• Table of Contents
• Pediatric Neurosurgery

   XXXIV. Bad Head - Bad Heart (Coartation)

    XXXV. Bad Head - Bad Heart (Aortic Stenosis)

       A. The primary hemodynamic goals are: Slow & tight.
	  The heart rate should be slow to allow for more
	  complete emptying, facilitating foward cardiac
	  output (CO).  If the heart rate gets too fast, 
	  CO will drop.  Vascular tone should remain high
 	  (tight), because CO through a tight stenotic
	  lesion is fixed.  If vascular resistance gets
	  too low, BP cannot be maintained.  Imagine trying
	  to fill a room with a water pistol.  

       B. Prior to induction, make sure the patient is
          well hydrated. This and the availability of a
          phenylepherine (neo) drip (put two 10 mg amps 
          of neo in 250cc bag of 0.9% NS with a 60 gtt/cc 
	  mini-dripper) are your main lines of defense 
          against what can be a precipitous death in the 
          face of hypotension with severe Aortic Stenosis.

       C. Induce with a priming dose of a milligram of
          vecuronium followed by 10-15 mcg/kg of fentanyl
          (in divided doses) and some etomidate.  Run the
          patient on 70% nitrous. This will often be
          sufficient for a two hour case. 

       D. Fast heart rate is worse (a lot worse) than a
          slow heart rate. A heart rate in the 40's is
          not unusual for this technique.  Let it ride
          unless hemodynamic instability occurs.

       E. The patient will probably have a ventricular
          strain pattern on the EKG so don't be fooled
          into thinking that there is ST depression
          secondary to ischemia. Nitroglygerine (NTG) can
          be very dangerous for aortic stenosis patients.

       F. Do not use naloxone (Narcan) if the patient fails
          to wake up. The tachycardia that could result
          would be disastrous.