A randomized trial of early versus delayed mediastinal drain removal after cardiac surgery using silastic and conventional tubes

Abstract

Objectives: Mediastinal drainage following cardiac surgery with traditional large-bore plastic tubes can be painful and cumbersome. This study was designed to determine whether prolonged drainage (5 days) with a silastic tube decreased the incidence of significant pericardial effusion and tamponade following aortic or valvular surgery.

Methods: One hundred and fifty patients undergoing valvular or aortic surgery in a tertiary cardiac surgery institution were randomized to receive a conventional mediastinal tube plus a silastic Blake drain (n = 75), or two conventional tubes (n = 75). Conventional drains were removed on postoperative day (POD) 1, while Blake drains were removed on POD 5. The primary end-point was the combined incidence of significant pericardial effusion (≥ 15 mm) or tamponade through POD 5. Secondary end-points included total mediastinal drainage, postoperative atrial fibrillation (AF) and pain.

Results: Analysis was performed for 67 patients in the Blake group and 73 in the conventional group. There was no difference between the two groups in the combined end-point of significant effusion or tamponade (7.4 vs 8.3%, P = 0.74), or in the incidence of AF (47 vs 46%, P = 0.89). Mean 24-h drainage was greater in the Blake group than in the conventional group (749 ± 444 ml vs 645 ± 618 ml, P < 0.01). Overall incidence of significant pericardial effusion at 30 days was 12.1% (n = 17), with 5% (n = 7) requiring drainage. The Blake group had a numerically lower incidence of effusion requiring drainage at POD 30 (3.0 vs 6.8%, P = 0.44). Postoperative pain was similar between groups.

Conclusions: In patients undergoing ascending aortic or valvular surgery, prolonged drainage with silastic tubes is safe and does not increase postoperative pain. There was no difference between the Blake and conventional drains with regard to significant pericardial effusion or tamponade in this cohort; however, this conclusion is limited by the low overall incidence of the primary outcome in this cohort.

Trial registration: ClinicalTrials.gov NCT00684125.

Figure 1:

Incidence of postoperative effusion according to group.

Figure 2:

Results of pain survey according to question. Mean scores in each group are represented. X-axis = postoperative day. Y-axis = pain on a scale of 1–10. Analysis of variance showed no significant difference in response to any question. Pain ‘at rest’ and ‘with activity’ = at the time the survey was completed.