北大基础医学病理生理学PPT课件 酸碱平衡紊乱.pptxVIP

(Acid-base disturbances);woman 38 ， 2-day history of weakness and postural dizziness（直立性眩晕 ）History：laxative（泻药）abuse with  multiple bowel movements each day Physical examination： BP 110/60 mmHg falls to 80/50 mmHg  HR 100 beats/min and regular Skin turgor is poor  The mucous membrane is dry;Laboratory test：[Na+] = 140 mmol/L[K+] = 3.3 mmol/L[Cl-] ＝ 116 mmol/LUrine [Na+] = 9 mmol/LBUN = 40 mg/dL Arterial pH = 7.25[HCO3-] = 12 mmol/L PaCO2 = 28 mmHg ;人动脉血pH是多少? 吃酸性食物后, 血液pH会发生改变吗? 人体有哪些维持酸碱平衡的方法? 都有哪些类型的酸碱平衡紊乱? 酸中毒或碱中毒对人体有哪些危害?;  因酸碱负荷过度、不足或调节机制障碍导致体液酸碱度稳定性失衡的病理过程。 ; (Acid-base balance  and its regulation );一、酸碱物质的来源;(一)酸性物质的来源;经肺呼出; 2. Fixed acid; (Sources of base);3CO2+2H2O+NaHCO3;(Regulation of acid-base balance);(一)体液缓冲系统; (bicarbonate / carbon dioxide buffer system);缓冲能力强;Henderson-Hasselbalch方程;2. 磷酸盐缓冲系统 ;特点:主要在细胞内缓冲 ;Hb-/HHb、HbO2-/HHbO2;缓冲机制(Mechanism of buffer) ; (Mechanisms of respiratory control);(central control);2.外周调节;(三)肾的调节机制;;重吸收的NaHCO3不 是滤过的NaHCO3 ; ;;远曲小管调节性泌H+, 尿液酸化明显 ;(Classification of acid-base disturbances and laboratory tests);(Classification of acid- base disturbances);;pH;(Laboratory tests);1．pH; pH(-); 2.动脉血二氧化碳分压 (PaCO2) partial pressure of carbon dioxide;3.标准碳酸氢盐 (standard bicarbonate SB);4.实际碳酸氢盐(actual bicarbomate AB);AB-SB:呼吸因素;AB＞SB;5.缓冲碱(buffer base BB) ;6.碱剩余 (base excess BE);7. 阴离子间隙(anion gap AG) ;AG = UA - UC;(Simple acid-base disturbance) ; (Metabolic acidosis); （一）原因与机制 (Causes and mechanisms);(metabolic acidosis with  increased anion gap);Na+ UC;入酸增多(excess intake) 摄入水杨酸类药(固定酸)过多;2．AG正常型代酸 (metabolic acidosis with  normal anion gap);Na+ UC;HCO3－丢失(loss bicarbonate)  严重腹泻、小肠及胆道瘘管、肠吸引术等 ;在代谢中产生H＋和Cl-;GFR尚可，肾小管泌H＋障碍;(二) 机体的代偿调节(Compensation);;血pH7.2 serum[K＋]5.6 mmol/L; hyperkalemia → acidosis;4. 肾的代偿;反常性碱性尿:(paradoxical baseuria); hyperkalemia → acidosis; ;(