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Introduction: Chest compressions during CPR induce oscillations in capnography (ETCO2) waveforms. Studies suggest ETCO2 oscillation characteristics are associated with intrathoracic airflow dependent on airway patency. Oscillations can be quantified by the Airway Opening Index (AOI). We sought to evaluate multiple methods of computing AOI and their association with return of spontaneous circulation (ROSC).Methods: We conducted a retrospective study of 307 out-of-hospital cardiac arrest (OHCA) cases in Seattle, WA during 2019. ETCO2 and chest impedance waveforms were annotated for the presence of intubation and CPR. We developed four methods for computing AOI based on peak ETCO2 and the oscillations in ETCO2 during chest compressions (ΔETCO2). We examined the feasibility of automating ΔETCO2 and AOI calculation and evaluated differences in AOI across the methods using nonparametric testing (α = 0.05).Results: Median [interquartile range] AOI across all cases using Methods 1-4 was 28.0 % [17.9-45.5 %], 20.6 % [13.0-36.6 %], 18.3 % [11.4-30.4 %], and 22.4 % [12.8-38.5 %], respectively (p < 0.001). Cases with ROSC had a higher median AOI than those without ROSC across all methods, though not statistically significant. Cases with ROSC had a significantly higher median [interquartile range] ΔETCO2 of 7.3 mmHg [4.5-13.6 mmHg] compared to those without ROSC (4.8 mmHg [2.6-9.1 mmHg], p < 0.001).Conclusion: We calculated AOI using four proposed methods resulting in significantly different AOI. Additionally, AOI and ΔETCO2 were larger in cases achieving ROSC. Further investigation is required to characterize AOI's ability to predict OHCA outcomes, and whether this information can improve resuscitation care. [ABSTRACT FROM AUTHOR]

Background: Transtracheal jet ventilation (TTJV) is recommended in several airway guidelines as a potentially life-saving procedure during the 'Can't Intubate Can't Oxygenate' (CICO) emergency. Some studies have questioned its effectiveness.Methods: Our goal was to determine the complication rates of TTJV in the CICO emergency compared with the emergency setting where CICO is not described (non-CICO emergency) or elective surgical setting. Several databases of published and unpublished literature were searched systematically for studies describing TTJV in human subjects. Complications were categorized as device failure, barotrauma (including subcutaneous emphysema), and miscellaneous. Device failure was defined by the inability to place and/or use the TTJV device, not patient survival.Results: Forty-four studies (428 procedures) met the inclusion criteria. Four studies included both emergency and elective procedures. Thirty studies described 132 emergency TTJV procedures; 90 were CICO emergencies. Eighteen studies described 296 elective TTJV procedures. Device failure occurred in 42% of CICO emergency vs 0% of non-CICO emergency (P<0.001) and 0.3% of elective procedures (P<0.001). Barotrauma occurred in 32% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). The total number of procedures with any complication was 51% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). Several reports described TTJV-related subcutaneous emphysema hampering subsequent attempts at surgical airway or tracheal intubation.Conclusions: TTJV is associated with a high risk of device failure and barotrauma in the CICO emergency. Guidelines and recommendations supporting the use of TTJV in CICO should be reconsidered. [ABSTRACT FROM AUTHOR]