For months following her Left Ventricular Assist Device (LVAD) implant, life for my 80-year-old Mom had found a new, stable rhythm. Supported by the HeartMate 3, she was navigating her new normal with strength and grace.

Then, the alarms started.

They didn’t happen during the day, when she was active, but in the quiet of the night. A series of disruptive, low-flow alarms from the LVAD controller, beeping insistently for a problem she couldn’t feel. She was asymptomatic—no dizziness, no shortness of breath, no signs of trouble. Yet the machine, her lifeline, was signaling a persistent problem that defied simple explanations.

This began a month-long journey into the complex world of LVAD data. This is a case study in decoding the alarms, questioning the easy fixes, and searching for the “why” behind a problem everyone else is ready to dismiss.

The Investigation Begins

The inciting incident for this new wave of alarms was a routine procedure on June 20, 2025: a Right Heart Catheterization (RHC) that included a “ramp study.” Based on the study, her team increased her pump speed from 4900 to 5000 RPM. The low flow alarms began almost immediately.

A week later, the disconnect we would come to know well began. The team called and prescribed a new blood pressure medication, Losartan (25mg), citing the “high pressures” they had seen during the cath procedure. This decision was made without once consulting the daily logs I kept, which showed months of stable Doppler blood pressures, consistently in the 72-86 mmHg range.

This led us to our follow-up visit on July 9th. During that appointment, they seemed to acknowledge the oversight by immediately cutting the new prescription in half to 12.5mg. Their primary theory for the alarms reverted to the simple and logical: my mom has a small frame, and the higher speed was likely causing “suction events.” The fix seemed simple, too: they lowered her speed back down to 4900 RPM.

But the alarms didn’t stop.

For the next month, the nighttime alerts continued, becoming a source of constant anxiety. We were now managing a new medication that seemed unnecessary while the core problem remained unsolved. The nightly beeping was a constant reminder that the simple fix hadn’t worked and the real problem was still hiding.

The Unsung Hero: Uncovering the Real Problem

After a month of unresolved alarms and feeling our concerns were being overlooked, we knew we couldn’t wait for the situation to escalate. On July 31st, we made the executive decision to take my mom to the Duke emergency room. We had to force the issue.

In the hospital, she underwent a battery of tests designed to find a catastrophic failure. An LVAD-protocol CT scan and a detailed echocardiogram were performed to hunt for the most feared complications: a pump thrombosis or a physical obstruction. The results came back, and the news was both a relief and a source of profound confusion: the pump and its tubing were perfectly clear. There was no clot. There was no kink.

With the “hardware” cleared of any wrongdoing, the mystery deepened. If the pump was fine, why were the alarms continuing? The investigation had to turn away from the machine and toward the engine that fuels it—the heart itself. Specifically, it was time to focus on the part of the heart that the LVAD doesn’t help at all: the right ventricle.

The Software Fix and My Doubts

With the tests confirming there was no clot, kink, or other "hardware" failure, the team's focus shifted from the pump itself to the way the pump's computer thinks. The only explanation left was that the alarms were a nuisance—a miscalculation.

The target of this new approach was the Hematocrit (HCT) setting. As we learned in Part 1, the HCT value is a crucial variable the pump uses to estimate blood flow. A higher HCT setting tells the pump the blood is "thicker," and a lower setting tells it the blood is "thinner." By lowering the HCT setting in the software, the pump's calculated flow number will go up, even if the actual amount of blood moving through the pump doesn't change at all.

This is exactly what the team did. On the evening of August 1st, they adjusted my mom's HCT setting on the controller down to 20. And just like that, the alarms stopped.

The HCT 'Fix'

Lowering the hematocrit (HCT) setting in the controller is a dangerous practice that masks a real problem. It makes the estimated flow number go up, which can stop an alarm, but does nothing to change the actual amount of blood your body is receiving.

Adjust HCT Setting: 39%

Notice: As you lower the HCT setting, the Estimated Flow (blue line) increases, potentially silencing an alarm. The True Physiological Flow (red line) and the Alarm Threshold (dotted line) do not change. This creates a false sense of security.

On the surface, the problem was solved. The disruptive beeping was gone. But for us, this was the most alarming moment of all. This wasn't a fix; it was a re-calibration designed to ignore the problem. It felt like putting tape over a blinking "check engine" light. The noise was gone, but the engine was still having trouble.

It silenced the machine for a few days, but it did nothing to address the real, underlying reason the alarms were happening every single night. This was the moment we realized that if we were going to find a true solution, we would have to be the ones to lead the charge. Was this Duke's limit? is this where they stop?

The Advocate's Toolkit

My mom's story isn't just a chronicle of frustration; it's a real-world lesson in patient advocacy. When you are the one sitting by the bedside day after day, you are not a passive observer—you are the most important member of the care team. This entire experience taught us several key lessons that can empower any family navigating the complexities of LVAD care.

Lesson 1: Think Like a Troubleshooter

As a caregiver, you bring your own unique skills to the table. For me, it was a background in logical, systematic problem-solving, similar to debugging a complex computer program.

This experience led me to an important realization. In the world of technology, you can't fix a bug without first understanding precisely when and why it happens. A developer runs a debugger and adds logs to capture data at the exact moment of the crash. You have to isolate the problem to solve it.

I found myself viewing the nighttime low flow alarms through this lens. The "bug" was happening at 2 AM, but the data collection—the "debugging"—was happening during routine checks in the afternoon. This isn't a critique of the dedicated individuals on her team, but rather an observation on the system itself. It highlights the gap that a caregiver's focused, logical troubleshooting can fill. Sometimes, the most valuable question you can bring to the team is the simplest one: "Are we truly looking for the problem at the time and place where it's actually happening?"

Lesson 2: Demand a Proactive Plan

Reactive care, or fixing problems only after they become critical, is not enough. With the knowledge that the right heart is the key to long-term success, you have the right to demand a proactive strategy. Don't be afraid to ask direct, specific, and informed questions until you get a clear answer.

Here are the questions we learned to ask, which you can use as a starting point:

• What is our proactive plan to manage the elevated CVP and reduce strain on the right heart?
• Given the healthy PAPi and TAPSE numbers, what is the long-term strategy to preserve this function?
• Could my loved one's nocturnal alarms be related to sleep-disordered breathing, and would a sleep study be beneficial to investigate this?
• Can we establish a firm protocol for consistent Doppler BP measurements at every check to ensure we have reliable data?
• To ensure continuity, can we identify one primary attending physician who will serve as our main point of contact for long-term strategy?

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Conclusion: The Journey Continues

My mom's case is not neatly closed with a simple solution. It's an ongoing journey. The alarms may be silent for now, but our advocacy is not. We are now armed with a deeper understanding of the machine, the physiology of her heart, and the right questions to ask.

The goal is no longer just to silence an alarm; it's to find a true clinical partner who will join us in the search for answers. It's about ensuring my mom receives the thoughtful, proactive, and individualized care she deserves. For any family on this path, remember that your voice, your observations, and your relentless pursuit of the "why" are the most powerful tools you have.

How Flow is Calculated

The flow rate you see on your LVAD controller is not a direct measurement of blood moving through the pump. It's a sophisticated calculation that uses three key inputs to provide an estimated flow rate.

Pump Speed (RPM)

The rotor's rotation speed.

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Power (Watts)

The energy being used.

+

Hematocrit (%)

The thickness of your blood.

=

Estimated Flow

The number on your screen.

This is a crucial distinction. The device relies on the correct hematocrit value to make an accurate estimate. If that setting is changed, you're only changing the calculation, not the actual blood flow in your body.