外科学课件：新水电平衡

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1、Fluid and Electrolyte Management of the Surgical PatientReferences:克氏外科学（第15版）Maxwell,M.H.Etal:Clinical disorders of fluid and electrolyte metabolism 4th ed.New York,McGraw-Hill,1987.SCHWARTZS PRINCIPLES OF SURGERY-8th Ed.(2005)体现在各个章节疾病中 原发和继发 联系疾病的发病发展机理 基础的基础(最基本的内环境平衡)上课讲的少,自学的不是不重要!美国没有教课书,但最后要

2、求比较严!第一节 概述：Total body water 50%-70%of total body weight deuteriun oxide or tritiated water:60%for male adult and 50%for female adult,both normal variation 15%.(lean body mass and age)52%and 47%with elder and 75%-80%for newborn infants,at 1 year of age,65%70kg Man 3500cc Plasma(5%)10500cc Interstiti

3、al fluid (15%)Total Extracellular volume 20%28000cc Total intracellular volume 40%Interstitial fluid:Functioning components(90%)Nonfunctioning components(10%)connective tissue water and transcellular water,which includes cerebrospinal and joint fluids.154mEq/L 154mEq/L cations anionsNa+142 K+4Ca+5Mg

4、+3CL_ 103HCO3_ 27SO4-3PO4-OrganicAcids 5Protein 16 Plasma 153mEq/L 153mEq/L cations anionsNa+144 K+4Ca+3Mg+2CL_ 114HCO3_ 30SO4-3PO4-OrganicAcids 5Protein 1 Interstitial fluid 200mEq/L 200mEq/L cations anionsK+150 Mg+40Na+10SO4-150HPO4-HCO3-10Protein 40 Intracellular fluid Osmotic PressureThe physiol

5、ogic and chemical activity of electrolytes depends on the number of particles(present per unit volume(moles or millimoles per liter),the number of electrical charges per unit volume(equivalents or milliequvalents per liter),and the number of osmoles or milliosmoles per liter)A Mole=the molecular wei

6、ght of that substance in grams Eg:a mole of NaCl:58 grams(Na,23;Cl,35)An Equivalent of an ion=its atomic weight expressed in grams divided by the valence.Eg:Ca+1 millimole equals 2 milliequivalents Osmole refers to the actual number of osmotically active particals present in solution.1mmol NaCl,2mOs

7、m;1mmol Na2SO4,3 mOs;1 mmol glucose,1mOsm.In each compartment the total number of osmotically active particles is 290 to 310 mOsm.The effective osmotic pressure depends on those substances that fail to pass through the pores of the semipermeable membrane.Such as sodium,glucose.The cell membranes are

8、 completely permeable to water.Any condition that alters the effective osmotic pressure in either compartment causes redistribution of water between the compartments.1体液平衡和渗透压的调节 神经-内分泌系统渗透压：下丘脑下丘脑-垂体后叶-抗利尿激素系统（敏感而弱）血容量：肾素-醛固酮系统（强）共同作用于肾共同作用于肾二.酸碱平衡的维持血液缓冲 HCO3-/H2CO3肺：CO2肾:排出固定酸、保留碱性物质 Case:男，42岁。柴

9、油烧伤60%，2-3度休克期平稳，伤后第3天行气管切开，四肢削痂生物敷料覆盖、并行悬浮床治疗术后4天：有一过性烦躁，嗜睡术后5天：昏迷，Na 158,Cl 119 血糖：704mg%BUN82,Cr3.36 进量 出量术后第1天 5250 4370术后第2天 5250 4670术后第3天 6560 3950术后第4天 5270 4800 结果：抢救抢救3天，死亡！天，死亡！每天最基本的生理需要量每天最基本的生理需要量0.9%氯化钠溶液氯化钠溶液500ml5-10%葡萄糖溶液葡萄糖溶液1500-2000ml10%氯化钾溶液氯化钾溶液30ml第二节 体液代谢的失调容量：等渗性体液的减少或增多浓度：

10、水分增加或减少，渗透压改变成分：钠以外的其他离子改变 先细胞外液，再细胞内液1水和钠的代谢紊乱（一）Isotonic dehydration (二)hypotonic dehydration (三)hypertonic dehydrationIsotonic dehydration病因：消化液急性丧失、体液丧失在软组织或感染区临床表现：一般症状；血容量不足症状（口渴不显）诊断：病史，临床表现 Hb 尿比重 血气分析治疗：病因治疗 补含钠的等渗液 见尿补钾（40ml/h）Quiz 4.About hypovolemic patient(isotonic dehydration)diagnosis

11、,which laboratory test is wrong?Urine sodium is a marker for Na avidity in the kidney.Urine Na+15 mEq is consistent with volume depletion,as is the fractional excretion of sodium(FeNa)1%.The latter can be calculated as(Urine Na Serum Cr)(Urine Cr Serum Na)100.Concomitant metabolic alkalosis may incr

12、ease urine Na excretion despite volume depletion due to obligate excretion of Na to accompany the bicarbonate anion.In such cases,a urine chloride of 20 mEq is often helpful to confirm volume contraction.Urine osmolality and serum bicarbonate levels may also be elevated.Hematocrit and serum albumin

13、may be decreased from hemoconcentration.Quiz 4.About hypovolemic patient(isotonic dehydration)diagnosis,which laboratory test is wrong?Urine sodium is a marker for Na avidity in the kidney.Urine Na+15 mEq is consistent with volume depletion,as is the fractional excretion of sodium(FeNa)1%.The latter

14、 can be calculated as(Urine Na Serum Cr)(Urine Cr Serum Na)100.Concomitant metabolic alkalosis may increase urine Na excretion despite volume depletion due to obligate excretion of Na to accompany the bicarbonate anion.In such cases,a urine chloride of 20 mEq is often helpful to confirm volume contr

15、action.Urine osmolality and serum bicarbonate levels may also be elevated.Hematocrit and serum albumin may be increased from hemoconcentration.DISORDERS OF WATER BALANCEHyponatremiaGENERAL PRINCIPLES Hyponatremia and hypernatremia are primarily disorders of water balance or water distribution.The bo

16、dy is designed to withstand both drought and deluge with adaptations to renal water handling and the thirst mechanism.A persistent abnormality in Na+thus requires both an initial challenge to water balance,as well as a disturbance of the adaptive response.Definition Hyponatremia is defined as a plas

17、ma Na+100 mOsm/L Hypovolemia The absence of conditions that stimulate ADH secretion,including volume contraction,nausea,adrenal dysfunction,and hypothyroidismQuiz 5.SIADH is diagnosed by the following except:Hypo-osmotic hyponatremia Urine osmolality 100 mOsm/L Euvolemia The absence of conditions th

18、at stimulate ADH secretion,including volume contraction,nausea,adrenal dysfunction,and hypothyroidismQuiz 6.About Acute symptomatic hyponatremia,following fluid administration should be considered except:The risks of correcting hyponatremia too rapidly are volume overload and the development of cent

19、ral pontine myelinolysis(CPM).CPM is thought to result from damage to neurons resulting from rapid osmotic shifts.In its most overt form,it is characterized by flaccid paralysis,dysarthria,and dysphagia,and in more subtle presentations,it can be confirmed by computed tomography(CT)scan or magnetic r

20、esonance imaging(MRI)of the brain.The risk of precipitating CPM is increased with correction of the Na+by 6 mEq/L in a 24-hour period.In patients with severe hyponatremia,in which an immediate rise in Na+is necessary,Na+should be corrected 1 to 2 mEq/L/hr for 3 to 4 hours.Quiz 6.About Acute symptoma

21、tic hyponatremia,following fluid administration should be considered except:The risks of correcting hyponatremia too rapidly are volume overload and the development of central pontine myelinolysis(CPM).CPM is thought to result from damage to neurons resulting from rapid osmotic shifts.In its most ov

22、ert form,it is characterized by flaccid paralysis,dysarthria,and dysphagia,and in more subtle presentations,it can be confirmed by computed tomography(CT)scan or magnetic resonance imaging(MRI)of the brain.The risk of precipitating CPM is increased with correction of the Na+by 12 mEq/L in a 24-hour

23、period.In patients with severe hyponatremia,in which an immediate rise in Na+is necessary,Na+should be corrected 1 to 2 mEq/L/hr for 3 to 4 hours.Quiz 7.About medication of hyponatremia,which is wrong?Loop diuretics promote urinary excretion of water by reducing the concentration gradient necessary

24、to reabsorb water in the distal nephron and impair the ability to excrete concentrated urine.Vasopressin antagonists are also being evaluated and may be helpful in both euvolemic(SIADH)and hypervolemic hyponatremia(particularly CHF).Lithium(锂)and demeclocycline(去甲氯四环素)interfere with the collecting t

25、ubules ability to respond to ADH,and are common used.Vasopressin antagonists promote a water diuresis and may be useful in the therapy of SIADH.As of yet,the only formulation approved in the United States is conivaptan,which is an IV preparation and thus not applicable to chronic outpatient manageme

26、nt of euvolemic hyponatremia.Quiz 7.About medication of hyponatremia,which is wrong?Loop diuretics promote urinary excretion of water by reducing the concentration gradient necessary to reabsorb water in the distal nephron and impair the ability to excrete concentrated urine.Vasopressin antagonists

27、are also being evaluated and may be helpful in both euvolemic(SIADH)and hypervolemic hyponatremia(particularly CHF).Lithium(锂)and demeclocycline(去甲氯四环素)interfere with the collecting tubules ability to respond to ADH,but are rarely used because of significant side effects.They should only be consider

28、ed in severe hyponatremia that is unresponsive to more conservative measures.Vasopressin antagonists promote a water diuresis and may be useful in the therapy of SIADH.As of yet,the only formulation approved in the United States is conivaptan,which is an IV preparation and thus not applicable to chr

29、onic outpatient management of euvolemic hyponatremia.适合高钠血症和低钠血症Na+=Na+i+K+i-Na+s TBW+1 Na+i and K+i are the sodium and potassium concentrations in the infused fluid and Na+s is the starting serum sodium(Intensive Care Med 1997;23:309).Because hypernatremia suggests a contraction in water content,TB

30、W is estimated by multiplying lean weight(kg)by 0.5 in men(rather than 0.6)and 0.4 in women/by 0.6 in men(and by 0.5 in women).in hyponatremia.Hypotonic dehydration 继发性或慢性Na+135mmol/L病因：1.2.3.4.临床表现：一般症状；血容量不足症状；神经症状诊断：病史，临床表现 尿比重(1.010)Hb 血气分 析 Na+135mmol/L治疗：病因治疗 补含钠的高渗液、纠酸 见尿补钾（40ml/h）Hypertonic

31、dehydration 原发性Na+150mmol/L病因：1.2.临床表现：口渴；一般症状；血容量不足症状、精神症状诊断：病史，临床表现 Hb 尿比重 血气分析 Na+150mmol/L治疗：病因治疗 补含钠的低渗液或补水 见尿补钾（40ml/h）所有治疗切记：公式作参考补丧失量的一半观察，复查实验室检查最重要补生理需要量，注意治疗过程中的继续丧失见尿补钾血容量不足时可先补胶体纠正酸中毒水中毒：自学二.体内钾的异常2%细胞外液 重要！3.5-5.5mmol/LHypokalemiaHyperkalemia 3K2Na,1HHypokalemia 原因:进少出多,移入胞内 临床表现:肌肉兴奋性

32、,伴随缺水缺钠时的症状被掩盖,碱中度的症状 治疗:逐步补充!Hyperkalemia 原因:进多出少,移出胞内 临床表现:肌肉兴奋性,治疗:1.停用 2.移入细胞 3.对抗心率失常 体内钙镁磷的异常 自学为主 要考试第三节 酸碱平衡的失调 代谢性酸中毒 代谢性碱中毒 呼吸性酸中毒 呼吸性碱中毒酸碱平衡公式代谢性酸中毒 阴离子间隙Na+-HCO3-CI-=10-15mmol/L主要指磷酸、乳酸和其他有机酸阴离子间隙正常：HCO3-丢失或盐酸增加阴离子间隙增加：有机酸增加如乳酸或硫酸、磷酸等潴留代谢性酸中毒 主要原因：碱性物质丢失过多 酸性物质过多 肾功能不全 代偿：呼吸 肾小管上皮细胞碳酸酐酶和谷氨酰胺酶活性增加，H+和NH3生存增加。NaHCO3再吸收增加代谢性酸中毒临床表现诊断治疗：不宜过早用碳酸氢钠 公式 副作用：碱中毒和低钙手足抽搐