Discussion
We have presented the results of cohort studies that compare early versus late chest tube removal following open-heart surgery. We judged three studies to be high quality15,22,23, and two studies to be of moderate quality.11,24 Articles with a relatively lower quality level emphasized on late chest tube removal.
There is no sufficient evidence on the timing of chest tube removal after open-heart surgery. Hence, some authors suggest removing them after 24 hours postoperative and some authors recommended to remove the chest tube after 48 hours postoperative.11,15,22-24
Three studies from the studies reviewed showed that early chest tube removal does not increase risk of pleural effusion.15,22,23. But two studies have stated that there is a link between early chest tube removal and pleural effusion.11,24
This variation in results is probably since that in the first three studies that recommended early chest tube removal, the timeframe for early in these studies were 24 hours and for late 48 hours while, this is different in the Andersen et al. (2015) study and the time to early chest tube removal in this study is up to 14 hours, which is shorter and earlier than the first three studies and maybe the reason for more occurrence pleural effusion. On the other hand, the timeframe for group late Chest tube removal of Andersen et al. (2015) study that approximately 24 hours, is consistent with timeframe of the early chest tube removal group in the three studies agree with the early chest tube removal in this systematic review. In this group of Andersen et al. (2015) study less pleural effusion has been observed which is in line with the results of the group early chest tube removal in three studies agrees with the early chest tube removal.
A recent systematic review of a similar issue in our study has shown that other properties, such as the chemical composition of pleural fluid, can be a predictor for the timing of chest tube removal. Also, the removal of chest tubes can occur only when the fluid is completely serosanguineous and lacks blood and chylous.14
According to our query, no intervention study was found on this issue and if available, it appears to be very low or not in English. Due to the growing perspective of evidence-based treatment, interventional studies are referred to as the gold standard for evaluating the effectiveness of an intervention or treatment.25Therefore, it is necessary to conduct interventional studies with high validity and controlled conditions on this topic to suggest the precise time to remove the chest tube in patients undergoing open-heart surgery. It is also recommended that writing a guideline can help improve the treatment process for these patients.
Another issue to consider is the diagnosis of pleural effusion after chest tube removal. In the studies investigated in our review, there was a disagreement that some study used Chest X-ray as a diagnostic test and some used CT scans. Even in the Abramov study, which used both diagnostic tests to detect pleural effusion, there were variations in results.15,16 Therefore, further research is needed to clarify this issue.
Because of the complexity of the issue and the relevance of multiple factors to pleural effusion, it is also recommended to look for other indicators to determine when to remove the chest tube. However, it has been suggested that the occurrence of pleural effusion may vary depending on the geographical location of individuals.26,27