There was a stabbing feeling in my chest as I watched Dad struggling to breathe. His oxygen saturation was holding at between 88% and 90% on 100% oxygen through a nonrebreather mask. He had a resting heart rate of 120 beats per minute and obvious right-sided heart failure with notable jugular distention while sitting upright in bed. His respiratory rate was in the 40s. How long could he struggle without having a respiratory or cardiac arrest?
FIGURE
When Mom had called me that Saturday morning, she was frantic and her story fragmented. Dad had passed out, and the local volunteer ambulance was taking him to the community hospital. My sister and I were on the next flight to South Dakota. When we landed, Mom had called, telling us to go straight from the airport to the Heart Hospital in Sioux Falls: they were "life-flighting" Dad there by an aeromedical jet service called CareFlight. He had lost consciousness again at the local hospital, and clinicians there couldn't get his oxygen saturation up; they didn't know if it was his heart or his lungs. It wasn't until I got the full story from the flight nurse and Mom-with the tidbit of information that Dad had had calf pain that week-that I realized it was probably PE.
Dad's risk factors were a history of congestive heart failure and hypertension, which most likely contributed to lower-extremity venostasis. His use of the diuretic hydrochlorthiazide (Esidrix and others) may have contributed to dehydration and a hypercoagulable state. He spends a lot of time driving, which causes pressure on the back of the legs, increasing risk of DVT.
My dad presented with syncope: upon arrival at the community hospital he was tachycardic, tachypneic, and hypoxic. He had basal rales and an S3 heart sound that could have been explained by his congestive heart failure. His chest X-ray was clear and his electrocardiogram was negative for an acute ischemic event, but he had continuing hypoxia. As an emergency-critical care nurse, I knew that the results of his V/Q scan indicated rather large right-sided emboli. We could not act quickly enough.
Once my Dad's cardiovascular surgeon confirmed the diagnosis of PE he recommended a "clot-buster"-the thrombolytic tissue plasminogen activator, or TPA. My family and the surgeon turned to me. As the nurse in the family, my advice would be critical in their decision. (Thrombolytics-first developed as rat poison-have many counterindications.) The cardiovascular surgeon ended his pitch by saying, "If it were my dad, I would want him to have the TPA." (Dad looked him in the eye and with two-to-three-word dyspnea asked, "How well do you like your dad?")
I thought, most people don't live to make this decision. How many cardiac arrests had I worked that were a result of PE? Despite the risks of bleeding associated with thrombolytics, I didn't think Dad's 75-year-old heart could otherwise survive the increased pulmonary pressure and hypoxia. I said, "Yes. As soon as possible."
The thrombolytic of choice in this case was alteplase (Activase), a recombinant-DNA TPA. (Other drugs in this class are reteplase [Retavase] and tenecteplase [TNKase]). Another class of thrombolytics is bacterial protein, like streptokinase (Streptase, Kabikinase). Alteplase is approved by the Food and Drug Administration to treat PE in the ED; it is administered over two hours as an IV infusion of 100 mg or in an accelerated 90-minute regimen, according to the patient's weight, not to exceed 100 mg.
Dad's case was a perfect example of the efficiency of rural medicine and nursing. The community hospital recognized the need for transfer to a specialty facility and used the lifesaving CareFlight to get Dad to the excellent critical care department of Heart Hospital. It's usually hard for a nurse to be "on the other side of the bed" but the staff was expert and empathetic and diligent about keeping me informed of Dad's status.
As the PE dissolved, Dad's clinical picture gradually improved. After a vena cava filter was placed and his anticoagulation levels were achieved, he was discharged on oxygen and warfarin. He was a bit frail but very alive and still full of that South Dakota humor: he tells everyone, "I'm on rat poison now."