Post-operative Pulmonary Dysfunction after Cardiac Surgery

Abstract

Summary P ostoperative pulmonary dysfunction (PPD) is a frequent and almost inevitablesignificant complication after cardiac surgery. It contributes to morbidity and mortality and increases hospitalization stay and its associated costs. Its pathogenesis is not clear but it seems to be related to the development of a systemic inflammatory response with a subsequent pulmonary inflammation. There are two principal mechanisms that have been identified as the fundamental causes for the development of PPD, one is the stress of the surgery and its associated factors (Extracorporeal Circulation, median sternotomy incision, hypothermia for myocardial protection, dissection of the internal mammary artery) that cause an important systemic inflammatory response.The other important factor is the lung injury caused by inflammation and aggravated by suboptimal mechanical ventilation There are many risk factors that increase the incidence of PDD includes (old age, obesity, debilitation, smoking,associated renal or respiratorydisease, chronic alcohol use, and chronic steroid use). PPD clinical manifestations include pleural effusion with A frequent presentation,atelectasis,postoperative hypoxemia without clinical symptoms, pneumothorax, pneumonia,pulmonary edema, and acute respiratory distress syndrome (ARDS), which have a low incidence but high mortality. PPD refers to expected alterations in pulmonary function such as increased work of breathing, shallow respiration, ineffective cough, and hypoxemia. Interventions aimed at decreasing pulmonary dysfunction associated with general anesthesia should begin prior to the operation and continue through the perioperative and postoperative periods. These interventions should be carried out regardless of the risk of the development of PPCs as Smoking cessation, Optimization of chronic lung conditions. Lung expansion, deep breathing and coughing, and incentive spirometry are best taught to the patient before surgery and are useful for postoperative reduction of atelectasis. Also there are intra-operative measures that help minimize PDD as duration of surgery (shorter procedure should be considered in extremely high-risk patients), andadequate use of neuromuscular blockade. All cardiac surgery patients who fail to easily wean from mechanical ventilation and who have no other obvious cause for respiratory failure should be investigated for phrenic nerve injury. Protective ventilation strategies can reduce the incidence of atelectasis (which still remains one of the principal causes of PDD) and pulmonary infections in surgical patients. Non Invasive Ventilationapplied early has shown to be effective in reducing atelectasias and PPD, minimising reintubation rates, length of stay in ICU, and hospital and ICU readmissions Early extubation is well documented and should be the goal in adults after cardiac surgery, as it may reduce postoperative complications and decrease ICUstay and costs. delayed extubation strategy may be mandatory in selected patients (eg: postoperative cardiac failure and surgery associated focal neurological insult.