# Following cardiac surgery, do digital drainage systems versus underwater seal impact postoperative outcomes?

## TL;DR

This study compares digital and underwater seal drainage systems after cardiac surgery and finds fewer cases of postoperative atrial fibrillation with digital systems.

## Contribution

The study provides new evidence on the impact of digital drainage systems on postoperative atrial fibrillation after cardiac surgery.

## Key findings

- Digital drainage systems were associated with lower odds of postoperative atrial fibrillation.
- No differences were found in reoperation rates or pleural effusion requiring intervention.
- Digital systems did not affect cumulative drain volume or hospital stay duration.

## Abstract

In this study, we compare digital and underwater seal drainage systems following cardiac surgery and assess postoperative outcomes.

Between August 2017 and August 2018, cardiac surgical patients at our hospital were managed postoperatively using underwater seal drainage systems, and between August 2022 and August 2023 using digital drainage systems. Propensity score matching was used to estimate the effect of drainage system on various postoperative parameters (continuous and binary outcome modelling). Primary outcomes were postoperative atrial fibrillation, reoperation for bleeding or tamponade and pleural effusion requiring intervention. Secondary outcomes were hourly and cumulative drain output within 24 postoperative hours.

347 patients met the entry criteria for the study. One hundred ninety patients were managed using an underwater seal drainage system, and 157 patients were managed using a digital drainage system. Three hundred fourteen patients from the original 333 patient cohort were matched according to the drainage system used. After matching, the odds of developing postoperative atrial fibrillation were 0.57 (95% CI 0.32–0.99, P = 0.046) times lower in the digital drainage group. There was no difference in the rates of reoperation for bleeding or tamponade, pleural effusion requiring intervention or cumulative drain volume within 24 h.

In this analysis, the odds of developing postoperative atrial fibrillation were lower in patients managed with digital drainage devices than underwater seal. However, there was no difference in rates of reoperation for bleeding, tamponade, pleural effusion, drain duration or overall length of stay. Digital drainage systems could therefore be considered as part of an enhanced recovery after cardiac surgery pathway.

There is wide variation and lack of consensus on the management of chest tubes after cardiac surgery.