Risk factors for late extubation after coronary artery bypass grafting

Prolonged Mechanical Ventilation Following Coronary Artery Bypass Graft in Santiago De Cali, Colombia

Purpose

The purpose of this study was to describe factors associated with prolonged ventilatory support in subjects undergoing coronary artery bypass graft.

Patients and Methods

This was an analytical retrospective case-control study. Cases were defined as subjects requiring prolonged mechanical ventilation (>48 hours) following isolated coronary artery bypass graft. Subjects older than 18 years who had undergone surgery were included, while subjects with missing clinical record data, subjects in coma or subjects with prior cardiac surgery were excluded. Variables were measured at the three time points surrounding surgery.

Results

A total of 204 cases and 408 controls were included. The final logistic model showed an association between prolonged mechanical ventilation and the following presurgical variables: chronic obstructive pulmonary disease (OR 1.85; 95% CI: 1.06-3.23, p = 0.03) and chronic kidney disease (OR 1.90; 95% CI: -3.31; p = 0.02). The associated transurgical variable was the use of intra-aortic balloon pump (OR 3.63; 95% CI: 1.73-7.61, p = 0.00), and associated postsurgical variables were venous oxygen saturation <60% (OR 2.00; 95% CI: 1.18-3.40, p = 0.01), mediastinitis (OR 18.51; 95% CI: 4.06-84.40, p = 0.00), inotrope use (OR 2.82; 95% CI: 1.77-4.48, p = 0.00), pleural effusion requiring drainage (OR 3.57; 95% CI: 2.02-6.32, p = 0.00) and delirium (OR 3.45; 95% CI: 1.91-6.25, p = 0.00).

Conclusion

This study identifies factors associated with prolonged mechanical ventilation in subjects subject to coronary artery bypass graft over the presurgical, transurgical and postsurgical periods, identifying a new factor, delirium, for this type of population.

The prophylactic effect of different levels of positive endexpiratory pressure on the incidence rate of atelectasis after cardiac surgery: A Randomized Controlled Trial

Background: The use of positive end-expiratory pressure (PEEP) can have an important role as one of the ways to prevent and treat atelectasis, but it seems that there is still no consensus about its beneficial level. The aim of this study was to determine the effect of different levels of PEEP on the incidence of atelectasis after heart surgery.

Methods: This is a double-blind randomized controlled trial that was adopted from a research project recorded in the Iranian Registry of Clinical Trials. This paper is the result of a research project undertaken at Fatemeh Zahra Hospital (Mazandaran Heart Center) in 2015. 180 patients underwent open heart surgery were selected and were divided randomly into three groups: control, PEEP=8, and PEEP=10 (60 in each group). The patients in the two PEEP8 and PEEP10 intervention groups separately received 8 cm H2O and 10 cm H2O PEEP, respectively, 30 minutes after admission to the ICU for 4 hours and then received 5 cm H2O PEEP until extubation. Atelectasis was examined two hours after the extubation and on the third day after surgery.

Results: The incidence rates of atelectasis two hours after extubation on the first day of surgery were 22 (36.7%), 20 (33.3%) and 10 (16.7%) patients in the control, PEEP8 and PEEP10 groups, respectively. The differences were statistically significant among the three groups (p=0.035). The incidence rates of atelectasis on the third day after surgery were 39 (65%), 36 (60%) and 21 (35%) patients in the control, PEEP8 and PEEP10 groups, respectively. The differences were also statistically significant among the three groups (p=0.003).

Conclusion: The use of 10 cm H2O PEEP can lead to a reduction in the incidence of atelectasis, intubation time at the ICU and length of ICU and hospital stay. Given that this level of PEEP is effective, this method is recommended to be used in postoperative care of patients.

Establishing the Content Validity of an Early Extubation Protocol: A Quality Improvement Project for Improving Early Extubation of Coronary Artery Bypass Graft Patients

Introduction: Patients undergoing coronary artery bypass graft surgery will require intubation and the use of mechanical ventilation during and after surgery. It is well accepted that early extubation is associated with not only positive patient outcomes but also organizational outcomes as well. Patients who are not extubated early are at risk for complications associated with prolonged intubation. The literature supports the use of protocol aid with early extubation. The goal and expected outcome of this project is to establish the usability of an early extubation protocol by assessing its appropriateness for use in the postoperative cardiac surgical adult patient. Methods: For the purpose of establishing content validity of an early extubation protocol, 2 protocols were chosen from the literature. Fifteen cardiac surgery experts were invited to select the protocol they felt was most appropriate for use in this patient population. These reviewers were then asked to further analyze the protocol based on a 5-question survey. Their response was used to calculate a scale-content validity index (S-CVI) and an item-content validity index (I-CVI). Results: Twelve of 15 experts participated in the project. The content validity was estimated using (a) interrater agreement for relevance for each item (I-CVI) and (b) S-CVI. The means were established for each item. Content validity was estimated using (a) interrater agreement for relevance for each item (I-CVI: 0.75-1.00); and the S-CVI/average = 0.92. Cronbach's alpha was estimated to establish reliability (0.972). Conclusion: Selecting an appropriate protocol to be used in this patient population is the first step in implementing an effective early extubation process. The results highly suggest that the content of this protocol is quite relevant in this patient population. It is hoped that this will set the stage for early extubation in postoperative cardiac surgery patients.

Factors influencing delayed extubation after infratentorial craniotomy for tumour resection: a prospective cohort study of 800 patients in a Chinese neurosurgical centre

OBJECTIVES

To investigate prospectively the rate of, and factors influencing, delayed extubation following infratentorial craniotomy in a Chinese neurosurgical centre.

METHODS

Patients undergoing infratentorial craniotomy for tumour resection were prospectively enrolled and stratified according to whether extubation was attempted in the operating theatre (early extubation) or not (delayed extubation). Pre- and intraoperative variables were collected and analysed. Multiple logistic regression analysis was performed, to identify factors related to delayed extubation.

RESULTS

The study included 800 patients, 398 (49.8%) of whom underwent delayed extubation. The overall rate of extubation failure was 3.6%. Independent factors related to delayed extubation were: preoperative lower cranial nerve dysfunction; hydrocephalus; tumour location; duration of surgery ≥ 6 h; estimated blood loss ≥ 1000 ml. Compared with patients in the early extubation group, those in the delayed extubation group had a higher rate of pneumonia, longer intensive care unit and postoperative hospital stays, and higher hospitalization costs.

CONCLUSIONS

Brain stem and lower cranial nerve function were the main factors affecting extubation decision-making. Further research is required, to establish criteria for delayed extubation following infratentorial craniotomy.

High levels of B-type natriuretic peptide predict weaning failure from mechanical ventilation in adult patients after cardiac surgery

OBJECTIVE

The failure to wean from mechanical ventilation is related to worse outcomes after cardiac surgery. The aim of this study was to evaluate whether the serum level of B-type natriuretic peptide is a predictor of weaning failure from mechanical ventilation after cardiac surgery.

METHODS

We conducted a prospective, observational cohort study of 101 patients who underwent on-pump coronary artery bypass grafting. B-type natriuretic peptide was measured postoperatively after intensive care unit admission and at the end of a 60-min spontaneous breathing test. The demographic data, hemodynamic and respiratory parameters, fluid balance, need for vasopressor or inotropic support, and length of the intensive care unit and hospital stays were recorded. Weaning failure was considered as either the inability to sustain spontaneous breathing after 60 min or the need for reintubation within 48 h.

RESULTS

Of the 101 patients studied, 12 patients failed the weaning trial. There were no differences between the groups in the baseline or intraoperative characteristics, including left ventricular function, EuroSCORE and lengths of the cardiac procedure and cardiopulmonary bypass. The B-type natriuretic peptide levels were significantly higher at intensive care unit admission and at the end of the breathing test in the patients with weaning failure compared with the patients who were successfully weaned. In a multivariate model, a high B-type natriuretic peptide level at the end of a spontaneous breathing trial was the only independent predictor of weaning failure from mechanical ventilation.

CONCLUSIONS

A high B-type natriuretic peptide level is a predictive factor for the failure to wean from mechanical ventilation after cardiac surgery. These findings suggest that optimizing ventricular function should be a goal during the perioperative period.