Part 4: Pulse Oximeter Case Study

This post is Part 4 of a series based on Nursine Jackson’s article, “What about that Device Data?”.

Pulse Oximeter Case Study

Pulse oximeters are one of the most common biomedical devices used in performing routine patient assessments. Pulse oximeters typically record and store oxygen saturation measurements and pulse rates at intervals set according to the facility’s or unit’s policies and procedures. The pulse oximeter device software also offers the capability of having ranges set for alarms, so that when the vital signs or other data being measured, exceed the range set, alarms will sound in the patient care unit. When alarms go off during patient care, the identity of person responding to the alarm, and who silences the alarm, may also be preserved.

The excerpt, below, is an actual pulse oximeter audit trail from the monitoring of on a mother in labor. This device audit trail documents all values, from measurements of oxygen saturations and pulses, along with other potentially valuable information. In contrast, the flowsheet produced with the medical record reflected only select measurements that were accepted into the flowsheet on the hour and half hour by the Labor and Delivery nurse - as late entries. The audit data from the pulse oximeter provided additional contemporaneous data collected and preserved by the device.

The values the nurse chose to “accept” into the flowsheet or to incorporate into handwritten notes, may not accurately reflect labile vital signs as accurately as the serial measurements from the device. In this case example, the handwritten Anesthesia Record illustrated a benign postpartum course. When deposed, the CRNA stated that after the delivery, she went to the central nursing station, monitored her patient’s device data and wrote down the vital sign values from the monitors, because she did not want to bother the new parents. In fulfilling the Plaintiff’s request for a complete medical record, the hospital provided the following scan of the hard copy, handwritten Anesthesia Record.

In stark contrast to the CRNA’s benign entries into the anesthesia report, the family’s and the nurses’ reports of events illustrated a serious emergency situation due to a postpartum hemorrhage. Medical record evidence showed that resuscitation efforts were seriously delayed and substandard, with no help from the CRNA or other anesthesia staff.

The hospital reluctantly provided the data from the pulse oximeter and Dynamap, the automated blood pressure cuff. The plaintiff’s team compared the data entered into the handwritten Anesthesia Record to the Device Audit Data and found a disconnect.

The pulse recordings on the pulse oximeter audit trail were seriously tachycardic, and wildly different from the data entered into the handwritten Anesthesia Record. Per nurse testimony, this mother’s blood pressures were so low that the Dynamap failed to record blood pressures; whereas, the CRNA documented normal blood pressures on her Anesthesia Record.

The device data from the pulse oximeter and automated blood pressure device were key in showing that the CRNA failed to monitor and resuscitate this mother who suffered hypoxic brain injury as a result of the delayed and inadequate resuscitation efforts. The information stored on the pulse oximeter and Dynamap in this case were not available anywhere on the produced medical record - or in any audit trail - other than the audit trail generated from the data stored by the devices.

Stay tuned for Part 5 of this series, “Mechanical Intravenous Infusion Pumps”.