Acid/Base Flashcards
What is the normal range for pH?
- 7.35-7.45 [<6.7 or >7.7 is BAD for life]
- <7.35 is acidosis & >7.45 is alkalosis
How do we know when an acid-base disorder affects a certain organ?
- Metabolic = Kidney [Lungs compensate]
- Respiratory = Lungs [Kidneys compensate]
What are the normal blood gas levels [arterial blood]?
- PaCO2 = 35-45 mmHg [“40”]
- HCO3 = 22-26 mEq/L [“24”]
- PaO2 = 95-100 mmHg
- SaO2 = >95%
What are some of the adverse consequences for Acidemia?
- Cardiovascular
- Metabolic
- CNS
- Other
What are some of the Cardiovascular Adverse Events for Acidemia?
- DECREASE Cardiac Output [heart isnt pumping]
- Impaired contractility
- INCREASE vascular resistance
- Arrhythmia [Related toward metabolic]
What are some of the Metabolic Adverse Events for Acidemia?
- Insulin Resistance
- INHIBTION of anaerobic glycolysis
- HYPERkalemia [cardio]
What are some of the CNS Adverse Events for Acidemia?
- Coma
- Altered mental status
What are some of the Other Adverse Events for Acidemia?
- Decreased respiratory muscle strength
- HYPERVENTATION
- SOB
- N/V
What are some adverse consequences for Alkalosis?
- Cardiovascular
- Metabolic
- CNS
- Other
What are some of the cardiovascular adverse events for Alkalosis?
- DECREASE blood flow
- Decreased anginal thershold
- Arrhythmia [related toward metabolic]
What are some of the Metabolic adverse events for alkalosis?
- DECREASE K, Ca, Mg
- Stimulation of Anaerobic glycolysis
What are some of the CNS adverse events for alkalosis?
- Lethargy, Delirium, Stupor, Seizures
What are some of the Other adverse events for Alkalosis?
- DECRASED respirations
What are the three [four-ish] standards mechanisms for acid-base regulation?
- Buffering
- Renal Regulation
- Ventilatory Regulation
- [Hepatic Regulation]
What is important to know about the buffering mechanisms?
- FIRST LINE defense
- Buffers: Bicarb, Phosphate, Proteins
What is important to know about Bicarb in the buffering mechanism?
- RAPID ONSET with intermediate capacity
- HCO3 has the largest conc. [CO2 is unlimited]
- Controlled by HCO3 & CO2 [kidneys & lungs]
What happens when there is acid added?
What does this mean?
- Large quantities of CO2 gets exhaled rapidly
What is important to know about Phosphate in the buffering mechanism?
- INTERMEDIATE ONSET and capacity
- Limited activity
- Ca/P in is the bone [must be broken down to get = bad to do]
What are the ways that the renal system regulation?
- Bicarb Reabsorption [reabsorb]
- Ammonium Excretion & Titratable Acidity [new]
Briefly describe what happens in the Bicarb Reabsorption pathway?
- HCO3 [lumen] combines with H [cell] making H2CO3
- H2CO3 splits into CO2 & H2O
- CO2 & H2O reabsorbs into cell to make H2CO3
- H2CO3 makes HCO3, absorbing to blood stream
Where does the Bicarb Reabsorption Pathway take place?
- Proximal Tubule [85-90%]
- Filters 4000-4500 mEq
What is important to know about the Carbonic Anhydrase Inhibitors in the Bicarb Reabsorption Pathway?
- It blocks the inhibition of H2CO3 breakdown; decreasing HCO3
Briefly describe what happens in the Bicarb generation pathway [ammonium & titrable]?
- Ammonium: H combines NH3 = NH4; HCO3 [cell] reabsorbs into the blood stream [300 mEq/d]
- Titratable: H combines HPO4 = H2PO4; HCO3 [cell] reabsorbs into the blood stream [40 mEq/d]
Where does the Bicarb Generation Pathway take place?
- Distal Tubule
What is important to know about the Ventilatory Regulation ?
- RAPID ONSET and LARGE CAPACITY
- Chemoreceptors detect increase in PaCO2 = increased respirations [blowing off CO2]
What is important to know about the Hepatic Regulation?
- NEW maybe in times of acidosis the liver shutdown urea; pushing it towards alkalosis
What is teh compensation charateristics for acid-base disorders?
- Mac: D HCO3 = D PaCO2 [increased breathing]
- Malk: I HCO3 = I PaCO2 [decreased breathing]
- Rac: I PaCO2 = I HCO3 [Kidneys compensate]
- Ralk: D PaCO2 = D HCO3 [Kidneys compensate]
What are the acid-base disorders?-
- Metabolic Acidosis
- Metabolic Alkalosis
- Respiratory Acidosis
- Respiratory Alkalosis
What are the characteristics of Metabolic Acidosis?
- Low pH: < 7.35
- Low HCO3: <24
- Decreased PaCO3 [ventilation]
What are the two types of Metabolic Acidosis?
- Non-Anion Gap
- Anion Gap
What is the pathosiology of non-anion gap acidosis?
- GI Bicarb Loss
- Renal Bicarb Loss
- Reduced Renal H Excretion
What is important about GI Bicarb Loss in non-anion gap acidosis?
Side Effects?
- Diarrhea: very common cause [lose 5-10 L of fluids (1 L has 30-50 mEq of HCO3)]
- Fistulas - rich in bicarb [might lose HCO3]
What is important about Renal Bicarb Loss in Non-anion gap acidosis?
- Type II Renal Tubular Acidosis [Proximal]
- Reabsorption of HCO3 in reduced in Proximal causing a loss in Na & Fluids = hypokalemia
What is important about Reduced Renal H Excretion in non-anion gap acidosis?
- Type I RTA [Hypokalemia]: H cannot go into lumen = increase K excretion
- ## Type IV RTA [Hyperkalemia]: Decreased aldsterone = H retention; holding on to K= acidosis
What is the Pathophysiology of Anion Gap acidosis [MULEPAK]?
- M: Methanol Intoxication
- U: Uremia
- L: Lactic Acidosis
- E: Ethylene Glycol
- P: Paraldehyde Ingestion
- A: Aspirin
- K: Ketoacidosis
After finding out the anion gap, what is the next thing that you should do?
- Calculate the Delta Gap
- DG = patients anion gap [Na - (Cl + HCO3)] - Normal Anion Gap
- Delta Gap makes elevated HCO3 = Acidosis + Alkalosis
What are the causes fo anion gap metabolic acidosis?
- Lactic Acidosis [Most Common]
- Ketoacidosis
- Drug Interactions
What is the importance of lactic acidosis in anion gap metabolic acidosis?
-most common for Anion
- Lactate is normally aroind 1meq/l but in Lactic Acidosis it ~5mEq/l
What are the possible causes for Lactic Acidosis?
- Shock [making more of it]
- Drugs: [Ethanol, Warfarin, NRTIs (HIV meds), Propofol, Propylene Glycol]
- Seizures: makes a lot
- Leukemia
- Hepatic/Renal Failure
- Diabetes
What is more likely to cause Drug Intoxication in anion gap metabolic acidosis?
- Salicylates: increase respiration & increase acid [Respiratory Alkalosis & Metabolic Acidosis]
- Methanol
- Ethylene glycol
What are the symptoms of Lactic Acidosis?
- Kussmaul respiration [deep & rapid]
- Tachycardia
- HYPERkalemia
- Lethargy/coma
- N/V
What is the treatment for Lactic Acidosis?
- Treat underlying cause FIRST
- Acute Bicarb Therapy [<7.10-7.15; Hyperkalemia; use 12 mEq/L –> give 1/3 to 1/2; supplement K]
What are some of the hazard of Bicarb therapy?
- Overalkanization: reduce cerebral flow
- Hypernatremia
- Eletrolyte shifts [Potassium: acidosis K moves out; added bicarb will move MORE K out & Calcium: cardio issues]
What are the characteristics of Metabolic Alkalosis?
- High pH: > 7.45
- High HCO3
- Increased PaCO2 [shallow breathing]
What is the pathophysiology of Metabolic Alkalosis?
- Rise in HCO3 b/c of loss of acid in the GI
- Give too much Bicarb
- Losing Cl-
What are the two type of Metabolic Alkalosis?
- Saline Responsive Alkalosis [
- Saline Resistant Alkalosis [
What are the causes of Saline Responsive Metabolic Alkalosis?
- DIURETIC THERAPY [MOST COMMON]
- Vomiting & NG Suction
- Blood Transfusions
What is important to know about Diuretic Therapy in Saline Responsive Metabolic Alkalosis?
- MOST COMMON
- Furosemide, Toresemide, Bumetanide, HCTZ
- The excretion of NaCl stimulates aldosterone; increasing Na reabsorption and H & K secretion; H secretion = HCO3 reabsorption
What is important to know about Vomiting & NG suction in Saline Responsive Metabolic Alkalosis?
- 2nd MOST COMMON
- 1L/d is lost from vomiting = 200mEq of Cl [losing Cl = Increased HCO3] & 25-100mEq H
What is important to know about Blood transfusion in Saline Responsive Metabolic Alkalosis?
- Involves Lactated Ringers, HCO3, TPN…
- Citrate breaks down into HCO3
What are the causes of Saline Resistant Metabolic Alkalosis?
- NO drop in Cl
- Increased Mineralocorticoid Activity [H secretion = increased HCO3]
- HYPOkalemia [H secretion = increased HCO3]
- Renal Tubular Cl Wasting [increased aldosterone = same as the diuretics]
What are some of the symptoms for Saline Resistant Metabolic Alkalosis?
- Muscle Cramps, Weakness [decreased K]
- Mental Confusion, Coma, Seizures
- Arrhythmias
What is the treatment for Saline Responsive Metabolic Alkalosis?
- Give fluids [Na & Cl reabsorbed; increase K = decreased H; caution in HF]
- Carbonic Anhydrase Inhibitors [Decreased HCO3 reabsorption; not good in severe alkalosis]
- HCl Acid [for those with NA replacement or failure of therapies]
- Ammonium Cl
- Arginine Monohydrocholride [last line]
What is the treatment options for Saline Resistant Metabolic Alkalosis?
- CORRECT decreasing K
- Decrease mineralocorticoid dose
- Give spironolactone
What are the two Respiratory Disorders in Acid Base?
- Respiratory Acidosis
- Respiratory Alkalosis
What is the characteristics of Respiratory Acidosis?
- Low pH: <7.35
- Increased PaCO2
- Increased HCO3
What is the pathophysiology of Respiratory Acidosis?
- “something blocking the airway; CO2 cant escape”
- Airway Obstruction [Asthma, Foreign Body, Aspiration]
- Reduced stimulus of Respiration [OD, Apena, Trama]
- Heart or Lung Failure
- CNS issues
- Mechanical Vent
What are the symptoms of Respiratory Acidosis?
- Respiratory: SOB
- CNS: HA, drowsiness, coma, seizures
- CV: Tachycardia, Arrhythmias, HYPOtension
What is the treatment for Respiratory Acidosis?
- Mechanical Vent or Oxygen [Caution in COPD]
- Maybe Bicarb if pH is 7.10-7.15
What are the characteristics of Respiratory Alkalosis?
- High pH: <7.45
- Decreased PaCO2
- Decreased HCO3
What is the pathophyisology for Respiratory Alkalosis?
- “Too much breathing”
- Stimulation of respiration
- Mechanical Vent [work too hard]
- PE
- Salicylate Intoxication [could cause Metabolic Acidosis & Respiratory Alkalosis]
What are some of the symptoms for Respiratory Alkalosis?
- CNS: Lightheadedness, Confusion, Seizures
- decreased cerebral blood flow
- muslce cramps
- N/V
What are some treatment options for Respiratory Alkalosis?
- Ventilation
- Sedation [b/c they are breathing too much]
- Paralysis