Local Wound Exploration Remains A Valuable Triage Tool For The Evaluation Of Anterior Abdominal Stab Wounds

Dissections

INTERVENTIONAL 31 July 2009

Evidence-based Medicine for Surgeons

Local wound exploration remains a valuable triage tool for the evaluation of anterior abdominal stab wounds Authors: Cothren CC, Moore EE, Warren FA, et al Journal: The American Journal of Surgery 2009; 198: 223-226 Centre: University of Colorado School of Medicine, Denver, Colorado, USA

BACKGROUND

Current standards of care do not support local wound exploration (LWE) and diagnostic peritoneal lavage (DPL) in the evaluation of hemodynamically stable patients with anterior abdominal stab wounds (AASW); computed tomography (CT) scanning or serial examinations are the recommended techniques. In theory, patients without fascial penetration on LWE can be discharged from the emergency department (ED), rather than undergo a mandatory in-hospital observation period. Those patients with a negative DPL can be observed for 12 to 24 hours in the ED before discharge, thus avoiding inpatient admission.

IN

RESEARCH QUESTION

SUMMARY

Local wound exploration in anterior abdominal stab wounds

Population A series of patients seen at a trauma centre in the USA. with anterior abdominal stab wounds (AASW). Indicator variable Local wound exploration (LWE) followed by diagnostic peritoneal lavage (DPL) in those with a breached posterior fascia. Outcome variable Primary: need for laparotomy, observation in the ED or discharge from the ED. Comparison None.

LWE - local wound exploration, DPL = diagnostic peritoneal lavage Authors' claim(s): “...Only 11% of patients with AASWs without overt indication for laparotomy require surgical care. LWE remains a valid method to exclude intra-abdominal injury and to eliminate hospitalization in more than one third of AASW patients.”

THE TISSUE REPORT Evidence-based Medicine, whatever its shortcomings, has driven home the necessity of randomized clinical trials as the basis for establishing the validity of interventions in practice, more so when making a claim that the study strategy is equal to or better than existing recommendations. A small trial, with no controls, is not evidence. Unfortunately, the anecdotal style of this paper, makes it easy to remember and quote as proof for support of this particular strategy.

EBM-O-METER Evidence level

Overall rating

Bias levels

Double blind RCT

Sampling

Randomized controlled trial (RCT) Prospective cohort study - not randomized Case controlled study Case series - retrospective

Trash Life's too short for this

Swiss cheese Full of holes

Safe Holds water



Newsworthy “Just do it”

Comparison Measurement

l | Novel l | Feasible l Ethical l | Resource saving l

Interesting

The devil is in the details (more on the paper) ...

© Dr Arjun Rajagopalan



SAMPLING Sample type Simple random Stratified random Cluster Consecutive

Inclusion criteria

Exclusion criteria

Stab wounds between the costal margins, inguinal ligaments, and bilateral anterior axillary lines 

Final score card AASW

Thoracoabdominal, back, or flank wounds 

Target

?

Accessible

2008

Intended

139

Convenience

Drop outs

-

Judgmental

Study

139

= Reasonable | ? = Arguable |  = Questionable Duration of the study: 3 years (actual dates not stated)



Sampling bias: A small series, from a single centre, analysed retrospectively.

COMPARISON Randomized

Case-control

Non-random

Historical

None

Controls - details Allocation details

After sterile preparation the wound was infiltrated with 1% lidocaine with epinephrine. If necessary, the stab wound was extended to facilitate adequate visualization of the fascia. A local wound exploration was considered positive if the posterior fascia was violated. DPL was performed in the standard fashion via an infraumbilical approach and considered positive or negative based on established criteria.

Comparability

No comparison made.

Disparity

-

Comparison bias: No attempt was made to compare this strategy with existing standards of care.

MEASUREMENT Measurement error

1.Outcome - laparotomy, observation in the ED, discharge from the ED

-

-

-

-

-

Blinding

N

Scoring

?

Protocols

Y

Training

Device suited to task

Observer error Gold std.

Device error Repetition

Device used

-

Measurement bias: All outcomes measured were simple, discrete items with little scope for measurement bias.

© Dr Arjun Rajagopalan

-