^a. The Agency for Healthcare Research and Quality (AHRQ) Patient Safety Indicators (PSI) software requires that the iatrogenic pneumothorax be reported as a secondary diagnosis (rather than the principal diagnosis), but unlike the Agency for Healthcare Research and Quality (AHRQ) Patient Safety Indicators (PSI) software, the secondary diagnosis could be present on admission.  Consistent with the AHRQ PSI software, the following cases are excluded: obstetric admissions and admissions with chest trauma, pleural effusion, thoracic surgery, lung/pleural biopsy, diaphragmatic surgery repair, and cardiac surgery.

^b. Rates are adjusted by age, gender, age-gender interactions, comorbidities, major diagnostic category (MDC), and diagnosis-related group (DRG).  The AHRQ PSI software was modified to not use the present on admission (POA) indicators (or estimates of the likelihood of POA for secondary diagnosis).

DNC - Data were not collected.

Key: SE: Standard error.

Source: Agency for Healthcare Research and Quality (AHRQ), Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project (HCUP) databases and AHRQ Quality Indicators, modified version 4.1.  State estimates are from the State Inpatient Databases (SID), and not all States participate in HCUP.  Estimates for the total United States are from the Nationwide Inpatient Sample, which is drawn from the SID and weighted to give national estimates.