酸碱平衡紊乱及分析-研究生PPT课件

Acid-base Balance and Imbalance,酸碱平衡紊乱及其分析,阎春玲Department of Pathophysiology,Acid-base balance,The basic meaning of acid-base balance is the stable H+ in the body fluid. pH: 7.357.45Compatible with life 6.8 - 8.0,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 disturbance：,In disease, because of overload, loss or deficiency and disorder in regulation of acid and base, the homeostasis can be destroyed.,Normal acid-base balance,Section 1,1. Acid- H+ donor,volatile acid (挥发酸 )Nonvolatile acid/fixed acid (固定酸 ),daily production ：300-400L/d,volatile acid H2CO3,CO2,H2O,H2CO3,CA,H+ + HCO3-,Reabsorption in kidney,RBC、kidney tubules-epithelium 、alveolar epithelial cell 、gastric mucosa,Source of acid,volatile acid,Pco2 is most important factor in pH of body tissues,Fixed acid (nonvolatile acid ),(50-100mmol/d),Base- H+ acceptor,碱性氨基酸分解 Endogenous： deaminationNH3 Less than acid production 有机酸盐转变Exogenous input： vegetables, and fruits,Regulation of acid-base balance,Buffer systems (体液缓冲) Respiratory regulation (肺) Renal regulation (肾) Cellular regulation (细胞调节),1. Buffer systems in body fluid,弱酸及其共轭碱构成的具有缓冲酸或碱能力的缓冲对,HCO3-/H2CO3 is the most important buffer pair,the most important buffer pair (50%)。fixed acid and base buffer systemPH is dermatied by HCO3-/H2CO3,特点：Open Buffer System反应快；但被消耗，不持久；不彻底，直接受肾、肺调节。,2. Respiratory regulation,PaCO2 (N:40mmHg) pH of CSF to stimulate central chemoreceptor the respiratory centerPulmonary ventilation volume PaCO2 60mmHg (8kPa) Pulmonary ventilation volume 10 times PaCO2 80mmHg (10.7kPa) inhibit respiratory center，named as carbon dioxide narcosis,特点：作用较快 (数分钟内开始发挥作用，30分钟达到高峰)；代偿能力大；只对挥发性酸有效。,3. Renal regulation,“排酸保碱” 起效慢，1224h作用强大持久,NaHCO3重吸收 (bicarbonate conservation),磷酸盐酸化 (phosphate acidification),氨的排泄 (ammonia excretion),Renal regulation,Bicarbonate conservation (NaHCO3重吸收),Phosphate acidification(磷酸盐酸化),K+,K+,Cl-,Ammonia excretion (氨的排泄),4.Cellular regulation,红细胞肌细胞,HHb,特点：缓冲强于细胞外液；24h起效；引起血钾改变。,组织细胞,血液,H,K,Na,肝脏细胞,NH3,H,OH-,NH4,NH3,尿素,骨骼,Ca3(PO4)2,H,Ca2,PO43-,Ca2,PO43-,H,H2PO4-,Parameters of acid-base balance,Section 2,1. pH,pH: acidosispH: alkalosis,7.357.45,kassier,pH正常,No disturbsnce Complete compensation Acidosis + Alklosis,2. PaCO2 -“respiratory factor”. (Partial pressure of carbon dioxide),正常值: 40mmHg (3346mmHg)H2CO3: 40 X 0.03=1.2mmol/L,Higher PaCO2 is due to the inhibition of respiration. Lower PaCO2 is due to overventilation.,PaCO2 是物理溶解在动脉血中的CO2产生的张力。,PaCO246mmHg Primary increase: respiratory acidosis Secondary increase: metabolic alkalosis (compensated by lung)PaCO2SB (CO2 retention) respiratory acidosisAB SB PaCO2 10mmHg HCO3代偿性 1 mmol/L,Chronic: pH PaCO2 AB SB PaCO2 10mmHg HCO3代偿性 3.5 mmol/L,(4)Changes of parameters and electrolytes,案例4-2：患者：男，15岁，因溺水窒息。查血气：PH 7.15，PaCO2 80mmHg，HCO3- 27mmol/L。分析？,与代酸相同，但CNS症状更明显,?,Why ?,(5）Alterations of metabolism and function,CO2 直接弥散进入脑组织,Carbon dioxide narcosis: PaCO2 80 mmHg,Celebral vascular dilation cerebral blood flow increase,Hypoxia,肺性脑病,(Pulmonary encephalopathy),intracranial hypertension and brain edema.,增加肺泡通气量(Increase alveolar ventilation),应用碱性药物(supplement of base),(6) Principles of prevention and treatment,Be careful to alkaline drug(NaHCO3) THAM,85,案例4-3：,一男性患者，60岁，因进食即呕吐10天而入院。近20天明显消瘦，卧床不起。精神恍惚，嗜睡，皮肤干燥松弛，眼窝深陷，呈重度脱水征。呼吸17次/min，血压120/70mmHg，诊断为幽门梗阻。血液生化检验：K+3.4mmol/L, Na+158mmol/L，Cl-90mmol/L；血气：pH7.50，PaO262mmHg，PaCO249mmHg，BE8.0mmol/L，HCO3-45mmol/L。思考题：该患者属于何种类型的酸碱平衡紊乱？原因和机制如何？该患者有无水电紊乱？,3. Metabolic alkalosis,Metabolic alkalosis is defined as an increase of pH induced by primary increase in plasma bicarbonate ( HCO-3).,(1) Etiology,1) H loss,vomiting ( HCl ),Loss from stomach：,Loss from kidney:,长期应用袢利尿剂（抑制髓袢升支对Cl-、Na+和H2O的重吸收）远端肾小管 H+-Na+交换排H+ 、排Cl- ，HCO3-重吸收 血HCO3-、Cl- Diuretics- furosemide低氯性碱中毒醛固酮增多或糖皮质激素使用过多 肾排H+、K+ -重吸收NaHCO3 ,Primary hyperaldosteronism Secondary hyperaldosteronism caused by: hypovolemiaCushings syndrome,低氯性碱中毒,利尿剂,2) Excessive intake of alkaline substances,3) Hypokalemia / hypochloremia低钾/低氯性碱中毒paradoxical acidic urine,Excessive intake of NaHCO3 or stored blood,4)Misuse of mechanical ventilation in chronic respiratory acidosis,原因呕吐丢失HCl；脱水造成浓缩性HCO3；低钾碱中毒,案例4-3：一男性患者，60岁，因进食即呕吐10天而入院。近20天明显消瘦，卧床不起。精神恍惚，嗜睡，皮肤干燥松弛，眼窝深陷，呈重度脱水征。呼吸17次/min，血压120/70mmHg，诊断为幽门梗阻。血液生化检验：K+3.4mmol/L, Na+158mmol/L，Cl-90mmol/L；血气：pH7.50，PaO262mmHg，PaCO249mmHg，BE8.0mmol/L，HCO3-45mmol/L。,(2) Clasification,Chloride-responsive alkalosis 盐水反应性碱中毒Chloride-resistant alkalosis 盐水抵抗性碱中毒,(3) Compensation,4) Renal regulation,Secrete H+ Secrete NH3 Reabsorb HCO3- Urine pH ,细胞外液H,肾小管腔,碱中毒低血钾,3) Intracellular regulation,原发性: pH SB AB BB BE继发性: PaCO2 血K,正值,(4) Changes of parameters and electrolytes,案例4-3,血气：pH7.50，PaO262mmHg，PaCO249mmHg，BE8.0mmol/L，HCO3-45mmol/L分析：患者幽门梗阻呕吐丢失HCl等而导致HCO3-pH，BE正值，继发性PaCO2，PaO2，属于失代偿型代谢性碱中毒。患者低Cl-、脱水应属于盐水反应性碱中毒,(1) Central Nervous System,-氨基丁酸(GABA),(5）Alterations of metabolism and function,restlessness，mental derangement，delirium.,2) Neuromuscular excitability(神经肌肉应激性升高),机制: pH，血中游离Ca2+,手足搐搦(Carpopedal Spasm),3) Hypoxia (left-shift of oxygen-Hb dissociation curve),4) Hypokalemia,治疗原发病(treatment of primary disease),saline-responsive alkalosisKClsaline-resistant alkalosis,(6) Principles of prevention and treatment,Replenish 0.9% NaCl Na+ Cl-( mmol/L)-0.9%NaCl 154 154Plasma 140 104-a) Dilute the HCO3-b) Increase the blood volume, reduce the reabsorption of HCO3-.c) increased Cl- in distal tubule leads to increased excretion of HCO3- in collecting duct.,103,案例4-4,4. Respiratory alkalosis,Respiratory alkalosis is defined as an increase of pH induced by Primary decrease in plasm H2CO3 Concentration.,(1) Etiology,CO2排出过多,Psychogenic factors: Nervousness, anxiety, hysteria, etc.(2) Brain diseases: Encephalitis, meningitis, etc.(3) Reflective stimulation: Hypoxemia, fever, pain, NH3, salicylate etc.(4) Misuse of mechanical ventilation,案例4-4原因发热、肺炎、肺水肿、低氧血症等刺激呼吸频率CO2呼出过多,(2) Classification and Compensation,Acute respiaratory alkalosis24h,血H2CO3,血K,1）Acute respiaratory alkalosis,RBC,plasma,2）Chronic respiaratory alkalosis,泌H+ 泌氨HCO3-重吸收 尿pH ,急性: pH PaCO2 AB SB PaCO2 10 mmHg HCO3代偿性 2 mmol/L,慢性: pH PaCO2 AB SB PaCO2 10mmHg HCO3代偿性 4 mmol/L,(4) Changes of parameters and electrolytes,案例4-4血气：pH7.52, PaCO230mmHg，PaO257mmHg，BE-1.2mmol/L，HCO3-23.3mmol/L，K+、Na+、Cl-正常。分析：患者发热、肺炎、肺水肿并缺氧，引起呼吸急促，使PaCO2原发性pH，继发性HCO3-，属于失代偿型呼吸性碱中毒。,眩晕、四肢感觉异常、意识障碍、抽搐等碱中毒症状,(5）Alterations of metabolism and function,CNS dysfunction：GABA，cerebral blood flow ,(6) Principles of prevention and treatment,Treatment of primary diseasePrevent mis-operation of mechanical ventilator5CO2 mixtrue gas inhalation or mask,115,各型酸碱平衡紊乱指标的变化,代酸,呼酸,代碱,呼碱,小结,117,单纯型ABD小结1、概念： 根据原发变化因素及方向命名。2、代偿变化规律： 代偿变化与原发变化方向一致。 3 、血气特点：呼吸性ABD，血液pH与其它指标变化方向相反；代谢性ABD，血液pH与其它指标变化方向相同。4、原因和机制： 代酸：固定酸生成及HCO3-丢失HCO3-降低。 呼酸：CO2排出减少吸入过多，使血浆H2CO3升高。 代碱：丢失，过量负荷，血增多。 呼碱：通气过度CO2呼出过多，使血中H2CO3降低。,118,5、对机体的影响： CNS 离子改变 其它酸中毒 抑制性紊乱 血钾增高 血管麻痹，心律失常 收缩力降低碱中毒 兴奋性紊乱 血钾降低 肌肉痉挛6、代偿调节(1) 代谢性ABD,各调节机制都起作用，尤其是肺和肾；呼吸性ABD,细胞内外离子交换是急性紊乱的主要机制（两对离子交换），肾调节是慢性紊乱的主要机制。（2）代偿是有限度的。（3）pH值取决于代偿能否维持HCO3-/H2CO3比值为20/1。,例一、患者腰痛3月入院，诊断为肾盂肾炎，血液生化测定 pH = 7.32, PaCO2 = 20 mmHg, BE=-15.3mmol/L， SB= 19.2mmol/L。 该病人发生何种酸碱平衡紊乱？,代酸,例二、糖尿病患者，血液生化测定 pH = 7.30, PaCO2 = 34 mmHg, SB= 16mmol/L， Na+= 140 mmol/L, K+=4.5 mmol/L CL- =104 mmol/L ， HCO3- = 21mmol/L该病人发生何种酸碱平衡紊乱？,AG增高性代酸,综合举例,例三某溃疡病患者,因反复呕吐入院,血气分析为pH 7.49，PaCO2 48mmHg，HCO- 36mmol/L。该病人酸碱失衡类型为： A 代酸B 代碱C 呼碱D 呼碱例四某肝性脑病患者, 血气分析为pH 7.47，PaCO2 26.6mmHg，HCO- .3mmol/L。应诊断为： A 代碱B 呼碱C 呼酸D 代酸,Mixed acid-base Disturbance,Section 4,A mixed acid-base disturbance is defined as the simultaneous existance of two or more simple acid-base disturbance in the same patient.,Concept,酸碱一致型（相加型）酸碱混合型（相消型）,Double acid-base disturbance(二重性),呼吸心跳骤停肺疾患并心衰或休克,pH PaCO2 HCO3-,Respiratory acidosis + metabolic acidosis,Causes,Characteristics,通气障碍（CO2潴留）伴有产酸（固定酸潴留）。,高热合并呕吐肝硬化应用利尿剂,pH PaCO2 HCO3-,Respiratory alkalosis + metabolic alkalosis,Causes,Characteristics,慢性肺疾患应用利尿剂或合并呕吐,pH PaCO2 HCO3-,Respiratory acidosis plus metabolic alkalosis,Causes,Characteristics,(-)、,水杨酸中毒或肾衰合并通气过度,Metabolic acidosis + respiratory alkalosis,Causes,Characteristics,pH PaCO2 HCO3-,(-)、,肾衰伴呕吐酮症酸中毒伴呕吐呕吐伴有腹泻,Metabolic acidosis + metabolic alkalosis,Causes,Characteristic,pH 、PaCO2 、HCO3- 不定,呼酸+代酸(AG)+代碱呼碱+代酸(AG)+代碱,Triple acid-base disturbance（三重性),Section 5,Judgment of acid-base disorders,“一划五看”简易判断法,一划：将多种指标简化成三项，并用箭头表示其升降,SB AB BB，BE(-),HCO3-,H2CO3,PaCO2,pH ,H+,五看：一看pH定酸碱,1. pH升高：失偿型碱中毒 pH降低：失偿型酸中毒 2. pH正常可能是 （1） 酸碱平衡 （2） 代偿性单纯性 （3） 混合性相消型,病史中有获酸，失碱或相反情况，为代谢性ABD病史中有肺过度通气或相反情况，为呼吸性 ABD,二看原发因素定代呼,HCO-3 H2CO3,pH N,病史？,1. 继发性变化的方向 (1) 与原发性变化方向一致：,三看“继发性变化”定单混,PaCO2 HCO-3 pH 接近正常,单纯型ABD 或混合型(相消型)ABD,PaCO2,HCO-3， pH ,(2)与原发性变化方向相反,混合型(相加型)ABD,“继发性变化”的数值 (代偿预计值）（1）数值在代偿预计值范围内，为单纯型（2）数值明显超过或低于代偿预计值，为混合型,代偿预计值（见书中表格）,如：慢性呼酸代偿预计公式： HCO-3=0.4PaCO23,单纯性酸碱失衡常用代偿预测公式,Acid-Base Disturbance,一位慢性肺心病人，其PaCO2为60mmHg/L，这位病人HCO-3的代偿最大限值是多少？,HCO-3 = 0.4x(60-40)+24 3 = 32mmol/L3 = 29 35 mmol/L,例5,一位肝性脑病病人，pH = 7.47, PaCO2 =26.6 mmHg , HCO-3