Precath preparation

1. Precath Preparation
Dr Fuad Farooq

2. Preparation of the Patient
•Elective cardiac cath should be deferred if
the patient is not prepared physiologically
and physically

3. Consent
•Detailed discussion with the patient and family
•Should be obtained by the operator or his or her
assistant
–Should outline the indication of procedure
–Explain in simple terms which procedure to take place and for
what reason each step of the procedure will occur
–Explain the risk for routine cardiac cath
•Major- stroke, myocardial infarction, kidney failure, death
•Minor- vascular injury, allergic reaction, bleeding, hematoma,
infection
•Possible need of emergency CABG
–Explain any portion of the study used for research
–Provide necessary information and explanation

4. History
•Including
–Reason of cardiac cath
–Precious allergies to dye, sea food
–Asthma, allergic rhinitis
–Medications esp. ASA, Clop, Metformin,
anticoagulants
–History of kidney disease
–In female, if child bearing age, ask especially
for pregnancy

5. Examination
•Thorough general physical examination
should be done
•All peripheral pulses should be palpated
and documented
•Look for arterial bruit and document it as a
baseline for future reference
•Perform Allen’s test if radial approach
•Auscultate chest
•Look for murmurs

6. Metabolic Profile
•Renal function e.g. BUN, creatinin
•Electrolytes e.g., Na, K
•CBC
•Coagulation profile
•Any abnormality in the lab should be
addressed before proceeding to LHC

7. •Precath orders preferably written on
preceding night
–If patient on long acting insulin dose should
be reduced to half
–NPO at least 8 hours before procedure
–Shave both groins for femoral access and
mostly right wrist for radial approach
•Avoid laceration or abrasions
–Apply Foley’s catheter or external/sheath
catheter in male

8. Choice of Dye
•Now a days mostly nonionic low osmolal dye is
used
–Causes less nausea and emesis, LV dysfunction,
bradycardia and hypotension
–Useful in cases of suspected LM stenosis, severe LV
dysfunction, and severe aortic stenosis
–In patients with renal insufficiency and reported
allergy to contrast dye
–More thrombogenic than ionic dye so used with
caution- use 5 IU of heparin per cubic centimeter of
contrast

9. Contrast Media Reaction
•Incidence 5%
•10-12% patients has history of asthma
•15% patients has the history of previous reaction
to the contrast media
•Three types
–Cutaneous and mucosal manifestations (angioedema,
flushing, laryngeal edema, pruritis, urticaria)
–Smooth muscle and minor anaphylatoid reaction
(bronchospasm, GI spasm, uterine contraction)
–Cardiovascular and major anaphylactoid reaction
(arrhythmia, hypotension, vasodilatation)

10. •More risk with the ionic contrast media than non-ionic
contrast media
•Any patient reported previous allergy to the contrast
media or history of atopy or prior anaphylactoid reaction
should be premedicated with
–Steroid ( prednisolone 40mg PO Q6H or I.V hydrocortisone
100mg once at least 6 hours before the procedure
–Diphenhydramine ( Benadryl 50mg I.V once )
–H2 blocker ( Clemestine 1mg I.V once)
•If history of life threatening dye allergy, it is prudent to
admister 1ml of dye and watch for few minutes before
proceeding
Contrast Media Reaction..

11. Contrast Induced Acute Kidney
Injury
•High risk patients are
–Patients with diabetes
–Patients with renal insufficiency (Cr >1.5)
–Patients who are dehydrated due to any reason
•Prevented by
–I/V hydration with 0.9% saline ( LV function should be taken into
consideration for selection of rate of infusion)
•Dose: 1ml/kg at least 2 hours before procedure and ideally Upto 6-
12 hours before procedure and continue Upto 6-12 hours post
procedure
–Alkalinization of urine prevent free radical injury to the kidney
•Dose: 3 ml/kg for one hour before procedure and continued as
1ml/kg/hr for 6 hours post procedure

12. Contrast Induced Acute Kidney
Injury
–Acetylcysteine- has antioxidant and vasodilator
properties
•Must be accompanied by I/V hydration and use of low or iso-
osmolal contrast agent
•Risk reduction Upto 50%
•Dose: 1.2 gm P.O twice a day starting day before the
procedure and continue for two days post procedure (I/V
admistration if in emergent procedure and orally cannot be
given-150mg/kg prior procedure and 50mg/kg post
procedure over 4 hours)
–Using low osmolal or iso-osmolal nonionic contrast
media (use in lower dose)
–Avoid closely spaced studies (<48 hours apart)
–Avoid NSAID’s

13. Diabetes Mellitus
•Patient with diabetes on insulin therapy, overnight fast
with normal dose of insulin can cause hypoglycemia
–Dose if insulin should be half
–Patient on NPH insulin has increase risk of protamine reaction
•Patient on Metformin, withheld it 48 hours before
procedure because of risk of lactic acidosis especially in
patients with renal insufficiency
–may resume after 48 hours only when renal function are found to
be normal
–Hydrate the patient before during and after the procedure ( i.v
saline @ 1ml/kg/hr)

14. Patient Education
•Patient should be warned that they might
feel hot sensation for few seconds when
contrast is injected, some patients may
feel nausea
•Patient should specially instructed to
cough when they hear anyone in the cath
lab say “cough” – this will accelerates
resolution of dye induced bradycardia

15. Equipment
•Before performing cath it is very essential
that the monitoring equipment is fully
functional
•Continues ECG recording, heart rate,
rhythm, ST segment an automated BP
and pulse oximetry are essential
•Resuscitation equipment should be tested
and ready – defib and intubation trolley
should be next to the patient