Respiratory infection and respiratory failure

Postoperative pulmonary complications (PPC) result in significant morbidity, mortality and healthcare costs. The incidence of “important” PPCs is 2-5% in the general surgical population. These consist of respiratory infection, respiratory failure, atelectasis, prolonged invasive mechanical ventilation, prolonged high-level respiratory support, and readmission to the ICU for pulmonary complications. However, additional patient factors and types of surgical procedures may increase the risks for PPCs.

Upper abdominal surgery

Pulmonary complications are especially common after thoracic and upper abdominal surgery. Other risk factors include advanced age, higher American Society of Anesthesiologists (ASA) physical status classification scores, functional dependency, congestive heart failure, chronic obstructive pulmonary disease (COPD); so smoking history and body mass index ≥ 30 kg/m2. Of these, ASA score ≥ 2 and functional dependency have consistently been associated with a higher rate of significant PPCs such as postoperative respiratory failure.

Occurrence of postoperative respiratory failure requiring prolonged mechanical ventilation or re-intubation accounts for poor outcomes and high economic costs. Although PPCs are an incompletely understood multifactorial occurrence, atelectasis is recognized as a critical component. Evidence suggests that atelectasis is a common precursor of PPCs. Nearly all patients undergoing major surgery experience some degree of transitory, clinically unimportant atelectasis. Most do not require aggressive therapy.

However, in subgroups of high-risk individuals, treatment of atelectasis and mobilization of secretions may help prevent deterioration to postoperative respiratory failure. The precise definition of PPC remains controversial. Reported incidence varies from 2% to 40%. In 2015, a European Perioperative Clinical Outcome taskforce recommended a definition of PPC including: respiratory infection, respiratory failure, pleural effusion, atelectasis, pneumothorax, bronchospasm, aspiration pneumonitis, acute respiratory distress syndrome, pulmonary edema and pulmonary embolism.

Pulmonary complications

In the present study, PPCs consisted of the following clinically relevant parameters: prolonged invasive mechanical ventilation, prolonged high-level respiratory support, requirement for non-invasive ventilation or CPAP above patient’s baseline; also diagnosis of pneumonia, and readmission to the ICU (or transfer to higher-level of care) for pulmonary complications. Our Stage they cohort had a 22.9% incidence of PPCs, comparable to previous studies.

Our study demonstrated that patients who received treatment with OLE experienced fewer PPCs and had less time on mechanical ventilation. Further, incorporating OLE resulted in significant reduction in HLOS. Importantly, patients with higher ASA scores had the largest PPC reduction. The results suggest the modality is feasible; also may help achieve value base quality care for surgical patients.

In addition, other disease entities with a high likelihood of pulmonary complications; which should be consider for future OLE studies, including those admit following blunt chest trauma, COPD exacerbation, cystic fibrosis, and pneumonia. Patients receiving oscillation and lung expansion (OLE) experience fewer postoperative pulmonary complications (PPCs); so less time on mechanical ventilation and a significant reduction in hospital length of stay compare with those receiving standard respiratory care. Higher risk patients, base on age and American Society of Anesthesiologists scores, had greatest PPC reduction.