Transcutaneous CO2 versus end-tidal CO2 in neonates and infants undergoing surgery: a prospective study.

Aim: End-tidal CO2 (EtCO2) is the standard in operative care along with pulse oximetry for ventilation assessment. It is known to be less accurate in the infant population than in adults. Many neonatal intensive care units (NICU) have converted to utilizing transcutaneous CO2 (tcPCO2) monitoring. This study aimed to compare perioperative EtCO2 to tcPCO2 in the pediatric perioperative population specifically below 10 kg, which encompasses neonates and some infants. Methods: After IRB approval and parental written informed consent, we enrolled neonates and infants weighing less than 10 kg, who were scheduled for elective surgery with endotracheal tube under general anesthesia. PCO2 was monitored with EtCO2 and with tcPCO2. Venous blood gas (PvCO2) samples were drawn at the end of the anesthetic. We calculated a mean difference of EtCO2 minus PvCO2 (Delta EtCO2), and tcPCO2 minus PvCO2 (Delta tcPCO2) from end-of-case measurements. The mean differences in the NICU and non-NICU patients were compared by t-tests and Bland-Altman analysis. Results: Median age was 10.9 weeks, and median weight was 4.4 kg. NICU (n=6) and non-NICU (n=14) patients did not differ in PvCO2. Relative to the PvCO2, the Delta EtCO2 was much greater in the NICU compared to the non-NICU patients (-28.1 versus -9.8, t=3.912, 18 df, P=0.001). Delta tcPCO2 was close to zero in both groups. Although both measures obtained simultaneously in the same patients agreed moderately with each other (r =0.444, 18 df, P=0.05), Bland-Altman plots indicated that the mean difference (bias) in EtCO2 measurements differed significantly from zero (P<0.05). Conclusions: EtCO2 underestimates PvCO2 values in neonates and infants under general anesthesia. TcPCO2 closely approximates venous blood gas values, in both the NICU and non-NICU samples. We, therefore, conclude that tcPCO2 is a more accurate measure of operative PvCO2 in infants, especially in NICU patients.

The Oro-Helical Length Accurately Predicts Endotracheal Tube Insertion Depth in Neonates.

We evaluated the reliability of the oro-helical length in predicting the ideal endotracheal tube depth in neonates and found the oro-helical length was a consistently more reliable and better predictor of the ideal endotracheal tube depth on chest radiograph than the 7-8-9 rule, especially in infants weighing ≤1500 g.

Serial head ultrasound studies in preterm infants: how many normal studies does one infant need to exclude significant abnormalities?

OBJECTIVE: We hypothesized that preterm infants with two normal head ultrasound (HUS) screening studies > or = 7 days apart would have subsequently normal follow-up studies. POPULATION: We reviewed reports of all HUS studies performed in preterm infants < or = 32 weeks gestation admitted to our nursery between January 1998 and July 2000. SETTING: Regional perinatal referral center. DESIGN: A normal HUS screening study was defined as either no findings; or grade I intraventricular hemorrhage (IVH) (Papile classification), germinal matrix irregularity or cyst, or normal but unequal ventricular size. An abnormal study was defined as any with IVH > or = grade II, periventricular leukomalacia (PVL), ventriculomegaly (VM), or periventricular echogenicity (PVE). RESULTS: Of 98 infants, 92 infants (94%) who had two normal HUS studies > or = 7 days apart had normal repeat studies subsequently, and six (6%) were abnormal. Four of the six abnormal infants were <25 weeks gestation at birth. One infant (27 weeks) became abnormal after culture-positive bacterial sepsis and necrotizing enterocolitis with bowel perforation requiring surgery. The remaining infant (29 weeks) had a question of PVE, and a normal repeat study. The positive predictive value for having a normal HUS after two previously normal studies > or = 7 days apart was 94% with a specificity of 86%. CONCLUSION: Stable premature infants > or = 25 weeks gestation without intervening deterioration may not need repeat screening HUSs after having had two normal studies > or = 7 days apart. Unstable or extremely premature infants <25 weeks gestation may be subject to late severe IVH, VM, and PVL, and therefore need a repeat study before hospital discharge, even if two initial studies > or = 7 days apart were normal.