Increased airway mucins after cardiopulmonary bypass associated with postoperative respiratory complications in children

Availability and threshold of the vasoactive-inotropic score for predicting early extubation in adults after rheumatic heart valve surgery: a single-center retrospective cohort study

BACKGROUND

Early extubation (EEx) is defined as the removal of the endotracheal tube within 8 h postoperatively. The present study involved determining the availability and threshold of the vasoactive-inotropic score (VIS) for predicting EEx in adults after elective rheumatic heart valve surgery.

METHODS

The present study was designed as a single-center retrospective cohort study which was conducted with adults who underwent elective rheumatic heart valve surgery with CPB. The highest VIS in the immediate postoperative period was used in the present study. The primary outcome, the availability of VIS for EEx prediction and the optimal threshold value were determined using ROC curve analysis. The gray zone analysis of the VIS was performed by setting the false negative or positive rate R = 0.05, and the perioperative risk factors for prolonged EEx were identified by multivariate logistic analysis. The postoperative complications and outcomes were compared between different VIS groups.

RESULTS

Among the 409 patients initially screened, 379 patients were ultimately included in the study. The incidence of EEx was determined to be 112/379 (29.6%). The VIS had a good predictive value for EEx (AUC = 0.864, 95% CI: [0.828, 0.900], P < 0.001). The optimal VIS threshold for EEx prediction was 16.5, with a sensitivity of 71.54% (65.85-76.61%) and a specificity of 88.39% (81.15-93.09%). The upper and lower limits of the gray zone for the VIS were determined as (12, 17.2). The multivariate logistic analysis identified age (OR, 1.060; 95% CI: 1.017-1.106; P = 0.006), EF% (OR, 0.798; 95% CI: 0.742-0.859; P < 0.001), GFR (OR, 0.933; 95% CI: 0.906-0.961; P < 0.001), multiple valves surgery (OR, 4.587; 95% CI: 1.398-15.056; P = 0.012), and VIS > 16.5 (OR, 12.331; 95% CI: 5.015-30.318; P < 0.001) as the independent risk factors for the prolongation of EEx. The VIS ≤ 16.5 group presented a greater success rate for EEx, a shorter invasive ventilation support duration, and a lower incidence of complications than did the VIS > 16.5 group, while the incidence of reintubation was similar between the two groups.

CONCLUSION

In adults, after elective rheumatic heart valve surgery, the highest VIS in the immediate postoperative period was a good predictive value for EEx, with a threshold of 16.5.

MUC5AC concentrations in lung lavage fluids are associated with acute lung injury after cardiac surgery

Heart surgery may be complicated by acute lung injury and adult respiratory distress syndrome. Expression and release of mucins MUC5AC and MUC5B in the lungs has been reported to be increased in acute lung injury. The aim of our study was to [1] investigate the perioperative changes of MUC5AC, MUC5B and other biomarkers in mini-bronchoalveolar lavage (minBAL), and [2] relate these to clinical outcomes after cardiac surgery. In this prospective cohort study in 49 adult cardiac surgery patients pre- and post-surgery non-fiberscopic miniBAL fluids were analysed for MUC5AC, MUC5B, IL-8, human neutrophil elastase, and neutrophils. All measured biomarkers increased after surgery. Perioperative MUC5AC-change showed a significant negative association with postoperative P/F ratio (p = 0.018), and a positive association with ICU stay (p = 0.027). In conclusion, development of lung injury after cardiac surgery and prolonged ICU stay are associated with an early increase of MUC5AC as detected in mini-BAL.

Bronchoscopy in the management of children from developing countries undergoing congenital heart surgery

OBJECTIVES

To study the clinical characteristics and impact of bronchoscopy in children from developing countries, referred for cardiac surgery, through the "Save a Child's Heart" (SACH) organization.

METHODS

We performed a retrospective hospital-chart review of SACH children (0-18 years old) referred between 2006 and 2021 who underwent fiberoptic bronchoscopy. We examined demographics, congenital-heart-disease (CHD) types, bronchoscopy's indications and findings, subsequent recommendations, number of ventilation, and intensive-care-unit days. The primary outcome was percent changes in management and diagnosis, following the bronchoscopy. We included a control group matched-for-age and CHD type, who did not undergo bronchoscopy.

RESULTS

We performed 82 bronchoscopies in 68 children: 18 (26.5%) preoperatively; 46 (67.6%) postoperatively; and four (5.9%) both. The most prevalent CHDs were Tetralogy-of-Fallot (27.9%) and ventricular-septal-defect (19.1%). The main indications were persistent atelectasis (41%) and mechanical ventilation/weaning difficulties (27.9%). Bronchoscopic evaluations revealed at least one abnormality in 51/68 (75%) children. The most common findings were external airway compression (23.5%), bronchomalacia (19.1%), and mucus secretions (14.7%). Changes in management were made in 35 (51.4%) cases, with a major change made in 14/35 (40%) children. Compared to the control group, the children undergoing bronchoscopy were both ventilated longer (median 6 vs. 1.5 days, p < 0.0001) and stayed longer in the intensive care unit (median 1.5 vs. 18.5 days, p < 0.0001).

CONCLUSION

A bronchoscopy is an important tool in the diagnosis and management of the unique group of children from developing countries with CHD referred for cardiac surgery. The results of our study, reveal a more complicated clinical course in children requiring bronchoscopy compared to controls.

Early extubation in current valve surgery requiring long cardiopulmonary bypass: Benefits and predictive value of preoperative spirometry

BACKGROUND

Early extubation (EEx) after cardiac surgery has been essentially studied in patients with short cardiopulmonary bypass (CPB). Whether preoperative spirometry can predict EEx remains controversial.

OBJECTIVES

To investigate whether EEx can be a goal and predicted by preoperative spirometry in valve surgery requiring long CPB.

METHODS

Nonemergent consecutive 210 patients who underwent valve surgery from January 2014 to August 2019 were investigated retrospectively.

RESULTS

EEx (<8 h) was achieved in 93 (44.3%) patients without increasing adverse events. Patients with EEx had shorter ICU and hospital stays than those without EEx. Multivariate analysis showed that higher estimated glomerular filtration rate and mitral valve repair were significant protective factors for EEx. Conversely, moderate and severe chronic obstructive pulmonary disease defined by spirometry, longer operation, CPB, and aortic cross-clamp time were significant risk factors.

CONCLUSIONS

EEx should be the goal in current valve surgery. Preoperative spirometry is a significant predictor.

Pulmonary injury after cardiopulmonary bypass: beneficial effects of low-frequency mechanical ventilation

OBJECTIVE

Pulmonary dysfunction is a frequent postoperative complication after cardiac surgery with cardiopulmonary bypass, and atelectasis is thought to be one of the main causes. The aim of this study was to evaluate whether low-frequency ventilation and continuous positive airway pressure during cardiopulmonary bypass reduce postcardiopulmonary bypass lung injury.

METHODS

Eighteen Yorkshire pigs were subjected to 120 minutes of cardiopulmonary bypass (1 hour of cardioplegic arrest) followed by 90 minutes of recovery before being sacrificed. Six animals served as control with the endotracheal tube open to atmosphere during cardiopulmonary bypass. The remaining animals were divided into 2 groups of 6: One group received continuous positive airway pressure of 5 cm H(2)O, and one group received low-frequency ventilation (5/minutes) during cardiopulmonary bypass. Lung tissue biopsy and bronchoalveolar lavage samples were obtained before and 90 minutes after discontinuation of cardiopulmonary bypass for measurement of adenine nucleotide (adenosine-5'-triphosphate, adenosine diphosphate, adenosine monophosphate), lactate dehydrogenase, DNA levels, and histology. Hemodynamic data and arterial blood gases were also collected through the study.

RESULTS

The hemodynamic parameters were similar in the 3 groups. After cardiopulmonary bypass, the low-frequency ventilation group showed significantly better oxygen tension and alveolar arterial oxygen gradient, higher adenine nucleotide, lower lactate dehydrogenase levels, and reduced histologic damage in lung biopsy, as well as lower DNA levels in bronchoalveolar lavage compared with the control group. The continuous positive airway pressure group showed only significantly reduced lactate dehydrogenase levels compared with control.

CONCLUSION

Low-frequency ventilation during cardiopulmonary bypass in a pig experimental model reduces tissue metabolic and histologic damage in the lungs and is associated with improved postoperative gas exchange.

Upper airway mucus deposition in lung tissue of burn trauma victims

Previous study in an ovine model of smoke inhalation and burn (S + B) injury has shown distal migration of upper airway mucus. This study examines the localization of an upper airway gland specific mucus, mucin 5B (MUC5B) in lung autopsy tissues of burn-only injury and in victims of S + B injury. We hypothesize that victims with S + B injury would exhibit increased distal migration of MUC5B than that seen in victims of burn-only injury. Autopsy lung tissue from victims of burn injury alone (n = 38) and combined S + B injury (n = 22) were immunostained for MUC5B. No normal lung tissues were included in the study. Semiquantitative analysis of the extent of MUC5B in bronchioles and parenchyma was performed on masked slides. Irrespective of injury conditions, all victims showed MUC5B in bronchioles. Mucin 5B was seen in the parenchyma except in two burn victims. No statistically significant difference was seen in the mean bronchiolar and parenchyma MUC5B scores between S + B and burn-only victims (P > 0.05). No strong statistical correlation of MUC5B scores with days postinjury or to the number of ventilatory days was evident. The percentage of pneumonia, identified histologically, was also similar between study groups. This study did not confirm our results in an ovine model of S + B injury. In contrast, virtually all pediatric burn victims, regardless of concomitant inhalation injury, showed MUC5B in their bronchioles and parenchyma. Increased mucus synthesis and/or impaired mucociliary function may contribute to the pulmonary pathophysiology associated with burn injury.

The role of flexible fibreoptic bronchoscopy in evaluation of pulmonary diseases in children with congenital cardiac disease

BACKGROUND

Diseases of the lungs and airways can be life-threatening in patients with congenital cardiac disease. External compression, and tracheobronchomalacia, as well as pathology of the large airways, can cause respiratory symptoms such as wheezing, stridor, fever, and dyspnoea, along with producing difficulty to wean the patient from mechanical ventilation. A definite diagnosis may be achieved by fibreoptic flexible bronchoscopy.

AIMS

To characterize the patients who underwent bronchoscopy for respiratory diseases associated with congenital cardiac disease, and to evaluate the safety, total diagnostic rate, and diagnostic rate, which yielded alteration of treatment in this group of patients.

METHODS

We reviewed retrospectively the records of 39 patients with congenital cardiac disease associated with abnormalities of the airways who underwent 49 fibreoptic bronchoscopies between 1999 and 2004. The patients were evaluated with regard to rate of diagnosis, the rate of procedures that resulted in alteration of management, and the rate of complications.

RESULTS

Fibreoptic flexible bronchoscopy was safe, and contributed to a specific diagnosis in almost nine-tenths of the procedures. A specific diagnosis that resulted in treatment alteration was achieved in one-fifth of the procedures.

CONCLUSIONS

Fibreoptic flexible bronchoscopy has an important role in the evaluation of pulmonary abnormalities in patients with congenital cardiac diseases, and should be considered as an initial diagnostic tool that may guide the clinician with regard to the proper therapy.