Association between administered oxygen, arterial partial oxygen pressure and mortality in mechanically ventilated intensive care unit patients

Introduction

The aim of this study was to investigate whether in-hospital mortality was associated with the administered fraction of oxygen in inspired air (FiO₂) and achieved arterial partial pressure of oxygen (PaO₂).

Methods

This was a retrospective, observational study on data from the first 24 h after admission from 36,307 consecutive patients admitted to 50 Dutch intensive care units (ICUs) and treated with mechanical ventilation. Oxygenation data from all admission days were analysed in a subset of 3,322 patients in 5 ICUs.

Results

Mean PaO₂ and FiO₂ in the first 24 h after ICU admission were 13.2 kPa (standard deviation (SD) 6.5) and 50% (SD 20%) respectively. Mean PaO₂ and FiO₂ from all admission days were 12.4 kPa (SD 5.5) and 53% (SD 18). Focusing on oxygenation in the first 24 h of admission, in-hospital mortality was shown to be linearly related to FiO₂ value and had a U-shaped relationship with PaO₂ (both lower and higher PaO₂ values were associated with a higher mortality), independent of each other and of Simplified Acute Physiology Score (SAPS) II, age, admission type, reduced Glasgow Coma Scale (GCS) score, and individual ICU. Focusing on the entire ICU stay, in-hospital mortality was independently associated with mean FiO₂ during ICU stay and with the lower two quintiles of mean PaO₂ value during ICU stay.

Conclusions

Actually achieved PaO₂ values in ICU patients in The Netherlands are higher than generally recommended in the literature. High FiO₂, and both low PaO₂ and high PaO₂ in the first 24 h after admission are independently associated with in-hospital mortality in ICU patients. Future research should study whether this association is causal or merely a reflection of differences in severity of illness insufficiently corrected for in the multivariate analysis.     

Passive movement therapy in patients with moderate to severe paratonia; study protocol of a randomised clinical trial (ISRCTN43069940)

Background

We studied whether the twelve-month use of a standard computer would induce complaints of upper limb pain or functional limitations in older novice computer users.

Methods

Participants between 64 and 76 of age were randomly assigned to an Intervention group (n = 62), whose members received a personal computer and fast Internet access at their homes, or a No Intervention control group (n = 61), whose members refrained from computer use during the twelve month study period.

Results

Difference scores between baseline and twelve months assessments on both complaint (SFS) and functional health scales (SF-36) did not differ between groups (all p > .05).

Conclusion

Prolonged, self-paced use of a standard computer interface does not put older persons at a risk of upper limb complaints or reduce functional health in older adults.     

肝细胞生长因子诱导前软骨干细胞向软骨细胞的分化

目的:探讨肝细胞生长因子诱导前软骨干细胞向软骨细胞分化的机制。方法:实验于2005-12/2006-03在河南省正骨研究院完成。①实验材料:普通级新生兔10只,平均体质量3kg。②实验干预:采用免疫磁珠分离技术分离新生兔长骨干骺端前软骨干细胞。利用肝细胞生长因子(浓度分别为0.5,1,2,4μg/L)作用前软骨干细胞;另以2μg/L肝细胞生长因子作用前软骨干细胞,对照用相同剂量的培养基,检测前软骨干细胞Ⅱ型胶原及Ⅱ型胶原mRNA的表达。③实验评估:采用光学显微镜观察前软骨干细胞形态及生长情况;四甲基偶氮唑盐比色法检测前软骨干细胞的增殖;免疫荧光检测Ⅱ型胶原表达;反转录-聚合酶链反应检测Ⅱ型胶原mRNA的表达。结果:①前软骨干细胞形态及生长情况:分离纯化的前软骨干细胞贴壁稳定,在光学显微镜下呈多角和梭形,生长旺盛,曲光度好。②前软骨干细胞增殖情况:细胞增殖率上升,在24,48,72h内呈时间浓度依赖。③Ⅱ型胶原表达:肝细胞生长因子作用第5天前软骨干细胞出现Ⅱ型胶原蛋白的表达。④Ⅱ型胶原mRNA的表达:在肝细胞生长因子刺激3d开始出现表达,并且5d,7d逐渐增加。结论:肝细胞生长因子作用前软骨干细胞后,出现软骨特征标志抗原Ⅱ型胶原的表达,细胞增殖活性上升,表明肝细胞生长因子能诱导前软骨干细胞向软骨细胞方向分化。其机制可能是前软骨干细胞也存在肝细胞生长因子受体。