Your SlideShare is downloading. ×
Interpretation of blood gases
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Interpretation of blood gases

438
views

Published on

presentation for interpretation of blood gases

presentation for interpretation of blood gases

Published in: Health & Medicine, Technology

2 Comments
7 Likes
Statistics
Notes
No Downloads
Views
Total Views
438
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
84
Comments
2
Likes
7
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. by dr M Osama Hussein
  • 2. Kidney fixes respiratory derangement, except if kidney malfunctioning occur (e.g. sepsis, dehydration, prematurity or renal pathology) Lung fixes metabolic derangement, except if lung malfunctioning occur (e.g. infection, ARDS, or any lung pathology ) Renal mechanism is slow, that’s why respiratory derangement is slowly fixed. While, respiratory mechanism is fast, that’s why metabolic derangement is rapidly fixed. Fixation ( compensation ) never brings acid-base balance to normal, but near normal )Hassel Bach equation: pH = 6.2 + log ( Bicarbonate / PaCO2 For simplification: pH = B/C by dr M Osama Hussein
  • 3. Compensation is an evidence of chronicity During compensation, bicarbonates & PaCO2 follow each other, so, both are changed & in the same direction. The one with the bigger magnitude of change, is the one who started the derangement ( the chronic element which is to be compensated, ).confirm with the resultant pH The one with the lesser magnitude of change, is the compensating .element Bicarbonates & PaCO2 serve the pH ( 2 servants & 1 lady ). Bicarbonates & base deficit are nearly the same in both arterial & . venous samples by dr M Osama Hussein
  • 4. : According to the equation B = pH C C = CO2 B= bicarbonate by dr M Osama Hussein
  • 5. NORMAL VALUES Arterialized Capillary & Arterial Samples Venous Samples PH 7.35 - 7.45 7.25 - 7.35 PO2 70 - 90 mmHg 60 - 80 mmHg PCO2 35 - 45 mmHg 45 - 45 mmHG Bicarbonates 18 - 25 meq/L Don't complete reading & interpretation of the result of the blood gas analysis when pH is within the normal range. by dr M Osama Hussein
  • 6. Derangement pH B&C Acute Affected Only one is affected Minimally affected (near normal) Both are affected, in the same direction, following each other. Highly affected Both are affected, in opposite directions, not following each other. Chronic Mixed Derangement pH Where is the error? H+ Metabolic Acidosis Lower than normal range BicarbonateH(B) Error in the Metabolite: Higher ions Respiratory Alkalosis Higher than the Respiratory gas: Lower H(C) Error in normal range PaCO2 ions by dr M Osama Hussein
  • 7. Acute ▼▼ B ACUTE DERANGEMENTS= ▼▼ pH Metabolic --------------Acidosis ◄► C Acute Respiratory Acidosis Acute Metabolic Alkalosis Acute Respiratory Alkalosis ◄► B --------------▲▲ C = ▼▼ pH ▲▲ B --------------◄► C pH= ◄► B --------------▼▼ C = ▲▲ ▲▲ pH pH is affected, Only B or C is affected In metabolic derangement: B goes with pH .In respiratory derangement: C goes the opposite direction by dr M Osama Hussein
  • 8. Compensated ACUTE CHRONIC (COMPENSATING) DERANGEMENTS ► RESULTANT DERANGEMENT by CHRONIC DERANGEMENT Chc. Met. Acidosis ▼▼▼B ----------- = ▼▼▼pH ◄►C . + Ac. Resp. Alkalosis + ◄►B ----------- = ▲▲pH ▼▼C ► + Ac. Met. Alkalosis ► ◄►B ----------- = ▼▼▼pH ▲▲▲C + ▲▲B ----------- = ▲▲pH ◄►C ► Chc. Met. Alkalosis + Ac. Resp. Acidosis ► ▲▲▲B ----------- = ▲▲▲pH ◄►C + ◄►B ----------- = ▼▼pH ▲▲C ► Chc. Resp. Alkalosis + Ac. Met. Acidosis ► + ▼▼B pH▼▼----------- = C ◄► Chc. Resp. Acidosis ◄►B pH▲▲▲----------- = C▼▼▼ by dr M Osama Hussein ► ▼▼▼B ----------- = ▼pH ▼▼C ? ▲▲B ----------- = ▼pH ▲▲▲C ? ▲▲▲B ----------- = ▲pH ▲▲C ? ▼▼B pH▲----------- = C ▼▼▼
  • 9. CHRONIC DERANGEMENT Chc. Met. Acidosis Compensated by ACUTE DERANGEMENT + Ac. Resp. Alkalosis ► RESULTANT ► ▼▼▼B ----------- = ▼pH ▼▼C ▲▲B ----------- = ▼pH ▲▲▲C ▼▼▼B ----------- = ▼▼▼pH ◄►C + ◄►B ----------- = ▲▲pH ▼▼C Chc. Resp. Acidosis + Ac. Met. Alkalosis + ▲▲B ----------- = ▲▲pH ◄►C ► + Ac. Resp. Acidosis ► ▲▲▲B ----------- = ▲▲▲pH ◄►C + ◄►B ----------- = ▼▼pH ▲▲C ► Chc. Resp. Alkalosis + Ac. Met. Acidosis ► + ▼▼B pH▼▼----------- = C ◄► ◄►B ----------- = ▼▼▼pH ▲▲▲C . Chc. Met. Alkalosis ◄►B pH▲▲▲----------- = C▼▼▼ by dr M Osama Hussein ► ? ▲▲▲B ----------- = ▲pH ▲▲C ? ▼▼B pH▲----------- = C ▼▼▼
  • 10. CHRONIC DERANGEMENT Chc. Met. Acidosis Compensated by ACUTE DERANGEMENT + Ac. Resp. Alkalosis ► RESULTANT ► ▼▼▼B ----------- = ▼pH ▼▼C ► ▲▲B ----------- = ▼pH ▲▲▲C ▲▲▲B ----------- = ▲pH ▲▲C ▼▼▼B ----------- = ▼▼▼pH ◄►C + ◄►B ----------- = ▲▲pH ▼▼C Chc. Resp. Acidosis + Ac. Met. Alkalosis ◄►B ----------- = ▼▼▼pH ▲▲▲C + ▲▲B ----------- = ▲▲pH ◄►C Chc. Met. Alkalosis + Ac. Resp. Acidosis ▲▲▲B ----------- = ▲▲▲pH ◄►C + ◄►B ----------- = ▼▼pH ▲▲C ► . + Ac. Met. Acidosis ► + ▼▼B pH▼▼----------- = C ◄► Chc. Resp. Alkalosis ◄►B pH▲▲▲----------- = C▼▼▼ by dr M Osama Hussein ► ? ▼▼B pH▲----------- = C ▼▼▼
  • 11. CHRONIC DERANGEMENT Chc. Met. Acidosis Compensated by ACUTE DERANGEMENT + Ac. Resp. Alkalosis ▼▼▼B ----------- = ▼▼▼pH ◄►C + ◄►B ----------- = ▲▲pH ▼▼C Chc. Resp. Acidosis + + ▲▲B ----------- = ▲▲pH ◄►C Chc. Met. Alkalosis + + ◄►B ----------- = ▼▼pH ▲▲C Chc. Resp. Alkalosis + + ► ▲▲B ----------- = ▼pH ▲▲▲C ► ▲▲▲B ----------- = ▲pH ▲▲C ► ▼▼B pH▲----------- = C ▼▼▼ Ac. Met. Acidosis ▼▼B pH▼▼----------- = C ◄► ► ▼▼▼B ----------- = ▼pH ▼▼C Ac. Resp. Acidosis ▲▲▲B ----------- = ▲▲▲pH ◄►C RESULTANT Ac. Met. Alkalosis ◄►B ----------- = ▼▼▼pH ▲▲▲C ► ◄►B pH▲▲▲----------- = C▼▼▼ ,pH is mildly affected (Both B & C are affected inby dr M Osama Hussein (following each other the same direction,
  • 12. MIXED DERANGEMENTS Metabolic Derangement plus Respiratory Derangement ► Resultant Metabolic Acidosis + Respiratory Acidosis ► Mixed Acidosis ▼▼B ----------- = ▼▼pH ◄►C + ◄►B ----------▲▲C Metabolic Alkalosis + Respiratory Alkalosis + ◄►B ----------▼▼C ▲▲B ----------- = ▲▲pH ◄►C = ▼▼pH ► ► = ▲▲pH ► ▼▼B ▼ ----------- = ▼ ▼ pH ▲▲ C ▼ Mixed Alkalosis ▲▲B ▲ ----------- = ▲▲ pH ▼▼C ▲ ,pH is markedly affected Both B & C are affected, but in 2 different directions (away (from each other by dr M Osama Hussein
  • 13. CORRECTION OF METABOLIC ACIDOSIS pH < 7.2 (7.25( Bicarb. < 15 meq/L BE > -10 meq/L Contraindicated when there is Hypercarbia CO2 wash can br induced by increasing RR either on ventilator, or applying few breaths by the Ambu bag. by dr M Osama Hussein
  • 14. Capillary blood gas (CBG) samples may be used in place of samples from arterial punctures or indwelling arterial catheters to estimate acid-base balance (pH) and adequacy of ventilation (PaCO2). by dr M Osama Hussein
  • 15. Capillary PO2 measurements are of little value in estimating arterial oxygenation. A puncture or small incision is made with a lancet or similar device into the cutaneous layer of the skin at a highly vascularized area (heel, finger, toe). by dr M Osama Hussein
  • 16. The lancet may be used freehand or as part of a device that limits puncture depth. To accelerate blood flow and reduce the difference between the arterial and venous gas pressures, the area is warmed prior to the puncture. As the blood flows freely from the puncture site, the sample is collected in a heparinized glass capillary tube. by dr M Osama Hussein
  • 17. ANION GAP  The anion gap refers to the concentration of unmeasured anions in blood. It represents anions other than chloride and bicarbonate that are required to electrically balance cations, such as sodium. Unmeasured anions include protein, phosphate, sulfate, and organic acids. by dr M Osama Hussein
  • 18. ANION GAP  Anion gap equation: ( [Na+]+[K+] ) - ( [Cl-]+[HCO3-] )  The most commonly used formula to measure the gap is ( [Na+] ) - ( [Cl-]+[HCO3-] ) by dr M Osama Hussein
  • 19. ANION GAP  The anion gap is primarily used to classify metabolic acidosis, which is caused by the retention of acid within the body. Hydrogen ion reacts with bicarbonate to form carbon dioxide, which is eliminated by the lungs. As acidosis develops, bicarbonate levels decrease and are replaced by the anionic component of the acid. In inorganic acidosis, the anion is chloride and the anion gap does not change. In organic acidosis, the anion gap increases because bicarbonate decreases, chloride remains constant, and the unmeasured anion (lactate, ketone, phosphate) increases. by dr M Osama Hussein
  • 20. ANION GAP  Metabolic acidosis can be divided into two categories: normal anion gap and high anion gap. High anion gap acidosis is caused by acid retention, while normal anion gap acidosis is usually due to loss of bicarbonate. by dr M Osama Hussein
  • 21. ANION GAP  High Anion Gap Ketoacidosis (diabetes, starvation, ethanol) Lactic acidosis (circulatory or respiratory failure, liver failure, tumors, oral hypoglycemics) Renal failure (uremic acidosis) Poisoning (salicylates, methanol, ethylene glycol) by dr M Osama Hussein
  • 22. ANION GAP  Normal Anion Gap Drugs (acetazolamide, carbonic anhydrase inhibitor) GI loss of bicarbonate (diarrhea) Ureteroenterostomy (loss of bicarbonate from chloride-bicarbonate exchange) Renal tubular acidosis Excess IV replacement with NaCl by dr M Osama Hussein
  • 23. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B ----------C ◄► pH? Derangement ◄ NORMAL pH ► by dr M Osama Hussein How you Should feel?
  • 24. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B 7.25 ▼ 10 ▼ ◄ 40 ► ----------C ◄► ▼▼B ----------C◄► pH? Derangement ◄ NORMAL pH ► PH ▼▼ by dr M Osama Hussein Ac. Met. Acidosis How you Should feel?
  • 25. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B 7.25 ▼ 10 ▼ ◄ 7.25 ◄ 20 ► ▲ ----------C ◄► 40 ► ▼▼B ----------C◄► 60 ▲ ◄►B ----------C▲▲ pH? Derangement ◄ NORMAL pH ► PH Ac. Met. Acidosis PH Ac. Resp. Acidosis ▼▼ ▼▼ by dr M Osama Hussein How you Should feel?
  • 26. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B 7.25 ▼ 10 ▼ ◄ 7.25 ◄ 20 ► ▲ 7.55 ▲ 30 ▲ ◄ ----------C ◄► 40 ► ▼▼B ----------C◄► 60 ▲ ◄►B 40 ► pH? Derangement ◄ NORMAL pH ► PH Ac. Met. Acidosis ▼▼ ----------C▲▲ ▼▼ PH Ac. Resp. Acidosis ▲▲B ----------C◄► ▲▲ Ac. Met. Alkalosis pH by dr M Osama Hussein How you Should feel?
  • 27. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B 7.25 ▼ 10 ▼ ◄ 7.25 ◄ 20 ► ▲ 7.55 ▲ 30 ▲ ◄ 7.55 ◄ 20 ► ▼ ----------C ◄► 40 ► ▼▼B ----------C◄► 60 ▲ ◄►B 40 ► 20 ▼ pH? Derangement ◄ NORMAL pH ► PH Ac. Met. Acidosis ▼▼ ----------C▲▲ ▼▼ PH Ac. Resp. Acidosis ▲▲B ----------C◄► ▲▲ Ac. Met. Alkalosis B ----------C▼▼ ▲▲ Ac. Resp. Alkalosis pH pH by dr M Osama Hussein How you Should feel?
  • 28. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B 7.3 10▼▼ 30▼ ----------C ◄► ▼▼B ----------C▼ pH? Derangement ◄ NORMAL pH ► pH▼ by dr M Osama Hussein Chr. Met. Acidosis & Ac. Resp. Alkalosis How you Should feel?
  • 29. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B ----------C ◄► pH? Derangement ◄ NORMAL pH ► 7.3 10▼▼ 30▼ ▼▼B ----------C▼ pH▼ Chr. Met. Acidosis 7.3 ▲26 ▲60▲ ▲B pH▼ Chr. Res. Acidosis ----------▲▲C by dr M Osama Hussein & Ac. Resp. Alkalosis & Ac. Met. Alkalosis How you Should feel?
  • 30. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B ----------C ◄► pH? Derangement ◄ NORMAL pH ► 7.3 10▼▼ 30▼ ▼▼B ----------C▼ pH▼ Chr. Met. Acidosis 7.3 ▲26 ▲60▲ ▲B ----------▲▲C pH▼ Chr. Res. Acidosis 7.5 ▲30▲ ▲50 ▲▲B ▲ Chr. Met.Alkalosis ----------C▲ pH by dr M Osama Hussein & Ac. Resp. Alkalosis & Ac. Met. Alkalosis & Ac. Resp. Acidosis How you Should feel?
  • 31. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B ----------C ◄► pH? Derangement ◄ NORMAL pH ► 7.3 10▼▼ 30▼ ▼▼B ----------C▼ pH▼ Chr. Met. Acidosis 7.3 ▲26 ▲60▲ ▲B pH▼ Chr. Res. Acidosis 7.5 ▲30▲ ▲50 ▲ Chr. Met.Alkalosis 7.5 13▼ ▼20▼ ----------▲▲C ▲▲B ----------C▲ pH ▼B ▲ ----------▼▼C pH by dr M Osama Hussein & Ac. Resp. Alkalosis & Ac. Met. Alkalosis & Ac. Resp. Acidosis Chr. Res. Alkalosis & Ac. Met. Acidosis How you Should feel?
  • 32. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B 7.1 ▼10▼ ▲60▲ ----------C ◄► pH? Derangement ◄ NORMAL pH ► ▼▼B ▼▼ --------C▲▲ ▼▼ pH by dr M Osama Hussein Mixed Acidosis How you Should feel?
  • 33. pH Bicarb. PCO2 ?B ----------?C 7.4 20 40 ◄►B 7.1 7.6 ▼10▼ ▲30▲ ▲60▲ ▼20▼ ----------C ◄► pH? Derangement ◄ NORMAL pH ► ▼▼B ▼▼ --------C▲▲ ▼▼ ▲▲B ▲▲ --------C▼▼ ▲▲ pH pH by dr M Osama Hussein Mixed Acidosis Mixed Alkalosis How you Should feel?
  • 34. by dr M Osama Hussein