hhjh

1. Predictors of Outcome in Acute Respiratory Distress
Syndrome in Acute Febrile Illness in Medical
Intensive Care Unit
Presented by : Dr.Tapas Tripathi
Moderator : Dr.Naman Bansal
Journal of the Association of Physicians of India, Volume 70 (March 2022)

2. Introduction
 The Acute febrile illness (AFI) also known as acute undifferentiated fever has
been defined as fever of two weeks or shorter in duration.
 In India AFI is an important cause of hospitalization, especially between the
months of June to September. The underlying etiology of AFI as per different
studies have been reported as follows - malaria in 5 to 50% cases, Rickettsial
fevers/scrub typhus in 4 to 49% cases, enteric fever in 7 to 30% cases,dengue in 4
to 19% cases, leptospirosis in 3 to 10% cases and influenza in 8 to 12% of cases.
 The common complications associated with AFI are hypotension, acute kidney
injury, acidosis, superimposed bacterial infections, acute respiratory distress
syndrome (ARDS), thrombocytopenia, acute liver failure or DIC ,depending on
the underlying etiology of AFI.

3.  The in-hospital mortality rate is estimated to be between 34 and 55%.Most
ARDS-related deaths are due to multi-organ failure. Refractory hypoxemia
accounts for only 16% of ARDS-related deaths.
 The Sequential Organ Failure Assessment (SOFA) score is an objective score
which calculates severity of organ dysfunction in six organ systems (liver,
cardiovascular, renal, neurologic, respiratory, coagulopathy).
 SOFA score has been studied in critically ill elderly patients. However, Indian
literature assessing the prognostic value of SOFA score in patients of AFI
complicated by ARDS is limited.
 This study assessing the clinical profile of and utility of SOFA score, Lung
Injury Score (LIS), Disseminated Intravascular Coagulation (DIC) score and
Arterial Blood Gas (ABG) parameters in patients with AFI complicated by
ARDS in the medical intensive care unit.

4. Material and Method
 This prospective observational study was performed on 130 patients at the
Medical Intensive Care Unit of Seth GS Medical College & KEM Hospital Mumbai,
over a period of 18 months from March 2016 to August 2017.
 Patients diagnosed with ARDS as per Berlin definition were included in the study.
The study included those diagnosed with an existing diagnosis of ARDS upon
admission into the ICU, provided they survived the initial 24 hours of the ICU stay.
 Patient details were noted in a proforma. Laboratory reports obtained at and after
48 hours of admission into the MICU were noted, consisting of ABG, complete
blood counts, liver and renal function tests and DIC profile.
 For fever, along with blood culture, the following tests were done - fever profile
consisting of Dengue NS1 antigen assay, Dengue IgM and IgG antibodies,
Leptospira IgM antibody, peripheral smear for malaria and malarial antigen test
(MAT), RT-PCR on throat swab for H1N1 virus and chest radiograph.

5.  From the above reports SOFA score, Lung Injury Score (LIS), DIC score (by
ISTH scoring system) were calculated.
 Delta SOFA score was calculated as the change in SOFA score over 48
hours(T0 SOFA score –T48 SOFA score).
 During the MICU stay, the mode of ventilatory support needed and
treatment given to each patient was noted.
 Main outcome measure was recorded as transfer out from MICU or death.
Criteria for transfer out from MICU to the ward were as follows- lack of the
need for invasive mechanical ventilation, CPAP support or NRBM support
along with hemodynamic stability.
 The patients were not followed up for readmissions for the purpose of this
study.

6. Statistical analysis
 Descriptive statistics were used for summarising the results of the study.
Data was analyzed by chi-squre test and multivariate logistic regression.
 Analysis of significance was done using computer-based program SPSS
version 17; p value of <0.05 was considered as significant.

7. Result
 Total admission in MICU during this study period was 999, out of which
13.01% (n=130) had AFI complicated by ARDS thus constituting this study
population.
 Mean age of the study population was 39.4+/-13.4 years, with majority of
them belonging to the age group of 26-45 years (49.2%).
 The major comorbidities in this study were diabetes mellitus (18.5%) and
hypertension (16.9%). Table 1 gives underlying etiology of ARDS with
mortality. The etiologies were as follows: Dengue-24.6% (n=32), H1N1-
23.8% (n=31),undifferentiated fever 23.1%(n=30),leptospirosis-
16.9%(n=22), vivax malaria-8.5%(n=11),falciparum malaria-31%(n=4).The
overall mortality rate was 25.4% (n=33).

11.  Highest mortality rate in AFI complicated by ARDS was seen amongst
patients with undifferentiated fever (46.7%), followed by leptospirosis
(45.4%), H1N1 (16.1%) and dengue (12.5%). Malaria associated ARDS
showed 100% survival rate.
 The modes of ventilation used on admission in this study were invasive
ventilation in 40.8% (n=53), non invasive ventilation in 59.2% (n=77). The
criteria used for patient selection for non invasive ventilation were
hemodynamically stable patients and patients who tolerated non invasive
ventilation (NIV) mask well and were compliant to it.
 The laboratory parameters having significant outcome predictive value
were BUN, creatinine, bicarbonate, total bilirubin, AST and albumin.

12.  The PaO2/FiO2 ratio was significant both on admission (0 hours) and at 48
hours. The scores having significant outcome predictive value were SOFA
score at admission and 48 hours, delta SOFA score. LIS and DIC score at
admission were not found to have significance for outcome prediction.
 Mean PaO2/FiO2 at admission and at 48 hours values was found to be
statistically significant in determining overall outcome in AFI with ARDS
(p=0.002 and p<0.001 respectively).
 PaO2/FiO2 at admission was a significant outcome predictor only in
leptospirosis and undifferentiated fever whereas at 48 hours was
significant in all etiologies of ARDS due to AFI.
 Analysis of DIC score as an outcome predictor in individual diseases
showed statistical significance only in H1N1 (p=0.001). However, DIC score
as an overall predictor of outcome in AFI with ARDS has no statistical value

13. Discussion
 Patients with ARDS constituted approximately 13.01 % (130/999) of the total
admissions in MICU during the study period of 18 months.
 The mortality rate in this study was similar (25.4%) to the mortality in ARDS
Network study done in 2003 (N-91) and 2005 (N-487), where the mortality was
29% and 26% respectively.
 According the literature review conducted by Zambon M and Vincent J L,
investigators reported improved survival with shortened duration of mechanical
ventilation by means of lung protective ventilation and conservative fluid
management as suggested by NIH-NHLBI ARDS Network trial.
 In this study, the 77 patients who could be ventilated by non-invasive ventilation
on admission had a survival rate of 96.1%. Of the patients requiring invasive
ventilation (n=53), only 37.7% of them survived.
 This difference might have arisen due to the fact that this group of patients was
not as sick at admission as those who needed invasive ventilation on admission.
More studies are required for determining criteria for using non invasive
ventilation.

16.  The usefulness of the SOFA score has been previously validated in large
cohorts of critically ill patients. Moreno et al recently showed that the
initial SOFA score can be used to quantify the degree of organ dysfunction
or failure score can demonstrate the degree of dysfunction or failure
developing during an ICU stay, and that the total maximum SOFA score can
represent the cumulative organ dysfunction experienced by the patient.
 One of the objectives of this study was to assess the utility of SOFA score
(at 0 hours and at 48 hours) and delta SOFA score in predicting the
outcome in patients with AFI admitted with ARDS and both were found to
be predictors of outcome.

17. Limitation
 The data in this study may be applicable only to the critically ill patients of
AFI since the study was conducted at a tertiary referral center where the
most sick of the patient population gets referred.
 This study also did not include patients who succumbed within the first 48
hours of admission as we needed SOFA score at 48 hours for data and
analysis

18. Conclusion
 AFI complicated by ARDS was associated with a mortality rate of 25.4%.
SOFA score and PaO2/FiO2 on admission and at 48 hours, delta SOFA
score, serum albumin, bicarbonate levels BUN and creatinine levels were
significant predictors of outcome in the patients in this study.

19. Take home message
 SOFA score on admission and at 48 hours, delta SOFA score, PaO2/FiO2
ratio on admission and at 48 hours, Blood Urea Nitrogen (BUN),
creatinine, bicarbonate and albumin are the significant predictors of
overall outcome.
 Hemoglobin, platelets and leukocyte counts, pH, pO2, pCO2 on admission
and at 48 hours, Lung Injury Score (LIS) and DIC score are not significant
predictors of outcome.

20. Thank you