Less pain with flexible fluted silicone chest drains than with conventional rigid chest tubes after cardiac surgery☆

Article Outline

• Abstract
• Method
  • Drain management and removal
  • Statistics
• Results
• Discussion
• Acknowledgements
• References
• Copyright

Abstract 

J Thorac Cardiovasc Surg 2002;124:1027-8

Drainage of the pleura and mediastinum after cardiac surgery is routinely achieved with rigid, wide-bore plastic drains.¹ Although these drains are effective, they are also painful, particularly during removal,² and they may cause damage to bypass grafts, impair ventilation, and cause cardiac arrhythmias.³

Flexible fluted silicone drains may be just as effective.⁴ Because of the fluted design, smaller sizes can be used without any reduction in the effective drainage capacity. The small size and flexibility may cause less pain, interfere less with the heart and surrounding structures, and result in fewer drain site infections. To investigate these potential benefits and to establish the efficacy of these drains, we designed a prospective, randomized trial that compared the two types of drain.

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Method 

The local ethical committee approved the study, and all patients gave written informed consent. Seventy consecutive patients undergoing elective coronary artery bypass grafting with the use of the left internal thoracic artery as a conduit were prospectively randomly assigned to receive either 28F rigid plastic Portex drains (Portex Ltd, Hythe, United Kingdom) or 19F flexible fluted drains. Patients in whom the right pleura was opened either accidentally or for right internal thoracic artery harvesting, patients with concomitant valve surgery, and patients undergoing either reoperative coronary artery bypass grafting or emergency coronary artery bypass grafting were excluded.

All patients received one mediastinal and one left pleural drain. Portex drains were inserted through a standard 2-cm incision. The flexible fluted drains were inserted with a trocar. The method of linear visual analog scoring of pain was explained before the operation (scale, 0-10).

Drain management and removal 

No descriptions of the two types of drains were given during consent, to avoid patient bias. Patients who had previous experience with chest drainage were excluded.

The criteria for drain removal were no air leak and drainage of less than 20 mL/h for 3 consecutive hours. Before drain removal, the patient was asked to score the amount of pain that he or she attributed to the chest drain. After drain removal, pain scores were again recorded by the patient and were also independently estimated by the nurse.

Intravenously administered morphine, dihydrocodeine tartrate, and paracetamol were the only analgesia used until drain removal. During the period from 30 minutes before to 30 minutes after drain removal, nurses were not allowed to offer analgesia to the patient. If the patient requested analgesia, however, it was given.

Echocardiography of the pericardium and the pleura was performed on day 5 by a single experienced echocardiographer (S.T.) who was blinded to the drain type used. Pleural effusions were measured in the posteroanterior plane (longitudinal and transverse measurements) with the patient sitting erect and in inspiration and expiration to calculate an area of effusion. Depths of anterior and posterior pericardial effusions were also measured with the patient in the left lateral and supine positions.

Statistics 

Proportions were compared with a χ² test or a Fisher exact test as appropriate. Continuous parametric data were compared with a Student t test, and nonparametric data were compared with a Mann-Whitney U test.

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Results 

The preoperative, intraoperative, and postoperative characteristics of the two groups are shown in Table 1.

Table 1. Preoperative, intraoperative, and postoperative characteristics

Patients with flexible fluted drains had significantly less pain than did patients with Portex drains both before and during the procedure of drain removal (Table 2). Patients with flexible fluted drains also required less analgesia than did those with Portex drains (Table 2).

Table 2. Drain data

There were no difference in the sizes of pleural effusions and pericardial effusions. Two patients in the flexible fluted drains group had pleural effusions greater than 60 cm². Both were treated conservatively. One patient in the Portex group had a 3-cm anterior pericardial effusion that was drained percutaneously. Three patients in the Portex group underwent reexploration for bleeding, compared with 1 in the flexible fluted drain group, and 1 patent in each group underwent exploration for tamponade.

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Discussion 

The impact of chest tubes on postoperative pain is underestimated. In a study by Paiement and coworkers,⁵ 22% of patients studied said that the pain caused by the chest drain was their worst memory of the whole experience of undergoing cardiac surgery. This was comparable to the 20% who mentioned the endotracheal tube or any event related to intubation.

We have demonstrated that flexible fluted silicone drains do not lead to an increase in pleural or pericardial effusions or reexploration for tamponade or bleeding. A shortcoming of the study is that nurses were not blinded to the type of drain used. The nurses' pain scores could be subject to bias and must be interpreted accordingly. However, the nurses' pain scores were similar to those of the patients.

Flexible fluted drains are as effective as traditional chest tubes but cause less pain. We advocate their use in patients undergoing cardiac surgery.

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Acknowledgements 

We thank all the nurses on the intensive care unit at the Northern General Hospital who made this study possible.

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References 

1. Munnell ER, Thomas EK. Current concepts in thoracic drainage systems. Ann Thorac Surg. 1975;19:261–268
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3. Taub PJ, Lajam F, Kim U. Erosion into the subclavian artery by chest tube. J Trauma. 1999;47:972–974
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4. Obney JA, Barnes MJ, Lisagor PG, Cohen DJ. A method for mediastinal drainage after cardiac procedures using small Silastic drains. Ann Thorac Surg. 2000;70:1109–1110
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5. Paiement B, Boulanger M, Jones CW, Roy M. Intubation and other experiences in cardiac surgery: the consumer's views. Can Anaesth Soc J. 1979;26:173–180
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