Prsent study is designed to evalaute utility of perfusion index for diagnosis of shock in neonates. In present study all
neonates will be enrolled at time of admission to NICU. Demographic
characteristics and antenatal details of enrolled infants, including maternal
hypertension, fetal growth restriction, umbilical artery Doppler abnormality,
chorioamnitis, antenatal steroid cover, and mode of delivery will be recorded
on a proforma. Neonates will be cared in
thermoneutral environment, under radiant warmer/incubator, with care to prevent
cold stress. Data recording:
Neonates will be continuously
monitored for clinical signs of perfusion including heart rate, BP, pulse
volume, CRT, central and peripheral temperature and urine output by attending
neonatal nurse.
HR and SPO2 and PI
will be recorded from Masimo pulse oximetry monitor, when neonate is in quiet
state. Pulse volume will be assessed by palpating radial pulse by attending
neonatologist and will be categorized as good or poor pulse volume. PI will be
recorded from Masimo pulse oximeters, Radical-7 display, with monitor
configured for long format so as to get an average of last 5 min.
BP will be measured
in right arm, by oscillometric method using dreager vista monitor, with neonate
is lying supine. An appropriate sized cuff (encircling 2/3rd
of the circumference of limb) will be applied, preferably to the right upper
arm. The infant will then left undisturbed for at
least 5 minutes, until he is quiet or asleep. Three successive BP recordings
will be taken at 2-minute intervals and average of these will be taken.
CRT will be
measured using electronic stop watch. An area over sternum will be pressed with
index finger for 2 seconds and then released; time taken from release to
refilling will be recorded.
Central and
peripheral temperature will be recorded from electronic display of
warmer/incubator with central probe applied over abdomen and peripheral probe
applied to sole of foot.
Urine output (per kg
per hour) will be calculated from diaper weight, by dividing output in
preceding 2 diapers with the interval between these diaper changes.
Blood gas analysis
(through arterial puncture or an indwelling arterial catheter) will be done if
a possibility of shock is considered, or for assessment of gas exchange in
cardio-respiratory disorders, or at per clinician’s discretion. Blood lactate
values will be noted from concurrent blood gas analysis.
To
evaluate predictive value of each hemodynamic parameter, ROC curves will be
drawn and comparison of area under curve for each parameter will be done.
Sensitivity, specificity, positive predictive value and negative predictive
value and 95% confidence intervals for each parameters will be reported.
Definition
of shock
Abnormal findings will
be confirmed by attending neonatologist. Diagnosis of shock will be made if
three or more of following are present:
·
Resting HR >180/min
·
Mean BP less than 10th
centile for gestational age
·
CRT > 3 sec
·
Central peripheral temperature
difference > 4 *C
·
Poor peripheral pulses
·
Urine output <1 ml/kg/hr (preceding 6
hrs)
·
Blood lactate >4 mmol/L
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