Worth repeating... Flushing IV tubing with unrecognized residual drug leads to adverse effects

Once again, we are reminded how residual drug in intravenous (IV) tubing can have severe effects if unrecognized when lines are flushed or other medications/infusions are administered through the same line, a subject we have covered in the past. We received a report about an elderly man hospitalized for prostate surgery. After the procedure, the patient complained of pain and was given HYDROmorphone IV in the post-anesthesia care unit (PACU). About a minute later, he developed slurred speech, body twitches, and a rapidly declining blood oxygen saturation level (SpO2) before losing consciousness. The anesthesia care team was called, and two doses of naloxone were administered without effect. Realizing that during surgery the same line was used to administer rocuronium, the anesthesia care team administered 100 mg of sugammadex to reverse the effects of the residual drug in the IV port and tubing that the patient apparently received when the HYDROmorphone was administered. In less than a minute the patient regained consciousness and began to breathe spontaneously, with an SpO2 of 93-95%.

If IV lines are not flushed, it is important to remember that the length of the IV tubing may contain 10 mL or more of uninfused medication. Additionally, needleless ports and stop-cocks also have dead space where the drug can accumulate.

In 2012, we published a nearly identical report in which a patient also lost consciousness in the PACU after an IV push dose of HYDROmorphone (ISMP. Medication within IV tubing may be overlooked. ISMP Medication Safety Alert! 2012;17[16]:1-2). In that case, the patient’s SpO2 dropped to 40%. The patient had been receiving rocuronium by continuous infusion during a procedure. While the drug had been stopped afterwards, the line had not been flushed. Anesthesia immediately responded, administering neostigmine for blockade reversal as they suspected the problem was caused by flushing residual rocuronium in the IV tubing into the patient when administering the IV dose of HYDROmorphone.

We are aware of similar events that have happened when IV lines were not flushed after patients received other high-alert drugs, including fentaNYL and oxytocin. In one case, the residual oxytocin left in an obstetrical patient’s IV line caused hypertonic, tetanic uterine contractions leading to deceleration of fetal heart rate and fetal hypoxia. Even small doses of residual medications in IV lines in pediatric patients could prove fatal. Thus, depending on the drug concentration, pharmacologic action, IV set volume, and point of injection, harmful unintended doses and overdoses are certainly possible.

When administering medications such as neuromuscular blockers, all residual drug must be flushed before the patient is extubated, or the IV line should be changed, and the source container removed. This should be confirmed at the point of patient “handoff” or transfer of care (e.g., from the surgical suite to the PACU), as the receiving providers may not be aware of the medications that were administered in the previous patient care setting. In addition, all drugs administered IV should be flushed through the IV line to be sure they reach the patient for effect and do not linger in the IV line.