Rectal sole temperature difference: A marker of neonatal Septicemia

Clinical suspicion forms the starting point for the management of neonatal septicemia. Neonates with sepsis often have cold peripheries even when they are hypothermic or euthermic. We planned this prospective study to evaluate the rectal sole temperature difference (RSD) as a marker of sepsis in preterm neonates.

Consecutive preterm neonates admitted to the NICU were enrolled in the study. Babies were considered to have sepsis when they had one or more clinical features of sepsis and one or more positive sepsis screen parameters. Temperature recordings were done at enrollment. Rectal temperature was measured with standard mercury in glass thermometer and sole temperature using the skin probe of the radiant warmer.

The study was powered at 80% with an error of 0.05, to detect 1°C mean difference in RSD between the controls and babies with sepsis

50 controls and 50 babies with sepsis were enrolled. The mean birth weight, the mean gestational age, the median age at study was 1801 ± 161gms, 33.83 ± 1.23 weeks and 4 days respectively. In babies with sepsis the common clinical features were lethargy and poor feeding (n=42, 84%), tachypnea (n=34, 70%), apnea (n=5, 50%), chest retractions (n=20, 40%), prolonged capillary refill time (n=20 40%), sclerema (n=20, 40%) and jaundice (n=18, 36%). 10% of babies were hypothermic and 21% were hyperthermic. In preterm controls, the mean rectal temperature was 37.18 ± 0.42°C and the mean sole temperature was 35.57 ± 0.67°C while in infants with sepsis it was 37.02 ± 0.75°C and 34.18 ± 1.02°C respectively. Compared with controls, those with sepsis had a lower mean sole temperature (p<0.001) and a higher RSD (2.07 ± 0.53°C vs. 2.82 ± 0.61°C; p value <0.0001). An RSD of ≥ 2°C had the best sensitivity, NPV, positive likelihood ratio and negative likelihood ratio.

Preterm sept icemic infants have lesser sole temperatures compared with controls and a RSD ≥ 2°C is a good diagnostic marker of sepsis.