Low-lying placenta not identified during ultrasound 16HDC014
Deputy Health and Disability Commissioner Rose Wall today released a report finding Pacific Radiology Group and a radiologist in breach of the Code of Health and Disability Services Consumers’ Rights (the Code) for failing to identify that a woman’s placenta was low-lying on a second trimester ultrasound scan report. This left the woman at risk of a life threatening bleed.
The woman had a routine ultrasound scan at the privately operated radiology service when she was 19 weeks pregnant. The sonographer recognised that the placenta appeared to be low lying, but forgot to return to look at this at the end of the scan and failed to note it on her worksheet. The radiologist who reviewed the worksheet and the sonography images then recorded that the placenta was not low lying. As a result there was no further antenatal scan to assess placental position.
While Ms Wall was critical that the appropriate placental position was not documented on the sonographer worksheet, she considered that the radiology service was at fault in that its electronic report template had "not low lying" as the default for placental position. Ms Wall found this left the report open to the type of human error that occurred. Nonetheless, Ms Wall said that it was the responsibility of the radiologist reporting on the scan to review the images carefully, irrespective of what was written on the worksheet, to satisfy himself of the findings and report appropriately on the images.
At 36 weeks gestation the woman was admitted to hospital urgently with vaginal bleeding. The obstetrician reviewed the 19 week scan and ruled out placenta praevia, which had been her initial suspicion. The woman’s bleeding was diagnosed as a mild abruption, and an induction was started. The correct diagnosis was not made until the following day, and the woman then underwent an emergency caesarean section which was complicated by excessive blood loss with the placenta low lying and abnormally adherent. While Ms Wall was critical that there was a missed opportunity for the obstetrician to confirm the woman’s diagnosis with a scan before undertaking a digital examination and inducing labour, she accepted that earlier scan result that clearly stated that the placenta was not low lying was falsely reassuring.
Ms Wall noted that the radiology service now uses a different software system, and that the sonographer worksheet cannot be sent to the radiologist for reporting unless the placental location has been completed. The radiology service advised that this case had led to a significant improvement in ultrasound accuracy, and it had reduced its minor error report to less than 1%, and had initiated a regional obstetrics and gynaecology ultrasound forum which meets quarterly, with the goal of sharing information and improving ultrasound quality.
Ms Wall recommended that the radiology service and the radiologist provide the woman with an apology, and that the DHB provide a training session for obstetric staff on placenta praevia, and update its policy on antepartum haemorrhage to reflect more clearly the need to be suspicious of the accuracy of radiological reports.
The full report for case 16HDC01486 is available on the HDC website.