Table 2.

Standardized Difference of Patient Characteristics between Airway Choice, Before and After Propensity Score Weighting

	Prior to propensity score analysis			After propensity score analysis
	BVM v ETI	BVM v SGA	ETI v SGA	BVM v ETI	BVM v SGA	ETI v SGA
Age, mean(SE)*	−13.4%	−61.3%	−43.7%	−7.0%	−18.3%	−12.9%
Female, n(%)*	2.6%	7.7%	5.1%	−0.3%	1.0%	1.2%
Witness and Bystander CPR, n(%)
Bystander witnessed*	−5.9%	−28.7%	−22.7%	−1.8%	−8.2%	−6.4%
EMS Witnessed*	−2.8%	−19.6%	−16.9%	−1.6%	−5.6%	−4.0%
Unwitnessed*	6.9%	37.7%	30.7%	2.4%	10.5%	8.0%
Bystander Compressions*	−2.5%	2.3%	4.7%	−3.5%	−0.2%	3.3%
Bystander Ventilations*	5.6%	21.3%	15.7%	2.6%	10.3%	7.7%
Time variables in minutes, mean(SE)
Time to EMS arrival*	−2.6%	−8.9%	−5.7%	−1.9%	−8.2%	−6.8%
EMS Scene Time	−35.1%	−68.0%	−27.5%	−39.5%	−39.3%	−10.4%
Transport Time	−9.7%	−29.4%	−16.4%	−14.0%	−26.2%	−16.7%
Location of arrest, n(%)
Healthcare*	0.7%	2.1%	1.4%	2.6%	8.7%	6.2%
Public Building*	−4.6%	−16.7%	−12.2%	−1.1%	−5.8%	−4.7%
Street/Highway*	3.6%	−11.9%	−15.3%	3.9%	−4.8%	−8.6%
Place of Recreation*	−3.8%	−22.8%	−19.4%	0.1%	1.8%	1.6%
Home*	6.0%	31.0%	25.0%	−0.3%	3.2%	3.5%
Other*	−9.3%	−9.3%	0.0%	−7.0%	−5.7%	1.3%
Initial rhythm, n(%)
Shockable*	0.9%	−38.2%	−39.1%	1.8%	−7.4%	−9.2%
PEA*	0.9%	−4.6%	−5.5%	1.1%	−4.8%	−6.0%
Asystole*	−11.3%	22.4%	33.9%	−6.3%	−5.3%	1.0%
Non-airway resuscitation, n(%)
Epinephrine given	−65.2%	−61.8%	3.4%	−59.1%	−57.6%	1.4%
Defibrillation	−5.8%	−48.8%	−43.1%	−1.6%	−10.9%	−9.4%

^*= Variables consistently known prior to airway management.