Case Study: Atropine & the Bradycardia Patient

Questioning the need for patient interventions is key to good EMS care


      The 9-1-1 dispatcher reports a call from a female who says her 66-year-old mother "may be having a heart attack, but is responsive." On arrival, the crew finds the older female can answer questions, but responds in a fashion the daughter says is abnormally slow and confused. The patient, Mrs. Jones, says she had a heart attack four months ago and is now taking medication for heart failure. She has felt progressively tired over the past two weeks, and feels dizzy when standing. Today, her chest started "feeling funny" about an hour ago, with some pain at about 2 on a 10 scale. She has a history of hypertension. She is not reporting shortness of breath, sweating or nausea.

   Initial physical exam reveals an elderly female with pale skin in no respiratory distress. Her vitals are: BP 90/55, pulse 48 and irregular, RR 24 with slight bilateral lower lobe crackles, pulse oximetry 92%. Her pupils are equal, round and reactive; blood glucose is 90; there is 1+ ankle edema, and the jugular veins are distended.

   Oxygen is given by NRB at15 LPM; IV access and the initial lead II strip are obtained. Every third P-wave lacks a subsequent QRS complex. All P-R intervals are 0.16 seconds and regular. The QRS complexes are 0.18 seconds wide and upright in lead II. A 12-lead EKG is obtained showing a left axis. The rhythm disturbance noted in the 3-lead rhythm strip is confirmed. Lead V1 shows deep QS waves and ST segment elevation (see Figure 1). These ECG findings point to the possibility of left bundle branch block. There are Q-waves in leads II and III, which raises concerns for inferior or right-sided infarction.

CRITICAL DECISIONS

   The nearest hospital with invasive cardiac capability is 45 minutes away, and the patient had received treatment at the facility for a heart problem that occurred four months ago. A closer community hospital is 10 minutes transport time. Oxygen has not improved the patient's pulse oximetry reading or mental status. She shows evidence of poor perfusion and is still confused. Her daughter can't provide any history of the patient's usual blood pressure, but in a patient with a history of hypertension, a blood pressure of 90/55 is almost certainly too low. Her heart rate is low, and she is not conducting the electrical impulses effectively and regularly. The patient shows signs that her vascular volume is not compromised, with jugular venous distention, lung crackles and leg edema. To increase perfusion, the patient needs a heart rate higher than 48 beats a minute. Questions the EMS crew will need to consider are: How should the bradycardia be treated in light of a suspected left-sided bundle branch block and possible MI? If this patient deteriorates, should she be given atropine or have transcutaneous pacemaking performed? In view of these questions and how they will impact the transport decision, medical control is contacted.

BRADYCARDIA TREATMENT OPTIONS

   The emergency physician on service initially asks for details regarding the patient's current health status and determines that although she continues to show symptomatic signs of hypoperfusion, her condition is not deteriorating. Therefore, transport should continue toward the hospital with invasive cardiac capability. With regard to patient care en route, the physician frames the decision into three groups: (1) supportive care only, (2) give medication, (3) use electrical intervention.

   Supportive care is appropriate if the patient has been deteriorating and transport has been directed to the nearby community hospital. In this case, the biggest assist to patient care would be maintaining the airway and oxygenation, as well as expediting the patient's hospital care by obtaining serial vital signs and ECG printouts. With this short transport, the critical decisions involving invasive procedures are better made in the more controlled environment of the emergency department. The other case in which supportive care would be warranted is when the patient is maintaining perfusion. If bradycardia is present but the patient has normal mental orientation and function, then no invasive intervention in the ambulance would be indicated.

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