Transcript TETRALOGY OF FALLOT

TETRALOGY OF FALLOT
• COMMONEST CYANOTIC
CONGENITAL HEART DISEASE
• 10 % OF ALL CONGENITAL HEART
DISEASES
MORPHOLOGY
• FOUR MORPHOLOGICAL DEFECTS
– VENTRICULAR SEPTAL DEFECT
– RIGHT VENTRICULAR OUTFLOW TRACT
OBSTRUCTION
• SUBVALVAR
• VALVAR
• SUPRAVALVAR
– OVERRIDING OF THE AORTA
– RIGHT VENTRICULAR HYPERTROPHY
MORPHOLOGY OF NORMAL HEART
MORPHOLOGY IN T.o.F
Subvalvar
Obstruction
ALTERED PHYSIOLOGY
• OBSTRUCTION TO FLOW OF
DEOXYGENATED BLOOD FROM THE
RIGHT VENTRICLE TO THE
PULMONARY ARTERY
• DECREASED OXYGENATION DUE TO
POOR PERFUSION OF THE BLOOD
ALTERED PHYSIOLOGY
• SHUNTING OF DEOXYGENATED
BLOOD FROM THE RIGHT
VENTRICLE TO THE AORTA ACROSS
THE VENTRICULAR SEPTAL DEFECT
(FACILITATED BY AORTIC
OVERRIDE)
• POOR SYSTEMIC OXYGENATION,
LOW HEMOGLOBIN SATURATION
AND CYANOSIS
CLINICAL PRESENTATION
• CYANOSIS NOT USUALLY NOTICED
AT BIRTH
• CAUSES
– CHILD LESS ACTIVE IN THE INITIAL
FEW MONTHS
– FOETAL HEMOGLOBIN HAS MORE
AFFINITY FOR OXYGEN THAN ADULT
HEMOGLOBIN
CLINICAL PRESENTATION
• CYANOSIS MANIFESTS MORE AS
CHILD BECOMES MORE ACTIVE
• PHYSICAL GROWTH IS USUALLY
GOOD
• MENTAL DEVELOPMENT MAY BE
DELAYED IN SEVERE CASES DUE TO
CHRONIC HYPOXIA OF THE BRAIN
CYANOTIC SPELLS
• TYPICAL OF FALLOT’S
TETRALOGY
• USUALLY OCCURS WHEN THE
CHILD CRIES OR IS VERY
ACTIVE AS WHEN THE CHILD
WAKES UP FROM SLEEP
CYANOTIC SPELLS
• ACTIVITY RESULTS IN
– INCREASES OXYGEN DEMAND
– DECREASES SYSTEMIC VASCULAR
RESISTANCE
– INCREASES SYMPATHETIC ACTIVITY
WHICH CAUSES INFUNDIBULAR SPASM,
I.E., INCREASE IN THE MUSCULAR
OBSTRUCTION TO THE RIGHT
VENTRICULAR OUTFLOW AT THE
SUBVALVAR LEVEL
DECREASED S.V.R.
• MORE SHUNTING ACROSS THE VSD –
MORE DESATURATION OF SYSTEMIC
BLOOD – PERIPHERAL ACIDOSIS –
FUTHER SYSTEMIC
VASODILATATION – FURTHER
DECREASE IN SVR – VICIOUS CYCLE
SQUATTING
• TYPICAL OF FALLOT’S TETRALOGY
• CHILD ASSUMES SQUATTING POSTURE
VERY FREQUENTLY
• SOME POSTURES MAY BE CALLED
‘SQUATTING EQUIVALENTS’
• REASON IS THAT SQUATTING CAUSES AN
INCREASE IN RESISTANCE TO SYSTEMIC
FLOW – DECREASED SHUNTING ACROSS
THE VSD – LESS DESATURATION OF
SYSTEMIC BLOOD
NATURAL HISTORY
• WIDE SPECTRUM OF CLINICAL
MANIFESTATIONS DEPENDING ON
SEVERITY OF ABNORMALITIES, I.E.,
DEGREE OF OBSTRUCTION TO
RIGHT VENTRICULAR OUTFLOW,
AND SIZE OF VSD
NATURAL HISTORY
• IN SEVERE CASES, CHILD MAY HAVE
REPEATED CYANOTIC SPELLS
• IN LESS SEVERE CASES, CHILD MAY BE
FREE FROM SPELLS, BUT SEVERLY
CYANOSED, WITH NORMAL PHYSICAL BY
DELAYED MENTAL DEVELOPMENT
• IN MILD CASES, CHILD MAY GROW
NORMALLY, WITH CYANOSIS BEING ONLY
MINIMAL
TREATMENT OPTIONS
• ONLY SURGICAL
– PALLIATIVE SURGERY
– DEFINITIVE SURGERY
PALLIATIVE SURGERY
• AIMED TO DIVERT SYSTEMIC BLOOD
INTO THE PULMONARY CIRCULATION
AND THUS ENHANCE PULMONARY FLOW
AND OXYGENATION
• STANDARD OPERATION IS THE MODIFIED
BLALOCK-TAUSSIG SHUNT OR OTHER
SYSTEMIC PULMONARY SHUNTS SUCH AS
POTT’S SHUNT AND WATERSTON-COOLEY
SHUNT
DEFINITIVE SURGERY
• RELIEF OF RIGHT VENTRICULAR
OUTFLOW TRACT OBSTRUCTION
• SEPARATION OF SYSTEMIC AND
PULMONARY CIRCULATIONS BY
CLOSURE OF THE VSD
TREATMENT STRATEGIES
• PALLIATIVE SURGERY IN EARLY
CHILDHOOD FOLLOWED BY
DEFINITIVE SURGERY IN THE LATER
YEARS, USUALLY AFTER 3 – 4 YEARS
OF AGE
• DEFINITIVE SURGERY IN THE
NEONATAL PERIOD OR EARLY
CHILDHOOD
T.O.F IN ADULT CARDIAC SURGICAL
HOSPITAL
• DELAYED DEFINITIVE REPAIR
FOLLOWING SHUNT IN EARLY
CHILDHOOD
• DELAYED PRESENTATION, FOR
DEFINITIVE REPAIR
• RE-OPERATION FOR DELAYED
COMPLICATIONS AFTER DEFINITVE
REPAIR
POSTOPERATIVE NURSING ISSUES
• MOST WILL HAVE A NORMAL
CIRCULATION POSTOPERATIVELY
• C.V.P MAY RUN HIGH DUE TO STIFF RIGHT
VENTRICLE AND HIGH RVEDP
• GAS EXCHANGE IS USUALLY NORMAL
• MAY HAVE HEART BLOCKS OR
BRADYARRYHTHMIAS