Recently, the Institute for Safe Medication Practices reported that a patient had received a lethal morphine overdose while connected to the Abbott Lifecare 4100 PCA Plus II machine.¹ This machine is easily misprogrammed by caregivers, who must manually enter the PCA parameters, and it needs a more sensible and forgiving user interface.² A number of patients have received opiate overdoses as a result of PCA errors: insertion of a 5 mg/mL morphine cartridge when the machine is expecting a 1 mg/mL concentration, or acceptance of the default (initial) drug concentration when the correct action is to scroll up to the correct value, among other errors.^3,4

In 1997, ECRI documented 3 deaths that occurred while patients were connected to the Lifecare 4100.⁵ In at least 2 of the cases, the alleged reasons for the deaths were the same. In the mode of operation in use, when nurses program the drug concentration the Lifecare 4100 display shows a particular concentration (e.g., 0.1 mg/mL). Nurses can either accept this initially displayed value or modify it using the arrow controls. The critical flaw in the design is that in this situation the Lifecare 4100 offers the minimal drug concentration as the initial choice. If nurses mistakenly accept the initially displayed minimal value (e.g., 0.1 mg/mL) instead of changing it to the correct (and higher) value (e.g., 2.0 mg/mL), the machine will "think" that the drug is less concentrated than it really is. As a result, it will pump more liquid, and thus more narcotic, into the patient than is desired.

The purpose of this letter is to warn clinicians of continuing fatal drug overdoses from the Abbott Lifecare 4100 PCA Plus II machine. If you use this machine, please contact your risk management officer and your biomedical engineering department for advice. Fortunately, Abbott is not the only supplier of PCA machines.

We have informed American and Canadian regulatory authorities; they are, of course, now studying the problem.