PA PSRS Patient Saf Advis 2007 Sep;4(3):90.
Distribution of Event Types in ASFs versus Hospitals
Anesthesiology; Emergency Medicine; Surgery
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Distribution of Event Types in ASFs versus Hospitals

PA-PSRS compared the distribution of event types in ambulatory surgical facilities (ASFs) relative to hospitals from June 2004 to May 2007. ASFs have proportionately more reports of the event types listed in the Table.  Significance was determined by Chi-square (results yielding p˂0.05).  ASF reports were proportionately more common in event types involving surgical or invasive procedures rather than in those involving medication errors, falls, or transfusions. Proportionately more events were reported in “other” (miscellaneous) categories by ASFs than by hospitals. On review, the analysts felt this phenomenon represented ASFs quickly defaulting to an “other” category rather than a disproportion of unusual events. ASFs may wish to make more effort in classifying an event in an existing event type category to get the most out of aggregate reports. 

 Table. Reports Submitted to PA-PSRS from Ambulatory Surgical Facilities and Hospitals

The most important specific category disproportionately represented by ASF reports is unplanned return to the operating room (OR).  In hospitals, Birkmeyer concluded that unplanned returns to the OR may be useful for monitoring quality and for identifying opportunities for quality improvement.1 In the Netherlands, Kroon found that most unplanned returns to the OR were caused by errors in surgical technique (70%) compared to patients’ comorbidities (21%).2

Proportionately, more reports from ASFs involve surgical or invasive procedures.  ASFs can use unplanned returns to the OR as cues for quality improvement.  Using existing event types rather than defaulting to “other” categories may make aggregate reports more valuable.


  1. Birkmeyer JD, Hamby LS, Birkmeyer CM, et al. Is unplanned return to the operating room a useful quality indicator in general surgery? Arch Surg 2001;136:405-11.
  2. Kroon HM, Breslau PJ, Lardenoye JW. Can the incidence of unplanned reoperations be used as an indicator of quality of care in surgery? Am J Med Qual 2007;22:198-202.

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