HSIB Report on Maternity Pre-arrival Instructions from 999 Call Handlers

The Healthcare Safety Investigation Branch ("HSIB") investigate NHS maternity incidents that meet the criteria set out by the two national maternity healthcare programmes, the more well known being by the Royal College of Obstetricians and Gynaecologists ("RCOG") and which is called "Each Baby Counts". Where an incident meets the criteria, the HSIB report replaces the NHS Trust's own investigation. Once the report is shared, the NHS Trust is responsible for carrying out any safety recommendations that have been made.

The most recent HSIB report published on 17 February 2022 involved an investigation into instructions given by 999 call-handlers to women who have called an ambulance due to difficulties with their pregnancy and are waiting for the ambulance to arrive - these are known as "pre arrival instructions". This is, in line with all HSIB reports, a thorough and independent review and has revealed some important inadequacies which will hopefully now be addressed by the Department of Health and Social Care to avoid harm to mothers and babies.

We have learnt from this report that there are currently two triage CDSS (clinical decision support systems) approved in England for 999 assessments: NHS Pathways and the Advanced Medical Priority Dispatch System (AMPDS). I was surprised to hear that individual ambulance trusts choose one of these two CDSS systems for 999 calls. In England, six ambulance trusts use AMPDS, which is an international tool, and four use NHS pathways. Surely it is obvious that this would give rise to inconsistencies and endorsing inconsistencies in emergency maternity patient scenarios should be discouraged?

The decision to investigate followed a case where a lady who was 39 weeks and 4 days pregnant called her local maternity unit following bleeding and was told to call 999 for an ambulance to take her urgently to hospital. The call handler gave her information to prepare for a home birth, should this happen, including gathering towels and string, and to lie in the centre of the floor or on her bed with her head propped up. The ambulance trust in this case was using AMPDS.

The ambulance arrived and took her to hospital and an emergency caesarean section was carried out. It turned out her placenta had prematurely detached and this was the cause of the bleeding. She suffered significant blood loss and her baby required resuscitation, intubation and cooling to reduce the chances of a brain injury.

It was identified by HSIB that the pre-arrival instructions, while aligned with AMPDS, were not following UK maternity guidance used for clinicians in clinical settings, and that this was increasing the risk of harm to women and their babies.

Positioning a pregnant woman on their back can cause aortocaval compression. This means that the weight of the baby in the uterus presses on the main blood vessels in the woman's abdomen. This can cause a restriction in oxygen supply and can cause a baby to become unwell or, in the most severe cases, die.

The recommended advice for a pregnant woman experiencing bleeding is to lie on their left side pending the arrival of the baby/clinical help. This is in line with NHS pathways' pre-arrival instructions. The Ambulance Trust in this case were recommended to remove the element of the maternity algorithm that advises mothers or family members to collect items such as string or shoelaces for the cord and to lay flat to avoid placental abruption.

In the above case, the call-handler also asked whether the mother had any high-risk complications but national standards recommend this information be volunteered by the caller. In this case, she did not know she was suffering a placental abruption which is a high-risk complication and is an important risk for women with no previously identified high-risk complications. This can therefore compromise the triaging.

It was revealed that the Ambulance Trust's guidelines flowing from using the AMPDS tool were such that any cramping/abdominal pain is assumed to be a contraction unless proven otherwise whereas the RCOG say that where there is bleeding and pain associated with the bleeding, placental abruption should be considered.

AMPDS and RCOG guidelines were found to have different interpretations for the symptom of bleeding accompanied by continuous abdominal pain.

In the study case, it was assumed the mother was in imminent labour and AMPDS was found not to be sensitive to the possibility of placental abruption.

It was further established that there were several key bodies whose advice is that there is no harm in delaying cord clamping save for exceptional cases. The instruction to the mother in the study case to gather string when there was a haemorrhage was not consistent with the NHS pathways. There was found to be a lack of consistency among guidelines about the timing of the clamping of the umbilical cord.

There were 15 similar incidents involving pre-arrival instructions given by 999 which had been referred to HSIB.

The investigation established that there are two triage clinical decision support systems in use in England which provide different pre-arrival instructions for the same maternity clinical scenario for women who are waiting for an ambulance to arrive and that where there is a woman with abdominal pain and bleeding, the two systems would provide significantly different pre-arrival instructions for collecting items in preparation for birth and positioning while waiting for ambulance/delivery, and umbilical cord clamping.

HSIB made the following three safety recommendations in response to these findings:

Safety recommendation R/2022/180:

HSIB recommends that the Department of Health and Social Care commissions the National Institute for Health and Care Excellence (NICE) to develop guidance for maternity emergencies in the non-visual, non-clinician-attended environment.

Safety recommendation R/2022/181:

HSIB recommends that the Department of Health and Social Care identifies a suitable regulatory mechanism to provide formal oversight of 999 maternity prearrival instructions across NHS-funded care in England.

Safety recommendation R/2022/182:

HSIB recommends that NHS England and NHS Improvement develops the content of the patient safety incident investigation (PSII) standards to further support cross-boundary investigations.

For my part, I am surprised that Ambulance Trusts are given discretion to depart from NHS pathways in favour of the international AMPDS tool which in this investigation was found to increase the risk of harm to mothers and babies. This investigation is commended for its hard work in bringing these inconsistencies to the attention of the Department of Health and Social Care and to the public. Placental abruption carries risks of harm and occurs in 1% of pregnancies. It is known to be a recognised contributor to mortality rates for both babies and mothers. This is sufficiently significant to take careful steps to identify it as distinct from labour so that the mother and baby receive the management and treatment needed to reduce the risks of harm.

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