Ordenha de dreno mediastinal em pós-operatório de cirurgia cardíaca: um ensaio clínico randomizado

Abstract

BACKGROUND: There are not enough scientific publications with adequate design that prove the effectiveness of mediastinal drain milking in preventing hematic occlusion and its complications and manipulating the drains may (or may not) lead to unknown outcomes. Such research is necessary to cope with scientific and professional uncertainties to point out what should be adopted in the postoperative period (PO) of cardiac surgeries. GENERAL OBJECTIVE: to evaluate the convenience of milking of mediastinal drains in patients submitted to cardiac surgery in the prevention of hematic occlusion of the drains. SPECIFIC OBJECTIVES: to estimate the efficacy of mediastinal drainage milking to prevent drain hematic occlusion in patients undergoing cardiac surgery; to track complications related to milking or non-milking of the drain; to support post-surgical care based on evidence; to elaborate an institutional protocol for mediastinal drainage care in a postoperative intensive care unit of cardiac surgery. METHODS: a randomized clinical trial was undertaken with 80 patients divided into two groups: 1) S-ORD, with 40 patients who were not submitted to mediastinal drain milking; and 2) C-ORD, with 40 patients who underwent milking according to the intensive care unit routine. The patients were recruited by the principal investigator and two researchers from the inpatient team among those who were to undergo cardiac surgery by median sternotomy with mediastinal drainage. The groups were evaluated for drainage volume, occurrence or not of cardiac tamponade and pericardial effusion, and exact date and time of mediastinal drain removal. Data were measured by project team members after standardization and training, using their own individualized form for each group of randomized patients. RESULTS: None of the groups presented cardiac tamponade, pericardial effusion or drainage obstruction. The withdrawal of the drain was more frequent between the second and third days, in groups C-ORD and S-ORD (85.0% and 72.5%). In the C-ORD group, the mean drain removal time was 2,8 days and, in the S-ORD group, it was 3,1 days. This difference was not statistically significant (p = 0.1189). The C-ORD group in relation to the S-ORD group presented a statistically greater volume of drainage in the immediate PO period (355.1 ml vs 236.6 ml; p = 0.0075). Complications (total atrioventricular block, low postoperative output syndrome, cardiorespiratory arrest, arterial hypertension and pneumothorax) occurred in a greater proportion in the S-ORD group (35,0%) from the immediate postoperative period up to the 3º PO day. In the C-ORD group, complications occurred in 17,5%, all only in the immediate postoperative period. This difference between the groups was statistically significant, both in the general proportion (p = 0,0005) and in the comparison between the periods (p = 0,0322). CONCLUSIONS: A lower number of postoperative complications with a statistically significant difference was found in the group where drains were milked. Therefore, milking mediastinal drains using the stripping technique is a recommended policy in the postoperative period of cardiac surgery. As a result of the findings of this study, an institutional protocol for the care of mediastinal drains was developed.