There is increasing recognition of the role that perioperative pulmonary complications play in the direct and indirect costs associated with surgery. Though current interventions to mitigate these costly complications are available, most remain unclear regarding efficacy. In this mini review, we’ll identify, define, and raise awareness regarding perioperative pulmonary complications.
Annually, more than 300 million surgical procedures are performed worldwide. Surgical volume has commensurately increased with the projected increase in global geriatric populations with an estimated two billion over the age of 60 years old by the end of 2050. Estimates of perioperative pulmonary complications (PPC) range from 6-9 per cent and substantially impact the cost and quality of care provided by surgical services1. For example, postoperative pneumonia (POP) is estimated to cost the United States healthcare system approximately US$11.9 billion dollars in additional expenditure per annum. This adds approximately US$717 dollars to the average cost of an elective surgical procedure and ~US$25,000 dollars per PPC2. These estimates are limited however by how PPC are measured. PPC endpoints are highly dependent on researcher or monitoring governmental agencies selection processes, a significant issue limiting precise estimates of cost of care and impact to national or international healthcare systems. It is highly probable that these costly complications are underreported. It is clear, however, that global healthcare systems should treat these adverse perioperative outcomes seriously as they generate substantial costs that negatively impact expected budgets, patient morbidity and mortality after elective surgical procedures.
The burgeoning global geriatric population is particularly prone to PPC, of which the causes are multifactorial and multisystemic. The ageing heart and lung (diastolic heart failure, pulmonary hypertension, and other age-related disorders), acquired disease (interstitial lung disease, smoking related emphysema, obstructive sleep apnea, and procedural invasiveness all independently contribute to PPC, adding length of stay, morbidity, and mortality. Comorbidities at particular risk for PPC include chronic obstructive pulmonary disease, interstitial lung disease and obstructive sleep apnea. These and many other disorders are associated with age-related increases, magnifying the risk of PPC-related morbidity in geriatric populations. Thoracic surgery, cardiac surgery and oncological surgery service lines are at heightened risk of substantial acquired cost of care related to PPC.
The conundrum on how to best reduce PPC remains. There is active ongoing clinical and translational research in PPC but, at this time, few clinical interventions have been proven to definitively prevent or mitigate the risk of PPC. Complex risk assessment tools are available but are generally time consuming or unwieldy for the typical high volume of preoperative patients seen by pre-surgical evaluation clinics3. Research has been performed in the area of preoperative risk stratification, particularly to target patient for pre-habilitative interventions before surgery. New evidence has supported the quantification of frailty as a superior measure to increasing age. Frailty may be defined as a condition of increased age-associated deterioration of physiology precipitating a lower cardiopulmonary reserve for stressors such as surgery or infection. Over 27 indices of frailty exist, although the most commonly used is the Phenotype of Frailty Index4,5. Appropriate identification is critical as there is supportive evidence that prehabilitation, defined as interventions performed with a focus on improving functional capacity prior to surgical procedure and the aim of reducing post-operative morbidity and mortality, may be effective interventions to reduce PPC6,7. These pre-habilitative interventions may be as simple as instructions regarding inspiratory muscle training or as complex as preoperative nutritional supplementation and physiotherapy. This is an active area of clinical research with encouraging findings regarding PPC reduction, however, the value is, as of yet, still unclear8. Some simple and costeffective intraoperative interventions have shown benefit such as application of lung-protective ventilatory strategies, appropriate selection of anaesthetic or neuromuscular blockade reversal9. After cardiac surgery, the selective use of noninvasive positive pressure ventilation devices has been observed to significantly reduce post-operative hypoxemia, pneumonia, reintubation, and intensive care unit readmission rates10. Simplified bundled respiratory care after surgery (aspiration precautions, oral care and incentive spirometry) have also shown promise in reducing PPC11,12.
The cost burden of PPC, particularly with a rapidly aging global population and commensurate increase in demand for surgical services, is a challenge for global healthcare systems. Postoperative pneumonia, in particular, is a costly complication with significant morbidity and mortality. Patients deserve a high-quality healthcare experience with reduced risk of pulmonary complications. Thoughtful integration of PPC mitigation strategies will reduce perioperative morbidity and mortality. Identifying PPC patients early allows for close observation and in the case of pneumonia early treatment. Bundling small interventions (oral care, early mobilisation, incentive spirometry, etc.) may act as a force multiplier in exploiting low-cost, high yield interventions. Some interventions, such as prophylactic highflow nasal cannula, although costly, may provide reduced downstream cost. The goal is to always identify, quantify and intervene prior to PPC and I am optimistic that ongoing clinical and translational research into these high-risk complications will continue to improve clinical outcomes and reduce cost of care.
