Anesthetic considerations in lung transplantation: past, present and future

Lung transplantation is a very complex surgical procedure with many implications for the anesthetic care of these patients. Comprehensive preoperative evaluation is an important component of the transplant evaluation as it informs many of the decisions made perioperatively to manage these complex patients effectively and appropriately. These decisions may involve pre-emptive actions like pre-habilitation and nutrition optimization of these patients before they arrive for their transplant procedure. Appropriate airway and ventilation management of these patients needs to be performed in a manner that provides an optimal operating conditions and protection from ventilatory injury of these fragile post-transplant lungs. Pain management can be challenging and should be managed in a multi-modal fashion with or without the use of an epidural catheter while recognizing the risk of neuraxial technique in patients who will possibly be systemically anticoagulated. Complex monitoring is required for these patients involving both invasive and non-invasive including the use of transesophageal echocardiography (TEE) and continuous cardiac output monitoring. Management of the patient's hemodynamics can be challenging and involves managing the systemic and pulmonary vascular systems. Some patients may require extra-corporeal lung support as a planned part of the procedure or as a rescue technique and centers need to be proficient in instituting and managing this sophisticated method of hemodynamic support.

The impact of invasive respiratory support on the development of postoperative atrial fibrillation following cardiac surgery

STUDY OBJECTIVE

Postoperative atrial fibrillation (POAF) is a frequent complication after cardiac valve- or coronary artery bypass (CABG) surgery and is associated with increased mortality. While it is known that prolonged postoperative invasive ventilation triggers POAF, the impact of ventilatory settings on POAF development has not been studied yet.

DESIGN

Prospective observational study.

SETTING

Postoperative Intensive Care Unit.

PATIENTS

Patients having undergone elective CABG and/or cardiac valve surgery.

MEASUREMENTS

Screening for the development of POAF. Patients' clinical data and postoperative ventilatory settings (driving pressure, controlled pressure above positive endexpiratory pressure (PEEP), respiration rate, and FiO2) were investigated to elucidate their impact on POAF.

MAIN RESULTS

Out of 441 enrolled individuals, a total of 192 participants developed POAF (43.5%). We observed that POAF patients received a higher peak driving pressure, and a higher peak respiration rate than non-POAF individuals. Within the multivariate regression model, plateau pressure (adjusted OR 1.199 [1.038-1.661], p = 0.019), driving pressure (adjusted OR 1.244 [1.103-1.713], p = 0.021), and peak respiration rate (adjusted OR 1.206 [1.005-1.601], p = 0.040) proved to be independently associated with the development of POAF. CART analysis revealed a cut-off of ≥17.5 cmH₂O of plateau pressure, ≥11.5 cmH₂O of driving pressure and ≥ 17 respirations per minute as high-risk for POAF development.

CONCLUSIONS

The ventilatory settings of plateau pressure, driving pressure, and respiration rate after cardiac surgery influence POAF occurrence probability. Optimized postoperative care such as lung-protective ventilation and increased awareness towards postoperative ventilatory efforts should be considered to prevent POAF development and poor patient outcome.

Knowledge and Practice of the Concept of Driving Pressure: A Survey of Pediatric Intensivists in Brazil

The objective of this study was to investigate the knowledge and clinical practices of Brazilian pediatric intensivists in relation to usage of the concept of driving pressure. Knowledge and practice patterns were assessed using a survey tool. The overall response rate was 22.8% (84 of 369); 69% of physicians responded that they had sufficient knowledge on the concept of driving pressure but only 56% correctly answered to specific knowledge questions about it. The majority of respondents (72.6%) claim to use this concept in their clinical practice although pediatric data are insufficient to routinely support the practice. This also suggests a good degree of knowledge translation from adult studies.

Tidal volume and mortality in mechanically ventilated children: a systematic review and meta-analysis of observational studies*

OBJECTIVE

To determine whether tidal volume is associated with mortality in critically ill, mechanically ventilated children.

DATA SOURCES

MEDLINE, EMBASE, and CINAHL databases from inception until July 2013 and bibliographies of included studies without language restrictions.

STUDY SELECTION

Randomized clinical trials and observational studies reporting mortality in mechanically ventilated PICU patients.

DATA EXTRACTION

Two authors independently selected studies and extracted data on study methodology, quality, and patient outcomes. Meta-analyses were performed using the Mantel-Haenszel random-effects model. Heterogeneity was quantified using I. Study quality was assessed using the Newcastle-Ottawa Score for cohort studies.

DATA SYNTHESIS

Out of 142 citations, seven studies met the inclusion criteria, and additional two articles were identified from references of the found articles. One was excluded. These eight studies included 1,756 patients. Mortality rates ranged from 13% to 42%. There was no association between tidal volume and mortality when tidal volume was dichotomized at 7, 8, 10, or 12 mL/kg. Comparing patients ventilated with tidal volume less than 7 mL/kg and greater than 10 mL/kg or greater than 12 mL/kg and tidal volume less than 8 mL/kg and greater than 10 mL/kg or greater than 12 mL/kg also showed no association between tidal volume and mortality. Limiting the analysis to patients with acute lung injury/acute respiratory distress syndrome did not change these results. Heterogeneity was observed in all pooled analyses.

CONCLUSIONS

A relationship between tidal volume and mortality in mechanically ventilated children could not be identified, irrespective of the severity of disease. The significant heterogeneity observed in the pooled analyses necessitates future studies in well-defined patient populations to understand the effects of tidal volume on patient outcome.