The efficacy of postoperative bronchodilator usage

1. The efficacy of postoperative bronchodilator usage Ri 林建志

2. The effect of nebulized salbutamol therapy on the incidence of postoperative chest infection on high risk patients Dilworth JP, Warley AR, Dawe C, White RJ.Department of Medicine, Frenchay Hospital, Bristol, U.K. Respiratory Medicine. 1994 Oct;88(9):665-8.

3. Introduction • Postoperative respiratory complication: respiratory infection • High risk: chronic airway obstruction, recurrent bronchitis, heavy smokers • Previous trials: prophylactic antibiotics, various physiotherapy technique, regional anaesthetic techniques • The study was designed to determine whether perioperative high dose salbutamol therapy in high risk patients reduced the risk of postoperative respiratory track infection

4. Methods • Frenchay Hospital, July 1989 to July 1991, patients for surgery requiring an anterior abdominal incision • Respiratory questionnaire and spirometric measurement • Patients eligible for inclusion: chronic bronchitisairflow obstruction: FEV1/FVC<70%current or previous smokers: at least 20 pack years

5. Randomized double-blind protocol was followed • Group A: 5 mg neubulized salbutamol at 6 hourly interval from 1h preoperatively for a total of 48h( 8 doses) • Group B: 5ml nebulized normal saline

7. Patients were seen on alternate days during the postoperative period and the presence of fever, cough, purulent sputum and new chest signs. • CXR and blood white count: preoperative and the second postoperative day • Respiratory infection: purulent sputum and one out of pyrexia, cough, new chest signs, radiographic change or leukocytosis

8. Results • No major difference between the two groups • Overall incidence of respiratory tract infection: 40 % • Analysis of subgroups: no any significant difference in smokers, chronic bronchitis or those with airflow obstruction alone

10. Discussion • The dominant finding in those at high risk: airflow obstruction and excess mucus production • Salbutamol: bronchodilator action, improving mucociliary clearance, may resulted in a useful reduction in the incidence of postoperative infection • No such result was obtained.

11. Patients had baseline spirometry prior to surgery • Serial measurement of ventilatory function was not made due to abdominal wounds in the immediate postoperative time • It cannot be stated that whether these patients exhibited any reversibility in airflow obstruction

12. This study has provided no support for the routine use of high dose bronchodilator therapy as a prophylactic measure against postoperative respiratory infection in high risk patients

13. Terbutaline improves efficiency of oxygenation after coronary artery bypass surgery. Waller DA, Saunders NR.Department of Cardiothoracic Surgery, Killingbeck Hospital, Leeds, UK. J Cardiovasc Surg (Torino). 1996 Feb;37(1):59-62

14. Post-CABG respiration complications: sputum retention, atelectasis, and hypoxia • Median sternotomy and internal thoracic artery dissection: restrictive ventilatory defect • Complement and neutrophil mediated injury secondary to extra-corporeal circulation: lung interstitial edema

15. To assess the therapeutic role of the beta-receptor agonist terbutaline in reducing postoperative pulmonary dysfunction following coronary artery bypass grafting

16. Methods • 22 patients undergoing CABG were randomized into two groups • Group C: no additional treatment • Group T: subcutaneous terbutaline 0.5 mg 6 hourly for the first 48 hours after extubation • Subcutaneous route: avoid the uncertainty of delivery from aerosol, and acute cardiovascular side effects form iv administration

17. Baseline spirometry: peak expiratory flow rate (PEFR), FEV1, FVC • Exclusion criteria: asthma, current use of bronchodilators, DM or prolonged assisted ventilation in excess of 36 hrs

19. Postoperative measurement: ABG, PEFR, FEV1, FVC, continuous invasive arterial blood pressure, continuous ECG • Analysis: alveolar-arterial oxygen difference (A-aDO2) and PaO2:FiO2: reflecting the degree of physiological shunt

20. Results

23. CABG resulted in a significant reduction in FVC, FEV1 and PEFR in both groups, no significant difference. • Significant increase from the immediate post-extubation in both groups • FEV1: FVC ratio was unaffected by CABG

25. Alveolar-arterial oxygen difference: increase significantly after extubation in both groups and remained significantly elevated for the next 18hrs in group C • At 6 hrs post-extubabation, there was no significant difference in A-aDO2 from pre-extubation values (P=0.069)

26. The results show no improvement in spirometric parameter • Improvement in oxygenation: stimulatory effects on mucociliary clearance , preventing small airways closure, or due to increased pulmonary blood flow • Little therapeutic role for the terbutaline as a bronchodilator in reducing respiratory insufficiency after CABG

27. Routine use of high dose bronchodilator therapy as a prophylactic measure against postoperative respiratory infection in high risk patients: not supported • Little therapeutic role for the terbutaline as a bronchodilator in reducing respiratory insufficiency after CABG