Use of point-of-care testing for C-reactive protein in reducing the duration of antibiotic therapy in neonatal sepsis- A randomized control trial from a tertiary care NICU in  Western India.

Introduction-

Neonatal sepsis is one of the leading cause of morbidity and mortality in neonatal intensive care units (NICUs), particularly in developing nations.[1] A recently conducted study in northern India reported a high incidence of sepsis (14.3%) with nearly two thirds occurring at or before 72 hours of life.[2]

The clinical signs of sepsis in neonates are often minimal or non-specific, and can mimic symptoms associated with other non-infectious conditions. Blood culture is the gold standard diagnostic test, however the turnaround time of the results is around 36-48 hours using the BacT/Alert microbial detection system. In NICUs, a “sepsis screen” comprising of total leukocyte count, absolute neutrophil count, immature to total leukocyte count ratio, C- reactive protein (CRP) and micro erythrocyte sedimentation rate (mESR), is commonly used in the diagnosis of neonatal sepsis and also in deciding the antibiotic duration. In addition to early diagnosis, evaluation of CRP also aids in limiting the use of empiric antibiotics to prevent emergence of multidrug resistant organisms.

Serial CRP values taken 24– 48 h after the onset of symptoms have an improved sensitivity and specificity when compared with single CRP values at presentation for diagnosis of sepsis.

Two consecutive CRP levels < 10 mg/L 24 hours apart, 8-48 hours after presentation, have a negative predictive value for sepsis of 99% .

Philip and Mills suggested that normalization of CRP levels can be considered as a criterion for the discontinuation of antibiotic therapy to minimize antibiotic exposure and shorten hospital stay. In a prospective study, Ehl et al. observed that CRP levels of < 10mg/L determined 24 hours after beginning antibiotic treatment correctly identified infants as not needing further antibiotics.

Jaswal et al. [9] reported a 100% negative predictive value with no relapse following discontinuation of antibiotic treatment after normalization of CRP levels.

Laboratory CRP is well studied modality for starting and stopping antibiotics in neonatal sepsis. However point of care (POC) analysis of CRP in comparison to standard of care CRP helps to further reduce the time required for antibiotic duration since prolonged duration of antibiotics and unwarranted antibiotics increases antibiotic resistance.  Hence this study is planned to use  POC CRP in reducing the duration of antibiotic therapy in NICU compared to current standard of care laboratory CRP.

AIM:

To determine the use of point-of-care testing for CRP in reducing the duration of antibiotic therapy in neonatal intensive care unit.

Objectives:

Primary: To determine the use of point-of-care testing for CRP in reducing the duration of antibiotic therapy in neonatal intensive care unit in neonates with sepsis.

Secondary:

To determine the use of point-of-care testing for CRP in reducing the total doses of antibiotics received.

To determine the use of point-of-care testing for CRP in reducing the duration of hospital stay.

To determine the use of point-of-care testing for CRP in reducing intravenous canula duration.

METHODOLOGY:

       Study type: A randomised control trial      

     Study duration: 6 months prospectively from ethics committee approval

    Study centre: Level III NICU

       Inclusion criteria: All neonates with a new episode of clinically suspected sepsis requiring intravenous antibiotics

     Exclusion criteria: Life-threatening congenital malformations.

    Sample size: As this is a pilot trial sample size of 50 neonates with 25 in each group will be taken.

Study methodology:

As per unit policy neonates who develop a new episode of clinically suspected sepsis are investigated with a sepsis screen and blood culture .Antibiotics are started as per unit policy if sepsis screen is positive. Antibiotics are continued until clinical improvement; blood culture has no growth and repeat sepsis screen is negative. Intravenous canula is removed as soon as decision is taken to stop antibiotics if there are no other infusions/injections being given through it, as per unit policy. No there is no difference in treatment given to both the groups.

Parents of the eligible infants will be approached following this new episode of clinically suspected sepsis. Written informed consent will be taken from the parent following which the infant will be enrolled in the RCT.
Randomisation-Computer based stratified randomization will be done by a statistician not included in the study
Allocation concealment- Sequentially numbered, opaque white sealed envelopes will be used. The principal investigator, treating doctors and the statistician will be blinded about the study allocation.

The two groups are

1)Testing with point of care CRP: Infants in this group will be screened for sepsis using CBC and point of care CRP. A point of care CRP and CBC will be repeated when decision to stop antibiotics is made.

2)Testing with standard of care laboratory CRP: Infants in this group will be screened for sepsis using CBC and standard of care laboratory CRP. A laboratory CRP and CBC will be repeated when decision to stop antibiotics is made.

1ml of blood via venepuncture is required for CBC and  0.1 ml from the same prick for point of care CRP in the intervention group.  1ml of blood via venepuncture is required for CBC and 1 ml from the same prick for laboratory CRP in the control group. Laboratory assistants performing standard blood testing will not be made aware of POC results. Rest of management in the both of groups with be the same as per standard neonatal guidelines.

1.     Clinically suspected sepsis: A new episode of sepsis is defined as onset of clinical signs and symptoms which are suggestive of sepsis and mandate starting of empirical antibiotics or upgrading the ongoing antibiotics. These may include hypothermia or fever, respiratory distress, need of respiratory support, feeding difficulties, abdominal distension, coagulopathy, shock, tachycardia, lethargy, seizure, apnea, erythema, sclerema, hypoglycaemia or any sign/symptom deemed as suspicious of sepsis by the team of treating neonatologists.

2.     Sepsis screen: The sepsis screen will include determination of total leucocyte count, absolute neutrophil count, immature to total neutrophil ratio, micro erythrocytic ratio and C-reactive protein. A total count of > 25000/mm³or < 5000/mm^3, absolute neutrophil count < 1750/mm³ and an immature to total neutrophil ratio greater than 20% will be considered abnormal. The micro ESR >15 mm at the end of one hour and c-reactive protein more than 10 mg/l will be considered abnormal. A “positive” screen will be defined as two out of five parameters abnormal as per the cut-offs.

Point-of-care estimation: The sample will be analysed by Lumira Dx CRP card (LumiraDx UK Ltd). The card will be stored at room temperature and the samples will be processed in our NICU. Lumira Dx machine and CRP cards are currently used in NICU and there won’t be any added cost to the patient. Lumira Dx point of care machine is already in use in the NICU. The CRP cards have been provided with the machine and are sufficient for the sample included.

Principle of test: The LumiraDx CRP test is a single use fluorescence immunoassay device. The analysis is based on the amount of fluorescence the instrument detects within the measurement area of the test Strip. The concentration of the analyte in the sample is proportional to the fluorescence detected

Blood sampling and cut-offs: 1ml of blood via venepuncture is required for CBC and  0.1 ml from the same prick for point of care CRP. POC CRP vslue more than 10mg/L is considered positive

Sample processing: The test procedure involves the addition of serum to the sample application area of the test strip inserted in the instrument. The instrument is programmed to perform the analysis when the sample has reacted with the reagents within the test strip. The results are displayed on the instrument touch-screen in 4 minutes from the addition of sample.

Data collection: Neonatal data collection will be made from the hospital in-patient records in a pre-designed data sheet. Details of antenatal risk factors and birth details such as mode of delivery, gestational age, and birth weight will be noted. The details of day of onset of sepsis, clinical features of sepsis, laboratory parameters and antibiotics therapy such as drug, dose and duration will be recorded. The time for estimation of sepsis screen and point-of-care CRP will be noted. The results of blood culture and sensitivity pattern of growth, if detected will be recorded. Days/Hours of life at which antibiotics were stopped, total duration and doses of antibiotics received prior to stopping and total duration of presence of intravenous canula will be recorded. Other important details such as underlying surgical or cardiac complication, mechanical ventilation, respiratory support, and placement of central lines or any invasive procedures will be recorded.

Ethical clearance: The study will be initiated after obtaining permission from the institution’s ethics committee.

Statistical analysis: Data will be entered in MS Excel and analysed using SPSS software version 23. Categorical variables will be represented as percentages while continuous variables will be depicted as mean (standard deviation) and median (range). An independent t-test will be used for continuous data and chi-square and Fischer exact test for categorical data. A p value of <0.05 will be considered statistically significant.