This presentation provides information about the role of RT in handling patients who had undergone Coronary Artery Bypass Graft

1. CABG
Aziza Alamri ..

2. :Outlines
 Definition of CABG
 Review of Coronary Arteries
 Purposes
 Indications for CABG
 Contraindications for CABG
 Procedure
 Respiratory management
 Complications
 References

3. Definition
 Is a surgical procedure performed to relieve
angina and reduce the risk of death from coronary
artery disease.
 Arteries or veins from elsewhere in the patient's
body are grafted (internal thoracic arteries, radial
arteries and saphenous) to the coronary arteries to
bypass atherosclerotic narrowing's and improve
the blood supply to the coronary circulation
supplying the myocardium (heart muscle). This
surgery is usually performed with the heart
stopped .

4. What does (single, double, triple,
quadruple and quintuple) bypass
refer to ?
They refer to the number of coronary arteries bypassed
in the procedure.

5. In other words :
 Double bypass means two coronary arteries are
bypassed (e.g. the left anterior descending (LAD)
coronary artery and right coronary artery (RCA)
 Triple bypass means three arteries are bypassed
(e.g. LAD, RCA, left circumflex artery (LCX)
 Quadruple bypass means four vessels are
bypassed (e.g. LAD, RCA, LCX, first diagonal
artery of the LAD)
 Bypass of more than four coronary arteries is
uncommon.

6. Review Of Coronary Arteries

7. Purposes
 Restore blood flow to the heart
 Relieves chest pain and ischemia
 Improves the patient's quality of life
 Enable the patient to resume a normal lifestyle
 Lower the risk of a heart attack

8. Indications
 Patients with blockages in coronary arteries
 Patients with angina
 Patients who cannot tolerate PTCA
(Percutaneous transluminal coronary
angioplasty ) and do not respond well to drug
therapy
 Acute myocardial infarction
 Sever coronary artery disease

9. Contraindications
 Aneurysms
 Valvular diseases
 Congenital diseases
 diseases of blood

10. Procedure
 An endotracheal tube is inserted and secured
and mechanical ventilation is started. General
anesthesia is maintained by a continuous very
slow injection of Propofol .

11.  The chest is opened via a median sternotomy and
the heart is examined by the surgeon involves
creating a 6-8 inch incision in the chest .

12.  The heart is cooled with iced salt water, while a
preservative solution is injected into the heart
arteries. This process minimizes damage caused
by reduced blood flow during surgery and is
referred to as "cardioplegia."

13.  The most commonly used grafts for the bypass
are the internal thoracic arteries, radial
arteries and saphenous veins.
 When the wanted vessels are harvested , the
patient is given heparin to prevent the blood
from clotting.

14.  Before bypass surgery can take place, a
cardiopulmonary bypass must be established.
Plastic tubes are placed in the right atrium to
channel venous blood out of the body for passage
through a plastic sheeting (membrane oxygenator)
in the heart lung machine

15. Do you think that
Cardiopulmonary bypass and
ECMO are the same ?

16. The differences between ECMO and
cardiopulmonary bypass are as follows:
ECMO is frequently instituted using only cervical
cannulation, which can be performed under local
anesthesia; standard cardiopulmonary bypass is
usually instituted by transthoracic cannulation
under general anesthesia
Cardiopulmonary bypass, which is used for short-
term support measured in hours, ECMO is used for
longer-term support ranging from 3-10 days

17. Cont ..
The oxygenated blood is then returned to the
body. Once Cardiopulmonary Bypass is
established, the surgeon places the aortic cross-
clamp across the aorta and instructs the
perfusionist to deliver cardioplegia to stop the
heart and slow its metabolism.

18. One end of each graft is sewn on to the coronary
arteries beyond the blockages and the other end
is attached to the aorta.
Chest tubes are placed in the mediastinal and
pleural space to drain blood from around the
heart and lungs.
The sternum is wired together and the incisions
are sutured closed.
The patient is moved to the (ICU) to recover.

19. Ones the patient is in the ICU he/she should be
monitored .
After awakening and stabilizing in the ICU
(approximately one day), the person is transferred
to the cardiac surgery ward until ready to go home
(approximately four days).

21. Respiratory management
A study was done by the Saudi journal of
anesthesia in 2011 about a Comparison of
two ventilation modes in post-cardiac
surgical patients ..

22. They were saying that The cardiopulmonary
bypass (CPB)-associated atelectasis accounted for
most of the marked post-CABG, increase in shunt
and hypoxemia.
They hypothesized that (PRVC) modes having a
distinct theoretical advantage over (PCV) by
providing the target tidal volume at the minimum
pressure may prove advantageous while
ventilating these atelactic lungs.

23. 36 post-cardiac surgical patients with a
PaO2/FiO2 < 300 after arrival to ICU .
They were randomized to receive either PRVC or
PCV .
 (Paw) and (ABG) were measured at four time
points :
• T1: After induction of anesthesia.
• T2: after CPB (in the ICU).
• T3: 1 h after intervention mode.
• T4: 1 h after T3

24. Oxygenation index was calculated for each
set of data and used as an indirect
estimation for intrapulmonary shunt.
(OI) =
[PaO2/ {FiO2 × mean airway pressure (Pmean)}]

25. Result:
There is a steady and significant improvement
in OI in both the groups at first hour and
second hour of ventilation.
However, the improvement in OI was more
marked in PRVC at second hour of
ventilation owing to significant low mean air
way pressure compared to the PCV group

26. They Concluded that PRVC may be
useful in a certain group of patients
to reduce intrapulmonary shunt and
improve oxygenation after
cardiopulmonary bypass-induced
perfusion mismatch.

27. Weaning
Pre-Weaning Criteria
Weaning Criteria

28. Pre-Weaning Criteria
No acute ischemia
Hemodynamically stable.
Absence of new arrhythmia
Blood loss < 2cc/kg/ hour
Urine output > 1cc/kg/hour
Demonstrating signs of awakening from
anesthesia
Core temp 97.0 or greater

29. Weaning Criteria
Patient is awake and cooperative ( follows
commands )
Able to lift head off pillow
PO2 > 80 mmHg with FIO2 < .40 with PEEP 5
cmH2O or less and PS 5cmH2O or less
Spontaneous tidal volumes > 5cc/kg
Respiratory rate < 30

30. Assess patient for placement on CPAP 5
cmH2O with PS 5 cmH2O.
After PS of 5cmH2O for 20 to 30 minutes,
obtain an ABG.
CPAP should not exceed one hour.
If ABG obtained in CPAP trial meets the
following criteria: pH > 7.35 , PCO2 < 45 ,
PO2 >80 with an FIO2 ≤ 40% . (Considered
Extubation)

31. Criteria assessed before extubation
..
NIF >30 cmH2O
 Vt > 5 cc/kg
VC > 12 cc/kg

32. After Extubation ..
After physician approval , the patient will be
extubated to 40% aerosol mask.
 After 4 hours on the aerosol mask, the patient
can be placed on a 5 LPM humidified nasal
cannula if pulse oximeter readings are
consistently above 95%. The oxygen can be
weaned as long as the pulse oximeter is

33. Post Extubation Treatments
IPPB treatments* should be started within 2
hours of extubation. If the patient is unable to
cooperate with a mouthpiece, IPPB with a mask
should be attempted.
*IPPB treatment with racemic epinephrine will
reduces glottic edema and the swelling caused by
the tube and its removal

34. Patients with a history of smoking and have
not quit within one year prior to the surgery
will receive a unit dose of albuterol with each
treatment.
Other patients will receive normal saline with
each treatment.
When patient is alert incentive spirometry
will be used .

35. Complications
Bleeding
Heart attack
Heart failure
Arrhythmia
Stroke
Pleural effusions
Wound infection
Renal failure
Death

36. References
 Medscape  http://emedicine.medscape.com/article/1893992-
overview
 AHA  http://my.americanheart.org/professional/General/2011-
ACCFAHA-Guideline-for-Coronary-Artery-Bypass-Graft-Surgery
 Textbook  Brunner and Siddhartha's Textbook of Medical-
Surgical Nursing , 12th edition, Brunner and Siddhartha's Textbook
of Medical-Surgical Nursing 2012
 CABG  Clinical Pathway Steering Committee
 Saudi J anasthesia 
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139311/
 EXTUBATION: GUIDELINES 
http://www.rcecs.com/myce/pdfdocs/course/v7020.pdf

37. Thank You For Listening