Intravenous Fluid & Acidbase Balance for Surgical. Patients

Transcription

1 Intravenus Fluid & Acidbase Balance fr Surgical Patients Dr. Abdullah F Alshehri, MBBS, FRCSC, MSc Assistant prfessr, cnsultant pediatric surgen

2 What is Intravenus fluid?

3 Why is understanding IV fluid imprtant fr yu? The cmmnest rder prescribed in every hspital Needed fr almst every patient Always dne by the junir dctrs Cnsidered basic medical knwledge Everyne expect yu t knw it Incrrect prescriptin can be very dangerus Usually the fluid is available in the flr, s n pharmacist t duble check yur rders

4 Objectives Review basics f fluid & electrlytes physilgy in surgical patient Be familiar with different types f cmmnly used IV fluids Be able t calculate fluid & electrlytes requirement fr a patient and chse the apprpriate type f fluid Understand different types f electrlytes and fluid disturbance and its management Understand basics f acid-base physilgy and cmmn disrders

5 What are we discussing? 1. Intravenus fluids 2. Electrlytes 3. Acid-base balance

6 Water & electrlyte balance

7 Electrlyte cmpsitin f the bdy cmpartments

8 Distributin f fluid between intravascular and extravascular spaces depends n: Onctic pressure: albumin Endthelial permeability Aldstern & ADH-> Na & water retentin ANP -> Na & water excretin

9 Nrmal water lss

10 Nrmal daily fluid requirement (maintenance) 3 methds: 1. 4,2,1 frmula (mst cmmnly used)- ml/hr ml/kg/day (rugh estimate) 3. Weight + 40 ml/hr

11 Nrmal daily fluid requirement (maintenance) Methd 1: 4,2,1 frmula: based n bdy weight First 10 kg 4ml/kg/hr Next 10kg 2ml/kg/hr Each kg ver 20kg 1ml/kg /hr Example: Calculate the fluid requirement f a 100kg- man First 10 kg: 4x10= 40 Next 10kg: 2x10= 20 Last 80kg: 1x80= 80 Ttal: = 140ml/hr =3360ml/day

12 Nrmal daily fluid requirement (maintenance) Methd 2: 35 x 100= 3500 ml/kg/day = 145 ml/hr Methd 3: = 140 ml/hr

13 Assessing fluid/electrlytes in surgical patient Fever: -200ml/day fr each 1 degree Celsius Sweating: Up t -1L/hr Na>K lss

14 Assessing fluid/electrlytes in surgical patient Effect f Surgery: Stress respnse: Increased ADH, Aldstern >> urinary retentin + liguria Third space lss: Surgical manipulatin resulting in fluid sequestratin within the tissues (extravascular) Lss f fluid frm gastrintestinal tract: Bwel bstructin: n fluid absrptin Paralytic ileus: lss f GI functin after abdminal surgery fr 2-3 days Nasgastric tube fluid lss Stma r intestinal fistula fluid lss Diarrhea

15 Vlume + Electrlytes in GI fluid

16 IVF administratin Befre rdering IVF, yu shuld ask yurself: Hw much maintenance fluid des the patient need? 4,2,1 frmula Is there any fluid deficit I shuld add? Dehydrated patient! What fluid cmpartment I want t replace? Des the patient have any electrlytes disturbance? Na, K, Cl What is the type f fluid apprpriate fr my patient? Crystallid vs. cllid Des the patient need blus r cntinuus fluid?

17 Types f IV fluids Crystallids: Dextrse slutins NaCl slutins 0.9% nrmal saline ½ nrmal saline ¼ nrmal saline Hypertnic saline Ri ger s Lactate Hart a s sluti Cllids: Natural: albumin Synthetic: Gelatins, Hetastarch, Dextran

18 Crystallids Dextrse fluids: Different cncentratin: 5%, 10%, 20%, 50% 5% Dextrse cntain 5gm f glucse in every 100ml f water (50g/L) N electrlytes After administratin: 60% will g t intarcellular cmpartment 30% will g t extracellular cmpartment (80% Interstitial, 20% intravascular) Nt gd ptin fr fluid resuscitatin > 12% dextrse can nt be administered in peripheral vein (central venus line is needed) Never blus any dextrse cntaining slutin!!! (hyptnic) Which patient culd benefit frm this type f fluid?

19 Crystallids Electrlytes slutins: NaCl slutins (0.9% NS, ½ NS, ¼ NS) LR sluti Hart a s Hyptnic fluid: 1/2NS, ¼ NS Never blus a hyptnic slutin!!! Istnic fluids: 0.9%NS, LR (similar smlality t plasma) 25% will remain in the IVC 75% will g t EVC Best ptin fr fluid resuscitatin e.g. dehydratin, trauma, periperative Can be given as blus r cntinuus fluid Hypertnic slutins E.g. 3% NS Rarely used ( fr cerebral edema and management f brain injuries)

20 Cllids Examples: Natural: albumin 5%, 20% Synthetic: Gelatins, Hetastarch, Dextran Cntain prtein particles that exert nctic pressure and cause fluid t remain in the intravascular cmpartment fr ~ 6-24hrs Disadvantages f cllid: Nt widely available Take time t prepare and administer Albumin is a bld prduct (stred in the bld bank) Expensive Can cause allergic reactins, pruritus, cagulpathy

21 Cmpsitin f IV fluid

22 Cmpsitin f IV fluid

23 Is cllid better than crystallid fr fluid resuscitatin?

24 Which ges t which?

25 Electrlyte requirement Adult: Na: 1-2 meq/kg/day K: 1mEq/kg/day Cl 1-2mEq/kg/day Children: Na: 2-3 meq/kg/day K: 2-3 meq/kg/day Cl: 2-3 meq/kg/day

26 Calculating fluid requirement fr 70kg adult Assuming nrmal, well hydrated patient, nrmal electrlytes Vlume: 4,2,1 frmula (4x10) + (2x10) + (1x50) = 110 ml/hr 2640 ml/day Electrlytes: Na: 1-2 x 70= meq/day K: 1x70= 70 meq/day Type f fluid: D5 1/2 NS is the best slutin Why: If yu give 0.9NS nly = 400mEq/day f Na (t much) If yu give ½ NS nly = 200mEq/day f Na (acceptable) But 1/2NS is hyptnic (150mOsml/L) >> add D5 will raise smlality t 400 mosm (acceptable) als will prevent muscle catablism Yu shuld add 20mEq KCL/L t the slutin = 52 meq/day Avid Dextrse in diabetic patient (use ½ NS)

27 Yur final rder: Start IV fluid D51/2 NS + 20mEq 110ml/hr

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29 Water depletin/ Dehydratin Very cmmn in surgical patients Usually water + Na Cmmnly caused by: Decreased intake Increased GI lss (diarrhea, vmiting, NGT lss, high stma utput)m;987 Signs f dehydratin: Decreases skin turgr Dry mucus membranes Tachycardia Oliguria <500ml/day (nrmal 0.5-1ml/kg/hr) Hyptensin Decreased level f cnsciusness Treatment: Rapid IV blus f istnic slutin (0.9% NS r LR) ml ver 30-60min Mnitr respnse t rehydratin

30 Water excess Due t excessive fluid administratin (especially hyptnic fluid e.g. Dextrse slutins Can cause hypnatremia (dilutinal) Water accumulate in ECC Difficult t detect clinically (edema, basal chest crackles, elevated JVP) Later stages >> tissue edema High risk patients: Cardiac failure Renal failure

31 Hypernatremia (Na >145mml/l) Causes Treatment Hypvlemic hypnatremia is treated with istnic saline Avid rapid lwering Na (cerebral edema, permanent brain damage)

32 Hypnatremia (Na <135 mml/l) Causes Treatment Depends f extracellular fluid vlume status: Nrmal r high: reduce water intake> Na will crrect Lw: istnic fluid administratin Avid rapid crrectin >> brain damage

33 Hyperkalemia K>5mml/l Can be life threatening

34 Hyperkalemia K>5mml/l

35 Hypkalemia K< 3mml/l Very cmmn in surgical patients Mst K is lst via kidneys Rx: Oral K IV K fr severe cases Avid K IV blus (arrhythmia)

36 Acid-base balance

37 Intrductin ph: measure f fluid acidity Nrmal plasma values: ph: PC2: mmhg HC3: Acidsis: ph <7.35 Can be respiratry r metablic Alkalsis: ph >7.45 Can be respiratry r metablic Arterial bld gas (ABG) is the methd t analyze acid-base status thrugh arterial bld sample frm the radial artery

38 ABG result

39 Hw t read bld gas?

40

41 Metablic Acidsis

42 Metablic alkalsis

43 Respiratry Acidsis

44 Respiratry alkalsis

45 THANK YOU REMEMBER: Frmula t calculate fluid requirement Cmparing different types f fluid Identifying and managing dehydrated patient Cmpsitin f different intravenus slutins