“Give me the Class IIa drug!”


IV Alteplase 50mg.

The left common femoral vein was non-compressible, suggesting a deep vein thrombosis. In this clinical context, the cause of cardiac arrest was from a presumed PE. No amount of high quality CPR, fluids or vasopressor would be of value to increase perfusion, unless you first relieve the obstruction.Amiodarone and atropine are class III here. Even adrenaline is only IIb. “When pulmonary embolism is presumed or known to the cause of cardiac arrest, empirical fibrinolytic therapy can be considered (class IIa, LOE B)”

He grabbed a bottle of alteplase , gave a bolus dose of 50mg, continued CPR and waited….

After around 10 mins, the pulse came back!

The parasternal long and short axis on echo was as shown:

Notice the improved cardiac contractility in the PLAX.

In the PSAX, the RV was grossly enlarged compared to the LV. The interventricular septum was D shaped during diastole, and became round again during systole. This suggested an acute RV pressure overload – since the RV has no time for hypertrophy, and therefore cannot exceed the LV pressure during systole.

The patient was sent for CT, which confirmed the pulmonary embolism.

Interestingly, looking at the “clot burden” on CT, a good friend of ours remarked that that is unlikely to be the cause of the patient’s cardiac arrest. Well, that's exactly right! For what was not seen, the "additional" clot that tipped the patient into cardiac arrest, has been thrombolysed.

Lesson learnt:

  1. Be systematic in screening for reversible cause of cardiac arrest.

  2. If there is an obstruction, relieve the obstruction! "Fluid responsiveness", or for that matter, to vasopressors or inotropic agents, is a misnomer in a patient with obstructive shock.


R. W. Neumar et al, C. W. Otto, M. S. Link, S. L. Kronick, M. Shuster, C. W. Callaway, P. J. Kudenchuk, J. P. Ornato, B. McNally, S. M. Silvers, R. S. Passman, R. D. White, E. P. Hess, W. Tang, D. Davis, E. Sinz, and L. J. Morrison, “Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.,” Circulation, vol. 122, no. 18 Suppl 3, pp. S729–67, Nov. 2010.


Dr. Toh Hong Chuen

Acute and Emergency Care Centre, Khoo Teck Puat Hospital. Singapore.



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