Continuous measurement of oxygen consumption using the reversed fick method

We developed a continuous oxygen consumption (Vo₂) measurement system employed the reversed Fick method, in which Vo₂ in computed from continuously measured sured arterial and mixed venous oxygen saturation assed by pulse oximetry and mixed venous oximetry, respectively, and cardiac output by the heat deprivation technique. This system was compared with the conventional intermittent reversed fick method in 7 patients during surgery and with indirect calorimetry in 4 intensive care unit (ICU) patients. The Vo₂ measured by the continuous reversed Fick method showed a high correlation with those simultaneously measured by the intermittent Fick method (r=0.97,P<0.01) and by indirect calorimetry (r=0.74,P<0.01). The 95% confidence limits (bias±2 SD) of the continuous reversed Fick method were −0.6±45 ml·min⁻¹ with the intermittent Fick method and −31±56 ml·min⁻¹ with indirect calorimetry. The continuous Fick method is in satisfactory agreement with the conventional methods for the measured of Vo₂ and potentially allows for convenient assessment of Vo₂ in critically ill patients. This study was supported in part by Grants-in-Aid for the Encouragement of Young Scientists 01771185 and 04857171 from the Ministry of Education, Science and Culture of Japan     

Evaluation of non-invasive blood pressure measurement by the Finapres method at rest and during dynamic exercise in subjects with cardiovascular insufficiency

The accuracy and precision of the Finapres in recording rest and exercise blood pressure compared with the intra-arterial (aortic and brachial) and random-zero sphygmomanometer methods was assessed in 84 ischaemic patients in three different studies. Firstly, comparison at rest with the aortic intraarterial pressure in 50 ischaemic patients demonstrated that the Finapres systolic (136.5 ± 21.1 vs. 129.3 ± 19.0 mmHg;p < 0.001) and mean (92.4 ± 13.4 vs. 90.7 ± 11.4 mmHg;p < 0.001) arterial pressures were higher and diastolic pressures lower (70.4 ± 11.5 vs. 71.5 ± 9.8 mmHg;p < 0.001). The reproducibility of the Finapres and invasive method was similar for systolic (4.6% vs. 4.0%), diastolic (2.8% vs. 2.7%) and mean (3.3% vs. 3.0%) blood pressures. Second, in seven subjects studied twice at rest and during 4 min supine bicycle exercise, the exercise increase in blood pressure was greater on the Finapres compared with the brachial intra-arterial pressure (systolic +10.2 ± 6.3 vs. +3.6 ± 9.8 mmHg; diastolic +9.6 ± 11.1 vs. +0.2 ± 2.1 mmHg;p = 0.02 for each); however, at steady-state the peak/trough differences in pressure between the methods were similar. Thirdly, compared under rest conditions, to random zero sphygmomanometer (RZO), the Finapres systolic pressure was higher (6.8 ± 3.5 mmHg) and diastolic pressure lower (–6.0 ± 1.9 mmHg). During upright bicycle exercise, the difference between the Finapres and RZO in systolic blood pressure increased at each level of exercise (+14.3 ± 4.2, +17.9 ± 4.0 and +22.2 ± 4.1 mmHg respectively at each exercise stage:p < 0.01). For RZO, diastolic blood pressure fell as exercise workload increased whereas Finapres diastolic blood pressure increased on exercise (3.1 ± 2.6, 7.0 ± 2.1 and 8.1 ± 2.0 mmHg respectively:p < 0.01). Thus there were systematic differences between the values recorded by the Finapres and proximal blood pressure methods and limited agreement in the rest to exercise increments related to light exercise. Calibration of the Finapres values in terms of the other methods is limited by the variable relationship to these related changes in arterial distensibility.     

A study of factors governing fluid filtration in the diabetic foot

Abstract. The effect of lowering the foot on the factors governing fluid filtration in the foot were studied in 12 male insulin-dependent diabetic subjects and 10 controls. Toe skin blood flow, measured by laser Doppler flowmetry, was significantly higher during dependency in the diabetic group. In the control subjects, the colloid osmotic pressure of venous blood sampled from the foot rose to 47·7 mmHg (range 45·1–53·8) after 50 min of foot dependency. In the diabetic group, colloid osmotic pressure failed to rise to the same extent (median 36·7 mmHg; range 28·6–43·0; P < 0·001). Capillary pressure, measured directly by the Landis microinjection technique, was significantly higher in the diabetic group (85·3±1·7 ( n = 6) vs. 92·2±4·6 cm H₂O ( n = 6); P < 0·007), as was foot swelling rate determined by mercury strain gauge plethysmography (0·069±0·022 vs. 0·099±0·025 ml min^-1 100ml^-1; P < 0·02). These results suggest an impairment of the oedema-preventing mechanisms in diabetic subjects which may contribute to the risks of ulceration in the diabetic foot.     

电刺激膈神经中枢端引起降压反应的外周机理

电刺激麻醉家兔膈神经中枢端呆引起动脉血压下降，此降压反应不能被剪断双侧迷走神经所阻断；但可被静脉注射心得１．０ｍｇ／ｋｇ部分阻断；也可被静注射酚妥拉明２．０ｍｇ／ｋｇ部分阻断，去除缓冲神经后其降压效应更为明显。     

血压家庭相似性研究

本文报道了北京市房山区１１４７人血压家庭相似性研究结果。亲子代回归法得出的血压遗传度估计值为０．４２（收缩压）和０．４８（舒张压），全同胞相关法得出的血压遗传度估计值为０．３７（收缩压）和０．５３（舒张压）。两种方法得出的遗传度估计值相差不大，这一结果提示血压的遗传符合加性多基因模型。本文报道的血压遗传度没有区分遗传效应和共同生活环境效应。此外，本文强调了将血压作为数量性状采用数量遗传学方法进行遗传度估计的合理性和有效性。     

大鼠延髓腹外侧区在可乐定心血管效应中的作用

目的：探讨大鼠延髓腹外侧区（VLM）在介导可乐定心血管效应中的作用。方法：氨基甲酸乙酯麻醉SD大鼠，应用微量注射和细胞外记录等方法观察尾端延髓腹外侧区（CVLM）和头端延髓腹外侧区（RVLM）内局部给予可乐定导致的心血管活动变化。结果：单侧CVLM微量注射可乐定（5nmol/100nl,n=10)不仅能明显升主动脉血压（AP）和增加心率（HR）（P＜0．01），而且能增加同侧RVLM压力敏感性神经元（n=80)的放电频率（P＜0．01），而单侧RVLM微量注射可乐定（5nmol/100nl,n=9)，明显降低AP和HR（P＜0．01）。结论：RVLM和CVLM在介导可乐定的心血管效应中具有不同的作用。     

玉郎伞提取物对大鼠自发性高血压的影响

目的：研究玉郎伞提取物(YLS)对自发性高血压大鼠(SHR)及正常大鼠血压(BP)的影响。方法：应用颈动脉插管测压法，连接MS2000多媒体生物信号记录系统测定静注YLS前及药后20s、30s、lmin、2min、5min时的收缩压(SP)、舒张压(DP)、平均动脉压(MP)。结果：YLS使SHR及正常大鼠血压明显降低(P＜0．01)，降压作用维持时间较短，给药后5min血压基本恢复正常；YLS对去甲肾上腺素(NA)和异丙肾上腺素（ISO)的作用无明显影响。结论：YLS对正常大鼠及SHR血压有明显的降低作用。     

服用左炔诺孕酮滴丸和妈富隆1年对血压、血糖和血脂的影响

目的：观察第二、三代口服避孕药(COC)对育龄妇女体重指数、血压、血糖和血脂的影响。方法：将自愿服用COC避孕1年的妇女105例随机分为两组，其中54例给予第二代COC(EE／LNG组)，51例给予第三代COC(EE／DG组)。并对研究前后所有病例的体重指数(BMI)、血压、血糖和血脂代谢指标进行比较分析。结果：EE／LNG组：BMI、收缩压、舒张压、甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白(LDL)和载脂蛋白B(ApoB)水平均升高，高密度脂蛋白(HDL)水平下降，血糖、载脂蛋白AI(ApoAI)水平无明显改变。EE／DG组收缩压、TG、HDL水平升高，BMI、舒张压、血糖、TC、LDL、ApoAI和ApoB均未发生显著变化。以上所有测量指标均未超出正常范围。结论：使用1年第二、三代COC对妇女BMI、血压和血脂代谢都有微弱的影响，对空腹血糖无明显影响。第三代COC对妇女BMI、收缩压、舒张压、TG、TC、LDL、HDL水平和ApoB的不利影响小于第二代，更加安全可靠。