Background: Cardiac tamponade may occur following cardiac surgery as a result of blood or fluid collecting in the pericardial space compressing the heart and reducing cardiac output. Mediastinal chest drains (including pericardial drains) are inserted as standard post-operative practice following cardiac surgery to assist the clearance of blood from the pericardial space and to prevent cardiac tamponade. Manipulation techniques including milking, stripping, fanfolding and tapping may be applied to the tubes to keep them from blocking. Evidence is required as to the safest and most effective means of preventing chest tube blockage and preventing cardiac tamponade.
Objectives: To compare different methods of chest drain clearance (i.e. varying levels of suction or suction in combination with milking, stripping, fanfolding and tapping of chest drains) in preventing cardiac tamponade in patients following cardiac surgery.
Search strategy: We searched the Cochrane Heart Group specialised register, the Cochrane Controlled Trials Register (CCTR) (Issue 1, 2001) The Cochrane Database of Systematic Reviews (CDSR), the Database of Abstracts of Reviews of Effectiveness (DARE), Issue 1, 2001, MEDLINE (1966 to May Week 1, 2001), EMBASE (1980 to 2001 Week 35), CINAHL (1982 to March 2001), the Clinical Trials site of the NIH, (USA) (10.09.01) and reference lists of articles.
Selection criteria: Randomised, quasi-randomised or systematically allocated clinical trials of chest tube manipulation techniques in adults and children with mediastinal chest drains following cardiac surgery were included.
Data collection and analysis: Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information where required. Adverse effects information was collected from the trials.
Main results: Three studies with a total of 471 participants were included. There was no data, however, which could be included in a meta-analysis. This was due to inadequate data provision by two of the studies and where adequate data were provided there were no common interventions or outcomes to pool. On the basis of single studies there was no difference between groups on incidence of chest tube blockage, heart rate, cardiac tamponade or incidence of surgical re-entry.
Reviewer's conclusions: There are insufficient studies which compare differing methods of chest drain clearance to support or refute the relative efficacy of the various techniques in preventing cardiac tamponade. Nor can the need to manipulate chest drains be supported or refuted by results from RCT's.