Terms in this set (22)
35-45 mmHg : the pressure of dissolved CO2 in the blood. Compensation: 40
80-100 mmHg: the pressure of dissolved oxygen in the blood
22-26 mEq/L Compensation: 24
>95%. The % of O2 that Hg is carried.
pH/pCO2/pO2/HCO3/O2 saturation. Alkalosis b/c greater than 7.45. Respiratory b/c pCO2 (acidic content) is less than normal contributing to higher pH.
Evaluation of Acid Base Disorder (to compensation)
Step 1: pH- acidosis or alkalosis Step 2: primary disorder: metabolic vs. respiratory. Step 3:COMPENSATION using charge of expected compensation, add it to the average values or either HCO3 or pCO2 using chart.
Step 4: Anion gap: Na- Cl - HCO3 normal is 12. Increase AG: metabolic acidosis Decrease AG: hypoalbuminuria Step 5: Excess gap: the amount of HCO3 that has been lost d/t buffering of unmeasured cations Excess Gap= Calculated AG - normal AG (consider HCO3 equivalent and add to patient HCO3) if it's high (>26) metabolic alkalosis If it's lower than (<22) non anion gap metabolic acidosis (anion gap -end)
Step 4: Anion gap: Na- Cl - HCO3 normal is 12. Increase AG: metabolic acidosis Decrease AG: hypoalbuminuria Step 5: Excess gap: the amount of HCO3 that has been lost d/t buffering of unmeasured cations Excess Gap= Calculated AG - normal AG (consider HCO3 equivalent and add to patient HCO3) if it's high (>26)= metabolic alkalosis If it's lower than (<22) =non anion gap metabolic acidosis
Metabolic acidosis general
Metabolic acidosis • if calculated AG >12 or if Excess gap +HCO3 is greater than 26= non anion gap metabolic acidosis • Compensation: respiratory hyperventilation is get rid of high pCO2 and to increase pH by breathing out the CO2
Metabolic acidosis; MUDPIES
Methanol Uremic renal failure Diabetic/alcoholic ketoacidosis Paraldehyde Ischemia (ie cause by lactic acidosis by medications) Ethylene glycol Salicylate toxity
NON-ANION GAP METABOLIC ACIDOSIS (EXCESS GAP +HCO3 <22)
GI loss Renal tubular acidosis Lead poisoning Drugs: Carbonic anhydrase inhibitors, amphotericin B, cholestyramine, Li
Use to neutralizes SEVERE metabolic acidosis (pH<7.1 with CV sx) . Do NOT CORRECT MORE THAN ½ OF DEFICIT INITALLY (to prevent overcorrection). STOP ADMIN once pH>7.2 .
Use to for metabolic acidosis through its amine moiety to buffer acid. Limited use due to HoGlycemia, HyK,Respiratory depression, extravasation.
Tx for Metabolic acidosis
NaHCO3 and THAM. (sodium bicarbonate and tromethamine)
Causes of Metabolic alkalosis (base on Cl urine < 10 mEq/L )
NASOGASTRIC SUCTIONING,severe vomiting, Chloride-responsive. Response to Normal saline treatment
Causes of Metabolic alkalosis (Cl urine >10 mEq/L)
DIURETICS,mineralcorticoid excess (aldosterone inducing dieresis), HoK, Chloride UNRESPONSIVE except for diuretic induced alkalosis
Tx of Metabolic Alkalosis
If chloride responsive Cl< 10 mEq/L: use Normal saline. If losing gastric juice: PPI or H2 - To increase HCO3 EXCRETION: acetazolamide (diuretic- unless renal failure) If K/Cl low: KCL supplementation Severe alkalosis: Central line HCl , 2nd line: NH4Cl, ArgHCl
Pearl or general tx guideline of Met. Alkalosis
If Cl urine >10, stop or reduce diuretic, Change to K sparing diuretic Change C.Steroid use to little mineralocorticoid activity ie predisone
Causes of Respiratory Acidosis ((these people probably can't breath out well)
CNS: tumor or infection or drugs Causinghypoverntilation resulting in an increase in pCO2. MECHANICAL: airway obstruction.LUNGS: loss of gas exchange area in severe pneumonia, emphysema, edema. NEUROMUX: spinal injury or muscular dystrophy. (loss of contraction/relaxation of lungs or accessory process)
Treatment of Repiratory acidosis
1. O2 supplementation 2. No NaHCO3 because breakdown can increase pCO2 content and exacerbate acidosis (unlike with Metabolic acidosis where you DO give NaHCO3)
Cause of Respiratory alkalosis (these patients are probably SOB, hyper, and panicky)
PSCYH: anxiety, panic. PULM:pulmonary embolism, edema, sepsis. DRUGS:nicotine, salicylate, methylxanthines, catecholamine.
Tx of Respiratory aLKalosis
Treat underlying cause. SEDATION. HYPOVENTILATION