RESEARCH ARTICLE |
https://doi.org/10.5005/jp-journals-10006-2290
|
Sequential Organ Failure Assessment Scoring Tool for Prediction of Outcome in Obstetric Intensive Care Unit at Tertiary Care Center
1,2Department of Obstetrics and Gynecology, SSG Hospital & Baroda Medical College, Vadodara, Gujarat, India
Corresponding Author: Nupur Anand, Department of Obstetrics and Gynecology, SSG Hospital & Baroda Medical College, Vadodara, Gujarat, India, Phone: +91 8828096948, e-mail: nupur28@yahoo.co.in
How to cite this article: Nupur A, Gokhale AV. Sequential Organ Failure Assessment Scoring Tool for Prediction of Outcome in Obstetric Intensive Care Unit at Tertiary Care Center. J South Asian Feder Obst Gynae 2023;15(4):456–461.
Source of support: Nil
Conflict of interest: None
Received on: 28 August 2019; Accepted on: 18 May 2021; Published on: 16 September 2023
ABSTRACT
Introduction: World Health Organization defines maternal death as the death of a woman while pregnant or within 42 days of termination of pregnancy from any cause related to or aggravated by the pregnancy or its management, irrespective of the duration and the site of the pregnancy, but not from accidental or incidental causes. Different types of scores have been used to know the degree of organ failure and outcome or prognosis of the disease during ICU stay. The sequential organ failure assessment (SOFA) score is one of the recent scores, which is used to know the degree of organ failure.
Aim and objectives: To validate that SOFA score can be used to know the prognosis of patients in the obstetric intensive care unit (ICU) and to decide treatment accordingly.
Materials and methods: Organ failure was evaluated based on the maximum score for each one of its six components and from that total maximum SOFA score was calculated. The study was conducted in the Department of Obstetrics and Gynaecology, Baroda Medical College and SSG Hospital, Vadodara, Gujarat, India from 1 September 2017 to 31 August 2018.
Results: The SOFA score trend in the patients who recovered was negative and showed a significant decrease with respect to time whereas the SOFA score trend in the patients who deteriorated and expired was positive and showed a significant increase. Interpretation of the area under the receiver operating characteristic (ROC) curve showed that the performance of the total maximum SOFA score was excellent [area under the curve (AUC) 0.972; 95% confidence interval (CI): 0.917–0.995].
Conclusion: Total maximum SOFA score proved to be an effective tool in obstetrics ICU in evaluating the severity of disease and estimating the prognosis of the patient.
Keywords: Maternal mortality, Obstetric intensive care unit, Sequential organ failure assessment score.
INTRODUCTION
The World Health Organization defines maternal death as the death of a woman while pregnant or within 42 days of termination of pregnancy from any cause related to or aggravated by the pregnancy or its management, irrespective of the duration and the site of the pregnancy, but not from accidental or incidental causes.1
According to the Registrar General of India – Sample Registration System (RGI-SRS) Report (Special Bulletin on Maternal Mortality in India 2017–2019); the Maternal Mortality ratio (MMR) of India is 103 per 100,000 live births.2 Critically ill obstetric patient management is challenging due to the presence of a fetus which leads to an altered physiology in the mother and the presence of disease-specific to pregnancy.3 In developed countries, pregnant patients account for a small number of intensive care unit (ICU) admissions (2%), but in developing countries such as India, they reach up to 10% or more.4,5 Based on various studies, the two main indications for admission are mainly hypertensive disorders (17.2–46%) and massive hemorrhage (10–32.8%). The remainder of admissions are due to medical and other problems of pregnancy (44%).6 (Fig. 1).
Fig. 1: Additional medical procedure/medication
In India, most common cause of obstetric ICU admissions is due to neurologic failure (63%) followed by hematologic (56%), renal (49%), respiratory (46%), cardiovascular (38%), and hepatic failure (36%).7
Various scores traditionally used in ICUs, such as the acute physiology and chronic health evaluation II (APACHE II), simplified acute physiology score II (SAPS II), and mortality probability models (MPMs)8 when used in obstetric patients had conflicting results, generally overestimating the severity of illness and maternal morbidity and mortality. Among these methods used in ICU, those scores which evaluated organ dysfunction appeared to have greater sensitivity and specificity.4
The sequential organ failure assessment (SOFA) score assesses the degree of organ system dysfunction of a patient. This score has a score for each of six major organ system of our body on a scale of 0–4 depending on severity and thus calculates the total score on each day of stay of patient in ICU (Fig. 2).
Figs 2A and B: Comparison of SOFA score trend with patient recovery (A) For maximum SOFA score; (B) For SOFA score trend
METHODOLOGY
This study was conducted during one year duration between 1 September 2017 to 31 August 2018.
Each patient was examined and general information and obstetric history of patient was taken which was followed by indication of obstetric ICU admission and associated comorbid conditions were noted. Complaints of patient during admission with duration was also noted and SOFA score was entered on admission, 12 hours after admission and 24-hourly during ICU stay. All data elements which were required for calculation of SOFA score (Table 1) was prospectively collected on standardized forms and entered into a prescribed sheet/pro forma for later analysis (Fig. 3).
System | 0 | 1 | 2 | 3 | 4 |
---|---|---|---|---|---|
Respiration PaO2/FiO2 mm Hg (kPa) |
≥400 (53.3) | <400 (53.3) | <300 (40) | <200 (26.7) with respiratory support |
<100 (13.3) with respiratory support |
Coagulation Platelets x 103/µL |
>150 | <150 | <100 | <50 | <20 |
Liver Bilirubin mg/dL (µmol/L) |
<1.2 (20) |
1.2–1.9 (20–32) |
2.0–5.9 (33–101) |
6.0–11.9 (102–204) |
>I2 0 (204) |
Cardiovascular | MAP >70 mm Hg |
MAP <70 mm Hg |
Dopamine <5 dobutamine (any dose) | Dopamine 5.1–15 or epinephrine ≤0.1 or norepinephrine ≤0.1 | Dopamine >15 or epinephrine >0 1 or norepinephrine >0 1 |
CNS GCS score |
15 | 13–14 | 10–12 | 6–9 | <6 |
Renal creatinine, mg/dL (µmol/L) Urine output, mL/day |
<1.2 (110) | 1.2–1.9 (110–170) | 2.0–3.4 (171–299) |
3.5–4.9 (300–440) <500 |
>5.0 (440) <200 |
Fig. 3: Indication for obstetric ICU admission
Apart from this, ICU interventions done and associated ICU complications were also noted. This SOFA score was a measure of the dysfunction in six organ system, namely, respiration, coagulation, liver, cardiovascular, central nervous system (CNS) and renal function. The minimum SOFA score was 0 and maximum was 24.
Mean arterial blood pressure was calculated using following formula:
Partial pressure of oxygen was obtained from arterial blood gas analysis (ABG).
In obstetric ICU of SSG Hospital, Vadodara, Gujarat, India, non-rebreathing mask (NRBM) was used. Table 2 was used to calculate fraction of inspired oxygen.
Oxygen flow rate (L/minute) | FiO2 |
---|---|
3 | 0.5–0.65 |
6 | 0.6–0.75 |
9 | 0.65–0.80 |
12 | 0.7–0.85 |
15 | 0.75–0.9 |
In some cases, due to use of continuous sedation, evaluation of neurological system according to Glasgow coma scale was impossible. In such cases, unless there was any sign to the contrary, the parameters were assumed to be normal and normal values for the variable was used for calculation of the score.
DATA ANALYSIS
Categorical variables were presented in number and percentage (%) and continuous variables were presented as mean ± standard deviation (SD) and median. Normality of data was tested by Kolmogorov–Smirnov test. If the normality was rejected then non-parametric test was used.
Statistical tests were applied as follows:
Quantitative variables were compared using independent t-test/Mann–Whitney test (when the datasets were not normally distributed) between survived and expired.
Pearson correlation coefficient was used to assess the correlation of value of parameters with time for each patient so that time trend of parameters can be calculated.
Receiver operating characteristic (ROC) curve was used to find out cut off point of parameters for predicting mortality.
A p < 0.05 was considered statistically significant.
The data was entered in Microsoft Excel spreadsheet and analysis was done using statistical package for social sciences (SPSS) software, version 21.0.
RESULTS
The study was conducted in the Department of Obstetrics and Gynaecology, Baroda Medical College and SSG Hospital, Vadodara, Gujarat, India, from 1 September 2017 to 31 August 2018. It was a hospital-based prospective study where 100 women were included if they were admitted during pregnancy or up to 42 days postpartum in morbid conditions and satisfied the inclusion criteria.
Furthermore, SOFA score was calculated at the time of admission, 12 hours after admission and every 24 hours after that till the patient was admitted in ICU.
A total of 83% of patients admitted belonged to 20–30 years age group. The mean stay in the ICU was 3.3 ± 1.02 days. Most common indication was preeclampsia and eclampsia which accounted for 43% of the patients.
In our study, among ICU interventions done ventilatory support was required in 72% patients, blood transfusion in 81% patients, and hysterectomy was done in 22% patients. Among medications, Antihypertensives, anticonvulsants and Inotropes were most commonly used in the patients.
The SOFA score trend in the patients who recovered was negative and showed a significant decrease with respect to time whereas the SOFA score trend in the patients who expired was positive and showed a significant increase with respect to time.
Interpretation of the area under the ROC curve showed that the performance of total maximum SOFA score was excellent (AUC: 0.972; 95% confidence interval [CI]: 0.917–0.995). When the performance of maximum SOFA scores was calculated individually for each organ function, the discriminatory power of the respiratory and cardiovascular scores were good; however, no individual score alone had better discriminatory power than the total maximum SOFA score. Respiratory, chorionic villus sampling (CVS) and total score were 100% sensitive but total score had maximum specificity among them (Fig. 4).
Figs 4A to F: The ROC of maximum score of individual organ system for predicting mortality
Respiratory and renal trend was 100% sensitive and on the other hand CVS and CNS trend was 100% specific. Although CNS and CVS trend had 100% specificity, only in 62.5% CNS trend and in 87.5% CVS trend were able to predict mortality among the total died patients; similarly, sensitivity of liver was quite good (93.75%) but its specificity was low, that is, 78.57%. Sensitivity and specificity of coagulation was 87.5 and 98.81%. Total score trend was 100% sensitive and 100% specific (Table 3). Thus, according to this study total SOFA score can be used to predict mortality in obstetric ICU and give prognosis of patient as increasing trend of SOFA score indicates a poor prognosis.
SOFA score trend | Sensitivity | 95% CI | Specificity | 95% CI | PPV | 95% CI | NPV | 95% CI |
---|---|---|---|---|---|---|---|---|
Respiratory trend | 100 | 79.4–100.0 | 95.24 | 88.3–98.7 | 80 | 56.3–94.3 | 100 | 95.5–100.0 |
Coagulation trend | 87.5 | 61.7–98.4 | 98.81 | 93.5–100.0 | 93.3 | 68.1–99.8 | 97.6 | 91.8–99.7 |
Liver trend | 93.75 | 69.8–99.8 | 78.57 | 68.3–86.8 | 45.5 | 28.1–63.6 | 98.5 | 92.0–100.0 |
CVS trend | 87.5 | 61.7–98.4 | 100 | 95.7–100.0 | 100 | 76.8–100.0 | 97.7 | 91.9–99.7 |
CNS trend | 62.5 | 35.4–84.8 | 100 | 95.7–100.0 | 100 | 69.2–100.0 | 93.3 | 86.1–97.5 |
Renal trend | 100 | 79.4–100.0 | 72.62 | 61.8–81.8 | 41 | 25.6–57.9 | 100 | 94.1–100.0 |
Total trend | 100 | 79.4–100.0 | 100 | 95.7–100.0 | 100 | 79.4–100.0 | 100 | 95.7–100.0 |
DISCUSSION
Maternal death is an indicator of the developmental level of a country. The study of near-miss cases is used to evaluate the quality of obstetrical healthcare systems.
To reduce maternal morbidity and mortality, most important step is early recognition of obstetric complications and referral of these patients to higher centers. Apart from this access to safe, affordable, and both basic and emergency, obstetric care is needed. Predicting severe morbidity and mortality in obstetric population is challenging as different patients tend to develop different patterns of organ dysfunction . Thus, an ideal scoring system should allow prediction of mortality and quantification of the severity of illness during hospitalization. The scoring system should also help in predicting morbidity and amount of success achieved by treatment.
This study was conducted over a period of 1 year in a tertiary care center which receives a large number of referred cases. In this study, evaluation of performance of total maximum SOFA score showed that the score had good performance. Assessment of the SOFA scores hence had potential utility in cases of obstetrics patients admitted in ICU. Very high scores were suggestive of very severe organ/system dysfunction.
The APACHE II and SAPS II scores which are usually used in obstetrics population tends to overestimate severity and maternal mortality ratios. Physiological changes in pregnancy and different patterns of obstetric morbidities are the factors which leads to this overestimation.9
Organ-specific-based scoring systems such as the SOFA score are superior to diagnosis-based systems for several reasons.10 As seen in our participants many patients can have multiple organ failure or dysfunction simultaneously with severe obstetric illness. Second, as shown in our study, obstetric patients may have multiple clinical diagnoses, at admission or during hospitalization. Furthermore, severity scoring systems such as the SOFA generates an overall score based on severity of condition of patient thus deciding ICU admission. Apart from this SOFA score can easily be calculated on a daily basis as parameters required are simple. These daily scores help in comparison and thus in knowing about response to treatment and predicting morbidity or mortality of patient. In addition, the SOFA could be also be used as a tool to audit the quality of care.9
The maximum SOFA score of individual organ system shows the maximum degree of alteration in the given organ system at that point of time and the trend of SOFA score gives us an idea of degree of alteration in organ function at different times in ICU.
The SOFA score was also excellent in predicting mortality as of 100 patients taken for study, 16 patients who expired had high total SOFA score just before mortality.
CONCLUSION
A scoring system for critically ill obstetric patients could lead to better monitoring in these patients and help in assessing response to treatment. The scoring system such as SOFA score can easily be adopted as it is easy to use, requires simple parameters to calculate score and hence should be practiced and be incorporated into guidelines.
The SOFA score was able to predict outcome in obstetric ICU patients. The trend of SOFA score was progressively declining in patients with good prognosis while those patients with high morbidity and mortality had higher scores. The study showed that the total maximum SOFA score had good predictive ability for survival or death in critically ill obstetric patients.
The SOFA scoring system can thus help the obstetricians in admitting patients, monitoring the clinical course, assessment of organ dysfunction, predicting mortality, and for transferring patients out from the ICU and thus in proper utilization of ICU resources also in developing countries like ours, where the resources are limited.
ETHICAL APPROVAL
This study has been approved by the Institutional Ethics Committee for Human Research (IECHR) on 18 September 2017 (No. ECR/85/Inst/GJ/2013/RR-16).
AUTHORS’ CONTRIBUTIONS
All authors had equal contribution in this study.
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