动脉血气分析课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,MIXED VENOUS BLOOD,PCO,2,46 mmHg,PO,2,40 mmHg,SO,2,75%,PCO,2,40 mmHg,PO,2,95 mmHg,SO,2,95%,ARTERIAL BLOOD,External Respiration,Internal Respiration,Obtaining the blood gas specimen,Obtaining the blood gas specimen,Blood collected anaerobically (radial artery),The specimen adequately anticoagulated (heparin),Free of air bubbles and clots,A 2 ml sample recommended,The specimen analyzed in a few minutes, otherwise stored in ice within 1 hour,Equipment calibration and quality control,The specimen adequately identified,常压环境下，无论患者的吸氧条件如何，只要PaO248mmHg，则提示标本多为动脉血,自然状态下吸空气检查：PaO2+PaCO2 140mmHg,若无原发代谢失衡证据，数小时内HCO,3,-浓度测量值变化5mmol/L,What Information Does Arterial Blood Gas provide?,Alveolar ventilation,Arterial oxygenation,Respiratory/metabolic acid-base balance,Alveolar ventilation,肺 泡 通 气 (1),PaCO,2,是体现病人肺泡通气状态的,唯一数值,PaCO,2,升高即肺泡通气不足，PaCO,2,降低即肺泡通气过度,PaCO,2,上升的,唯一生理原因,是对于产生和运输到肺的CO,2,量，肺泡通气水平不足,VCO,2,(ml/min),PaCO,2,VA,(L/min),肺 泡 通 气 (2),VCO,2,: 代谢产生并运输到肺的CO,2,量,VA: 肺泡分钟通气量,分钟通气量(VE)死腔通气量(VD),(潮气量死腔量) 呼吸频率,Anatomic dead space,Alveolar dead space,PaCO,2,与氧合及酸碱平衡的关系,肺 泡 通 气 （5）,PaCO2,VA(L/min),PAO,2,=PIO,2,-1.2(PaCO,2,),pH=6.1+log,HCO,3,-,0.03 PaCO,2,Arterial oxygenation,Hb,PaO,2,和肺泡-动脉PO,2,差,PaO,2,、SaO,2,和CaO,2,SaO,2,与SpO,2,ctHb,c,tHb =,c,O2Hb +,c,HHb +,c,COHb +,c,MetHb,c,tHb is a measure of the total potential for oxygen transport in the blood,FO2Hb,It is a measure of the utilization of the potential oxygen transport capacity.,FCOHb,The affinity of hemoglobin for carbon monoxide is 200 to 250 times as great as the affinity for oxygen.,oxygen transport capacity,the left shift of the ODC.,FMetHb,Fe2+ Fe3+.,oxygen-carrying capacity ,the affinity for oxygen ,caused by drugs or chemicals containing nitro- and aminogroups.,Newborns can get methemoglobinemia if given nitrate-containing well water. Excessive methemoglobinemia may be treated with intravenous infusion of methylene blue or by red-cell transfusion.,PaO,2,O,2,通过扩散进入肺毛细血管，所以,PaO,2,决不可能超过,PAO,2,PaO,2,=100-0.33年龄,型呼吸衰竭,PaCO2正常或下降，PaO250mmHg， PaO260mmHg,肺泡-动脉PO,2,差,PAO2-PaO2,指肺泡气和动脉血氧分压之间的差值。是判断氧弥散能力的一个重要指标，,FiO2、V/Q、Qs/Qt、,膜弥散障碍、机体耗氧量（VO2）、,心排量（CO）、氧合血红蛋白解离曲线均可影响。,在所谓的理想肺中，,PaO,2,=,PAO,2,PAO,2,=,PIO,2,-K,PaCO,2,=FIO,2,(P,B,-47)-,K,PaCO,2,=,713,FIO,2,-,K,PaCO,2,当FIO,2,时，,当,FIO,2,时，,P(A-a)O,2,=PAO,2,-PaO,2,中青年，FIO,2,，5-15mmHg,老年人，,FIO,2,，15-25mmHg,FIO,2,，10-110mmHg,P,(A-a),O,2,15mmHg for subjects30y/o and increases by 3mmHg/decade after 30y,肺泡-动脉PO,2,差,给氧时FiO,2,的估计值,100% O,2,流量(L/min) FiO,2,(%),鼻导管,1 24,2 28,3 32,4 36,5 40,6 44,面罩,5-6 40,6-7 50,7-8 60,储氧面罩,6 60,7 70,8 80,9 90,10 99,+,P(A-a)O,2,在临床实践中的不足,正常值随FIO,2,变化明显,计算繁琐,PaO,2,/FIO,2,正常值=100/0.21=480,300： ALI,45 and pH 45 and pH 7.35-7.45, then compensated respiratory acidosis,If PCO,2,7.45, respiratory alkalosis,If PCO,2,35 and pH 7.35-7.45, then compensated respiratory alkalosis,方法二：,Metabolic?,If HCO,3,-,22 and pH 7.35, metabolic acidosis.,If HCO,3,-,27 and pH 7.45, metabolic alkalosis,If HCO,3,-,27 and pH 7.35-7.45, then compensated metabolic alkalosis,方法三,电解质和阴离子间隙(AG),阴离子间隙的算法是常规检测的阳离子总数减常规检测的阴离子总数,它所表示的是机体,代谢性,的酸碱紊乱,AG=(Na,+,+K,+,)-(Cl,-,+ HCO,3,-,)=Na,+,-(Cl,-,+CO,2,),12,2mEq/L,在实际情况中，认为AG,16mEq/L反映阴离子间隙代谢性酸中毒,利用电解质诊断酸碱平衡紊乱的步骤,1. 看血清电解质中的CO,2,值,升高,1)代碱,2)呼酸的HCO,3,-,代偿,正常,减少,1)代酸(AG和/或HCA),2)呼碱的代偿性HCO,3,-,排泄,2. 计算AG,升高,找AG酸中,毒的原因,正常,降低,考虑低蛋白血症,异常蛋白,异常阳离子,3. 计算 HCO,3,-,+ HCO,3,-,1)代碱,2)呼酸的HCO,3,-,代偿,- HCO,3,-,1) HCA,2)呼碱的代偿性HCO,3,-,排泄,4. 看动脉血气,单纯性酸碱紊乱时的代偿预计值,DuBose(1983) Bidani(1986),代酸,PCO,2,HCO,3,-,)+82 ,PCO,2,=,HCO,3,-,代碱,PCO,2,HCO,3,-,)+9 ,PCO,2,=,HCO,3,-,急性呼酸,HCO,3,-,=,PCO,2,0.2 ,HCO,3,-,=,PCO,2,0.2,慢性呼酸,HCO,3,-,=,PCO,2,0.35 ,HCO,3,-,=,PCO,2,0.25,急性呼碱,HCO,3,-,=,PCO,2,0.2 ,HCO,3,-,=,PCO,2,0.2,慢性呼碱,HCO,3,-,=,PCO,2,0.5 ,HCO,3,-,=,PCO,2,女性，60岁，COPD并肺心病，咳喘加重1个月,PH,PaCO,2,HCO,3,-,K,+,Na,+,Cl,-,AG,PaO,2,FiO,2,（71）,42,5.1,134,72,20,（62）,分析：患者,PH,、,PaCO,2,结合病史，可诊断为慢性呼酸，又因为患者,AG 16,，还存在高,AG,性代酸，,根据慢性呼酸公式：,HCO,3,-,=PaCO,2,（,），,HCO,3,-,应为,35.5SB提示有呼吸性酸中毒，,ABSB提示有呼吸性碱中毒，,AB=SB正常值提示有代谢性碱中毒,酸碱平衡,缓冲碱（Buffer bass，BB）：,是血液中一切具有缓冲作用的碱（负离子）的总和，包括HCO,3,-,，血红蛋白，血浆蛋白和HPO,4,-,。,正常值,4555mmol/L，平均50mmol/L。,临床意义：,降低提示代谢性酸中毒。,酸碱平衡,碱剩余（BE）：,是在38，PaCO,2,（40mmHg），SaO,2,100%条件下，血液标本滴定至时所需酸或碱的量，反映缓冲碱的多少。,正常值：,+,3 -3mmol/L。,临床意义：,+3 mmol/L提示代碱，,-3 mmol/L提示代酸。,酸碱平衡,Summary,Was the blood gas specimen obtained acceptably?,Is pH within normal limits?,Whats the cause of acid-base imbalance? Respiratory / Metabolic,How about the oxygenation?,Are blood gas results consistent with patients clinical status?,THANK YOU,The End,谢谢您的聆听！,期待您的指正！,