Insulin

Insulin is an ordinary medication whose presence in the wrong patient, at the wrong time, becomes one of the book’s most consequential clues. In the episodes described, externally administered Insulin drives patients into dangerous hypoglycemia, while unexplained blood results and altered IV bags expose possible deliberate harm. The substance moves between bedside treatment, physical evidence, hospital policy, and police investigation; the difficulty is not only recognizing its effects, but establishing how it reached a patient and who had access to it.

A clinical anomaly becomes evidence

On February 11, 1991, pharmacy nurse Pam Allen brought a suspicious IV bag to Karen Seiden, the risk manager at Saint Barnabas Medical Center. The bag’s port looked used, yet it was filled so full that it leaked. Seiden involved Thomas Arnold, the assistant director of security, who sent it to the pathology lab. The bag was supposed to contain saline and heparin; testing found Insulin as well. A commonplace fluid bag had become evidence that its contents might not be what staff believed them to be.

Three days later, Anna Byers, a patient in the hospital’s Critical Care Unit, became confused, nauseous, weak, and drenched in a cold sweat within half an hour of receiving heparin. Her blood Insulin level was extraordinarily high. Orange juice did not reverse the crash, and IV dextrose—the direct delivery of sugar into her bloodstream—could not keep her stable. Her condition improved after the heparin drip was removed for a planned procedure. When it was restarted, the instability returned; by late evening, her blood sugar was too low to register. The sequence made the drip itself difficult to dismiss as incidental.

Fred Belf, in another part of the unit, developed a parallel crisis while receiving heparin. He vomited, could not keep down orange juice, and required dextrose alongside the drip. Once nurses connected the symptoms to the heparin bags and removed his, he quickly began to feel better. Staff sent the bag for testing. It too contained Insulin. Microscopic examination found tiny needle punctures across its surface, including three along the edge. Because bags might be punctured while being connected to a stopcock, marks in an ordinary location could have an innocent explanation; punctures around the perimeter did not fit that routine account and suggested intentional interference.

From individual crises to a suspected pattern

With two positive bags and the episodes involving Byers and Belf, Arnold and Seiden reviewed recent Critical Care Unit records for similar unexplained crashes. The review widened the problem: for months, codes had become so frequent that they sometimes overlapped, requiring nurses to leave one patient to attend another. The incidents were scattered across intensive-care, critical-care, and cardiac units rather than confined to a single ward or shift. Patients appeared to be developing sudden, unexplained diabetic crises.

Laboratory work strengthened the suspicion. The affected patients had unprecedented concentrations of Insulin in their blood, much of it identified as foreign—that is, not produced by their own bodies. At first, Arnold and Seiden considered familiar medication errors, such as a nurse misreading a physician’s order or a vial being mislabeled. But the charts contained neither prescriptions for Insulin nor records that nurses had administered it. The missing documentation left two troubling possibilities: an undocumented medication mistake, or deliberate administration that was never supposed to appear in the chart.

Arnold and Joe Barry, Saint Barnabas’s senior vice president in charge of security and a former New Jersey State Police major, compared nursing schedules with the times of the patient codes. Only three nurses had been working every code. Charles Cullen drew particular attention. When Arnold interviewed staff, most nurses appeared anxious about the patients and their own professional standing; Cullen did not seem worried and, in Arnold’s assessment, was defiant. Because Cullen worked for a staffing service and had irregular shifts, arranging an interview proved difficult. When Arnold and Barry finally brought him into a conference room, he refused to answer questions. The evidence made him a focus of inquiry, but the scheduling pattern alone did not establish who had contaminated the bags.

A method of harm and a recurring blind spot

Elsewhere in the book, Insulin appears not only as a suspected contaminant in IV bags but as a drug deliberately injected into a patient. During an overnight shift at Liberty Nursing and Rehabilitation Center, Charles Cullen injected a large dose directly into Francis Henry’s IV. Henry was elderly, had a broken vertebra, and wore a halo device fixed to his skull. He suffered violent seizures, fell into a coma, and died soon after. An internal investigation found massive amounts of foreign Insulin in his blood, but no prescription or chart entry recording its use. Since Henry was immobilized, an accidental self-overdose was considered highly unlikely. Suspicion fell on the night shift, yet Liberty fired senior nurse Kimberly Pepe; her lawyer then argued that Cullen was more likely responsible and that the facility had suspected as much.

The episodes show how Insulin’s clinical usefulness can also make it difficult to distinguish treatment from assault until the pattern becomes visible. In one setting, an infusion that should have delivered heparin repeatedly coincided with severe crashes, and removing it brought improvement. In another, a large injection left an elderly patient in seizures and coma. In both, the absence of a prescription or administration record mattered: it separated the observed bodily effects from any documented therapeutic decision. But missing entries also complicated accountability by leaving investigators to reconstruct events from laboratory tests, charts, timing, and staff access.

From evidence to safeguards and investigation

Insulin also became the subject of stricter workplace controls. On Amy Loughren’s unit, management introduced an Insulin adjustment form requiring nurses to electronically sign for their estimate of how much remained in a vial. Loughren objected that estimating the amount by sight was unreliable and could place a nurse’s license at risk. She demanded to know why the drug was being treated like a narcotic and what made it dangerous. Her manager would not explain the underlying concern, and Loughren refused to sign. The exchange shows the costs of a safeguard imposed without disclosure: the form signaled that something had changed, but staff were not told what had happened or why the change was necessary.

The investigation depended on more than one kind of evidence. At Saint Barnabas, abnormal blood results and punctured bag surfaces turned unexplained illness into a suspected pattern. At Liberty, Henry’s laboratory findings conflicted with his medication chart. Later, Amy’s recollection of the Insulin sign-out dispute connected her to the investigation around Cullen and made her anxious that the missing drug or a patient death might implicate her. When a detective showed her Cullen’s Pyxis record from the night Reverend Florian Gall died, the document disrupted her belief that her friend could not have done something terrible. Her decision whether to assist the detectives therefore involved not just the suspicious use of medication, but the danger of betraying a friend and jeopardizing her work.

Across these episodes, Insulin functions as a potent but incomplete clue. Its presence in a patient’s blood can show that the body received more than it produced naturally; it cannot, by itself, name the person who administered it. A bag with unexplained needle marks, a missing order, an abnormal timeline, or a nurse’s account can add context, but each must be joined to the others. The book’s recurring contrast is between the apparent precision of medical records and the gaps that leave room for concealed action: a drug can be detected, a patient’s crisis recognized, and a pattern suspected before the chain of responsibility is proved.