From the day the very low birth weight infant was admitted to hospital, monitoring was recorded once a day, and continuous monitoring was recorded for 1 month. Before collection, the infant was confirmed to be in supine position with neutral temperature, and at the same time, the infant was in a quiet state, without the contact and operation of medical personnel. This study will first use LMS curve to fit the trend of perfusion index in very low birth weight infants within one month after birth.The perfusion index threshold of the outcome index was determined by ROC curve.
To explore the predictive value of peripheral perfusion index in late onset sepsis of very low birth weight infants , obtain the threshold by observing the perfusion index of very low birth-weight infants within one month after birth, this value can be used as a threshold to predict late onset sepsis in very low birth weight infants.