The impact of an obstetrician-led, labor ward critical care unit: A prospective comparison of outcomes before and after establishment

Abstract

Objective

To investigate the outcomes of critically ill obstetric patients managed in a obstetric critical care unit in South Africa.

Methods

Patients with severe maternal morbidity managed in the labor ward of Tygerberg Hospital were studied over three months before the establishment of the obstetrician-led obstetric critical care unit. One year later, patients managed in the obstetric critical care unit were studied using the same methods. The primary outcome measures were maternal morbidity and mortality.

Results

In the before-obstetric critical care unit prospective audit 63 patients met criteria for obstetric critical care. During the second period 60 patients were admitted to the obstetric critical care unit. There were no significant differences between the groups in baseline characteristics, admission indications or Acute Physiology and Chronic Health Evaluation scores. Continuous positive airway pressure (p < 0.01) was utilized more in the second group. Seven deaths occurred in the first, but none in the second group (p = 0.01).

Conclusion

The establishment of an obstetrician-led obstetric critical care unit facilitated a decrease in maternal mortality.

Trial registration: Not applicable.

Introduction

Life-threatening complications during pregnancy and childbirth may develop unexpectedly and can rapidly progress to organ failure and even death. In South Africa, the conversion rate of obstetric patients with severe acute maternal morbidity (SAMM) to mortality is high resulting in a high incidence of maternal mortality.^1,2 The institutional maternal mortality rate in South Africa from 2011 to 2013 remained high at 155 deaths/100,000 deliveries.³ The limited critical care skills and resources in South Africa often contributes up to 25% potentially avoidable maternal deaths.^3,4

The incidence of patients admitted with SAMM has increased at the Tygerberg Academic Hospital due to mass migration to metropolitan areas and changes in the population characteristics. Despite being a tertiary obstetric unit where comprehensive emergency obstetric care was routinely accessible, the required level of resuscitation and critical care management was often not available in time to prevent further deterioration leading to the increase in preventable maternal mortalities. Intensivist and ICU bed availability are limited in South Africa and the incidence of maternal mortality in obstetric patients admitted to general intensive care units (ICU) is high ranging from 21% to 38%.⁵ Critical care for medical and surgical patients can be facilitated by transferring the patients to a dedicated area with the necessary infrastructure, equipment and re-allocation of existing skilled medical and nursing staff.⁶ In most cases, these patients with morbidity are currently cared for within standard hospital labor wards. The anesthetic doctor on duty might be called for assistance, but is often busy in theatre and thus not timeously available. Under such circumstances, obstetricians and midwives must provide the initial critical care management without the appropriate skills and resources.

There is a need to evaluate the provision of dedicated obstetric critical care services South Africa. There are no recently tested detailed models, nor criteria to identify which patients will benefit from obstetric critical care intervention, the expected main causes of critical illness and no evidence-based interventions or outcomes.^4,7 Due to these omissions and limited resources, the establishment of obstetric critical care units (OCCUs) is currently not one of the South African Department of Health’s recommendations to target preventable mortality.

The aim of this study was to compare the outcomes of critically ill obstetric patients before and after the establishment of an obstetrician-led critical care unit (OCCU) within the labor ward at a South African Hospital.

Methods

The study was performed in the labor ward at Tygerberg Academic Hospital, which serves as a secondary (specialist care) and tertiary (subspecialist care) referral unit. Tygerberg and Groote Schuur Hospitals are the only tertiary hospitals for adults in the Western Cape Province of South Africa. The number of deliveries performed in the entire Tygerberg referral region during 2005 was 35,506, while the number of predominantly high-risk deliveries was 7489. The study population comprised mainly of women of mixed race or African origin, who were of low socio-economic status.

To quantify and clarify the need for level two (high dependency) and level three (intensive) obstetric critical care in Tygerberg Academic Hospital, a prospective, structured, pre-establishment audit was designed and carried out using general intensive care organ dysfunction criteria as well as the indications for proposed management principles.⁸ This prospective audit of patients in the labor ward, who qualified for basic critical care management, was performed over a three-month calendar period before the establishment of the Tygerberg Obstetric Critical Care Unit (“Before OCCU” group). Thereafter, a unique, detailed OCCU design blueprint was developed and implemented with the establishment of the OCCU within the labor ward.⁹ Finally, a prospective, post-establishment (“After OCCU”) audit of patients managed in the OCCU during the same three-month calendar period, one year later, was performed using the same criteria with the goal of comparing the data sets. The same methodology applied and outcomes were followed up to 42 days post-delivery. The triaging of obstetric patients Before OCCU was as follows. All patients passed through the obstetric admission area before entering the labor ward. When severe morbidity or criteria for higher level care were present, a multidisciplinary team was consulted to assist with management in the labor ward and/or the transfer to general intensive care units. After the establishment of the OCCU, patients with severe morbidity were transferred from the labor ward to the OCCU. Patients with criteria for general ICU were first stabilized and then transferred to the ICU when a bed became available. The inclusion criteria for patients requiring care in an OCCU or general ICU were obstetric patients with impending, developing or established organ dysfunction with potential long-term morbidity or death. This included any obstetric patient with an indication for intra-arterial monitoring, central venous pressure monitoring and mask continuous positive airway pressure (CPAP) support. Non-obstetric patients and those with early complications such as miscarriage or ectopic pregnancy were excluded, as these patients were admitted to the surgical ICU as per hospital policy. Patients in the Before OCCU group were managed in the labor ward, where the emergency obstetric care, recommended by the World Health Organization was routinely available as standard of care. Standard care for early and severe pre-eclampsia included magnesium sulfate (4-g bolus, then 1 g/h IVI) for pre-eclampsia, strict blood pressure control with oral nifedipine or labetalol boluses IV (per protocol) and a fluid balance chart conservative policy of 80 mL/h 0.9% normal saline infusion. Patients in the Before OCCU group were managed by the on-call obstetric team comprised of a consultant, registrar (resident), and house officer with qualified midwives in the delivery and postnatal rooms. Maternal and fetal observations were recorded by nursing staff and abnormal observations were reported. Critically ill patients requiring intensive care were referred to the general ICU or the Accident and Emergency Critical Care Unit depending on bed availability. The Tygerberg Academic Hospital OCCU was established in March 2006 and the After OCCU group of patients with severe morbidity or other inclusion criteria for critical care were managed in this unit. The size of the unit was set as four beds in an open area of 80 m². The electric points, wall suction, and piped oxygen were extended from the existing labor ward infrastructure. The unit was equipped with four bedside patient monitors, which included ports for invasive blood pressure measurement. The respiratory support equipment available included one CPAP machine and a standard ventilator. The latter was only used when no general ICU bed was immediately available. A consultant obstetrician (unit director—principal investigator) and a professional nurse with critical care experience managed the unit. No additional doctors were appointed. The midwife: patient ratio was 1:2. Doctors and midwives allocated to the OCCU received additional informal, in-service training in basic critical care knowledge and skills. Admission and discharge policies were clearly defined. Specific critical care management protocols were available and implemented. Obstetric registrars (one per shift) were responsible for patient management from 08:00 to 16:00, Monday to Friday while the unit director provided clinical supervision. The senior gynecology registrar on-call, under supervision of the obstetric consultant on-call was responsible for clinical management after hours. In both the Before OCCU and After OCCU groups, consultant and registrar anesthetists were available for critical care advice or procedures such as epidurals. Other inter-disciplinary consultation was also available for both groups.

The primary outcome measures were maternal mortality and major morbidity after admission. No similar studies were identified in the literature review. Although a reliable sample size calculation was not possible, severe morbidities and mortalities in the study region are concentrated in the tertiary referral units. Therefore, differences following a definitive change in management were expected to be demonstrable after the recommended audit periods. The Statistics Department of Stellenbosch University using the Statistical Package SPSS version 10 analyzed data (IBM Corporation). Categorical data were analyzed using the chi-square test, as well as odds ratios with 95% confidence intervals where applicable. Where an expected cell value was less than five, the Fisher exact test was used. Continuous data were analyzed using the Student’s t-test, and for non-parametric data, the Mann–Whitney U-test was used. All tests utilized the 5% level of significance (p value <0.05). The Health Research Ethics Committee of Stellenbosch University (NO7/05/112) approved the study protocol). The committee granted a waiver of consent for the following reasons: the necessary audits as well as the establishment of the unit were required by the hospital administration. The outcomes were recorded retrospectively. The Western Cape Department of Health approved the project as part of the policy to improve obstetric service delivery; it was therefore not required to register the project with a registry of national trials.

Results

Patient data were collected from 1 September to 30 November 2005, prior to the establishment of the OCCU (Before OCCU) and thereafter from 1 September to 30 November 2006 (After OCCU). There were 1804 high-risk deliveries during the first and 1727 high-risk deliveries during the second audit period in the labor ward of Tygerberg Academic Hospital. Not all patients qualifying for critical care in the study groups were necessarily delivered in the study hospital. During the three-month Before OCCU period, 63 patients met criteria for obstetric critical care or general ICU admission. In the After OCCU group, 60 patients were included. There were no significant differences in maternal baseline characteristics or the incidence of SAMM on admission as defined by the Mantel et al. criteria,¹ between the groups (Table 1).

Table 1.

Maternal baseline characteristics on admission to labor ward.

	Before OCCU group (n = 63)		After OCCU group (n = 60)
	Mean or number	Range or %	Mean or number	Range or %	p value
Age	26	14–43	27	15–47	0.61
Gravidity	2	1–5	2	1–6	0.72
Parity	1	0–5	1	0–5	0.25
Antenatal admissions	38	60%	32	51%	0.54
Postnatal admissions	25	40%	28	39%	0.43
Gestation at time of event (weeks)	35	20–42	34	20–42	0.08
HIV cases	14	22%	15	25%	0.35
APACHE score	10	0–42	8	3–29	0.89
SAMM	46	73%	40	67%	0.44

OCCU: obstetric critical care unit; APACHE: Acute Physiology and Chronic Health Evaluation; SAMM: severe acute maternal morbidity.

The main causes for admission were hypertensive disorders in pregnancy, obstetric hemorrhage, sepsis, and underlying medical disorders as shown in Table 2.

Table 2.

Important direct and indirect causes of admission.

	Before OCCU	After OCCU	p value
Hypertensive disorders in pregnancy	38	36	0.97
Obstetric hemorrhage	14	9	0.3
Severe pregnancy-related sepsis	4	5	0.67
Severe non-pregnancy-related sepsis	7	14	0.03
Pre-existing cardiac disorders	11	12	0.72

OCCU: obstetric critical care unit.

Results given as n = number of causes, patients may have more than one admission indication.

There were no significant differences in the organ-based dysfunction admission categories. The most common organ systems involved were respiratory and renal dysfunction or failure as shown in Table 3. The underlying causes for respiratory failure were mainly pre-eclampsia-related pulmonary edema, 16 in the Before OCCU group and 14 in the After OCCU group, respectively (p = 0.83) and more cases of pneumonia in the After OCCU group (9 vs. 19; p = 0.02). There were no significant differences in the sub-categories of SAMM markers¹ on admission between the Before OCCU and the After OCCU groups as shown in Table 4.

Table 3.

Admission indications based on organ system dysfunction/failure.

Organ dysfunction based criteria	Before OCCU	After OCCU	p value
Resistant acute severe hypertensiona	38	36	0.97
Hemorrhage	14	9	0.30
Cardiac	11	12	0.72
Pulmonary	26	33	0.13
Renal	20	17	0.68
Metabolic/endocrine	8	14	0.12
Neurological	11	5	0.13
Severe sepsisb	11	19	0.07
Other	2	0	0.24

OCCU: obstetric critical care unit.

Results given as n = number of organ system dysfunctions. A patient may have more than one organ system dysfunction.

^aSBP remains >160 mmHg despite oral calcium channel blockers and or IV hydralazine boluses.

^bSepsis and organ dysfunction/failure.

Table 4.

Severe acute maternal morbidity markers on admission.

	Before OCCU (n = 63)	After OCCU (n = 60)	p value
Total SAMMa	46	40	0.44
ICU transfer	20	13	0.21
Pulmonary edema	18	16	0.81
Acute renal failure	10	7	0.50
>5 U blood transfusion	11	10	0.90
Hysterectomy for hemorrhage	2	4	0.37
Hysterectomy for sepsis	1	2	0.53
Intubation and invasive mechanical ventilation	14	7	0.13
Pulmonary embolus	2	0	0.16
Platelet transfusion	4	8	0.19
Coma	4	3	0.44

OCCU: obstetric critical care unit.

Results given as n = number of cases, patients may have more than one category of SAMM.

^aSevere acute maternal morbidity defined by Mantel et al.¹

The predefined, recommended, basic critical care management and monitoring received in the Before OCCU and After OCCU groups were audited.

Ideal predefined monitoring, cardiovascular drug, and respiratory support management were received more often in the After OCCU group as shown in Table 5.

Table 5.

Basic critical care monitoring, drug infusions, and respiratory support.

	Before OCCU	After OCCU	p value
Circulation monitoring
Intra-arterial blood pressure monitoring	3	47	<0.001
Central venous pressure monitoring	10	31	<0.001
Circulation pharmacological support
Intravenous titrated anti-hypertensive  medication	2	23	<0.001
Intravenous inotropes	4	9	0.01
Intravenous nitrates	0	13	<0.001
Respiratory support
Mask CPAP/Bi-PAP	0	11	<0.001
Intubation	13	5	0.05
Transferred to general ICU for  invasive mechanical ventilation	10	7a	1.00

OCCU: obstetric critical care unit; CPAP/Bi-PAP: continuous positive airway pressure/bi-level positive airway pressure.

Results given as n = number of cases, patients may have more than one category.

^aTwo patients received ventilation in OCCU.

Twenty patients in the Before OCCU group were transferred to general ICU and 13 patients in the After OCCU (p = 0.92). Seven patients died in the labor ward in the Before OCCU group compared to no maternal deaths in the After OCCU group (p = 0.01). No women requiring OCCU admission died in the labor ward before reaching the OCCU during the After OCCU audit. The SAMM/mortality ratio in the Before OCCU group was one death per every five cases with SAMM morbidity criteria, while the ratio in the After OCCU group was one death per 20 patients with SAMM criteria. Details of deaths are shown in Table 6.

Table 6.

Primary causes and location of maternal mortality.

	Before OCCU (n = 63)	After OCCU (n = 60)	p value
Mortality in labor ward	7	0	0.01a
Mortality in general ICU after transfer	2	2	1.00a
Total mortality including general ICU	9	2	0.05a
Causes of mortality			Location of death
Bacterial pneumonia (HIV−)	2	0	Labor ward
Bacterial pneumonia (HIV+)	3	0	Labor ward
Tuberculosis, bacterial pneumonia, HIV	0	1	General ICU
Obstetric hemorrhage	3	0	Labor ward2General ICU1
Pre-eclampsia	1	0	Labor ward
AFLP	0	1	General ICU

OCCU: obstetric critical care unit; AFLP: acute fatty liver of pregnancy.

^aFisher exact test (two tailed).

With regard to neonatal outcomes, the mode of delivery was similar with 37 caesareans in the Before OCCU and 36 caesareans in the After OCCU groups. The median/range neonatal birthweight was 2358 g in the Before OCCU group (640–4380 g) compared with 2040 g in the After OCCU group (630–4328 g; p = 0.13). There were three neonatal deaths in the Before OCCU and two in the After OCCU groups (p = 0.71).

Discussion

This study evaluated the impact of a newly established obstetrician-led OCCU in the labor ward of an academic hospital, on the management of critically ill obstetric patients, comparing this to the pre-existing standard of care. It demonstrated a statistically significant decrease in maternal mortality (p = 0.01). In addition, the SAMM or “near miss”/mortality ratio at the institution was decreased from one in five to one in 20 cases. Major maternal morbidities “after admission” were also decreased by the intervention. Although the numbers of neonatal deaths were similar, the OCCU provided a “baby friendly” advantage over the general ICU in that stable babies could be together with stable mothers, thereby promoting bonding and breastfeeding. The study groups were comparable in terms of organ dysfunction, SAMM as well as Acute Physiology and Chronic Health Evaluation (APACHE) scores on admission. Furthermore, the APACHE scores in both groups are comparable to the median APACHE scores of patients admitted to European general ICUs.¹⁰ The most common causes for admission in this study, namely complicated pre-eclampsia, obstetric hemorrhage, and underlying medical conditions, are similar to intensive care unit admissions in higher income countries.¹¹ However, unlike high income countries, almost a quarter of the patients in both study groups were HIV positive which is likely to have contributed to the higher incidence of sepsis than wealthy countries.¹²

Intra-arterial blood pressure monitoring was utilized frequently in the After OCCU group, with the lines being inserted mainly by the obstetric registrars (residents). This safe, accurate, monitoring intervention allowed goal-directed titrated infusion of vasoactive drugs. The most common organ system dysfunction was respiratory distress due to pulmonary edema and pneumonia. In this study, early respiratory support using Bi-PAP, CPAP, and at times ventilation contributed to fewer deaths in the After OCCU group. The fact that transfers to a general ICU were necessary for both study groups emphasizes the importance of such a facility. However, in both the Before OCCU and After OCCU groups, general ICU beds were often not immediately available. This probably contributed to mortality in the Before OCCU group due to the difficulties in managing critically ill patients in the standard labor ward with a limited infrastructure and lack of critical care skills. The principal reason for the improved outcomes in the latter group was the early on-site obstetric critical care management received. It is important to understand that the goal was not to provide an alternative general intensive care unit but rather a higher level of early support, by registrars and consultants (rather than a single enthusiast), to obviate the need for prolonged intensive and especially ventilator support. The OCCU provided a regulated environment with continuous, accurate monitoring. Through the performance of effective resuscitation and organ support, maternal collapse was avoided and skills were enhanced, in both the OCCU and the labor ward. It could be argued that the positive results were merely due to the “Hawthorne effect”. While this may certainly have contributed, the positive results exceeded this explanation alone. The study took place in the context of a continuous education and training environment and therefore both Before OCCU and After OCCU groups would have been subject to this effect.

The limitation of this study is that it was a descriptive study performed within the specific time frames in order to timeously identify the need, establish the unit and then compare outcomes between the two groups. It was therefore not possible to do a sample size calculation. The principal author could not identify any other peer-reviewed comparative or randomized studies on the impact of an OCCU in a labor ward. There are however, several case series, mainly in higher income countries, describing improved outcomes of patients managed in obstetric high dependency and obstetric intensive care units.^13–16 Sadly, even in high-income countries such as the United Kingdom maternal deaths often occur outside the ICU.¹⁷

To understand the context of this study better, a brief description of practices following the study is appropriate. Subsequent to the establishment of the OCCU, the number of deliveries in the region increased continuously resulting in more cases with severe morbidity. The OCCU admissions rose from 255 during 2007, to 356 during 2010. As a consequence, the acceptance rate decreased and it was deemed necessary to appoint and train a dedicated doctor to work in the unit. This improved the situation but as the pressure of absolute number of cases remained, a three-bed, step-down room adjacent to the OCCU was added for post-partum cases, to facilitate throughput. This latter area was staffed by only one enrolled nurse assistant who was supervised by the OCCU team. During 2017 the OCCU admitted 471 patients, of whom 49% were undelivered. Non-invasive mask respiratory support was provided to 143 cases and invasive ventilation to 56 cases.¹⁸

The establishment of an OCCU (within the labor ward setting) with the aim of decreasing maternal morbidity and mortality was successful in the Tygerberg Academic Hospital. This study demonstrated that an OCCU could be established in a low resource environment without major changes in infrastructure and staffing. The authors recommend replication of this model in similar institutions with high throughput of critically ill pregnant women.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Ethical approval

Ethics approval was gained from the Institutional Health Research Ethics Committee of Stellenbosch University (reference number HREC NO7/05/112).

Informed consent

A waiver of consent for the publication of the anonomysed patient audit data was obtained from the Ethics committee (N07/05/112).

Guarantor

EJL.

Contributorship

DR Hall, F Mattheyse and E Langenegger designed and planned the study. E Langenegger conducted the study and collected the data. J Harvey performed the statistical analysis. All authors participated in the data analysis. E Langenegger and DR Hall wrote the manuscript. All authors read and approved the final manuscript.