Coronary artery bypass surgery (CABG) is the most commonly performed heart operation in most countries, and its mortality and morbidity results are one of the most studied and scrutinized in the world. As a large operation involving long surgical times, sternotomy and cardiopulmonary bypass, long-term postoperative ventilation is a dreaded possible complication. Failure to wean from the ventilator can result both as a consequence of previous risk factors and as a cause of future morbidity and mortality. Not only it impacts patients’ well-being and recovery times, but also can lead to further complications such as lung infections, sepsis, loss of general muscle function and need for tracheostomy.

Therefore, the current study of Dallazen-Sartori et al. is a timely and useful attempt to better characterize the incidence and risk factors for the development of prolonged ventilation (PV) after CABG. As previous authors did before, the authors focus on preoperative and per-operative factors to try to expose, by multiple logistic regressions, which ones are causally associated to PV in order to construct a practical Risk Score. It is needless to stress the importance of such a study in our Brazilian population, which might behave differently from well-known previous reports from other countries. Unfortunately, we still face a paucity of local and regional studies that would better represent our own results, outcomes and challenges. The situation when we need to base our decisions in external sources of data instead of using the national one happens very often. The current study by Dallazen-Sartori et al, is an attempt to change that.

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OBJECTIVE: To assess cardiorespiratory variables during weaning from mechanical ventilation by using the T-tube and pressure support techniques, and to compare them in groups of patients with and without heart disease. METHODS: To assess the following parameters of 20 patients (57±15 years) undergoing weaning from mechanical ventilation: oxygenation; CO2 elimination; respiratory and heart rates; tidal and minute volumes; blood pressure; and electrocardiographic alterations. Data were recorded by using both techniques at the following times: zero, 15, and 30 minutes, and after a 30-minute interval. The patients were divided into 2 groups, with heart disease (n=11) and without heart disease (n=9), and then compared. RESULTS: The pressure support ventilation showed significantly more elevated oxygenation and CO2 elimination values, and reduced respiratory rate as compared with those of the T-tube ventilation. No difference was found in regard to blood pressure and heart rate. More patients with heart disease had alterations in the ST segment [7 (64%) patients versus 2 (22%)] and arrhythmias [3 (27%) versus 1 (11%)], as compared with patients without heart disease. A lower frequency of tachycardia was observed in those with heart disease. CONCLUSION: When comparing pressure support ventilation with T-tube ventilation, a better response was observed in the measurements of the respiratory and oxygenation parameters when using pressure support ventilation. No significant difference was observed in the measurements of cardiovascular parameters. In both weaning techniques, patients with heart disease had tachycardia less frequently, more alterations in the ST segment, and a greater tendency towards the occurrence of arrhythmias.