Scientific paper
Factors related to the failure of radiographic recognition of occult posttraumatic pneumothoraces

Presented at the 91st Annual Meeting of the North Pacific Surgical Association, Tacoma, Washington, November 12–13, 2004
https://doi.org/10.1016/j.amjsurg.2005.01.018Get rights and content

Abstract

Purpose

Although posttraumatic pneumothoraces (PTXs) are common and potentially life threatening, the supine chest radiograph (CXR) is an insensitive test for their detection. Computed tomography (CT) often identifies occult pneumothoraces (OPTXs). Previous descriptions of OPTX topography have been poor. Our purpose was to define their distribution and aid in the targeting of thoracic ultrasound.

Methods

Posttraumatic supine CXRs and CTs were reviewed for occult, overt, and residual PTXs. PTXs were compared according to their apical, basal, anterior, lateral, medial, and posterior components. A comparative size index was calculated.

Results

Among 761 patients, 338 CT scans revealed 103 PTXs in 89 patients; 55% were OPTXs. OPTXs were apical (57%), basal (41%), anterior (84%), lateral (24%), and medial (27%), with 0% posterior.

Conclusions

CXR missed over half of all PTXs. OPTXs had a greater anterior versus lateral (nearly 4-fold) and both basal and apical versus lateral (2-fold) distribution. OPTXs are often located at easily accessible sonographic windows.

Section snippets

Material and methods

All trauma patients (Injury Severity Score [ISS] ≥12) with CXRs and CT scans of the chest and/or abdomen who presented to our adult regional trauma center between June 30, 2002, and July 1, 2003, were identified via our trauma registry. Institutional review board ethics approval was obtained before commencement of this retrospective cohort study. Each of the paired CT scans and CXRs were then re-reviewed for the presence of any PTX.

CT scans were performed on a LightSpeed QX/I-Plus scanner (GE

Results

During the 12-month study period, 338 of 761 (44%) trauma patients underwent a CT scan. Of these, 185 (55%) patients had a complete chest, abdomen, and pelvis CT scan, whereas 152 (45%) had abdomen and pelvis imaging only. One patient also had a chest CT only. All patients had a supine CXR. The study group was 75.3 % male and injured by blunt trauma in 98.5% of cases. One hundred three PTXs were present in 89 patients. Fifty-seven (55%) were occult (Fig. 2). Considering only those with a

Comments

Clinicians are often required to diagnose PTXs when treating seriously injured patients. Large symptomatic PTXs should be detected clinically and treated solely on speculation in hemodynamically unstable patients. The supine AP chest radiograph remains the initial imaging test in most stable trauma patients. The nonradiologist usually diagnoses a PTX based on an appreciation of a visible pleural line, beyond which there is an absence of lung markings [31], [32]. Other potential diagnostic signs

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