The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

Changes in Respiratory Movements of

Cardiac Surgery Patients

María Ragnarsdóttir, PT, MSc Department of Rehabilitation

Landspítali - University Hospital,

Reykjavík, Iceland.

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

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

IntroductionIntroduction

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 is one of the most frequently reported.

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

IntroductionIntroduction

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

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

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

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

MethodMethodThe hospital’s Ethics Commity and the 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

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

Method Respiratory 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

Method Respiratory Movements

RMMI measures abdominal- lower thoracic- and upper thoracic 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

MethodMethod Lung Volumes 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

MethodMethodX-ray analysesX-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

MethodA scale for the position of the left diaphragmA 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

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

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

MethodStatistical analysis

Descriptive statistics.

Wilcoxon Signed Ranks Test were used for analysis.

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

ResultsPeri-operative information/measurements

Surgery: AVR 6, AVR and CABG 6, OPCAB 4, CABG 2, MVR 1, 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

Results Pre-operative respiratory movements in mm

0

5

10

15

20

25

Right AB, LT and UT Left AB; LT and UT

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

Results Postoperative respiratory movements in mm

0

5

10

15

20

25

Right AB, LT and UT Left AB; LT and UT

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

Results Proportion of pre-operative respiratory movements

0

20

40

60

80

100

120

Right AB, LT and UT Left AB, LT and UT

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

ResultsSignificance of changes in breathing movements

Mean

95%

confidence interval

t df Sig. (2 tail) difference Lower Upper

R. Abd. -6.20 19 0.000 -0.68 -0.91 -0.45

L. Abd. -5.63 19 0.000 -0.71 -0.98 -0.45

R. LTh -4.00 19 0.001 -0.40 -0.62 -0.19

L. LTh -4.27 19 0.001 -0.39 -0.59 -0.20

R. UTh. 0.11 19 0.907 ns 0.01 -0.18 0.20

L. UTh. -1.77 19 0.929 ns -0.15 -0.33 0.03

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

Results Proportion of preoperative lung volumes

0

10

20

30

40

50

60

70

80

90

100

VC FVC FEV1

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

ResultsSignificance of changes in LUNG VOLUMES

Mean

95%

confidence interval

t df Sig. (2 tail) difference Lower Upper

VC -11.65 19 0.0001 -0.54 -0.63 -0.44

FVC -9.01 19 0.0001 -0.52 -0.64 -0.40

FEV1 -6.90 19 0.0001 -0.54 -0.70 -0.38

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

0102030405060708090100

PleuralEffusion

Atelectasis Elevateddiaphragm

ResultsX-rays

Proportion of patients with abnormal findings post-op.

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

ResultsCorrelations

No correlation was found between any of the variables analysed.

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

DiscussionDiscussion

The study results in a nutshell!

Future studies.

The VI Nordic Congress on Cardiac Rehabilitation, June 14th 2002

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.