电解质代谢的生理基础.ppt

Water and electrolyte disorders 一、水、电解质代谢的生理基础 (一) 体液 1. 体液及其分布 Intracellular fluid Total (ICF) 40% (60%) interstitial fluid 15% extracellular fluid plasma 5% (ECF) 20% transcellular fluid 2% (透细胞液) 2. 体液中主要电解质及其分布 extracellular fluid: Na+、Cl-、HCO3- intracellular fluid： K+、HPO42- 在Na+- K+-ATPase作用下，细胞内外 Na+ 、K+保持不对等分布。 3. Osmotic pressure of body fluid (plasma) Positive ion: 151mmol/L Negative ion: 139mmol/L total 280- 310mmol/L Nonelectrolyte: 10mmol/L (678.3kpa) Plasma colloidal osmotic pressure: 3.72kpa(28mmHg) （二） movement of water and electrolytes 1. plasma interstitial fluid capillary protein 2. intra- and extra- cellular fluid proteins and positive ion: permeability water and negative ion: permeability (water movement balance of osmotic pressure) R B C 3. Balance of body water and sodium drink 1200ml water intake food 1000ml (2000-2500ml) oxidation 300ml balance of water urine 1200-1500ml water loss skin 500ml (2000-2500ml) respiration 350ml feces 150ml Balance Intake/d 100-200mmol (digestive tract) of sodium Loss/d 100-200mmol (urinary system) ECF:50% Distribution ICF: 10% of sodium 骨基质:40% (正常血清钠:130- 150mmol) (三) Regulation of osmotic pressure and volume Hypertonic thirst of ECF 1.body water ADH ; aldosterone sodium thirst Ang ADH body volume aldosterone receptor of volume ADH 2.body water sodium ADH reabsorption of sodium 3.blood volume ANP aldosterone(ADS) tension 4.others ADH pain Figure: regulation of ADH secretion osmotic pressure R pressure R ADH volume R heart 二、water and sodium disorders hypertonic hypertonic dehydration isotonic water excess isotonic hypotonic hypotonic (一) 细胞外液容量不足(extracellular fluid deficit) 1. Hypotonic dehydration sodium loss water loss serum sodium 130mmol/L plasma osmotic pressure 280mOsm/L 1) cause and Pathogenesis excessive loss of water and sodium replaced with water only. vomiting, diarrhea; burn; diuretics; Addisons disease (ADS ) ; chronic renal failure; renal tubular acidosis 2) adaptive response and effect on body movement of body fluid ECF ICF cellular swelling Blood volume Extracellular fluid Shock dehydrated signs edema of brain and lung urinary alteration urine specific urine volume gravity Na+ - early ADH or stage ADS late ADH stage ADS - (注：经肾失钠的低渗性脱水，尿钠不减少) 3) principles of treatment treating primary disease 0.9%NaCl 2. hypertonic dehydration water loss sodium loss serum sodium 150mmol/L plasma osmotic pressure 310mOsm/L 1) cause and pathogenesis lack of water(desert;sea) intake to drink inability(coma;baby) lung: hyperpnea(hypoxia;acidosis) skin: fever; hyperthyroidism; sweat; exposure to hot environment loss digestive tract: vomiting; diarrhea; baby diarrhea(Na+: 60mmol/L) kidney: diabetes(ketosis); diabetes insipidus diuretic(mannitol;hypertonic glucose) 2) effect on body hypertonic of ECF thirst movement of the body fluid ICF ECF cell dehydration Brain dehydration Sleepiness subarachnoid space bleeding Dehydration of sweat glands dehydrated fever dehydration of heat regulating center urinary alteration urine specific urine volume gravity Na+ - early ADH stage ADS late ADH stage ADS - 3) principles of treatment 先水，后盐；补水大于补钠。 病例1：患者，男性，40岁，吐、泻伴发热、口渴、 尿少4天入院。 体格检查：体温 38.2，血压 110/80mmHg，汗 少，皮肤黏膜干燥。 实验室检查：血Na+ 155mmol/L，血浆渗透压 320mOsm/L，尿比重 1.020。 给予 5%葡萄糖溶液 2500ml/d 和抗生素，2天后 体温、尿量正常，口不渴，眼窝凹陷，皮肤弹性明 显降低，无力，肠鸣音减弱，腹壁反射消失。浅表 静脉萎陷，脉搏 110次/分，血压 72/50mmHg，血 Na+ 120mmol/L，血浆渗透压 255mOsm/L，血K+ 3.0mmol/L，尿比重1.010，尿钠8mmol/L。 3. isotonic dehydration water loss sodium loss serum sodium = 130-150mmol/L plasma osmotic pressure:280- 310mOsm/L 1) cause and pathogenesis vomiting; diarrhea; gastrointestinal suction; biliary fistula; intestinal fistula ascitic fluid; pleural effusion 2) effects on body slight thirst blood volume dehydrated signs; BP urinary alteration urine specific urine volume gravity Na+ - early ADH stage ADS late ADH stage ADS - 3) principles of treatment 补偏低渗液；先补0.9%NaCl 病例2： 患者，女性，38岁，因减肥连续服用泻 药一周，现感虚弱乏力，偶有直立性眩晕 而入院。 体格检查：体温36.7，血压从入院时 的110/60mmHg 很快降至 80/50mmHg，心率 100次/分，皮肤弹性差，黏膜干燥，尿量 120ml/24h。 实验室检查：血Na+ 140mmol/L，血浆渗 透压295mOsm/L，尿比重 1.038，尿钠 6mmol/L。 (二) 细胞外液容量过多(extracellular fluid excess) 1. water intoxication water intake , total sodium ; ECF , ICF ; hyponatremia; Serum sodium 130mmol/L 1) cause excessive water intake renal loss (acute renal failure; acute congestive heart failure) 2) effects on body brain cells swelling water moves into cells pulmonary edema 3) principles of treatment diuresis 病例3：患者，女性，因外伤急救误输异型血 200ml 后，出现黄疸和无尿。 体格检查：体温37，脉搏 80次/分，呼吸 80 次/分，血压从入院时的110/60mmHg 很快降至 80/50mmHg。神志模糊，表情淡漠，皮肤黏膜干燥 、黄染，静脉塌陷。 实验室检查：血清尿素氮 15.0mmol/L，非蛋白 氮 57.12mmol/L，血 K+ 6.7mmol/L。 入院后急速输入5%10%葡萄糖溶液1500ml，生 理盐水500ml后，当晚做血液透析，透析中血压上 升并稳定在110140/70mmHg，透析后查尿素氮为 9.46 mmol/L，非蛋白氮 44.3mmol/L，血 K+ 5.7mmol/L。 患者5天内一直无尿，并逐渐出现明显气喘、心 慌、不能平卧，嗜睡、呕吐、头痛、精神错乱症状 。查体发现，心率 120次/分，两肺布满湿罗音。 血 Na+ 120mmol/L，血浆渗透压 230mOsm/L，红细 胞比容 32%。 2. Edema interstitial fluid fluid in the body cavities hydrops fluid in the cells cellular edema (1) pathogenesis 1)imbalance of exchange between intra- and extra - body fluid (retention of water and sodium) basic mechanism: glomerular-tubular imbalance GFR acute glomerulonephritis heart failure reabsorption of proximal tubule sympathetic nerve filtration fraction ANP reabsorption of water and sodium reabsorption of distal tubule ADH , aldosterone redistribution of renal blood flow sympathetic nerves and renin 2) imbalance of exchange between intra- and extra-vascu