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Dr. S. Parthasarathy MD., DA., DNB, MD ( Acu ), Dip. Diab . DCA, Dip. Software statistics Ph d( physio ) Mahatma gandhi medical college and research institute, puducherry , India . Anaesthetic concerns in cyanotic congenital heart disease – incidental surgery . Why to know??.
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Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statistics Ph d( physio) Mahatma gandhi medical college and research institute, puducherry, India Anaesthetic concerns in cyanotic congenital heart disease – incidental surgery
Why to know?? • Number of children reaching adulthood with CHD has increased over the last 5 decades • advances in diagnosis, medical, critical and surgical care, • not uncommon for adult patients with CHD to present for non-cardiac surgery
Incidence • 7 to 10 per 1000 live births • Commonest cong. Disease • 15 % have associated anomalies • 15% survive to adulthood without treatment
What happens after birth ?? There are 4 shunts in fetal circulation: placenta, ductusvenosus, foramen ovale, and ductusarteriosus In adult, gas exchange occurs in lungs. In fetus, the placenta provides the exchange of gases and nutrients
Ductusvenosus • Removal of placenta results in following: • ↑ SVR(because the placenta has lowest vascular resistance in the fetus) • Cessation of blood flow in the umbilical vein resulting in closure of the ductusvenosus
Foramen ovale • Lung expansion → reduction of the pulmonary vascular resistance (PVR), an increase in pulmonary blood flow, & a fall in PA pressure • Functional closure of the foramen ovaleas a result ↑ LAP in excess RAP LAP increase ? RAP decrease ? DA closure D/T ↑ arterial oxygen saturation So all shunts close !!
Classification of CHD • Acyanotic • Cyanotic
Incidental surgery – concerns • Spectrum • Corrected fallots adult for I & D • to • Also uncorrected fallots for intestinal gangrene
Preop assessment • Patients cardiac disease • Age • Present illness ,others
Patients cardiac disease • Cyanosis • Cyanotic spells • Cong. Cardiac failure Pulm. Vs Sys. Shunt > 2:1 Exercise tolerance – siblings Adequate weight ? Sweating, dyspnoea during feeds??
AGE • Heart rate • LV pressure less • Educating the child ,family • Age related airway and IV access problems
Present illness ,others • Gangrene gut • Sepsis , dehydration • Pregnancy for LSCS • Orthopedics
Present illness ,others • Evidence of downs syndrome • Macroglossia, hypoplastic mandible, protuberant teeth • Blood pressure in all limbs
Investigations • Hb% • Cyanosis Hb % may be upto 20 gm/dl. • Hb level ?? Hct decrease PBF increase • Polycythemia – increased viscosity sludging of blood flow – • So cold OR ?? • Proper hydration is a must
Coagulation • Polycythemia – increased viscosity sludging of blood flow leads to IV thrombosis • Fibrinolysis and consumptive coagulopathy • Think of tonsillectomy • Remove 20 ml/ kg RBC • fill it with FFP.
Other investigations • Electrolytes • Digoxin, diuretics • Hypoglycemia , hypocalcemia • ABG • PaO2 30- 40 mmHg – SaO2 <70 % = risk • Cardiology consultation
Preop URI • Desaturation , • Laryngospam • Bronchospasm • Post ext. stridor common • 4-6 weeks – gap ideal • Can we get such patients without URI ??
Anaesthesia • Cardiac grid • Five factors • 1. preload • 2. SVR • 3. PVR • 4. HR • 5.contractility
Preload • increase • Volume load • Capacitance vessel constriction • Decrease • Phlebotomy • Less volume replacement
SVR • increase • Arteriolar constriction • Anaesthetics – ketamine • Decrease • Anesthetics (volatile & IV) • Histamine releasing drugs
PVR • increase Hypoxia, hypercarbia peep high Hct • Decrease Pulm. dilators And others
Heart rate • Increase Atropine Pancuronium Isoflurane • Decrease Beta blockers Fent Digoxin
Contractility • increase Inotropes Digoxin Calcium • Decrease All inh. Agents Ca. channel blockers
Cardiac grid -- Five factors • 1. preload • 2. SVR • 3. PVR • 4. HR • 5.contractility
Premedication • Avoid IM • Child may cry , precipitate cyanotic spell • Fasting 2 hours clear fluids for kids • Withhold • diuretic(one day) • anticoagulants to normalize coagulation profile
Premedicants described • Oral / nasal midazolam • IV fentanyl + atropine • Morphine + atropine + midazolam • Nasal ketamine
For Infective endocarditis • IV Ampi 2 gm + Genta 80 mg ½ hour before and 6 hours later • 50 mg /kg and 2mg/kg • Allergic to penicillin • Vancomycin 20 mg/kg + genta 2mg/kg
Venous access • No ambulatory surgery • Always IV access even minor procedures • No air • Rigorous debubbling techniques to follow
Debubbling techniques • De bubble all IV tubing • Free flow before connection • Aspirate or eject air before Injection • Don’t use till last drop • IV air traps if possible • Inject vertical • Don’t open catheter to atmosphere • Avoid N2O if suspicion
Monitor • SaO2 • ETCO2 , TEE if air embolism possible • Other monitoring as usual • ECG – arrhythmias common • USG guided central line and • post Catheter X ray to ascertain position
Anaesthesia • Ketamine ok • Pancuronium if necessary • High FiO2 • Opioids • Inh. Agents • Maintain cardiac grid
Anaesthesia • Maintain temperature • Adequate hydration • IV induction ?? • Inh. Induction ??
Regional anaesthesia • No pain related side effects • No coagulopathy • Intrathecal narcotics • Fibro adenoma breast with Fallots ??
Post op • Care of pain Blocks , IV para , opioids • No hypoxemia or hypercarbia • Supplemental oxygen
Special for TOF • Prevent cyanotic spell β blockers alpha agonist ready Preserve SVR
Treatment of Hypercyanotic Spells • High FiO2 → pulmonary vasodilator → ↓ PVR • Hydration (fluid bolus) → opens RVOT • Morphine (0.1mg/kg/dose) → sedation,↓ PVR • Ketamine→ ↑ SVR, sedation, analgesia → ↑ PBF • Phenylephrine (1mcg/kg/dose) →↑ SVR • β-blockers (Esmolol 100-200mcg/kg/min) →↓HR,-veinotropy→ improves flow across obstructed valve &↓infundibular spasm
Cardiac grid • Preload -- N • Adjust SVR/PVR = 1 • HR = N • Contractility = N
Cardiac grid –ebsteins • Preload = increase • SVR = N • PVR = decrease • HR = N • Contractility = N
Tricuspid atresia • Preload = N • SVR = decrease • PVR = increase • HR = N • Contractility = N
Transposition of great vessels • Preload = N • SVR = N • PVR = • HR = • Contractility = N • Adequate mixing if we balance PVR and SVR
GENERAL PRINCIPLES RINCIPLESQ= P/R Q = Blood flow (CO) P = Pressure within a chamber or vessel R = Vascular resistance of pulmonary or systemic vasculature Inf. endocarditis prophylaxis , debubbling techniques, present illness, hydration, induction ,coagulopathy