considerations by an anesthetist during cardiopulmonary bypass,presentation made for PG students

1. CARDIOPULMONARY BYPASS
DR. ARUN SAGAR JR II
MODERATOR: DR RITURAJ

2. CARDIOPULMONARY CIR

3. CARDIOPULMONARY BYPASS
• IT IS TO PROVIDE A NON BEATING BLOODLESS
HEART WITH FLOW TEMPORARILY DIVERTED
TO AN EXTRA-CORPOREAL CIRCUIT THAT
FUNCTIONALLY REPLACES HEART AND LUNGS

4. SURGICAL PROCEDURES REQUIRING
CPB
• CORONARY ARTERY BYPASS SURGERY
• CARDIAC VALVE REPAIR AND/OR REPLACEMENT ( MITRAL
VALVE, TRICUSPID VALVE ETC.)
• REPAIR OF LARGE SEPTAL DEFECTS ( ASD,VSD ETC.)
• REPAIR AND/OR PALLIATION OF CONGENITAL HEART DEFECTS
( TOF , TOGV ETC.)
• TRANSPLANTATION ( HEART TRANSPLANT, LUNGS
TRANSPLANT ETC. )
• REPAIR OF SOME LARGE ANEURYSMS LIKE AORTIC ANEURYSM
• PULMONARY THROMBOENDARTERECTOMY AND
THROMBECTOMY

5. PREANAESTHETIC WORKUP
• DO THE PAC OF PATIENT WITH HISTORY AND
PHYSICAL EXAMINATION,METS ETC.
• CBC,COAGULATION PROFILE,RENAL AND LIVER
FUNCTION TESTS,
• CHEST X RAY, RESTING ECG ,2D ECHO, STRESS
ECHO
• MYOCARDIAL PERFUSION SCANS
• ANGIOGRAPHY
• CONTRAST VENTRICULOGRAPHY

6. PATIENT PREPARATION
• PUT A 18G OR PREFERABLY 16G CANNULA
• AN INTERNAL JUGLAR CENTRAL LINE
• A RADIAL AND FEMORAL ARTERIAL LINE( FOR ABG
AND IBP )
• PATIENTS BLOOD TAKEN FOR ACT ( ACTIVATED
CLOTTING TEST) IT IS TIME FROM ADDING BLOOD TO
MACHINE UP TO TIME WHEN FIRST CLOT APPEARS. AN ACT
LONGER THAN 400-480 SECS IS CONSIDERED SAFE.
• HEPARINIZATION FOR ANTICOAGULATION
DURING SURGERY IS BASED ON ACT.

7. PREMEDICATION AND INDUCTION
• NARCOTICS OR ANXIOLYTICS OR BOTH FOR
PAIN AND ANXIETY AS PREMEDICATION
( PATIENTS WITH EF <40% AND PATIENTS WITH LOW CARDIAC
OUTPUT ---SHOULD BE GIVEN PREOP MEDICATIONS SLOWLY
AND CAREFULLY TO AVOID MYOCARDIAL DEPRESSION AND
HYPOTENSION )
• GOAL OF INDUCTION IS TO AVOID
HYPOTENSION AND ATTENUATE
HEMODYNAMIC RESPONSE TO
LARYNGOSCOPY AND INTUBATION

8. • SMALL INCREMENTAL DOSES OF INDUCING
AGENT TO BE GIVEN ( pref. ETOMIDATE)
• IF BP FALLS > 20% OF BASELINE THEN USE
INOTROPES INFUSION
• THERE MAY BE HYPERTENSION ALSO, DUE TO
PRE INDUCTION ANXIETY AND SYMPATHETIC
STIMULATION
• MUSCLE RELAXATION AND CONTROLLED
VENTILATION TO ENSURE ADEQUATE
OXYGENATION AND PREVENT HYPERCARBIA

9. TOTAL INTRAVENOUS ANAESTHESIA
• INFUSION OF PROPOFOL @ 25-100 mcg/kg/min
• REMIFENTANYL 1 mcg/kg FOLLOED BY 0.25-1
mcg/kg INFUSION
• TOATAL DOSE OF FENTANYL SHOULD 5-7 mcg/kg
• REMIFENTANYL should be supplemented by
MORPHINE at the end of sx for post op pain

10. MIXED INTRAVENOUS ANAESTH.
• MIDAZOLAM 0.05mg/kg FOR SEDATION
• ETOMIDATE 0.1-0.3 mg/kg FOR INDUCTION
• OPIOIDS ARE GIVEN INTERMITTENTLY ( total
dose of fentanyl <15mcg/kg and remifentanyl
< 5mcg/kg)
• IN FRAIL PATIENTS KETAMINE AND
MIDAZOALM PROVIDES HEMODYNAMIC
STABILITY, GOOD AMNESIA,ANALGESIA AND
MINIMAL RESPIRATORY DEPRESSION

11. INHALATIONAL ANAESTHESIA
• VOLATILE AGENTS 0.5-1.5 MAC for
maintenance of anaesthesia and sympathetic
response suppression
• ISOFLURANE , SEVOFLURANE OR DESFLURANE
CAN BE USED

12. PRE BYPASS CHECKS
• CHECK B/L AIR ENTRY
• PROTECT EYES
• CHECK ALL MONITORS AND TUBINGS AFTER
FINAL POSITIONING
• ADMINSTER ANTIBIOTICS
• CHECK BASELINE ACT
• CHECK BASELINE ABG
• PRIMING OF BYPASS MACHINE AND CIRCUITS
BY BALANCED SALT SOLUTION (RINGER
LACTATE ETC.) IN SEVERLY ILL PATIENTS WITH
BLOOD

13. CONSIDERATIONS IN STEPS OF BYPASS
• SKIN INCISION MAY CAUSE SYPATHETIC STIMULATION
SO↑ DEPTH OF ANAESTHESIA SO AMNESIC AGENTS
LIKE BENZODIAZEPINES AND PROPOFOL TO BE USED
• AT THE TIME OF STERNAL SPLITTING THERE MAY BE
PAIN, AWARENESS, TACHYCARDIA AND RAISED BP SO
TO BE MANAGED BY NTG OR ESMOLOL AND
FENTANYL HIGH DOSES
• LUNGS TO BE DEFLATED AT THE TIME OF SPLITTING
BY DISCONNECTION OF GAS FROM WORKSTATION
• HEPARINIZATION BEFORE OPENING PERICARDIUM
ACCORDING TO BASE LINE ACT (target 400-480 secs)
@ 300-400mcg/kg .

14. CANNULATION IN CPB

15. • AORTIC CANNULATION IS DONE FIRST TO
ALLOW RAPID VOLUME INFUSION IN CASES
OF HAEMORRHAGE DURING VENOUS
CANNULATION.
• VENOUS CANNULATION OF MAJOR VEINS-SVC
& IVC OR RIGHT ATRIUM.

16. CARDIOPLULMONARY BYPASS
MACHINE

17. CPB BASIC CIRCUIT

21. CARDIOPLEGIA AND HYPOTHERMIA
• THESE ARE TWO IMPORTANT ROUTINELY
USED COMPONENTS OF CPB
• CORE BODY TEMP. IS REDUCED TO 20-32 ◦ ©
PROFOUND HYPOTHERMIA 15-18 ◦© FOR
COMPLEX REPAIR OF AORTA.
• HYPOTHERMIA HELP IN MYOCARDIAL
PRESERVATION AND ↓O2 DEMAND
( metabolic O2 demand generally cut in half with
each 10 degree reduction)

22. CARDIOPLEGIA
• TO PROVIDE A MOTIONLESS FIELD,HEART IS
STOPPED IN DIASTOLE BY ADMINISTERING A
POTASSIUM RICH CARDIOPLEGIC SOLUTION
• ( it interrupts myocardial electromechanical
activity, reduces O2 consumption by 90% and
cold cardioplegia reduces it by 97% )
• COMPLETE CARDIOPLEGIA ACHIEVED BY BOTH
ANTEGRADE AND RETROGRADE APPROACH
AND IT IS SUPERIOR TO ONLY ANTEGRADE
TECH.

23. CARDIOPLEGIA
• CARDIOPLEGIA IS USUALLY ADMINISTERED
EVERY 20-30 MINS.(excessive cardioplegia
may cause absence of electrical activity, AV
conduction blockade or a poorly contracting
heart at conclusion of CPB)
• THERE IS OFTEN A PERIOD OF “WASH OUT”
NEEDED IN LONG CASES , TO ALLOW THE
MYOCARDIUM TO CONTRACT FULLY AND
WITHOUT ANY DEPRESSION.
• ARREST IS REVERSED BY REPERFUSING WITH
WARM NORMOKALEMIC BLOOD( HOT SHOT)

25. INTRA OP MONITORING
• HEMODYNAMIC PARAMETERS –HR/NIBP/
SPO2/ INTRAOP ABGs/ INTRAOP ACT
• IBP-dominant hand radial is prefered
• ECG-to see ST changes and T wave changes
• CVP- internal jugular vein
• PA CATHETER ( SWAN GANZ CATHETER)
• TRANSESOPHAGEAL ECHO- can assess regions
supplied by all three major coronary arteries
and regional wall motion abnormality can be
seen before ECG and PA/SGC changes

26. MAINTENANCE OF BYPASS
• ACT repeated every 30-60 min, IF LESS –
supplemental Heparin is to be added.
• ABG to be evaluated every 30-60 min.
• PaO2 to be maintained between 100-
300mmHg and PaCO2 between 30-40mmHg.
• Blood Glucose and Haematocrit measured
every 30-60 min.
• DEPTH OF ANAESTHESIA IS MAINTAINED BY
adding anaesthetic agents and muscle
relaxants directly into the circuit and adding
volatile agents by connecting vapourizer to
oxygenator of bypass machine.

27. • PUMP FLOW RATE is to be maintained
@50-70 ml/kg/min.
• Urine Output to be atleast 0.5ml/kg/hr.
• Core temperature to be monitored at
Nasopharynx or Tympanic membrane.
• DE-AIRING OF HEART TO BE DONE BEFORE
WEANING FROM CPB by increasing venous
pressure by inflating lungs and tapping of
tubings .

28. WEANING FROM BYPASS
• BEFORE TERMINATION ,PATIENT SHOULD BE
REWARMED ,HEART IS DE-AIRED, REGULAR
CARDIAC ELECTRICAL ACTIVITY CONFIRMED OR
SUPPORTED BY PACE MAKER, LAB VALUES
CONFIRMED AND CORRECTED
• VENTILATION OF LUNGS IS ESTABLISHED BY
CONNECTING TO WORKSTATION WHEN PA
BLOOD FLOW IS RESTORED.
• VENOUS DRAINAGE IS SLOWLY REDUCED AND
CARDIAC FILLING VOLUME IS GRADUALLY
INCREASED.
• VASOPRESSORS OR INOTROPIC SUPPORT MAY BE
NEEDED

29. •WHEN PT. BECOMES HEMODYNAMICALLY STABLE
PROTAMINE SULPHATE IS ADMINISTERED
1-1.3mg protamine per 100 units of HEPARIN slowly
over 10-15 mins
• ACT should be brought to baseline
•WHEN PRE-LOADING IS OPTIMAL AND
CONTRACTILITY IS ADEQUATE, AORTIC INFLOW LINE
IS CLAMPED TO SEPERATE FROM BYPASS MACHINE.
•VISUALISATION OF HEART BY TEE TO SEE
CONTRACTILITY.
•VOLUME EXPANSION TO BE DONE IF NEEDED.

30. POST BYPASS
• PATIENT IS SHIFTED TO CARDIAC ICU BEING
INTUBATED AND ON MECHANICAL
VENTILATION FOR 2-12 hrs WITH SEADTION
AND ANALGESIA TO BE CONTINUED
• EXTUBATION IS CONSIDERED WHEN-pt.
become conscious,muscle paralysis gone,ABG
acceptable, surgical hemostasis is adequate
and the patient is hemodynamically stable

31. BYPASS COMPLICATIONS
• ISCHEMIA AND INFARCTION
• LV DYSFUNCTION
• RV DYSFUNCTION
• RV FAILURE
• HYPOTENSION
• DYSRYTHMIAS (AF MOST COMMON, VF,
BRADYCARDIAS AND HEART BLOCK)
• BLEEDING AND COAGULOPATHY
• ATELECTASIS,HEMOTHORAX/
PNEUMOTHORAX, PULMONARY EDEMA

32. BYPASS COMPLICATIONS
• METABOLIC DISTURBANCES
(HYPOKALEMIA,HYPERKALEMIA,HYPOCALCEM
IA,HYPOMAGNESEMIA,HYPERGLYCEMIA)
• TRANSIENT NEUROPSYCHIATRIC
DYSFUNCTION AND/OR STROKES
• DECREASED RENAL PERFUSION

33. OFF PUMP CABG
• OFF PUMP OR BEATING HEART CABG IS SURGERY
WITHOUT CARDIOPULMONARY BYPASS and REQUIRED
IN
1. patients with anterior lesions,single or double vessel disease
2. Pts. With high risk of stroke, renal failure, pulmonary
dysfunction and severe valvular disease.
• Hypothermia is avoided throughout sx.
• Goal of heparin anticoagulation is >2 times of baseline ACT
or >300sec or sometimes >400
• Only focal area of heart is stabilized with epicardial
stablizers.SBPkept< 100mm hg
• HEMODYNAMIC DISTURBANCES AND ARRYTHMIAS ARE
MORE FREQUENT