动脉血气分析与酸碱平衡

ICU‡‡‡‡„ƒƒ:CO2+H2OH2CO3H++HCO3—,.:,:ß-„ƒƒ:30minCO2ƒ3-5H+HCO3-NH4+ƒ3-4hH+-K+CL--HCO3-‡„PH[H+]PH=-lg[H+]Ka=[H+][A-]/[HA]PH=-lg[Ka[HA]]=-lgKa+[-lg]=pKa+lg[A-]henderson-hassalbachPH=pKa+lg[HCO3-][H2CO3]=PaCO2henry=6.1+lg24=7.4(7.357.45)H+4535mmol/L[A-][HA][A-][HA][H2CO3][0.0340]1PH7.45PH7.352HCO3-/H2CO3=201PH„CO2PaCO2CO235-45mmHg1PaCO2CO2PaCO2PACO22345mmHg35mmHg„PaO280-100mmHg1PaO2HbO2%2)()aPaO2PaO2PaCO2140mmHgbV/Q-PaO2PaCO2„A-aDO2FiO=21%):20mmHg,30mmHgA-aDO2=2.5+0.21)mmHg:1)(V/Q2aPaO260mmHgARDSbcPaCO2CNSNMdPaCO23„SO2%:PO2HbO2Hb:SO2%=[HbO2/(HbO2+Hb)]10091.9~99%:SaO2PaO2PaO2150mmHgSaO2100%“S”60100mmHgSaO2PO2PO260100150mmHgSaO29097100PO2PO2SaO260mmHgPO2SaO2PO2HbO2P50=26.3mmHgPaO2SO2%PaO260mmHgSO2%„50%P5026.3mmHg:HbO2P50PaO2SO2%HbHbO212PCO23PH423,RBC23DPGHbO2„(OI):/PaO2/FiO2)400-500mmHg1)FiOPaO22)OI300mmHg3)ALI)ARDS)OI300mmHgALIOI200mmHgARDS„O2CAPO2CTO2CAP100mlHbO2CAP=1.34ml/g)Hb(g/dl)20ml/dl12HbO2O2CT100mlHbO2CT=1.34HbSO2%+0.003PO217.5~23ml/dl(16~21.5ml/dl(12HbSO2%PO2„TCO2)CO295HCO3-TCO2[HCO3-]+PaCO20.03mmol/L24-32mmol/L(28mmol/L)12PHPHPHPH„AB):PaCO2SaO2HCO3-22-27mmol/L(24mmol/L)1CO2+H2OH2CO3H++HCO3-HCO3–PaCO22HCO3-PHHCO3–CACA„SB):37Hb100%PaCO240mmHgHCO3-22~2724mmol/L)12AB=SBABSBPaCO240mmHgABSBPaCO240mmHg„BB):BBp)=HCO3-+Pr-=41~42mmol/LBBb)=HCO3-+Pr-+Hb0.42=41~48mmol/LBBecf=HCO3-+Pr-+50.42=43.8mmol/LHbHCO3-35%HCO3-18%Hb35%7%5%„(BE)37Hb100%PaCO240mmHg1LPH7.4mmol/L(012+-3HCO3-=0.6BEkg)2/3-1/2‡„„„„z1HCO3-PaCO2pH7.40.05HCO3-/PaCO2=20/1HCO3-PaCO210-55mmHgPaCO2HCO3-1245mmol/Lz1HCO3-/PaCO2z2HCO3-/PaCO2PHz2z3PH1pH7.32PaCO230mmHgHCO3-15mMol/L2pH7.42PaCO229mmHgHCO3-19mMol/L„zAGAGUA)UC)Na+HCO3-CL-Na++UCHCO3-+CL-+UAAGUAUCNa+-HCO3-+CL-816mmol116mmolHCO3-+CL-AG2AG3AGUAUCPH7.4PaCO240mmHgHCO3-24mmol/LCL-90mmol/LNa+140mmol/L[]“”AG=26mmol16mmolAGzHCO3-AGHCO3-HCO3-HCO3-=HCO3-+AGAGHCO3-1AGHCO3-AGHCO3-2AGpH7.4PaCO240mmHgHCO3-24mmol/LCL-90mmol/LNa+140mmol/L[]HCO3-24mmol/LAG=26mmol16mmolAGHCO3-HCO3-=HCO3+AG=24+AG=34mmol/L27mmol/LAGz1)(HCO3-PaCO2=1.5HCO3-+82PaCO2PaCO2=0.9HCO3-52)(PaCO2HCO3-35:PaCO2HCO3-34mmolHCO3-(HCO3-=0.35PaCO25.58HCO3-(HCO3-=0.49PaCO21.72„zpHPaCO2HCO3-zzHCO3-/PaCO2zTABDAGHCO3-TABD:PH7.33PaCO270mmHgHCO3-36mmol/LNa+140mmol/LCL-80mmol/Lz[]PaCO240mmHg70mmHgHCO3-24mmol/L36mmol/LpHpH7.47.33HCO3-zHCO3-HCO3-=0.35PaCO25.58=0.3570-405.58=4.9216.08HCO3=24+HCO3-=28.9240.08zAGHCO3AG=Na+-HCO3-+CL-816mmol=140-116=24mmolHCO3-=HCO3+AG=36+8=44mmolzHCO3-HCO3-HCO3-3628.9240.08HCO3-44AG16mmolAGAG‡„„„„z1HCO3-2ß-3[HCO3-]GSNS4H+-K+(AGAGCNSHCO3-15mmol/LNaHCO3z1H+2HCO3-NaHCO3(H2ONaCL)3K+-H+123KCl(H+ClHCO3-)4HClNaClPH•1CO22CO224h(12PaCO2HCO3-PaCO23HCO3—+H+H2CO3)„HbO2O2ƒAG1PaCO2HCO3-CLAGHCO3-HCO3-CLAG2AGHCO3-AGƒTABD)AGTABDTABDAGHCO3-TABD