Changes in Respiratory Movements of Cardiac Surgery Patients

1. Changes in Respiratory Movements of Cardiac Surgery Patients María Ragnarsdóttir, PT, MScDepartment of Rehabilitation Landspítali - University Hospital, Reykjavík, Iceland. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

2. Changes in Respiratory Movements of Cardiac Surgery Patients Coworkers: Ásdís Kristjánsdóttir, PT, MSc Ingveldur Ingvarsdóttir, PT, MA Pétur Hannesson, PhD, chief radiologist Bjarni Torfason, chief physician, ass. professor The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

3. Introduction • Restrictive respiratory defect following cardiac surgery is well documented. • The ethiology for these findings is not fully understood. • Several factors can contribute to the restrictive respiratory defect. • Diaphragmatic dysfunction isone of the most frequently reported. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

4. Introduction • Altered ribcage mechanics have been suggested to be an additional factor • Only one study was found on respiratory movements during quiet breathing following cardiac surgery. • No study was found on deep breathing where submaximal effort is required of the motor system of the respiratoy organs. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

5. Introduction • The surgical procedure. • Are the costo-transversal and costo-vertebral joints affected? • Are the respiratory muscles affected? The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

6. Introduction • What happens when the internal mammary artery is used for CABG? • Does the distortion of the ribcage make the injury more severe? The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

7. Purpose • To quantify the changes in bilateral respiratory movements following median sternotomy. • To study the correlation between postoperative respiratory movements and: • the width of the sternal opening during the operation; • the difference in height of the two sternal margins during the operation; • spirometri and x-ray analysis. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

8. Method The hospital’s Ethics Commity andthe Data Protection Authority accepted the study. All patients signed an informed consent to participate. Exclusion criteria: • Previous cardiac surgery. • Inability to walk 50 meters. • Late discharge from intensive care (>48 hours). The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

9. MethodDemographic data • Subjects: 20 (13 men and 7 women). • Mean age: 65 years, + 16.6 SD. • Mean BMI: 27.9, + 5.4 SD (range 15.4 - 36.5). • Smoking: 7 never smoked, 13 smoked (mean p/y 25). The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

10. MethodRespiratory Movements • Respiratory movements were measured using a novel instrument, the Respiratory Movement Measuring Instrument, RMMI. • Manufacturer: ReMo ehf, Keldnaholti 112 Reykjavík Iceland. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

11. MethodRespiratory Movements • RMMI measures abdominal- lowerthoracic- and upperthoracic anterior-posterior movements, bilaterally. • Respiratory movements during vital capacity breathing were measured preoperatively and on the 7th postoperative day. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

12. Method Lung Volumes The following lung volumes were measured preoperatively and on the 7th postoperative day, using a portable spirometer: • Vital capacity, VC • Forced Vital Capacity, FVC and • Forced Expiratory Volume in one second, FEV1. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

13. MethodX-ray analyses Chest X-rays were taken prior to the operation and on the first, second and fifth postoperative day as routinely. On the 5th postoperative day the study patients had an extra sidelying picture taken. All pictures were evaluated by the same radiologist according to a 4 point scale made by him for this study. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

14. MethodA scale for the position of the left diaphragm • 1 = Normal. • 2 = Minor. Left diaphragm is slightly higher than the right diaphragm. • 3 = Medium. Left diaphragm is elevated up to the half the height of the left heart border. • 4 = Major. Left diaphragm is elevated above half the height of the left heart border. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

15. MethodPeri-operative measurements All the study patients were operated on by the same surgeon Measurements: Pump time Clamp time Lowest temperature Width of sternal openig Difference in hight of the sternal margins The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

16. MethodPhysiotherapy • All patients received pre- and postoperative physiotherapy according to the standard of the deparment. • The same physical therapist treated all patients. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

17. MethodStatistical analysis • Descriptive statistics. • Wilcoxon Signed Ranks Test wereused for analysis. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

18. ResultsPeri-operative information/measurements Surgery: AVR 6, AVR and CABG 6, OPCAB 4, CABG 2, MVR1, VSD 1. Measurements: • Pump time: Mean 75 minutes (0 – 161) • Clamp time: Mean 50.5 minutes (0 – 122) • Lowest temperature: Mean 33.9° C (31.8° - 36.6°) • Sternal opening: Mean width 8.3 cm + 1.2 Mean difference in hight 4.2 cm + 0.5 The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

19. Results Pre-operative respiratory movements in mm The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

20. Results Postoperative respiratory movements in mm The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

21. Results Proportion of pre-operative respiratory movements The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

22. ResultsSignificance of changes in breathing movements The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

23. ResultsProportion of preoperative lung volumes The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

24. ResultsSignificance of changes in LUNG VOLUMES The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

25. ResultsX-raysProportion of patients with abnormal findings post-op. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

26. ResultsCorrelations • No correlation was found between any of the variables analysed. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

27. Discussion • The study results in a nutshell! • Future studies. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

28. Conclusion • The motor system of the respiratory organs are significantly impaired one week after cardiac surgery through median sternotomy. • Further studies are needed to find out what role this impairment plays in the recovery of these patients and how long lasting the imapirment is. The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002