tipology:editorial

numero rivista e pagine: HSR Proceedings in Intensive Care and Cardiovascular Anesthesia 2011; 3(1): 5-7
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Non-invasive ventilation after cardiac surgery

Authors: L. Cabrini*1, A. Zangrillo1

Department of Anesthesia and Intensive Care, UniversitÓ Vita-Salute San Raffaele, Milan, Italy

Corresponding author: * Corresponding author:
Luca Cabrini, MD
Department of Anesthesia and Intensive Care
UniversitÓ Vita-Salute San Raffaele, Milan, Italy
Via Olgettina, 60 - 20132 Milano, Italy

E-mail: cabrini.luca@hsr.it

Anaesthesia and surgery induce major changes in respiratory function, in particular when the thorax or the upper abdomen are involved. Pulmonary volumes decrease, and atelectasis can develop. Postoperative pain and diaphragm dysfunction further worsen the respiratory function, contributing to the risk of acute respiratory failure.
Non-invasive ventilation proved to be beneficial in the postoperative period, reducing atelectasis, decreasing the work of breathing and finally improving gas exchange.
Both continuous positive airway pressure and pressure support were studied with positive results when correctly used.
Postoperative non-invasive ventilation can be applied to prevent acute respiratory failure in high-risk patients (elderly, obese, or with pre-existing poor lung or heart function) or to treat it. Cardiac surgery is associated with marked alteration of lung function. So far, few studies evaluated the benefits of non-invasive ventilation after cardiac surgery: all of them took place in intensive care unit in the immediate postoperative phase early after tracheal extubation, to prevent acute respiratory failure.
Some studies reported positive results on perioperative oxygenation, atelectasis, pulmonary function tests, venous admixture, while other authors found continuous positive airway pressure ineffective on atelectasis, pulmonary function and oxygenation.
Despite the contradictory results non-invasive ventilation appears a promising tool to prevent acute respiratory failure after cardiac surgery: in the most recent randomized study, Zarbock et al. [1] reported a significant reduction in pulmonary complication, re-intubation rate and readmission to the intensive care unit in the non-invasive ventilation group.
So far, no study has evaluated the efficacy of non-invasive ventilation in treating postoperative acute respiratory failure in cardiac surgery.
Not rarely acute respiratory failure ensues after patient’s discharge from the intensive care unit. In many countries the demand for intensive care beds exceeds their availability.
An earlier postoperative discharge from and a lower rate of readmission to the intensive care unit of cardiac surgery patients can allow a more appropriate utilization of available intensive resources. The common shortage of intensive beds forces to consider the feasibility of postoperative non-invasive ventilation in the surgical wards, while preserving efficacy and safety.
The hospital avoids unnecessary admissions to the intensive care unit, leaving intensive beds available to the surgical activity. Non-invasive ventilation application in the surgical ward is potentially advantageous also for the patient, treated in an early, more responsive phase in a less intimidating ward. Nevertheless, caution should be exercised before implementing non-invasive ventilation in general wards.
For every non-intensive setting the ward monitoring capabilities, staff experience and training, ready availability of a team able to treat the patient in case of sudden deterioration must be carefully considered. Beside that, not all patients can be treated outside the intensive care unit. Before every single non-invasive ventilation treatment is prescribed, patient’s severity and his/her risk of non-invasive ventilation failure must be determined: in particular, caution should be exercised in hypoxemic patients, patients affected by severe co-morbidities, uncooperative or not fully conscious patients.
Finally, the patients should be able to call for help and not be completely dependent on non-invasive ventilation: a weaning test (at least 30-60 min without non-invasive ventilation but with oxygen supplementation) should be successfully tolerated.
In our daily experience, postoperative non-invasive ventilation to prevent or treat postoperative mild to moderate acute respiratory failure is feasible, safe and effective also when applied in the cardiac surgical ward.
Usually, a respiratory therapist service manages the treatment in conjunction with cardiac surgeons and ward nurses, with an anaesthesiologist and a cardiologist as consultants.
As a matter of fact, however, little is known about non-invasive ventilation use in the “real life” of non intensive wards. Non-invasive ventilation effectiveness, safety as well as technical, organizational and training aspects must be continuously verified in each theatre. Non-invasive ventilation use in postoperative cardiac surgery, above all when performed in the surgical ward, is a fascinating but still young field of research.
A prudential approach is required, but results could be very satisfactory for the surgeons, the anaesthesiologists, and above all for the patient.

 

References

  1. Zarbock A, Mueller E, Netzer S, et alii. Prophylactic nasal continuous positive airway pressure following cardiac surgery protects from postoperative pulmonary complications. Chest 2009; 135: 1252-1259.

Cite as: Cabrini L, Zangrillo A. Non-invasive ventilation after cardiac surgery. HSR Proceedings in Intensive Care and Cardiovascular Anesthesia 2011; 3(1): 5-7

 

Source of support: Nil.

 

Conflict of interest: None declared.