Recommended
Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (20)
Similar to Acid base lecture (1)
Similar to Acid base lecture (1) (20)
Recently uploaded
Recently uploaded (20)
Acid base lecture (1)
- 3. It’s as simple as the HendersonHasselbalch Calculation…
- 5. Acid-Base is about 2 things: The patient’s pH & what is causing it
- 6. WHY DOES A PATIENT’S Acid-Base Status MATTER?
- 8. So let’s learn how to do what we do BETTER.
- 9. What is pH?
- 10. pH is the potential for Hydrogen pH = Hydrogen = H+ So, when you think pH, think H+
- 12. pH < 7.35 = Acidosis
- 14. pH > 7.45 = Alkalosis
- 16. So, pH < 7.35 = acidosis pH > 7.45 = alkalosis
- 17. Now the money question: What is causing the imbalance?
- 19. Four Categories of Disturbance Metabolic Metabolic Acidosis Metabolic Alkalosis Alkalosis Respiratory Respiratory Acidosis Respiratory Alkalosis
- 20. Metabolic The most basic way to determine metabolic disturbance is to look at a patient’s bicarb level. Metabolic = HCO3
- 22. Metabolic HCO3 is a base. So, if a patient’s HCO3- is low, what is their acid-base disturbance?
- 23. Metabolic Acidosis The patient’s body has a deficit of bicarbonate. -< HCO3 22
- 25. Causes of Metabolic Acidosis • • • • • • • Ketones (Diabetic, Alcoholic, Starving) Uremia Lactic Acidosis Glycols Salicylates Rhabdomyolysis Various Toxins
- 26. Metabolic Alkalosis The patient’s body has an excess of bicarbonate. -> HCO3 26
- 27. Causes of Metabolic Alkalosis • • • • • • • Renal Failure Excessive Vomiting GI Suctioning Overuse of Antacids (Calcium Carbonate) Diuretics, Laxative Abuse Hypo-kalemia, calcemia, chloremia Hyperaldosteronism
- 29. Respiratory The most basic way to determine respiratory disturbance is to look at a patient’s PaCO2. Respiratory = PaCO2
- 31. Respiratory CO2 is an acid. So, if a patient’s PaCO2 is high, what is their acid-base disturbance?
- 32. Respiratory Acidosis Respiratory acidosis is an excess of carbon dioxide. PaCO2 > 45
- 34. Causes of Respiratory Acidosis Practically every Respiratory Disorder known in Medicine Anything that causes decreased ventilation. - COPD, Asthma, CHF, Pneumonia, Aspiration, Flail Chest, Pneumothorax, Pleural Effusion, etc… Anything that causes decreased respiratory rate. - Narcotics, Sedatives, Brainstem Injury, Cardiac Arrest, etc.
- 35. Respiratory Alkalosis Respiratory alkalosis is a deficit of carbon dioxide. PaCO2 < 35
- 37. Causes of Respiratory Alkalosis Anything that can cause increased minute volume. Pulmonary Embolism Alcohol Fever Head Trauma CVA’s Pneumonia Hyperthyroidism Exercise Anxiety Overaggressive Mechanical Ventilation
- 38. Four Categories of Disturbance Metabolic Acidosis Respiratory Acidosis Metabolic Respiratory Alkalosis Alkalosis
- 39. To Sum it Up: HCO3- = Metabolic Acidosis - HCO3 = Metabolic Alkalosis PaCO2 = Respiratory Acidosis PaCO2 = Respiratory Alkalosis
- 41. Simple Disorders: Case 1 65 y/o Female Carbon Monoxide Poisoning pH: 7.20 torr HCO3: 12 mEq/L PaCO2: 38 torr What is her acid-base status?
- 42. Simple Disorders: Case 2 32 y/o Male Acute Asthma pH: 7.08 torr HCO3: 26 mEq/L PaCO2: 60 torr What is his acid-base status?
- 43. Simple Disorders: Case 3 21 y/o Male Suspected Pulmonary Embolism pH: 7.48 torr HCO3: 22 mEq/L PaCO2: 20 torr What is his acid-base status?
- 44. Simple Disorders: Case 4 28 y/o Pregnant Female Excessive Vomiting X4 days pH: 7.58 torr HCO3: 32 mEq/L PaCO2: 35 torr What is her acid-base status?
- 45. well, that was easy.
- 46. Well, we aren’t quite there yet…
- 47. Keep Going
- 48. Let’s talk about exceptions. Sometimes a pH is normal, but there is still a disturbance. Sometimes there is more than one disorder at play.
- 50. The Body STRIVES for a pH of about 7.40
- 52. Buffer System • Activates in Seconds • Fastest & First Line of Defense • The MOST important buffer system is the bicarbonate-carbonic acid system. • Hemoglobin and Oxyhemoglobin, Protein, and Phosphate Buffer Pairs
- 53. TENACITY
- 54. Respiratory System • Activates in Minutes to Hours • Second Defense to Activate • H+ concentration stimulates breathing center
- 56. Renal System • Activates in Days • Works by conserving or excreting H+ and HCO3• Strongest mechanism for control.
- 57. When the body uses these systems to attempt to maintain a pH that is NORMAL, this is called COMPENSATION
- 58. Example: Pt has Respiratory Acidosis Buffer System increases HCO3- in Blood Increase in pH
- 59. Example: Pt has Metabolic Acidosis Increases Respiratory Rate Decreases CO2 Increase in pH
- 60. Compensation If changes in pH don’t normalize, the disturbance is called Partially Compensated If changes in pH normalize, it is called Fully Compensated
- 61. Compensation: pH normal = Fully Compensated pH abnormal = Partially Compensated
- 63. Compensated Disorders: Case 1 65 y/o Female COPD Exacerbation pH: 7.35 torr HCO3: 18 mEq/L PaCO2: 60 torr What is her acid-base status?
- 64. Compensated Disorders: Case 2 18 y/o Female Type I Diabetic Patient pH: 7.30 torr HCO3: 18 mEq/L PaCO2: 24 torr What is her acid-base status?
- 65. Compensated Disorders: Case 3 18 y/o Male Traumatic Brain Injury pH: 7.45 torr HCO3: 18 mEq/L PaCO2: 22 torr What is his acid-base status?
- 67. Extra Bad Mixed Disorders Sometimes you have two independent disorders that drive the pH in the same direction. This is extra BAD. Example: COPD patient in Shock (Respiratory and Metabolic Acidosis)
- 70. Summary
- 71. Summary • Determine the pH
- 72. Summary • Determine the pH • Determine the category of disorder
- 73. Summary • Determine the pH • Determine the category of disorder • Is it a mixed disorder?
- 74. Summary • • • • Determine the pH Determine the category of disorder Is it a mixed disorder? Is it fully or partially compensated?
- 75. the patient you have, ot the one you wish you had.