CD31 + CD45RA + RO -lymphocytes contain high numbers of T cell receptor circle (TREC)-bearing T cells; however, the correlation between CD31 + CD4 + lymphocytes and TREC during aging and under lymphopenic conditions has not yet been sufficiently investigated. We analyzed TREC, telomere length and telomerase activity within sorted CD31 + and CD31 -CD4 + lymphocytes in healthy individuals from birth to old age. Sorted CD31 + CD45RA + RO -naive CD4 + lymphocytes contained high TREC numbers, whereas CD31 + CD45RA -RO + cells (comprising 5% of CD4 + cells during aging) did not contain TREC. CD31 + overall CD4 + cells remained TREC rich despite an age-related tenfold reduction from neonatal (100 : 1000) to old age (10 : 1000). Besides a high TREC content, CD31 + CD45RA + RO -CD4 + cells exhibited significantly longer telomeres and higher telomerase activity than CD31 -CD45RA + RO -CD4 + cells, suggesting that CD31 + CD45RA + RO -CD4 + cells represent a distinct population of naive T cells with particularly low replicative history. To analyze the value of CD31 in lymphopenic conditions, we investigated six children after allogeneic hematopoietic stem cell transplantation (HSCT). Reemerging overall CD4 + as well as naive CD45RA + RO -CD4 + cells predominantly expressed CD31 and correlated well with the recurrence of TREC 5-12 months after HSCT. Irrespective of limitations in the elderly, CD31 is an appropriate marker to monitor TREC-rich lymphocytes essentially in lymphopenic children after HSCT.

The new recommendation presented for the use of second-generation Microcuff PETs with improved OD to ID ratio allows the selection of cuffed tracheal tubes with larger IDs than previously recommended for small children without increased need for tracheal tube exchange or increased incidence of post-intubation stridor in these age groups.

The use of cuffed ETT in children significantly reduced the costs of sevoflurane and medical gas consumption during anaesthesia. Increased costs for cuffed compared with uncuffed ETT were completely compensated by a reduction in sevoflurane and medical gas consumption.

SummaryWe evaluated the near-infrared spectroscopy based tissue haemoglobin index for continuous non-invasive monitoring of haemoglobin concentration during paediatric surgery. Blood samples from 40 children (from birth to 16 years old) were analysed oximetrically. From the first blood sample the tissue haemoglobin index ⁄ haemoglobin concentration coefficient was calculated for further tissue haemoglobin index-derived haemoglobin concentrations in each patient. Comparison of corresponding values revealed a bias and precision of -0.02 and 5.41 g.l )1 , respectively.Sensitivity and specificity of tissue haemoglobin index were 73.1% and 70.0%, respectively, for predicting falling haemoglobin concentration values. Currently, the tissue haemoglobin index is not suitable for monitoring haemoglobin concentration in children undergoing surgery.

The use of intrathecal opioids for perioperative pain control from spinal fusion in severely handicapped children is feasible. Intrathecal opioids provide adequate postoperative analgesia and allow early extubation without persisting relevant respiratory compromise in most of these patients.