Wake-Up Stroke in the Air: tPA Questions and a Blood Pressure Demand
A 68-year-old right-handed woman with a right middle cerebral artery syndrome - left hemiplegia, left neglect, gaze preference, NIHSS 19 - is being flown 40 minutes to a thrombectomy center. Her daughter found her at 06:30 with symptoms and last saw her normal at 22:00 the night before. The referring hospital has no thrombolytic protocol and has not given tPA. BP is 192/110, HR 88 in sinus rhythm, SpO2 97% on room air, glucose 132 mg/dL, platelets 210,000, INR 1.1. She is drowsy but arousable, dysarthric, and has already coughed on a sip of water. The daughter asks why you cannot just give the clot buster in the helicopter, and the sending physician asks you to bring her pressure down to 140 systolic before takeoff.
1. How do you answer the daughter's question about giving the thrombolytic in flight?
Read the worked answer
Answer her real question first - she is asking whether her mother is being denied treatment. Name the treatment she is still getting: 'She is going to a center that can pull the clot out of the artery directly. That is the treatment that helps her, and the flight is how she gets there.'
Then explain why not tPA, in plain terms
- The clock is not the issue by itself. The window for intravenous thrombolysis is generally up to 4.5 hours from when the patient was last known well. Here, last known well is 22:00 the night before - this is a wake-up stroke, and the true onset could be anywhere in that eight-hour window. The count starts at last known normal, not at the time she was found.
- The decision is not mine, and it is not made in the air. Wake-up stroke thrombolysis depends on advanced imaging - CT perfusion or MRI - to determine how much brain is salvageable. That imaging does not exist at the referring hospital.
- Blood pressure has to be under control first. Her pressure is 192/110, and the standard threshold before giving a thrombolytic is under 185/110. Giving it at this pressure raises the risk of intracranial hemorrhage.
- The consequences are not manageable in a helicopter. If she bleeds into her brain at altitude, there is no CT, no neurosurgery, and nowhere to land. A hemorrhagic conversion discovered 40 minutes later is a catastrophe.
Close the loop - tell her you will hand the question to the stroke team on arrival and that she should ask them directly, and document that the conversation happened.
2. Respond to the request to lower her systolic to 140 before takeoff. What is your target and how do you achieve it?
Read the worked answer
I do not bring her to 140.
- This is an ischemic penumbra. Her cerebral perfusion depends on pressure - the territory around the clot is already maximally vasodilated and is pressure-passive. Taking a stable, asymptomatic 192 systolic down to 140 removes the perfusion that is keeping the penumbra alive, and a drop in pressure in the back of an aircraft is much harder to reverse than it is to avoid.
- The thresholds that matter here: for a patient who is not receiving a thrombolytic and is proceeding to thrombectomy, maintaining BP at or below 185/110 before the procedure is a defensible approach, and the value of lowering further is uncertain. What is clearly harmful is hypotension. A systolic below 140 or a MAP under 70 in this patient is a worse error than 192.
My target: keep systolic between roughly 140 and 185, never below 140, and treat only above 185.
If I have to treat
- Labetalol 10-20 mg IV, titrated slowly, or nicardipine infusion if the service carries it. Both are controllable. Avoid sublingual nifedipine and avoid anything with a long, unpredictable tail.
- Recheck every 5 minutes after any dose. In the air, an overshoot presents as a falling level of consciousness, and the differential includes both hemorrhage and hypoperfusion.
Conversation with the referring physician
- 'Her pressure is high, but it is high for a reason and she is protecting her own penumbra. I will keep her under 185 and above 140. If the thrombectomy center wants a different number, I will follow their instruction - they are the ones who will be doing the procedure. But I am not taking her to 140 on the way to the pad.'