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Objective To determine the level of near-miss maternal mortality and morbidity due to severe obstetrical complications or maternal disease in a tertiary maternity hospital.
Design Retrospective review.
Setting A free-standing maternity hospital delivering 5500 infants per year.
Methods The information coded in the perinatal database concerning women who had required transfer for critical care to a general hospital was reviewed for the 14 year period 1980 to 1993. The complications necessitating transfer and the specialised consultants and services required were noted.
Results Over 14 years there were 76,119 women delivered with two maternal deaths (2.6/100,000). Fifty-five women required transfer for critical care (0.7/1000). The main reasons for transfer were hypertensive disease (25%), haemorrhage (22%) and sepsis (15%). Transfer to an intensive care unit was required by 80%, and the remainder were transferred to specialised medical or surgical units. Twenty different specialist groups were consulted. The 55 patients spent 280 days in critical care and 464 days hospital after-care (mean 13 days, range 3–92).
Conclusion A review of near-miss maternal mortality helps delineate the continuing threats to maternal health and the type of support services most commonly required.
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For the 14-year period comprising 1980 to 1993, all maternal deaths and any woman requiring transfer from the free-standing Grace Maternity Hospital for critical care in the two adjacent (< 1 km) general hos- pitals were reviewed. Such cases are coded in, and were retrieved from, the hospital perinatal data base. The Grace Maternity Hospital delivers about 5500 women each year and is the only maternity unit serving Halifax City and County with a population of 350,000. About 15% of the deliveries are maternal and/or fetal high risk transfers from a provincial referral base of one million. Only women at ≥ 20 weeks gestation are cared for in the Grace Maternity Hospital, so this review excludes abortion and ectopic pregnancy.
The two general hospitals are within one kilometer of the Grace Maternity Hospital, and transfer of patients by ambulance is necessary. The maternity hospital has 24 hour on-site consultants in anaesthesia and obstetrics, with both groups also providing care at the general hospitals. Laboratory, blood bank and haematology facilities are available in the obstetric unit. Intubation, ventilation, central venous pressure and arterial lines can be established, but sophisticated long term monitoring and ventilation requires transfer. Invasive radiological procedures such as major arterial embolism and other diagnostic tests (eg, angiography, VQ and CT scans) also necessitate transfer of the patient.
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Over the 14-years period under review there were 76,119 women delivered, of whom 55 required transfer for critical care (0.7/1000). Of those delivered, 11,529 (1 5.2%) were high risk transfers to the Grace Maternity Hospital from outside Halifax County; 17 of these women required critical care (1.5/1000). Thus, for the unselected Halifax County population there were 64,590 deliveries with 38 transferred for critical care (0.6/1000).
There were two maternal deaths in hospital during this 14-year period: one due to postpartum pulmonary embolism and the other to postpartum haemorrhage associated with thrombotic thrombo- cytopenic purpura. The woman with postpartum pulmonary embolism was transferred from the Grace Maternity Hospital and initially had a successful cardiopulmonary bypass performed, but sub- sequently she died. The second maternal death, the result of disseminated intravascular coagulation associated with thrombotic thrombocytopenic purpura, died at the maternity hospital and was not transferred.
There were 27 nulliparae and 28 multiparae, which reflects the parity demographics of our hospital population. Antepartum transfer was required in 10 of 55(18%) and the remainder, 45/55 (82%) were post- partum. Three patients needed delivery by caesarean section at the general hospital because of the need for perioperative invasive monitoring: two with severe hypertension and pulmonary oedema and one with unstable angina. A fourth patient with Stage 1B cancer of the cervix was delivered electively by caesarean hysterectomy at the general hospital.
Table 1 shows the primary indication for maternal transfer. Hypertensive disease and haemorrhage account for almost half of the cases. The primary clinical service and the number of days’ care required after transfer are shown in Table 2. Of the 55 patients transferred, 44 (80%) were admitted to intensive care units and the remainder required critical care in spe- cialized medical or surgical units. From the time of transfer these 55 patients required 744 days of hospital care [mean 13 days (range 3–92 days)]. There were 280 days of intensive or critical care and 464 days of hospital after-care: 266 days on general hospital wards and 198 days back at the maternity hospital.
Table 1. Primary indication for maternal transfer.
|Hypertensive disease in pregnancy||14||(25)|
| Antepartum||6|| |
| Postpartum||6|| |
| Gastrointestinal||6|| |
| Neurological||4|| |
| Pulmonary embolism||4|| |
| Respiratory||3|| |
| Acute fatty liver||2|| |
| Cardiac||2|| |
Table 2. Speciality to which primary transfer occurred. Values are given as n (%).
|Intensive care unit|
| Surgical||25 (46)||94 (34)|
| Neurosurgical||3 (5)||12 (4)|
| Cardiac care unit||2 (4)||21 (7)|
|Specialty surgical service*||7 (13)||50 (18)|
|Specialty Medical Service*||4 (7)||17 (6)|
The complexity of these cases is reflected by the fact that consultants in 20 different specialties were involved with the transferred patients: anaesthesia (n= 18), internal medicine (n= 14), general surgery (n= 12), radiology (n= 12), infectious disease (n= l0), cardiology (n= 8), haematology (n= 8), respirology (n= 8), neurosurgery (n= 5), nephrology (n= 5), other (n= 10). Excluding obstetrical colleagues, an average of two consultants were involved per transfer (range 1–6).
The surgical procedures required are shown in Table 3. Just over half of these patients had caesarean section or caesarean hysterectomy. Interventional diagnostic and monitoring procedures were required in 28 patients (51%): Swan-Ganz catheterisation (n= 11), central venous pressure mon- itoring (n= 7), VQ scan (n= 7), intubation and venti- lation (n= 7), angiography (n= 6), CT scan (n= 6), others (n= 3). Blood products were transfused in 29 patients (53%) at the maternity hospital and/or after transfer. Of these, 26 received red cells (mean 8 units), 14 fresh frozen plasma (mean 8 units), 13 platelets (mean 14 units), 12 albumin (mean 4 units) and four cryoprecipitate (mean 10 units).
Table 3. Surgical procedures. CS = caesarean section; CH = caesarean hysterectomy.
|At Grace Maternity Hospital before transfer n = 25)||At General Hospital after transfer (n = 21)|
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The provision of maternal intensive care in an obstetric unit is dependent upon the available facilities. These include intensive care units on the labour and delivery floor9–10, transfer to an intensive care unit in another part of a general hospital of which the obstetric unit is an integral part111–16 or, as in the case of Dublin hospitals6 and our unit, transfer to a geographically separate intensive care unit. We have reviewed 10 reports from six countries outlining experience with maternal intensive care over the last decade6,9–16 Two of these had an obstetric intensive care unit as part of the labour and delivery area9,10. In both of these units 9/1000 maternities were treated in the obstetric intensive care unit, which is probably a level of critical care carried out on most labour and delivery wards. However, 0.4 per 10009 and 0.8 per 100010 needed further transfer to a medical or surgical intensive care unit. These figures are similar to our own (0.7/1000) and the Dublin experience6 (0.54/1000)-both free-standing maternity units. In obstetric units that were part of a general hospital complex, the transfer rates for intensive care ranged from one to four per 100011–16. All of these reports involved hospital reviews and the most consistent complications requiring critical care were hypertension, haemorrhage and sepsis. This pattern is similar to the main causes of maternal mortality in national surveys, except for thromboembolism, which tends to dominate national mortality figures1–5. This may be due to the fact that many deaths due to thromboembolism occur after discharge from hospital and do not therefore appear in hospital reviews of maternal intensive care2. Any obstetric unit must be able to provide initial critical care for obstetric emergencies. From this review, efforts to reduce maternal morbidity and mortality may best be achieved by developing agreed protocols for the management of severe hypertension, haemorrhage and sepsis. The ability to provide initial cardiopulmonary support and manage acute rise in intracerebral pressure are rarely needed but essential skills. With 24 hour availability of consultants in anaesthesia and obstetrics, the initial acute management can usually be provided on the obstetric unit. When invasive diagnostic, monitoring and/or therapeutic measures are required, transfer for intensive care is necessary.
In this review there were only two maternal deaths, yet 54 additional women required transfer for critical care, supporting the view that near-miss mortality appraisal is more relevant in assessing the threats to maternal life. Not surprisingly, the conditions requiring intensive care tend to mirror the causes of maternal deaths and are similar in all of the hospital studies reviewed. Facilities, equipment and training should be available in obstetric units along with protocols to manage these predictable, though infrequent, life-threatening disorders.
Due to the rarity of maternal death in modern maternity units the safety of the mother is often taken for granted. Resources tend to be focused on the fetus and newborn, along with the psycho-social aspects of pregnancy and childbirth. A review of pregnant women requiring critical care reminds us that it is inappropriate to reduce the vigilance and resources that assure maternal safety.