Agreement of Mixed Venous Carbon Dioxide Tension (PvCO2) and Transcutaneous Carbon Dioxide (PtCO2) Measurements in Ventilated Infants

Background: Noninvasive transcutaneous carbon dioxide monitoring has been shown to be accurate in infants and children, limited data are available to show the usefulness and limitations of partial transcutaneous carbon dioxide tension (PtCO2) value. Objectives: The current study prospectively determines the effectiveness and accuracy of PtCO2 measurements in newborns. Materials and Methods: Venous blood gas sampling and monitoring of the PtCO2 level (TCM TOSCA, Radiometer) were done simultaneously. All measurements are performed on mechanically ventilated infants. Partial venous carbon dioxide tension (PvCO2) values divided into three groups according to hypocapnia (Group 1: < 4.68 kPa), normocapnia (Group 2: 4.68–7.33 kPa), hypercapnia (Group 3: > 7.33 kPa) and then PvCO2 and PtCO2 data within each group were compared separately. Results: A total of 168 measurements of each PvCO2 and PtCO2 data were compared in three separated groups simultaneously (13 in Group 1, 118 in Group 2, and 37 in Group 3). A bias of more than ± 0.7 kPa was considered unacceptable. PtCO2 was related to PvCO2 with acceptable results between the two measurements in hypocapnia (mean difference 0.20 ± 0.19 kPa) and normocapnia (0.002 ± 0.30 kPa) groups. On the other hand in hypercapnia group PtCO2 values were statistically significant (P < 0.001) and lower than PvCO2 data (mean difference 0.81 ± 1.19 kPa) Conclusions: PtCO2 measurements have generally good agreement with PvCO2 in hypocapnic and normocapnic intubated infants but there are some limitations especially with high level of CO2 tension. Monitoring of PtCO2 is generally a useful non-invasive indicator of PvCO2 in hypocapnic and normocapnic infants.

Supra-treatment threshold neonatal jaundice: Incidence in HIV-exposed compared to non-exposed neonates at Queen Elizabeth Central Hospital in Blantyre, Malawi

Introduction Jaundice is the yellowish pigmentation of the skin, sclera, and mucous membranes resulting from bilirubin deposition. Children born to mothers with HIV are more likely to be born premature, with low birth weight, and to become septic—all risk factors for neonatal jaundice. Further, there has been a change in the prevention of mother-to-child transmission (PMTCT) of HIV guidelines from single-dose nevirapine to a six-week course, all of which theoretically put HIV-exposed newborns at greater risk of developing neonatal jaundice. Aim We carried out a study to determine the incidence of severe and clinical neonatal jaundice in HIV-exposed neonates admitted to the Chatinkha Nursery (CN) neonatal unit at Queen Elizabeth Central Hospital (QECH) in Blantyre. Methods Over a period of four weeks, the incidence among non-exposed neonates was also determined for comparison between the two groups of infants. Clinical jaundice was defined as transcutaneous bilirubin levels greater than 5 mg/dL and severe jaundice as bilirubin levels above the age-specific treatment threshold according the QECH guidelines. Case notes of babies admitted were retrieved and information on birth date, gestational age, birth weight, HIV status of mother, type of feeding, mode of delivery, VDRL status of mother, serum bilirubin, duration of stay in CN, and outcome were extracted. Results Of the 149 neonates who were recruited, 17 (11.4%) were HIV-exposed. One (5.88%) of the 17 HIV-exposed and 19 (14.4%) of 132 HIVnon- exposed infants developed severe jaundice requiring therapeutic intervention (p = 0.378). Eight (47%) of the HIV-exposed and 107 (81%) of the non-exposed neonates had clinical jaundice of bilirubin levels greater than 5 mg/dL (p < 0.001). Conclusions The study showed a significant difference in the incidence of clinical jaundice between the HIV-exposed and HIV-non-exposed neonates. Contrary to our hypothesis, however, the incidence was greater in HIVnon- exposed than in HIV-exposed infants.

Pre-Discharge Screening Trans-Cutaneous Bilirubinometry in Healthy Newborns in Mahdieh Hospital, Tehran

Background: Incidence of jaundice is high in newborn infants. Since well appearing newborns are rapidly and routinely discharged from hospital, performing an inexpensive noninvasive pre-discharge screening test for evaluation of jaundice seems to be necessary. Objectives: This study was conducted to compare the accuracy of cutaneous v/s serum bilirubin measurements in this regard. Patients and Methods: This was a prospective cross sectional study conducted in Mahdieh hospital, Tehran. 613 neonates weighing ≥ 1,800 g with gestational age of ≥ 35 weeks were enrolled. A pre discharge transcutaneous bilirubin test (TcB) was performed in all. Serum samples were taken from neonates with TcB ≥ 5 mg/dL in first and > 8 mg/dL in second 24 hours. Decision for treatment or recheck of bilirubin level after discharge was made based on serum bilirubin results. Results: Based on the study protocol, among 613 studied neonates, 491 (80%) revealed high TcB, of them 240 (49%) cases showed TBC ≥ 5 mg/dL in first and 251 (51 %) in second pre-discharge 24 hours. TcB ranged 3.3 - 17.1, mean TcB in first 24 hours was 6.9 ± 1 .7 (mode 6) and in second 24 hours 9.1 ± 2.1 (mode 10). Of 491 neonates with high TcB, capillary serum sample was taken as the second step and 398 neonates revealed high total serum bilirubin (TsB) with the same protocol for TcB. 108 (27.1%) neonates showed TsB ≥ 5 mg/dL in first and 290 (72.9%) in second 24 hours. According to the study results TcB has a 81% positive predictive value (PPV) in diagnosis of hyperbilirubinemia. Correlation coefficient of TcB and TsB in highest rate is equal to 72% (P value < 0.001). Conclusions: TcB is an inexpensive, noninvasive and precise pre-discharge screening test for evaluation of hyperbilirubinemia, with a high PPV. It is highly recommended to be performed routinely due to high incidence of hyperbilirubinemia in neonates.