Fix the Rate First ?

CASE PRESENTATION:
Providers respond to a 68 yo female with a sudden onset of paroxysmal nocturnal dyspnea. The patient reports slight dyspnea on exertion for the past few weeks and endorses a mild, non productive cough. The patient speaks in 2-3 word sentences and appears in severe respiratory distress. The patient denies chest discomfort, nausea, vomiting or fever. The patient is in severe respiratory distress and is profoundly diaphoretic. Another paramedic provider onscene diagnoses SVT and readies adenosine for administration.

EXAM:

BP:     220/120
P:        168
R:        40
Spo2:  88%


12 LEAD ECG:

12 LEAD ECG ANALYSIS:

There is a supraventricular tachycardia. P waves are difficult to discern but the QRS complexes are narrow and occur at regular intervals. Diffuse repolarization abnormalities in the form of biphasic T waves are present in the inferior leads. There is no obvious ST segment elevation.

TREATMENT:

High flow oxygen is administered and an intravenous line is inserted. The senior paramedic recommends against adenosine administration. A total of 1.2 mg of nitroglycerin is administered sublingually. 324 mg of aspirin is administered. As the patient is prepared for transportation, CPAP is started at 10 cm H20. The patient experiences rapid improvement and the hypoxia resolves. A repeat ECG shows sinus rhythm with some lateral ST segment depression. Vital signs following CPAP and NTG are as follows: BP: 180/100, P: 110, R: 22, Sp02: 100%. A chest xray shows cardiomegaly and bilateral opacities consistent with pulmonary edema are present.

DISCUSSION:

Though fixing a fast heart rate can reduce ischemia, it is important to consider the underlying cause of a dysrhythmia. Administration of adenosine could convert this ECG but the SVT is very likely due to the catecholamine surge that accompanies acute pulmonary edema. A reduction in cardiac output and afterload results in improved oxygenation, reduced work of breathing, and resolution of the supraventricular tachycardia. Following a hospitalization for acute heart failure, the patient was discharged to home on an aggressive medical regimen targeted at maintaining an acceptable blood pressure. The prehospital application of CPAP is consistently linked to a reduced endotracheal intubation and improved mortality.