Shock:  Solution 1

      
   

 

      
     

► An 84 year old female is admitted with an episode of loss of consciousness. Her blood pressure is 76/44 on cuff measurement. Her heart rate is 40. No collateral history is available.

 

  • Is this genuine hypotension?

  • Is the heart rate appropriate for the blood pressure?

  • What is the patient’s volume status (cardiac filling)?

  • Does the heart contract normally?

  • Is the patient abnormally vasodilated?

 		        
      Solution
This patient’s heart rate is inappropriately low for the blood pressure. The most likely scenario is that the patient has a bradyarrhythmia, and is unable to mount a stroke volume sufficient to maintain blood pressure. This would occur for example if her myocardium lacked elasticity, such as with myocardial fibrosis, or with outflow obstruction, such as with aortic stenosis or mitral stenosis. A vaso-vagal episode would manifest in the same way.
The essential immediate test is an electrocardiograph, which would show complete heart block, with an escape rhythm, or a sinus bradycardia. The treatment is atropine: this reverses vagally mediated bradycardia, and will reassert the blood pressure. If this is not successful, then the use of more potent chronotropes (such as isoproteranol), or external pacing may be necessary.
Other things to think about here are: inferior wall myocardial infarction causing complete heart block, hypothyroidism, and overdosing on nodal blocking drugs – beta blockers, calcium channel blockers and digoxin.

Diagnosis (Dx): cardiogenic shock due to inappropriate heart rate.