How Often Are ICU Chest Tubes Malpositioned?
Abstract & Commentary
By David J. Pierson, MD, Editor, Professor, Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, is Editor for Critical Care Alert.
Synopsis: In this study of surgical ICU patients in whom chest tubes were placed percutaneously for pneumothorax or sterile pleural effusion, 21% of the tubes were found on chest CT to be in a fissure, and another 9% were intraparenchymal. Only a minority of the malpositions were described in the official radiology reports.
Source: Remerand F, et al. Anesthesiology. 2007;106:1112-1119.
In this study from a surgical ICU in Paris, the investigators prospectively gathered data on chest tubes percutaneously inserted in consecutive critically ill patients. After the presence of pleural fluid or air was determined using bedside thoracic ultrasound, chest tubes were inserted either by blunt dissection or using a trochar by senior physicians, residents, or medical students under direct supervision by senior staff. Bedside chest radiographs were taken after insertion to screen for obvious malposition such as kinking or new parenchymal density around the tube. When patients with chest tubes subsequently underwent CT scanning for separate clinical indications (not part of the study), the authors used a special protocolized method for determining the position of the tubes, in an attempt to determine the incidence of previously unsuspected malposition.
During the period of the study, 122 chest tubes were inserted in 75 patients with pneumothoraces or sterile pleural effusions. Of these, 63 patients with 106 tubes also had a chest CT scan. The mean interval between chest tube insertion and CT scanning was 3.5 ± 2.9 days. In all, 32 (30%) of the chest tubes were determined to be malpositioned—22 (21%) in a fissure and 10 (9%) intraparenchymal. Two additional tubes had proximal drainage holes outside the pleural space, and one tube was believed to be inside the chest but extrapleural. In none of the instances of tube malposition was this suspected on the basis of the standard chest radiograph.
In 103 of the 106 instances, the radiologists officially reading the chest CT scans were unaware of the study and the protocol used for determining chest tube position. Of the 9 intraparenchymal tubes in this group, only 2 were correctly diagnosed; 4 were reported to be in correct position and 3 were not described. Overall, the sensitivity, specificity, and negative and positive predictive values of the radiologists' reports in detecting malpositioned chest tubes were 23%, 49%, 63%, and 18%, respectively.
Use of a trochar during insertion was associated with a higher incidence of tube malposition (p = 0.032). Operator experience and level of training were not related to the incidence of this complication. One patient with an intraparenchymal tube developed a bronchopleural fistula, associated with lung abscess, empyema, and septic shock. Three intraparenchymal and 2 intrafissural tubes were inefficient in draining the pleural fluid or air and required additional procedures—new tubes in 4 patients and thoracotomy in one. No other observed clinical outcomes were different in patients with correctly placed vs malpositioned chest tubes.
Malpositioning of chest tubes inserted percutaneously in critically ill patients is common, and is missed frequently by both clinicians and radiologists. The CT scans used for determining malposition in this study were not obtained specifically for that purpose, and as the authors point out, the radiologists were likely focusing on the clinical indications for which the scans had been ordered. Nonetheless, given the potential clinical importance of incorrect positioning, it is discouraging to note that it was missed on the official readings most of the time.
The adverse effects of malpositioned chest tubes include ineffective drainage of the fluid or air for which they were placed, along with more serious complications such as bronchopleural fistula, abscess formation, and life-threatening bleeding. Thus, increased efforts to identify tube malpositioning when it occurs would seem worthwhile, particularly when a recently-placed chest tube does not function as intended. Radiologists who interpret chest CT scans should be asked to comment on the course and location of chest tubes, even when the study is obtained for other reasons.