Cullen's insulin

Cullen's insulin is the ordinary hospital medication at the center of an early pattern of unexplained patient crises at Saint Barnabas Hospital. In the account of Charles Cullen's conduct, it was not only a substance used to harm patients: it could disappear into routine IV care, while the bags, laboratory results, and nursing records offered investigators clues—and left gaps that could not always be resolved.

A routine medication becomes evidence

The first warning was clinical rather than forensic. Fred Belf received heparin at 7 a.m.; by noon he was vomiting and unable to keep down orange juice. Doctors ordered dextrose through an IV alongside the heparin. The two drips continued to counteract one another through the day and night. By 7 p.m. the following evening, staff had connected the heparin bags with the symptoms. When nurses disconnected Belf's drip, he quickly improved, and they sent his IV bag for testing.

The laboratory result transformed an ambiguous deterioration into a possible crime: the bag tested positive for Cullen's insulin. Microscopic examination found tiny needle punctures across its surface, including three along the edge. Needles could puncture saline bags during ordinary connection to a stopcock, but the edge marks did not fit that explanation. The pattern suggested deliberate, repeated tampering in the Saint Barnabas Hospital storage room. Investigators had two bags as evidence and anecdotal reports involving Anna Byers and Belf; the suspicious marks made the physical container itself part of the case.

From scattered crises to a suspected pattern

Thomas Arnold and Seiden returned to intensive-care records to see whether Belf's experience was isolated. They found that patients had been crashing with troubling regularity for months. Codes sometimes overlapped, forcing nurses to leave one emergency to attend another, and the incidents crossed intensive-care, critical-care, and cardiac units rather than clustering in one ward or shift.

Laboratory findings strengthened the pattern. Patients described as suddenly becoming diabetic had exceptionally high, unprecedented levels of the hormone in their blood, and much of it was foreign: it had not been produced by their bodies. The findings established that the substance had been administered, but did not by themselves identify who had done it or prove the source of every patient's exposure.

The first explanation considered was an ordinary medication error, such as a nurse misreading an order or a mislabeled vial. Arnold and Seiden reviewed the charts and found neither a physician's order for the drug nor a nursing entry recording its administration. That left two troubling possibilities: an unprescribed dose followed by a separate failure to document it, or an intentional act. Arnold took the findings to Joe Barry, Saint Barnabas Hospital's senior security vice president and a former police officer. After investigators ruled out patients' visitors, they compared staff schedules with the times of the codes. Three nurses were present for every incident; Charles Cullen drew the most scrutiny.

Bags, omissions, and concealment

Later-recovered investigation fragments described conduct that made an accidental explanation harder to sustain. Cullen had been written up for checking a patient's hormone levels repeatedly at inexplicable and inappropriate intervals. In another incident, he left an unlabeled IV hanging after his shift instead of the prescribed potassium chloride solution. When a supervisor called him at home, he appeared apathetic and said that if the bag was hanging there, it must contain the prescribed solution. The contents were never established, and investigators could not determine whether this was one of the saline bags Cullen later admitted to randomly spiking.

The account describes the substitution as more than a single mistaken dose: Cullen withheld a prescribed medication, hung an unlabeled bag in its place, and pinched off the line so the next nurse would start the drip. The drug in the bag was ostensibly saline, but its actual contents remain unknown. Cullen's later-described practice was to spike such bags with the hormone and sometimes arrange for another nurse to infuse them while he was absent. This method exploited the ordinary division of labor: an apparently helpful handoff could conceal who had prepared the fluid, and the nurse starting the line might have no reason to suspect it.

Controls, suspicion, and limits of the record

The medication also became a flashpoint for staff accountability. Saint Barnabas introduced an insulin adjustment form requiring nurses to enter an electronic signature and estimate how much remained in a vial. Amy Loughren objected that eyeballing the amount was unreliable and refused to sign. Her manager would not explain why the protocol had changed; Loughren questioned why the drug was being treated like a narcotic and suspected that something had happened on her unit, perhaps to her patients. The evidence establishes her refusal and concern, not that the new form itself revealed the full investigation to her.

As police interviews spread anxiety through the unit, coworkers knew Loughren as Cullen's friend and remembered her dispute over the sign-out form. Some avoided her, and she feared for her job and nursing license. When Danny Baldwin showed her a Pyxis printout from the night Reverend Florian Gall died, she began to consider that Cullen could have done something terrible. The printout concerned medication activity around that death; it did not, by itself, resolve the separate questions about which bags contained the hormone. Loughren later risked her employment by helping investigators and passing along records, while struggling with the conflict between loyalty to a friend and the possibility that he had harmed patients.

The institutional record remains qualified. Investigations into the Saint Barnabas incidents closed in late December 1991 without a conclusion. Cullen was fired in the first week of January 1992, and the insulin spikes stopped; Saint Barnabas maintained that these facts were unrelated and that administrators had not then had reason to consider him a danger to patients. Later, a former supervisor recalled that staff had liked Cullen because he was helpful. That recollection sharpens the contrast between his reputation and the alleged use of routine medication work to hide harm. The bags and laboratory results made a disturbing pattern visible, but they did not turn every suspicious incident into a conclusively identified poisoning.