conclusion: CPAP helps visualize LC by flexible endoscopy obviating transition to direct laryngoscopy and manual exploration.

Reports on accidental intravenous epinephrine overdose in children are extremely rare, although medication errors in the management of pediatric anaphylaxis seem to be frequent. We report a case of a 12-year-old boy presenting with a long-lasting skin rash and dyspnea who was incorrectly diagnosed with early anaphylactic shock and was treated with 10-fold the recommended dose administered by the wrong route (intravenous instead of intramuscular). He reacted with acute loss of consciousness and acute cardiorespiratory failure due to arterial hypotension, ischemic heart failure, and severe pulmonary edema. He responded rapidly to mechanical ventilation, treatment with diuretics, and low-dose inotropes and recovered without sequelae. Despite this ultimately favorable outcome, we report this case to remind the scientific community that inadvertent and accidental epinephrine overdosing is probably an underrecognized event, which can result in potentially lethal complications. Heightening the awareness of the personnel, implementing safety precautions for the dosage and the route of administration, stocking of prefilled intramuscular dose syringes for emergency use in anaphylaxis and, ideally, introducing a standardized drug order form should reduce potential risks and facilitate proper and optimal treatment for all acutely ill children.

Purpose Much of the common practice in paediatric mechanical ventilation is based on personal experiences and what paediatric critical care practitioners have adopted from adult and neonatal experience. This presents a barrier to planning and interpretation of clinical trials on the use of specific and targeted interventions. We aim to establish a European consensus guideline on mechanical ventilation of critically children. Methods The European Society for Paediatric and Neonatal Intensive Care initiated a consensus conference of international European experts in paediatric mechanical ventilation to provide recommendations using the Research and Development/University of California, Los Angeles, appropriateness method. An electronic literature search in PubMed and EMBASE was performed using a combination of medical subject heading terms and text words related to mechanical ventilation and disease-specific terms. Results The Paediatric Mechanical Ventilation Consensus Conference (PEMVECC) consisted of a panel of 15 experts who developed and voted on 152 recommendations related to the following topics: (1) general recommendations, (2) monitoring, (3) targets of oxygenation and ventilation, (4) supportive measures, (5) weaning and extubation readiness, (6) normal lungs, (7) obstructive diseases, (8) restrictive diseases, (9) mixed diseases, (10) chronically ventilated patients, (11) cardiac patients and (12) lung hypoplasia syndromes. There were 142 (93.4%) recommendations with “strong agreement”. The final iteration of the recommendations had none with equipoise or disagreement. Conclusions These recommendations should help to harmonise the approach to paediatric mechanical ventilation and can be proposed as a standard-of-care applicable in daily clinical practice and clinical research.

Background: Topical lidocaine has been found to result in overestimation of the severity of laryngomalacia in infants undergoing flexible bronchoscopy under conscious sedation with midazolam and nalbuphine. This effect has never been confirmed and may depend on the level of sedation and the drugs used. We assessed the effect of topical lidocaine on laryngomalacia in infants undergoing flexible bronchoscopy under general anesthesia with propofol. Methods: Thirteen infants with congenital stridor referred to diagnostic flexible video-bronchoscopy were studied under propofol anesthesia before and 3 minutes after topical lidocaine administration to the larynx at a dose of 3 mg/kg body weight. Laryngomalacia was scored using 60 seconds video recordings of the larynx before and after lidocaine administration in random order by 2 independent blinded observers using the previously described arytenoid score (AS), epiglottis score (ES), and the total score (TS=AS+ES). Results: No significant differences in AS, ES, and laryngomalacia score were found between the prelidocaine and postlidocaine assessments by the 2 raters. The intraclass correlation coefficients were 0.995 (95% confidence interval, 0.986-0.998) and 0.975 (0.930-0.991) and 0.989 (0.971-996) for AS, ES, and TS, respectively. Conclusions: The assessment of laryngomalacia is not affected by topical lidocaine under propofol anesthesia. The lidocaine effect on laryngomalacia may vary depending on the medication regime used and the depth of procedural sedation.