Assessing the human factors involved in chest compression with superimposed sustained inflation during neonatal and paediatric resuscitation: A randomized crossover study.

Background: A new cardiopulmonary resuscitation technique, chest compressions with sustained inflation (CC + SI) might be an alternative to both the neonatal [3:1compressions to ventilations (3:1C:V)] and paediatric [chest compression with asynchronous ventilation (CCaV)] approaches. The human factors associated with this technique are unknown. We aimed to compare the physical, cognitive, and team-based human factors for CC + SI to standard CPR (3:1C:V or CCaV). Methods: Randomized crossover simulation study including 40 participants on 20 two-person teams. Workload [National Aeronautics and Space Administration Task Load Index (NASA-TLX)], crisis resource management skills (CRM) [Ottawa Global Rating Scale (OGRS)], and debrief analysis were compared. Results: There was no difference in paired NASA-TLX scores for any dimension between the CC + SI and standard, adjusting for CPR order. There was no difference in CRM scores for CC + SI compared to standard. Participants were less familiar with CC + SI although many found it simpler to perform, better for transitions/switching roles, and better for communication. Conclusions: The human factors are no more physically or cognitively demanding with CC + SI compared to standard CPR (NASA-TLX and participant debrief) and team performance was no different with CC + SI compared to standard CPR (OGRS score).

Cardiopulmonary resuscitation with 3:1 Compression:Ventilation or continuous compression with asynchronized ventilation in infantile piglets.

BACKGROUND: To compare neonatal and pediatric resuscitation approaches to ventilation and chest compression by using either continuous chest compression with asynchronized ventilation (CCaV) or 3:1 Compression:Ventilation ration (3:1 C:V) during infant cardiopulmonary resuscitation. We hypothesized that 3:1 C:V compared to CCaV will reduce time to return of spontaneous circulation (ROSC) in infantile piglets with asphyxia-induced bradycardic cardiac arrest. METHODS: Twenty infantile piglets (5-10 days old) were anesthetized and asphyxiated by clamping the endotracheal tube. Piglets were randomized to 3:1 C:V or CCaV for resuscitation (n = 10/group). Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded throughout the experiment. RESULTS: The median time (IQR) to ROSC among survivors was 157 (113-219) vs 421 (118-660) for 3:1 C:V and CCaV, respectively (p = 0.253). The duration of resuscitation with 3:1 C:V compared to CCaV was 206 (119-660) vs 660 (212-660)sec, respectively (p = 0.171). The number of piglets achieving ROSC with 3:1 C:V and CCaV were 7/10 and 6/10, respectively (p = 1.00). There was no difference in hemodynamic and respiratory parameters between groups. CONCLUSIONS: Time to ROSC and survival was not different between 3:1 C:V and CCaV in infantile piglets. Either approach appears reasonable during infantile cardiopulmonary resuscitation. IMPACT: Similar time to return of spontaneous circulation and survival with 3:1 C:V and CCaV in infant piglets equivalent to 28-day-old children. Either approach appears reasonable during infantile cardiopulmonary resuscitation. Lack of scientific data to provide recommendations on when to switch between neonatal to pediatric resuscitation guidelines. No difference in time to return of spontaneous circulation or survival between 3:1 C:V and CCaV in infantile piglets with asphyxia-induced bradycardic cardiac arrest. Both methods are viable options during infant cardiopulmonary resuscitation.

Continuous chest compression during sustained inflation versus continuous compression with asynchronized ventilation in an infantile porcine model of severe bradycardia.

Background: Recently, the American Heart Association released a statement calling for research examining the appropriate age to transition from the neonatal to pediatric cardiopulmonary resuscitation approach to resuscitation. Aim: To compare neonatal and pediatric resuscitation approach by using either continuous chest compression with asynchronized ventilation (CCaV) or continuous chest compression superimposed with sustained inflation (CC + SI) during infant cardiopulmonary resuscitation. We hypothesized that CC + SI compared to CCaV would reduce time to return of spontaneous circulation (ROSC) in infantile piglets with asphyxia-induced bradycardic cardiac arrest. Methods: Twenty infantile piglets (5-10 days old) were anesthetized and asphyxiated by clamping the endotracheal tube. Piglets were randomized to CC + SI or CCaV for resuscitation (n = 10/group). Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, intrathoracic pressure and respiratory parameters were continuously recorded throughout the experiment. Main results: The median (IQR) time to ROSC with CC + SI compared to CCaV was 179 (104-447) vs 660 (189-660), p = 0.05. The number of piglets achieving ROSC with CC + SI and CCaV were 8/10 and 6/10, p = 0.628. Piglets resuscitated with CC + SI required less epinephrine compared to CCaV (p = 0.039). CC + SI increased the intrathoracic pressure throughout resuscitation (p = 0.025) and increased minute ventilation (p < 0.001), compared to CCaV. There was no difference in hemodynamic parameters between groups. Conclusions: CC + SI improves resuscitative efforts of infantile piglets by increasing the intrathoracic pressure and minute ventilation, and thus reducing the duration of resuscitation, compared to CCaV.

Chest compressions superimposed with sustained inflations during cardiopulmonary resuscitation in asphyxiated pediatric piglets.

BACKGROUND: Pediatric resuscitation guidelines recommend continuous chest compression with asynchronized ventilation (CCaV) during cardiopulmonary resuscitation. We recently described that providing a constant high distending pressure, or sustained inflation (SI) while performing continuous chest compressions (CC = CC + SI) reduces time to return of spontaneous circulation (ROSC) in neonatal and pediatric piglets with asphyxia-induced cardiac arrest. METHODS: To determine if CC + SI compared to CCaV will improve frequency of achieving ROSC and reduce time to ROSC in asphyxiated pediatric piglets. Twenty-eight pediatric piglets (21-24 days old) were anesthetized and asphyxiated by clamping the endotracheal tube. Piglets were randomized to CC + SI or CCaV for resuscitation (n = 14/group). Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded throughout the experiment. RESULTS: The mean(SD) duration of resuscitation was significantly reduced with CC + SI compared to CCaV with 208(190) vs. 388(258)s, p = 0.045, respectively. The number of piglets achieving ROSC with CC + SI and CCaV were 12/14 vs. 6/14, p = 0.046. Minute ventilation, end-tidal carbon dioxide, ventilation rate, and positive end expiratory pressures were also significantly improved with CC + SI. CONCLUSIONS: CC + SI improves duration of resuscitation and increases number of piglets achieving ROSC secondary to improved minute ventilation. IMPACT: Chest compressions superimposed with sustained inflation resulted in shorter duration of resuscitation Chest compressions superimposed with sustained inflation resulted in higher number of piglets achieving return of spontaneous circulation Further animal studies are needed to examine chest compressions superimposed with sustained inflation.

Performance of pressurized metered-dose inhalers at extreme temperature conditions.

The performance of pressurized metered-dose inhalers (pMDIs) under a variety of temperature conditions was investigated. The effects of both inhaler temperature and ambient temperature were considered. The inhaler temperature ranged from -13.0°C to 41.7°C and the ambient temperature ranged from -12.0°C to 41.7°C. The in vitro lung dose was measured for four widely available pMDIs: Airomir(TM) , QVAR(TM) , Symbicort(®) , and Ventolin(®) . The in vitro lung dose through an Alberta Idealized Throat was measured by gravimetric assay, which was verified by UV spectroscopic assay. A decrease in the in vitro lung dose was observed for all evaluated pMDIs when ambient temperature and device temperature were simultaneously reduced, decreasing on average by 70% at the coldest temperatures, whereas increasing on average by 25% at the elevated temperature condition. In vitro lung dose is strongly dependent on both inhaler temperature and ambient temperature with the tested pMDIs.

The effect of altitude on inhaler performance.

The purpose of the study is to understand the effect of altitude on the performance of selected pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs). A testing apparatus that created consistent breath profiles through the Alberta Idealized Throat was designed to test five pMDIs and two DPIs at altitudes of 670, 2450, 3260, and 4300 m. Both gravimetric and chemical assays were conducted to determine the in vitro lung dose. Additionally, spray duration and shot weight for pMDIs and device resistance for DPI were measured. There was no significant change in in vitro lung dose for any of the pMDIs tested. Shot weight and spray duration were unaffected. The device resistance of the DPIs decreased with increasing altitude and was successfully modeled as a function of ambient pressure. The in vitro lung dose of both DPIs showed no significant change when operated with an inhaler pressure drop of 4 kPa, but for the Bricanyl(®) Turbuhaler(®), a significant decrease occurred when matching the volumetric inspiratory flow rate to that of the baseline altitude.