How to Treat Emergency Low Blood Pressure

Reviewed on 9/3/2021

Baroreceptor Signals Sent to the Heart
If blood pressure becomes too low, baroreceptors send signals to the heart telling it to beat faster and pump more blood per minute. The result is blood flow increases and blood pressure rises. Source: BigStockPhoto / Norman Chan

What Happens When You Call 911 for a Health Emergency?

When someone calls 911 for a medical emergency, the ambulance calls the ER department and tells the police and he or she calls an ambulance. "We're running lights and siren with a 67-year-old male. He's confused, lethargic, has a blood pressure of 80 over 40, a thready pulse (a pulse that is very fine and barely perceptible), and is sweaty. We'll be at your door in a couple of minutes."

The nurses start setting up the equipment to care for the patient. We've been through this drill before when someone arrives at the ER with low blood pressure. I hope it's an easy diagnosis and something that we can treat quickly. IVs are set up, monitor pads ready. The respiratory tech arrives with her machines just in case they are needed. The EMTs unload a man in obvious distress, sweaty, struggling to breathe, and limp. "He's had a fever for a couple of days with a cough. History of COPD, heart problems, and smokes."

How Are the Causes of Medical Emergencies Diagnosed?

The diagnosis could be easy, but there are a variety of factors that could be causing this man's condition. He is in shock; his blood pressure is so low there is not enough pressure to provide blood flow and oxygen to his brain. That's why he is lethargic. No doubt the rest of his organs are at risk too. But why?

  • Is it an infection that has caused dehydration because of sweating from the high fever and inability to drink enough fluid?
  • Are his lungs filled with infection so that they can't get oxygen into his bloodstream?
  • Is the septic, (has the infection spread through the bloodstream causing the blood vessels to leak fluid)?
  • Has his heart weakened because of a lack of oxygen? Is he having a heart attack?
  • Is it a combination of any or all of the above?
  • Or is the fever a "red herring" and something else is going on?

What is the Prognosis for the Victim?

The victim's vital signs are poor.

  • His blood pressure has fallen to a little to 70 over 40,
  • his heart rate is 130, and he's breathing over 30 times per minute.
  • His body temperature is 103 F. 

All bad; however, they all are pointing to an infection that perhaps can be fixed with IV fluids.

  • The man is struggling to breathe but is alert enough to complain that his chest hurts to breathe.
  • His right lung sounds like there's pneumonia or infection.
  • But he's also wheezing heavily in both lungs.

What else could it be? A pulmonary embolism (blood clot to the lung) could cause shock and fever. Tuck that thought away in case it's needed.

What Happens when Emergency Treatment Begins?

The nurses are already in motion, and two IVs have been placed. Fluid is being pumped in. Lab tests and a chest X-ray have been ordered. No time to wait for test results. The patient needs help now. The respiratory tech sets up a BiPAP machine to help support his breathing. It pushes air into the mouth and lungs to try to force air into the lungs. Medication is added to relieve wheezing.

  • There is a downside to BiPAP. It can lower the blood pressure for a while as the body gets used to it, but the alternative is to intubate this patient and put him on a ventilator.

The patient has a history of smoking and COPD; putting him on a ventilator increases his mortality (risk of death) significantly. He has to hold on so that the medical procedures and tests we are doing can reverse his illness and raise his blood pressure.

  • The chest X-ray confirms the diagnosis of pneumonia. Say goodbye to the diagnosis of pulmonary embolism. Antibiotics are given.
  • The intravenous fluid infusion hasn't increased the blood pressure yet, but it's still early.
  • He's tolerating the BiPAP machine, not an easy feat since it feels like sticking your head outside a car window as you go down the road at 50mph.

The good news is that he's waking up a little bit. While the blood pressure is low, perhaps the fluid is allowing more oxygen delivery to the brain.

How Do You Stabilize the Person's Blood Pressure? What Drugs Do You Use?

Two liters of fluid have been run in; 4.4 pounds - the same amount as a large bottle of soda. The blood pressure refuses to move higher, and more needs to be done. You're not supposed to treat a number, since the clinical picture is more important than getting the patient to look good on paper. Still, a systolic blood pressure of 70 is too low and it may mean that the organs in the body are lacking sufficient blood flow and oxygen to maintain aerobic metabolism. If he goes anaerobic (lack of oxygen) for a prolonged period of time, then the acid-base balance in the bloodstream will cause everything to spiral downhill and the battle will be lost.

Norepinephrine bitartrate (Levophed) is a drug that acts like adrenaline on the body, and will cause the blood vessels to constrict or narrow, to support the blood pressure is started intravenously. It will also put a strain on his heart, not necessarily something we want to do since he has had heart problems, but there isn't much choice.

More fluids... more oxygen...more time. The blood pressure creeps up to the mid-80s...success? He's more alert, and the catheter that was placed in his bladder is starting to show signs of urine. That means his kidneys are receiving enough blood supply to produce urine, and they are sensing that there is starting to be enough fluid in the body to allow that to happen.

The intensive care team has shown up at the bedside. He will be theirs in ICU, and it's time to start transitioning responsibility to them. His systolic blood pressure is 90 now, and his heart rate is down to 100. Things are looking up, but who knows for how long. He's older, undergoing a lot of stress, and still needs machines to help him breathe and medications to support his blood pressure. But he's alive when he leaves the ER; another win.

The next ambulance call comes in.

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Reviewed on 9/3/2021

Fauci, AS, et al. Harrison's Principles of Internal Medicine, 20th Ed. United States: McGraw-Hill Education, 2018.