Table 3.

Instrumental Variable Analysis of Differences Between BLS and ALS in Health Outcomes^*

Variable	Trauma	Stroke	AMI	Respiratory Failure
30-d survival	3.7 (1.3 to 6.0)	5.3 (2.7 to 8.0)	4.8 (1.2 to 8.4)	4.2 (−0.9 to 9.4)
90-d survival	4.1 (1.3 to 6.9)	4.3 (1.3 to 7.3)	5.9 (2.2 to 9.6)	0.2 (−4.7 to 5.1)
1-y survival	1.8 (−1.4 to 5.0)	3.6 (0.4 to 6.8)	7.1 (2.6 to 11.6)	−2.9 (−7.8 to 1.9)
2-y survival	2.4 (−1.3 to 6.1)	3.2 (−0.2 to 6.7)	8.4 (2.7 to 14.2)	−2.4 (−7.2 to 2.3)
Poor neurologic performance	−0.30 (−0.60 to 0.04)	0.2 (−0.1 to 0.5)	−0.7 (−1.5 to 0.2)	−0.6 (−2.5 to 1.2)

ALS = advanced life support; AMI = acute myocardial infarction; BLS = basic life support.

^*Instrumental variable estimates represent the effect on survival (in percentage points [95% CIs]) of receiving BLS rather than ALS for a “switcher” (i.e., a person who would receive BLS in an area with a higher rate of BLS use but ALS in an area with lower BLS use).