Near-Infrared Spectroscopy Monitoring of Cerebral Oxygenation and Influencing Factors in Neonates from High-Altitude Areas.

BACKGROUND: Accurate detection of cerebral oxygen saturation (rSO2) may be useful for neonatal brain injury prevention, and the normal range of rSO2 of neonates at high altitude remained unclear. OBJECTIVE: To compare cerebral rSO2 and cerebral fractional tissue oxygen extraction (cFTOE) at high-altitude and low-altitude areas in healthy neonates and neonates with underlying diseases. METHODS: 515 neonates from low-altitude areas and 151 from Tibet were enrolled. These neonates were assigned into the normal group, hypoxic-ischemic encephalopathy (HIE) group, and other diseases group. Near-infrared spectroscopy was used to measure rSO2 in neonates within 24 h after admission. The differences of rSO2, pulse oxygen saturation (SpO2), and cFTOE levels were compared between neonates from low- and high-altitude areas. RESULTS: (1) The mean rSO2 and cFTOE levels in normal neonates from Tibet were 55.0 ± 6.4% and 32.6 ± 8.5%, significantly lower than those from low-altitude areas (p < 0.05). (2) At high altitude, neonates with HIE, pneumonia (p < 0.05), anemia, and congenital heart disease (p < 0.05) have higher cFTOE than healthy neonates. (3) Compared with HIE neonates from plain areas, neonates with HIE at higher altitude had lower cFTOE (p < 0.05), while neonates with heart disease in plateau areas had higher cFTOE than those in plain areas (p < 0.05). CONCLUSIONS: The rSO2 and cFTOE levels in normal neonates from high-altitude areas are lower than neonates from the low-altitude areas. Lower cFTOE is possibly because of an increase in blood flow to the brain, and this may be adversely affected by disease states which may increase the risk of brain injury.

[Preliminary analysis on respiratory syncytial virus identified in children with acute respiratory infections in Tibet Autonomous Region, China].

To understand the role of respiratory syncytial virus (RSV) in children with acute respiratory infections (ARI) in Tibet Autonomous Region and the contribution of two major groups of RSV, nasopharyngeal aspirates (NPA) were collected from hospitalized children with ARI in Department of Pediatrics, Tibet People's Hospital in Lasa, Tibet from April to July in 2011 and tested for seven common respiratory viruses and human metapneumovirus (hMPV) by direct immunofluorescence assay (DFA). Total RNAs were extracted from RSV positive samples by DFA and reverse transcripted to cDNA. Nested-PCR was employed to determine the genogroups of RSV, which were confirmed by real time-PCR and sequence analysis for G protein encoding gene. The Characteristics and variations of G genes from RSV in this project were identified by sequence comparison with those G genes in GenBank. Out of 167 samples, 65 were positive for respiratory viruses with a total positive rate of 38.9%, including 45 (69.2%, 45/65)positive samples for RSV. Among 42 samples that were positive for RSV and genotyped, 40 were identified as group A and 2 as group B. Sequence analysis of full-length G genes for 7 RSV of group A indicated that all of these belonged to subgroup GA2. The nucleotide identities between RSVs from Tibet and prototype A2 strain were 90.7%-91.8%, with 86.5%-87.2% identities of amino acid. The mutations of amino acids were mainly located in both ends of a highly conserved region in the ectodomain of the G proteins. The data indicated that RSV was the most important viral etiologic agent of ARI in spring of 2011 in Tibet and group A of RSV was predominant during the study period. High divergence existed in the ectodomain of G proteins of RSVs from Tibet.

[Viruses and clinical features associated with hospitalized children with acute respiratory infections in Lhasa, Tibet].

OBJECTIVE: To investigate the viral etiology and clinical features of hospitalized children with acute respiratory tract infections in Tibet. METHOD: Nasopharyngeal aspirate samples were collected from children with acute respiratory tract infection hospitalized at the department of Pediatrics, Tibet Autonomous Region People's Hospital from April to July, 2011. The specimens of nasopharyngeal aspirate were screened for antigens of 7 common respiratory viruses by direct immunofluorescence (DIF) [respiratory syncytial virus (RSV), adenovirus (ADV), parainfluenza viruses type I-III, influenza virus A and B] and human metapneumovirus. Clinical data of the children were analyzed by statistical software SPSS16. RESULT: A total of 167 children with acute respiratory tract infections hospitalized from April to July 2011 were enrolled in this investigation. Sixty-five out of 167 specimens were positive for viral antigens. The virus positive rate for specimens was 38.9% (65/167). Two of 65 positive specimens were positive for 2 virus antigens (RSV + influenza B) and (hMPV + parainfluenza virus type III), respectively. RSV was detected in 45 cases (67.2%, 45/67) which was the most predominant, followed by parainfluenza virus type III detected in 7 cases (10.4%, 7/67), ADV in 6 cases (9.0%, 6/67), parainfluenza virus type I in 4 cases (6.0%, 4/67), influenza virus type B in 3 cases (4.5%, 3/67), and hMPV in 2 cases (3.0%, 2/67). In addition to clinical manifestations of pneumonia, such as cough and shortness of breath, only 3 virus positive cases (6.67%) presented with wheezing, but the signs of severe cyanosis, fine rales in lung were common. Most of the children in this study recovered soon, only a few younger children with underlying diseases or complications had severe illness. CONCLUSION: Virus is an important pathogen for acute respiratory infections for hospitalized children in Tibet. RSV was the most predominant etiological agent, especially for those younger than 3 years old.

[Clinical characteristics and changes in blood electrolyte and renal function of neonates with polycythemia at high altitude].

OBJECTIVE: To analyze the relationship between neonatal hypoxia and polycythemia and to study clinical characteristics of Tibetan neonates whose family lived in Tibetan plateau for generations and Han neonates whose family moved to the plateau. METHOD: From Jan. 2005 to Oct. 2006, totally 739 patients were hospitalized in the ward of neonatology of the hospital. Of these patients, 40 (20 were Tibetan and the other 20 were Han) with neonatal polycythemia. The clinical features, transcutaneous oxygen saturation (TcSO2), peripheral routine tests and myocardial enzyme profile were studied. RESULT: The values of hemoglobin (Hb), hematocrit (HCT), and erythrocyte count (RBC) of the Han neonates were significantly higher than those of the Tibetan newborns. Han neonates with polycythemia had lower TcSPO2 than Tibetan neonates (P < 0.01). Comparison of myocardial enzymes showed that Han neonates had higher CKMB than that of Tibetan groups before treatment (P < 0.01), troponin was not significantly different between the Han and Tibetan groups before treatment (P > 0.05). The major common clinical manifestations of the Han and Tibetan newborns were tachypnea, cyanosis, irritability, weak reflexes and hypoxemia. The Han neonates additionally had poor responses, apnea, lower muscle tone, confusion and asphyxia. CONCLUSION: The clinical characteristics, TcSO2, peripheral blood routine tests and myocardial enzyme profile are helpful in diagnosis and treatment of neonatal polycythemia. Newborn infants born to mothers who moved to the plateau area may be more susceptible to neonatal polycythemia and are prone to impairments of other organs, esp. the functions of the heart and brain.