Respiratory Parameters Using Advanced Airways During In-hospital Cardiac Arrest

Patients meeting the AIRWAYS-3 inclusion criteria will be enrolled. Aged \> 18, undergoing cardiopulmonary resuscitation and a clinician present able to perform both tracheal intubation and insertion of an SGA.

Patients in the emergency department, patients under 18 and pregnant patients will excluded. Patients will be treated exactly as per the AIRWAYS-3 protocol.

Following randomisation a VFD device will be placed in the breathing system (Figure 2). The device will be left in situ until manual ventilation ceases during the IHCA event. The VFD will be used with the screen deactivated so as not to affect the airways rescuers normal practice. Cessation of manual ventilation may occur for the following reasons: patient resumed breathing spontaneously, use of mechanical ventilator, decision to stop resuscitation event (death).

Anonymised ventilation data will be downloaded following each IHCA event. The following data will be collected alongside from the existing NCAA data and AIRWAYS-3 CRF.

* Age * Actual Weight (kg) - Measured or estimated * Height (cm) * Gender (M/F) * Calculated Ideal Body Weight (kg) * Duration of arrest * Presenting rhythm * Outcome of arrest - dead/alive * Recorded respiratory disease * Timeline of airway insertion events * Advanced airway arm

Respiratory data to be collected from VFD:

* Duration of intervention * Average TV (ml) * Largest TV (ml) * Smallest TV (ml) * Average (mean) leak volume (ml) * Average respiratory rate * Average (mean) inspiratory time (s) * Average (mean) expiratory time (s)

Mean and range values will be recorded for each parameter and grouped according to advanced airway device used.

Data will be analysed using a commercial statistical software package. Descriptive and comparative statistical calculations will be performed including mean/median average, standard deviation, correlation, the Chi Square and Student t tests. Correlations and predictions will include regression analysis, Wilcoxon Rank Sum and ANOVA. If more advanced statistical analysis is required (the need for which will be based on the results from the simple statistical calculations and quality of data obtained), then a formal statistical consult will be sought from the Warwick Clinical Trials Unit.

Sample Size A power calculation has been completed. Experimental bench data suggests manual bag ventilation achieved tidal volumes of 480ml during cardiopulmonary resuscitation. Based on a mean tidal volume of 500ml to detect a minimal difference of 100ml with a standard deviation of 100ml with power set at 80% and significance of 0.05. The study will require 15 participants per group. Total sample size = 30.

• Mean leak [Срок оценки: assessed from the initiation of advanced airway management to the cessation of the resuscitation treatment (Return of spontaneous circulation or death). Through completion of data collection, ranging between minutes to 1 hour.]
• inspiratory time [Срок оценки: assessed from the initiation of advanced airway management to the cessation of the resuscitation treatment (Return of spontaneous circulation or death). Through completion of data collection, ranging between minutes to 1 hour.]
• Expiratory time [Срок оценки: assessed from the initiation of advanced airway management to the cessation of the resuscitation treatment (Return of spontaneous circulation or death). Through completion of data collection, ranging between minutes to 1 hour.]