低通气量呼吸对犬左空心肌收缩性的影响

大量的研究表明,急性呼吸衰竭时多伴有心血管功能的损害,但有关急性呼吸衰竭对于左室心肌收缩性的影响所知甚少。本文对开胸麻醉犬在低通气引起呼吸衰竭时,左室心肌收缩性的变化进行了观测和分析。结果表明,在实验组(n=9)低通气呼吸(通气量小于160ml/min/kg,PaO_2小于60mmHg)时,心率(HR)、主动脉平均压(MOP)、左室收缩峰压(LV-SP)、左室内压最大上升速率(dP/dt_(max))、节段心肌发展张力(DT)及其最大发展速率(dT/dt_(max))均显著降低,心肌开始收缩至dp/dt_(max)的时间(t-dp/dt_(max))和至dT/dt_(max)的时间(t-dT/dt_(max))则显著增加,与低通气呼吸前比较均有统计学差异。而在对照组(n=5)保持正常通气(通气量大于450ml/min/kg,PaO_2大于70mmHg),观察45min,未见上述指标有明显改变。本研究表明,急性呼吸衰竭时左室心肌收缩性严重受损。     

Raised Interleukin‐6 Levels in Obese Patients

Objective: Obese patients demonstrate a variety of biochemical, metabolic, and pulmonary abnormalities. Inflammatory mediators such as tumor necrosis factor‐α and interleukin‐6 (IL‐6) may have a direct effect on glucose and lipid metabolism. Hypoxemia in itself induces release of IL‐6. The aim of this study was to examine the relationship between IL‐6 levels in healthy volunteers (control group) and three different groups of obese patients: patients without obstructive sleep apnea syndrome (OSAS), patients with OSAS, and patients with obesity hypoventilation syndrome (OHS) (daytime baseline oxygen saturation of <93%). Research Methods and Procedures: We measured serum IL‐6 levels in 25 obese patients (body mass index of >35 kg/m²) and 12 healthy women. Results: The results demonstrate statistically significant differences in serum IL‐6 levels between the control group (1.28 ± 0.85 pg/mL) and obese patients without OSAS (7.69 ± 5.06 pg/mL, p < 0.05) and with OSAS (5.58 ± 0.37 pg/mL, p < 0.0005). In the patients with OHS, IL‐6 concentrations were highest (43.13 ± 24.27 pg/mL). Discussion: We conclude that serum IL‐6 is increased in obese patients. The highest IL‐6 levels were found in the patients with OHS.     

Genetic mosaicism of a frameshift mutation in the RET gene in a family with Hirschsprung disease

Mutations and polymorphisms in the RET gene are a major cause of Hirschsprung disease (HSCR). Theoretically, all true heterozygous patients with a new manifestation of a genetically determined disease must have parents with a genetic mosaicism of some extent. However, no genetic mosaicism has been described for the RET gene in HSCR yet. Therefore, we analyzed families with mutations in the RET gene for genetic mosaicism in the parents of the patients. Blood samples were taken from patients with HSCR and their families/parents to sequence the RET coding region. Among 125 families with HSCR, 33 families with RET mutations were analyzed. In one family, we detected a frameshift mutation due to a loss of one in a row of four cytosines in codon 117/118 of the RET gene (c.352delC) leading to a frameshift mutation in the protein (p.Leu118Cysfs*105) that affected two siblings. In the blood sample of the asymptomatic father we found a genetic mosaicism of this mutation which was confirmed in two independent samples of saliva and hair roots. Quantification of peak-heights and comparison with different mixtures of normal and mutated plasmid DNA suggested that the mutation occurred in the early morula stadium of the founder, between the 4- and 8-cell stages. We conclude that the presence of a RET mutation leading to loss of one functional allele in 20 to 25% of the cells is not sufficient to cause HSCR. The possibility of a mosaicism has to be kept in mind during genetic counseling for inherited diseases.     

Effects of inhalational anesthesia on blood gases and pH in California sea lions

Despite the widespread use of inhalational anesthesia with spontaneous ventilation in many studies of otariid pinnipeds, the effects and risks of anesthetic‐induced respiratory depression on blood gas and pH regulation are unknown in these animals. During such anesthesia in California sea lions (Zalophus californianus), blood gas and pH analyses of opportunistic blood samples revealed routine hypercarbia (highest P_CO2 = 128 mm Hg [17.1 kPa]), but adequate arterial oxygenation (P_O2 > 100 mm Hg [13.3 kPa] on 100% inspiratory oxygen). Respiratory acidosis (lowest pH = 7.05) was limited by the increased buffering capacity of sea lion blood. A markedly widened alveolar‐to‐arterial P_O2 difference was indicative of atelectasis and ventilation‐perfusion mismatch in the lung secondary to hypoventilation during anesthesia. Despite the generally safe track record of this anesthetic regimen in the past, these findings demonstrate the value of high inspiratory O₂ concentrations and the necessity of constant vigilance and caution. In order to avoid hypoxemia, we emphasize the importance of late extubation or at least maintenance of mask ventilation on O₂ until anesthetic‐induced respiratory depression is resolved. In this regard, whether for planned or emergency application, we also describe a simple, easily employed intubation technique with the Casper “zalophoscope” for sea lions.     

Health-related quality of life in young adults with congenital central hypoventilation syndrome due to PHOX2B mutations: a cross-sectional study

Background

Congenital central hypoventilation syndrome (CCHS) is a rare genetic disease due to PHOX2B mutations. CCHS patients suffer from many autonomic disorders, dominated clinically by defective ventilatory automatisms. From birth, the life of CCHS patients depends on ventilatory support during sleep, involving a high burden of care. Whether or not this impairs the quality of life of these patients during adulthood remains unknown.

Methods

We applied the medical outcome study short form-36 (SF-36) to 12 CCHS patients aged 15–33 (9 women) at the time of their passage from pediatric to adult care. Scores for the SF-36 dimensions were compared to the age- and gender-matched French reference population after transformation into standardized Z-scores. The SF-36 physical component summary score (PCS) and mental component summary score (MCS) were compared to American reference values.

Results

Median Z-scores were significantly different from zero for PF (physical functioning, p = 0.020) and GH (general health perception, p = 0.0342) and for PCS (p = 0.020). The other physical dimensions (RP, role limitation due to physical function; BP, bodily pain) and the mental dimensions (VT, vitality; SF, social functioning; RE, role limitation due to emotional function; MH, mental health) and MCS were not altered.

Conclusions

We conclude that, despite the physical constraints imposed by CCHS and its anxiogenic nature, this disease is associated with an impairment of health-related quality of life in young adults that remains moderate. Whatever the underlying explanations, these results convey hope to parents with a child diagnosed with CCHS and for patients themselves.