3.10 Time to Ischemic Limb Treatment

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Description of Indicator

Relationship to Quality Medical care should be timely
Type of Indicator Prehospital and Hospital process, System level
Proposed Data Source EMS Records, Trauma Registry
Definition Time from onset of injury to treatment (surgery or percutaneous therapy) for an ischemic limb*
Numerator Time of initiation of treatment‡ for patients age 18 years and older diagnosed with an ischemic limb* - time of injury†β
Denominator Not applicable
Benchmark Not specified at present
Risk Adjustment Geographic area of injury (urban, rural)

* Ischemic limb diagnoses will be restricted for the purpose of operationalizing the indicator to include major arterial injuries of the extremities. Limb ischemia secondary to compartment syndrome will not be included as part of the proposed indicator.
‡ Time of initiation of treatment = Time procedure starts (skin incision for surgical therapy or needle insertion for percutaneous therapy).
† Time of injury may not be precisely known, but can likely to be accurately estimated. We believe that using time of injury as a starting point for a time based measure of treatment of an ischemic limb is conceptually attractive from both a physiological and quality improvement perspective as it represents the onset of tissue injury. It is analogous to using time of symptom onset in patients with stroke or myocardial infarction.
ß Time to ischemic limb treatment will be reported as an interval measure (mean or median) with a measure of variation (standard deviation or interquartile range).


Summary
This indicator is intended to monitor the timeliness of treatment for patients with an ischemic limb.


Panel Review
Panelists noted this to be an important indicator that reflects the effectiveness of triage, prehospital time management and hospital care. Concerns regarding the challenge of identifying time of ischemic injury diagnosis were reported. Discussions relating to implementation of this indicator suggested that acceptable intervention would be within 6 hours of time of injury or 4 hours of ED arrival. In addition, panelists emphasized the need to adjust the measure for geographic area.


Trauma Center Review
The trauma centers suggested that the indicator would benefit from greater specificity of interventions that should be used for treatment of an ischemic limb. Similar to previous indicators, trauma centers questioned the appropriateness of using time of injury as a reference point and suggested that time of EMS arrival may be more suitable.


Review of Literature & Evidence
Face Validity: No studies identified.
Construct Validity: One study demonstrated that implementation of a trauma quality improvement program that included the quality indicator was associated with reduced hospital mortality44.
Reliability: No studies identified.
Risk Adjustment: No studies identified.
Utilization: Time to Ischemic Limb Treatment is used by a small number of trauma centers: USA 0% (0/200), Canada 9% (3/35), Australasia 8% (1/12).
Prompt diagnosis of acute limb ischemia and rapid restoration of perfusion has been demonstrated to be associated with lower rates of amputation and shorter length of hospital stay. It remains unclear if major improvements in these key time segments (e.g. diagnosis and revascularization) would further improve short-term and long-term outcomes65.

 

Source
The indicator was initially proposed by Chadbunchachai et al.44.

 

References
44. Chadbunchachai W, Saranrittichai S, Sriwiwat S, Chumsri J, Kulleab S, Jaikwang P. Study on performance following Key Performance Indicators for trauma care: Khon Kaen Hospital 2000. J Med Assoc Thai. 2003;86(1):1-7.
65. Keo H, Baumgartner I, Oldenburg N, et al. Effect of time delays on outcomes of acute limb ischemia. J Am Coll Cardiol. 2010;55(10A):A213.E2019.