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RI LON THNG BNG TOAN KIMBS CKII PHM TH NGC THO I CNG: pH : ch s bnh thng: pH: 7,35- 7,45 Bao gi cng nn bt u nh gi tnh trng toan kim bng vic xem pH. Thng s ny cho bit ton cnh ca thng bng toan kim, quyt nh cho vic ch nh iu tr triu chng PaCO2: ch s bnh thng: PaCO2: 35- 45mmHg c nh gi ngay tip sau nh gi pH. Thng s ny c my o trc tip. HCO3: ch s bnh thng: HCO3: 22- 26 mEq/L Thng s ny ch c tnh ton gin tip NHN BIT RI LON TOAN KIM K thut phn tch ri lon toan kim da vo phn tch kh mu ng mch Trnh t phn tch: nh gi pH, PaCO2, HCO3. Da vo pH v PaCO2 c th phn chia ri lon toan kim thnh cc loi chnh sau: pH PaCO2 PaCO2 PaCO2 Kim chuyn ha Toan h hp Kim h hp pH RL toan- kim hn hp Bnh thng RL toan- kim hn hp pH Toan h hp Toan chuyn ha Toan chuyn ha

Khi pH thay i cng chiu vi PaCO2 hoc khi c thay i pH m khng c thay i PaCO2 th l ri lon chuyn ha. Khi pH thay i ngc chiu vi PaCO2 th l mt ri lon h hp

RI LON THNG BNG TOAN KIM I. NHIM TOAN ( pH ) 1. Toan h hp: ( PaCO2 ) a. Chn on. Cho rng pH bnh thng l 7,40 v PaCO2 bnh thng l 40mmHg, c th thit lp: pH Y= PaCO2 = PaCO2 bnh nhn PaCO2 bnh thng pH bnh nhn pH bnh thng

Nu Y = 0,008 th y l toan h hp cp

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Nu Y = 0,003 th y l toan h hp mn Nu Y = 0,004- 0,008 th y l t cp toan h hp mn c ch trung tm h hp Ng c thuc an thn, thuc gy nghin Cc tn thng thn kinh trung ng, ph no Bnh l lng ngc G vo ct sng Bo ph Bnh l thn kinh c Nhc c Guillain- Barr St bi lit H kali nng Tc ng th trn Bnh l phi Bnh phi tc nghn mn tnh Suyn Ph phi cp Hi chng nguy ngp h hp cp

b. Nguyn nhn:

c. X tr Xc nh tng quan gia PaCO2 v pH bit toan h hp cp hay mn iu tr toan h hp cp ch yu l ci thin thng kh v gii quyt bnh nguyn nhn

2. Toan chuyn ha ( khng c PaCO2 ) a. Chn on C th d on mc gim PaCO2 b tr cho gim HCO3 , theo cng thc : X ( PaCO2 d on ) = 1,5 ( HCO3 ) + 8 ( 2 ) mEq/L Nu PaCO2 = X th y l toan chuyn ha c b tr. Nu PaCO2 > X, trong trng hp ny c km mt nhim toan h hp phi hp Nu PaCO2 < X, trng hp ny nn c l c mt nhim kim h hp phi hp.

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b. Mt s xt nghim h tr chn on trong nhim toan chuyn ha: Khong trng anion ( anion gap ): y l sai bit gia tng s ion m khng o c v tng s ion dng khng o c Tr s anion gap = UA UC = ( Na+ K ) ( Cl + HCO3 ) Tr s bnh thng 16 mEq/L 2 ( cng thc c K ) v 12 mEq/L 2 (cng thc khng c K) Gip nh hng nhim toan chuyn ha thnh 2 c ch chnh: nhim acid c nh c khong trng anion tng (ngoi tr nhim HCl) v mt HCO3 c khong trng anion bnh thng . -

anion gap / bicarbonate ( AG / HCO3 )Gip xc nh thm mt c ch th hai gy nhim toan chuyn ha (c khong trng anion bnh thng) hoc mt tnh trng nhim kim chuyn ha cng hin din . * AG / HCO3 = 1 (trong nhim toan chuyn ha do tng acid c nh) * AG / HCO3 < 1, s gim bicarbonate khng th gii thch n thun bng c ch nhim acid c nh, nh vy phi c thm mt nguyn nhn chuyn ha khc gy gim bicarbonate cng hin din (nhim toan chuyn ha do mt HCO3) * AG / HCO3 > 1 , c nguyn nhn chuyn ha khc cng hin din gi cho HCO3 khng gim nhiu mc d bnh nhn b nhim acid c nh (nhim kim chuyn ha) .

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Khong trng anion niu: * Gip phn bit toan chuyn ha c khong trng anion bnh thng, tc mt HCO3 qua ng thn hay ng tiu ha

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* Toan chuyn ha, thn p ng tng bi tit NH4+ (khng bnh l ti thn , mt HCO3 qua ng tiu ha)., nu NH4 khng gia tng thch hp hoc gim th mt HCO3 c ngun gc ti thn * Khong trng anion niu = UA UC = Na + K _ Cl , bi v NH4+ ch yu c bi tit di dng kt hp vi Cl- nn : tr s m: mt bicarbonate qua ng tiu ha, km chlor niu tng; tr s bng khng hoc dng gi mt bicarbonate qua thn (bnh toan ha ng thn) c. Nguyn nhn v x tr: Toan chuyn ha c khong trng anion cao: Nhim ctone: do tiu ng, ung ru v nhn i. Nhim ctone trn bnh nhn tiu ng: x tr quan trng nht l s dng insulin, b dch. Ung ru thng ch gy nhim ctone nu c km theo nn i , suy dinh dng v gim th tch dch ngoi bo. Nhim acid lactic : do thiu oxy m (sc, nhi mu mc treo), tng chuyn ha m (co git) v mt s nguyn nhn khc nh bnh l c tnh, h ng mu. iu tr nhim toan acid lactic nn hng ti x tr nguyn nhn Suy thn: thng ch gy toan chuyn ha khi lc cu thn gim < 20- 30 ml/ pht. Ng c methanol, paraldehyte, salicylate: cc bin php iu tr ch yu trong ng c salicylate gm tng bi niu, kim ha nc tiu, chy thn nhn to. Toan chuyn ha c khong trng anion bnh thng: y l trng hp toan chuyn ha do mt bicarbonate Da vo khong trng anion niu c th chn on mt bicarbonate qua thn hay tiu ha. Nguyn nhn mt bicarbonate qua thn: bnh vim ng thn m k, bnh t min, bnh toan ha ng thn; Mt bicrbonate qua ng tiu ha: tiu chy, dn lu, d mt, ty. iu tr nn gii quyt hng ti nguyn nhn S dng bicarbonate trong toan chuyn ha: Trong trng hp toan chuyn ha do c ch mt bicarbonate th nn cho bicarbonate Tnh lng bicarbonate thiu ht theo cng thc = 0,5 cn nng ( 24 [ HCO3] ) Lng bicarbonate ny nn chia ra b nhiu ln, cn th li pH mu nh gi p ng iu tr. La chn nng dung dch bicarbonate ty thuc vo p sut thm thu mu. Theo di cc bin chng ca truyn bicarbonate gm: ph phi, h kali v h canxi mu

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II NHIM KIM ( pH ) 1. Kim h hp: ( PaCO2 ): Chn on : Cho rng pH bnh thng l 7,40 v PaCO2 bnh thng l 40mmHg , c th thit lp: pH Y= PaCO2 = PaCO2 bnh nhn PaCO2 bnh thng pH bnh nhn pH bnh thng

Nu Y = 0,008 th y l kim h hp cp Nu Y = 0,003 th y l kim h hp mn Nu Y = 0,003- 0,008 th y l t cp ca kim h hp mn Thiu oxy m: bnh phi, thiu mu nng Kch thch trung tm h hp au n , lo lng Bnh l thn kinh, nhim trng, u bu St Nhim trng huyt Thuc : salicylate, catecholamine Cng gip

Nguyn nhn:

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Bnh gan Bnh phi Vim phi Nhi mu phi Ph phi Trn kh mng phi Th my iu tr : Trn phng din iu tr th nguyn nhn cn xc nh ca kim h hp l thiu oxy m Ni chung khng cn iu chnh kim chuyn ha v iu tr nn hng ti gii quyt nguyn nhn Trong trng hp nng c th cho bnh nhn th li qua ti giy hoc dng thuc an thn 2. Kim chuyn ha ( Khng gim PaCO2 ) Chn on : X ( PaCO2 d on ) = 0,7 ( HCO3 ) + 20 ( 1,5 ) mEq/L. Nh vy khi em so snh X vi PaCO2 thc s ca bnh nhn, th s c 3 kh nng: Nu PaCO2 = X th y l kim chuyn ha c b tr Nu PaCO2 < X: trong trng hp ny c km mt nhim kim h hp phi hp. Nu PaCO2 > X: trong trng hp ny c l c km mt nhim toan h hp phi hp.

Nguyn nhn v x tr: 6

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C hai loi: nhim kim chuyn ha c chlor niu thp < 10- 20 mEq/L v nhim kim chuyn ha c chlor niu bnh thng. Kim chuyn ha c chlor niu thp : do gim th tch dch ngoi bo, mt acid HCl qua ng tiu ha, dng thuc li tiu. iu tr: b dch, thuc khng H2 hoc Omeprazone . Kim chuyn ha c chlor niu bnh thng: do h kali mu nng, cng aldosterone tin pht..Nu do gim kali mu th b kali, cn do cng aldosterone th dng spironolactone.

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Ni chung x tr kim chuyn ha hng ti gii quyt nguyn nhn. Trng hp nng, c th iu tr triu chng: truyn acid HCl , chy thn nhn to, gim thng kh kim sot.

KT LUN : Ngoi cc s n gin ny th c th da vo bng d on p ng b tr gia PaCO2 v HCO3 phn tch ri lon toan kim. Tuy nhin thm khm lm sng v nht l hi bnh s l iu khng th thiu c. Vic x tr ri lon toan kim bn cnh cc bin php iu tr triu chng th lun nn hng ti gii quyt nguyn nhn TI LIU THAM KHO 1. Figge J, Jabor A, Kazda A, et al. Anion gap and hypoalbunemia . Crit Care Med 2007; 26 (11) : 1807- 1810 2. Black RM. Metabolic acidosis and metabolic alkalosis. Intensive care medicine 2007 (3th). Little Brown and Company. Chap 80: 984- 999 3. Ewald GA, McKenzie CR (ed)- Manual of medical therapeutics 30 th ,2009- Little & Brown 4. Malley WJ (ed). Clinical blood gases: 2002 5. Paul L Marino (ed) 3ed 2007- Algorithms for Acid- Base Interpretations- The ICU Book.

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28-Roi Loan Thang Bang Kiem Toan