Inadvertent intra-arterial infusion of hydroxyethyl starch through a radial arterial line: a case report
This case report describes a rare instance of inadvertent intra-arterial infusion of hydroxyethyl starch in a septic patient, highlighting that the error was best identified by a viscous aspirate rather than waveform changes and that systemic anticoagulation was appropriately withheld due to bleeding risks, ultimately resulting in preserved limb perfusion.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
In the high-stakes environment of an operating room, doctors rely on thin tubes inserted into a patient's arteries to monitor blood pressure in real time. These lines are kept open and flowing by a continuous, gentle drip of fluid, usually a simple saltwater solution mixed with a tiny amount of a blood thinner to prevent clots. This setup is standard for patients undergoing major surgery or those who are critically ill. However, a rare and dangerous mistake can occur if a bag of fluid meant for a vein is accidentally connected to an artery instead. While doctors are well aware that injecting the wrong medication into an artery can cause severe tissue damage, the specific risks of accidentally pumping a thick, jelly-like fluid into an artery are not well understood. This uncertainty leaves medical teams unsure of how to react when such an error happens, particularly regarding whether to flood the patient's system with more blood thinners to prevent clots, a move that could be disastrous if the patient is already at risk of bleeding.
A team of anesthesiologists at a major medical center in India recently documented a case that clarifies these questions. They described an incident involving a man in his forties who was rushed to the operating room for emergency surgery to repair a perforated intestine. The patient was already in a fragile state, suffering from a severe infection and low body temperature. To monitor his condition, the medical team placed a catheter into the artery of his right wrist. During the chaotic preparation for surgery, a bag of hydroxyethyl starch, a thick synthetic fluid used to support blood volume, was mistakenly mixed with heparin and connected to the arterial line instead of the standard saltwater flush. This error happened because the bags looked nearly identical and were stored next to each other.
For about two hours, the fluid dripped into the artery. The first sign that something was wrong came from the monitor, which showed a flattened, sluggish wave pattern. However, the doctors could not be sure this was caused by the wrong fluid, as the patient's low body temperature and low blood volume could have caused the same signal. The true nature of the mistake was revealed only when a nurse tried to draw a blood sample from the line. Instead of the expected dark red liquid, the syringe filled with a strikingly thick, viscous fluid. This physical observation, rather than the monitor's reading, confirmed that the thick starch solution had entered the artery.
The medical team immediately stopped the infusion. The total amount of fluid that had entered the artery was very small, approximately six milliliters. They aspirated the line, flushed it with the correct saltwater solution, and confirmed that blood flow to the hand remained strong. The patient's hand stayed warm, and pulses were felt in both the wrist and the elbow. Despite the initial fear that the thick fluid would cause a clot, the team decided against giving the patient a large dose of systemic heparin, a powerful blood thinner. They reasoned that the patient was already at high risk of bleeding due to his severe infection and the major abdominal surgery he was undergoing. Adding more blood thinners would have offered little benefit for a clot that might not form, while significantly increasing the danger of uncontrolled bleeding from his surgical wounds.
Over the following days and weeks, the patient recovered without complication. Ultrasound scans performed on the first, second, third, fifth, and seventh days after surgery showed that the artery remained open with normal blood flow. A follow-up scan six months later confirmed the artery was still clear, and the patient had no loss of function or sensation in his hand. The only symptom he experienced was a mild ache in his forearm that disappeared within a few days. The authors of the report concluded that the error was identified more reliably by the physical texture of the fluid drawn from the line than by the monitor's waveform, which can be misleading. Furthermore, they argued that the instinct to aggressively treat such an error with strong blood thinners should be tempered, especially in patients who are already prone to bleeding.
This case highlights that while the mistake of connecting the wrong fluid is a known hazard, the specific reaction to a thick colloid entering an artery does not require the same panic as a toxic drug. The thick fluid did not cause the limb to die or the artery to close, likely because the volume was small and the body's natural blood flow in the hand is robust enough to compensate. The medical team's decision to hold back on aggressive treatment proved correct, as the patient's condition remained stable without the need for dangerous interventions. In response to this event, the hospital has since changed its protocols to separate different types of fluid bags, use color-coded labels, and require a second person to verify any fluid before it is connected to a patient. The report serves as a reminder that in medicine, observing the physical reality of a situation can be more telling than the signals on a screen, and that the most cautious path is not always the safest one.
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