Recommended
More Related Content
What's hot
What's hot (20)
Similar to Better Understanding of Critical Blood Gas Values
Similar to Better Understanding of Critical Blood Gas Values (20)
More from Saleh Al-Qarni
Recently uploaded
Recently uploaded (20)
Better Understanding of Critical Blood Gas Values
- 1. Better Understanding of BLOOD GASES Presented by Saleh Al-Qarni
- 2. Note to Blood Gas Techs: FYI â«It is NOT the responsibility of the BGT to alert the ICU Therapist to abnormal values â«However: â«For Critical Values, the sooner the RRT is aware of these values, the sooner appropriate measures can take place to correct a potentially serious situation â«Prompt identification and reporting of Critical Values might save a patientâs LIFE â«In this presentation, if you see âAlert Therapistâ: â«Quick action may be critical to patient outcomes
- 3. What IS a Blood Gas? â«Analysis of a sample of blood, preferably Human â« Recently obtained from blood vessel or indwelling catheter â« Transported in a safe, BG-specific tube or syringe â« Must be: â« Timely: Avoid degradation / clotting â« Well-mixed: Accurate Hb / Hematocrit â« Free of Bubbles / Exposure to Air: Affects âGasâ values & clotting â« Free of contamination by other fluids / materials â« Analyzed on a properly-calibrated instrument â« Analyzed by proper procedure â« Critically assessed against patient condition, history & care
- 4. Blood Gases: What Value? â«Blood Gas Analysis data reflects: â«Functional balance between Lungs / Kidneys â« Acid-Base Balance â«Efficiency of Lung Function â« Elimination of Carbon Dioxide (CO2) from the blood â« Uptake of Oxygen (O2) into the blood â«Clues regarding: â« Cardiac Function / Health â« Metabolic Function / Health
- 5. Blood GAS Analysis? â«Both O2 and CO2 dissolve, as gases, in blood plasma â«This dissolved gas exerts a measurable force â«Normal values â« Indicate level of system health and system balance â«Abnormal Values â« Indicate that something may be wrong â« For some patients, abnormal IS normal â« Very often corrected by the patient â« Correction, or lack of it, may be noted as symptoms â« Medical intervention when patient unable to correct â« Often based on BG data
- 6. Sources of BG Contamination â«Air Bubbles â«Air bubbles in the sample syringe s/b removed ASAP â«As little as 0.01 mls air -> potential 10% change in PO2 â«IV Fluid(s) â«Prior to sampling, 3-10 mls of âwasteâ blood drawn off â« Longer lines require more âwasteâ blood drawn off â«If insufficient blood drawn off, some IV fluid may be mixed in with sample â« Depending on content, may significantly affect values
- 7. Acid-Base Balance: Briefly CO2 â RESPIRATORY - Lungs Kidneys â METABOLIC - HCO3- Acidosis: pH < 7.40 Acidosis: pH < 7.40Alkalosis: pH > 7.40 Alkalosis: pH > 7.40 pH Ideal : 7.40
- 8. Acid-Base Balance: Briefly ACIDOSIS: pH < 7.40 ALKALOSIS: pH > 7.40 Is the pH Acidotic or Alkalotic? Driver Compensation PCO2 HCO3- PCO2 HCO3- Respiratory Acidosis - - Metabolic Acidosis - - Respiratory Alkalosis - - Metabolic Alkalosis - - Drivers move in OPPOSITE directions to each other. Compensation moves in SAME DIRECTION as the Driver
- 9. Blood Gas Parameters: PO2 â«PO2 â«Partial Pressure of Oxygen dissolved in blood plasma â«Affected by: â« Ventilation: Breathing well or properly ventilated? â« Ambient Oxygen: Concentration of O2 delivered? â« Lung Function: Efficiency of exchange within the lung â« Blood Flow (Cardiac Function): Transport â« Metabolic Rate â«A function of the LUNG â«Arterial (PaO2) vs Venous (PvO2) â« Oxygen Saturation: SvO2 â Cardiac / Metabolic balance
- 10. PO2 â«High PaO2 â«Risk of Oxygen Toxicity (Lung damage) â«BGT concern if very high PaO2 with low FiO2 â« Possibility of bubble-contamination, false high value â« eg. PaO2 â 18 kpa Patient on R/A âŠ. Impossible. â«Therapist should make this connection â«Low PaO2 â«Risk of Hypoxia, Lactic acidosis (SEE Lactic Acid) â«Assess together with SaO2 / O2Hb â«If below 8.0 kPa, worth alerting Therapist
- 11. Blood Gas Parameters: PCO2 â«PCO2 â«Partial Pressure of Carbon Dioxide dissolved in plasma â«Affected by: â« Metabolism: Production of CO2 at cellular level â« Availability of Oxygen at cellular level â« Circulation: Transporting blood to lungs â« Lung Function: 20x the ease of Oxygen transfer â« Ventilation: Exchange with fresh gas in lungs â«A function of the LUNG â«Arterial (PaCO2) - best indicator regarding Ventilation â«Normal Value (A) 4.5 â 5.5 kPa
- 12. PaCO2 â«Low PaCO2 â«Assess with pH / HCO3- â«Excessive ventilation / Pt Hyperventilating â« May be required to compensate for low HCO3- â« May be required for certain medical condition â« Alert Therapist if pH > 7.55 (Alkalosis) â«High PaCO2 â«Assess with pH, in particular â« OK if associated with relatively normal pH â« Alert Therapist if pH < 7.20 (Acidosis) â«Insufficient Ventilation
- 13. Blood Gas Parameters: HCO3 - â«HCO3- â«Bicarbonate (sl. Bicarb), the primary âbufferâ for CO2 â«A form of CO2 transport / elimination â« CO2 + H2O <=> H2CO3 <=> H+ + HCO3- â«A function of the KIDNEYS and LIVER â« For our part, we look at kidney function â« LUNGS and KIDNEYS work together to regulate pH â«Normal Values (A) 22 â 25 mmol/L (V) 22-29 â«Balance between HCO3- and PCO2 = pH
- 14. HCO3 - â«Low Bicarb < 22 â« Promotes Acidosis or â« Compensates for Alkalosis (Low PCO2) â«High Bicarb > 29 â« Promotes Alkalosis or â« Compensates for Acidosis (High PCO2) â« Much more common eg. Long-term CO2 retainers â«Alert Therapist if associated pH highly abnormal â« 7.20 > pH < 7.55
- 15. Blood Gas Parameters: pH â«pH â«Measure of Acid-Base balance in the blood / body â«Regulated by Lungs & Kidneys (systems) â« Balance between PCO2 (Lungs) & HCO3- (Kidneys) â«Narrow range of normal (7.35 â 7.45) â« Less than 7.40 - Acidotic side (High H+) â« Greater than 7.40 - Alkalotic side (Low H+) â«If one system changes, other moves same direction to compensate.
- 16. Blood Gas Parameters: BE â«Base Excess / Base Deficit (FYI) â«Represents the quantity of buffers in the blood (primarily HCO3-) that would be required to be either added or eliminated to return the pH to 7.40 with a PCO2 of 40. â« Example: If the BE is +4.5, then 4.5 mmol/L of added acid (H+) would be required to return pH to 7.40 (or 4.5 mmol/L of HCO3- eliminated). â« If the BE is negative, that quantity of acid (H+) would have to be eliminated to bring the pH back to 7.40 (or HCO3- added) â«Possibly the least-assessed parameter in BG analysis
- 17. Blood Gas Parameters: Hb / O2Hb â«Hemoglobin (Total Hb) â«O2 / CO2 â carrying component of Red Blood Cells â«Majority of O2 / CO2 transported attached to Hb â«O2 must offload from Hb before CO2 can load, vice versa â«Thoroughly MIX samples; re-run, PRN, if low â«Normal Values: (F) 120-160 g/L (M) 140-180 g/L â«Low tHb â«O2 delivered to tissues may be compromised â« If poor delivery --> Lactic Acidosis (Incrâd Lactic Acid) â«Alert Therapist if tHb < 70 (after verifying value)
- 18. Blood Gas Parameters: O2Hb â«Oxyhemoglobin (O2Hb / Measured Saturation) â«Ratio of Oxygenated-to-Deoxygenated blood â« Normal typically > 96% (A) 70 - 75% (V) â« ICU: Wide variation of âNormalâ, especially in CSICU â« Therapist will identify abnormalities in CSICU â«Outside of CSICU, Alert Therapist if: â« Arterial O2Hb < 88 % â« High risk of Hypoxia â« Venous O2Hb < 60 % â« Suggests very poor Cardiac Output
- 19. Blood Gas Parameters: COHb â«Carboxyhemoglobin (COHb) â«% of Carbon MONOxide attached to Hb â«O2 cannot attach to COHb â« CO Binds to Hb ~ 300 x as easily as O2 â«Typically, Smoke Inhalation / Car Exhaust / Braziers â« Normal: 0 â 5 % â« Smoker 2 â 10 % (8-10% in Heavy Smokers) â« Serious Symptoms: 10 â 30 % Alert Therapist! â« Post-Mortem: 30 â 90 % â«Higher Levels: Blood is CHERRY Red, very bright
- 20. Blood Gas Parameters: MetHb â«Methemoglobin â«Created by injury or toxic agents in the blood â« May be elevated with use of Nitric Oxide â«Incapable of oxygen transport â«Naturally occurring, at very low levels â«Alert Therapist if MetHb > 5 % â«Therapist should be monitoring if iNO in use
- 21. Blood Gas Parameters: K+ â«Potassium (K+) â«Most important intracellular Cation in the body â«Maintains cellular resting membrane potential / osmotic pressure of the cells â«Significant role in electrical events involving excitable tissue (muscle, especially heart muscle) â«Poor compensation mechanisms in the body, so serious fluctuation can be a life-threatening event â«The most commonly requested check requested by RNs
- 22. K+ â«High K+ (Hyperkalemia) â«Impairment of vital muscle functions â« Heart: Arrhythmias, V-Fib, Cardiac Arrest â« Intestinal: Spasms â« Respiratory: Paralysis â«Renal dysfunction (Oliguria, Anuria) â«Potential for significant cell destruction â«Can cause Respiratory / Metabolic Acidosis â«May be rapidly reduced with high-rep MDI Ventolin
- 23. K+ â«Low K+ (Hypokalemia) â«Similar to Hyperkalemia â« Heart: Tachycardia, Cardiac Arrest â« Respiratory: Paralysis â« Intestinal: Spasm, Ileus â« Renal: Renal acidosis â«Typical Causes â« Extensive cutaneous burns â« GI: Loss through vomiting, diarrhea â« Malnourishment: Anorexia, alcoholism
- 24. K+ â«Normal Values â« KFSH: 3.5 â 5.0 mmol/L â«Critical Values â« 2.5 > K+ > 6.5 â«Very Important â« Measurement MUST be accurate â« Treating K+ on incorrect information very dangerous to patient â« Alert Therapist if contaminated sample suspected â« CLUE: Several other electrolytes also severely abnormal
- 25. Blood Gas Parameters: N+ â«Sodium (N+) â«Most important extracellular Cation in the body â«Central role in maintaining fluid volume â«Mainly responsible for: â« Regulation of body fluids â« Maintenance of electrical potential in muscle cells â« Control of cellular membrane permeability â«Normal Values 135 â 145 mmol/L â«Alert Limits 125 > N+ < 155 mmol/L
- 26. N+ â«Hyponatremia < 130 mmol/L â« Most common electrolyte shift â«Hypernatremia > 150 mmol/L â« Essentially, dehydration â« More salt than water â«Both Hypo- and Hypernatremia cause â« Clouding of consciousness â« Seizures â« Vomiting
- 27. Blood Gas Parameters: Ca2+ â«Ionized Calcium (Ca2+) â«Important to: â« Conversion of nerve impulse to muscular activities â« Regulates membrane permeability of Na+ and K+ â« Key role in: â« Coagulation â« Enzymatic activities â« Secretion of hormones such as Adrenaline â«Normal Values 1.15 â 1.35 mmol/L â«Alert Limits 0.9 > Ca2+ < 1.75 mmol/L
- 28. Blood Gas Parameters: Cl- â«Chloride (Cl-) â«The most important Anion in body fluids â« Counter-ion to Na+, metabolism closely related to Na+ â« Changes usually very similar, unless assoc. with â HCO3- â« Chloride replaces Bicarb during renal output â«Occurs mostly in extra-cellular spaces â« Role in regulating water distribution in these spaces â«Normal Values 95 â 105 mmol/L â«Alert Limits 80 > Cl- < 118 mmol/L
- 29. Blood Gas Parameters: Lactate â«Lactate / Lactic Acid: â«End-product of glucose metabolism, produced under anaerobic conditions â« Produced naturally in the tissues of the brain, skin, GI tract, erythrocytes and muscle (1400 mmol/Day) â« Moves from cell into blood, transformed back into glucose mainly in liver, small part in kidneys â«Normal Value < 1.8 mmol/L â«Produced when insufficient O2 delivered to tissues â«In critically ill patients, indicates tissue hypoxia â« Can lead to multiple organ failure â« Damaged organs cannot decompose the metabolite
- 30. Normal Values (A) Alert / (V) â« pH * 7.35 â 7.45 7.20 > Alert > 7.55 â« PCO2 (A) 4.5 â 5.5 kPa (V) 5.3 â 6.6 mmol/L â« PO2 (A) 10 â 12 kPa (V) 4.6 â 5.3 mmol/L â« HCO3- (A) 22 â 25 mmol/L (V) 22 â 29 mmol/L â« Hb * 120 - 180 g/L (or mg/dL) Alert < 70 â« K+ * 3.5 â 5.0 mmol/L 2.5 > Alert > 6.5 â« N+ 135 â 145 mmol/L 125 > Alert > 155 â« Ca2+ 1.15 â 1.35mmol/L 0.9 > Alert > 1.75 â« Cl- 95 â 105 mmol/L 80 > Alert > 118 â« Lactate < 1.8 mmol/L Alert > 5.0 â« COHb * 2 â 9 % Alert > 10 % â« MetHb * 0 â 2 % Alert > 5 % ( * The âBig 5â ) mmHg = kPa x 7.5 kPa = mmHg / 7.5 MAX PO2 â FiO2(PB-43) â PaCO2
- 31. Acid-Base Balance: Re-visited CO2 â RESPIRATORY - Lungs Kidneys â METABOLIC - HCO3- Acidosis: pH < 7.40 Acidosis: pH < 7.40Alkalosis: pH > 7.40 Alkalosis: pH > 7.40 pH Ideal : 7.40
- 32. Acid-Base Balance: Re-visited ACIDOSIS: pH < 7.40 ALKALOSIS: pH > 7.40 Is the pH Acidotic or Alkalotic? Driver Compensation PCO2 HCO3- PCO2 HCO3- Respiratory Acidosis - - Metabolic Acidosis - - Respiratory Alkalosis - - Metabolic Alkalosis - - Drivers move in OPPOSITE directions to each other. Compensation moves in SAME DIRECTION as the Driver
- 33. Blood Gas Interpretation â«Look at pH â«Decide if on âAcidoticâ or âAlkaloticâ side of 7.40 â«Look at CO2 and HCO3- â«One or both abnormal? Supports above? â«Both can support âAcidosisâ or âAlkalosisâ â«Respiratory, Metabolic or combined? â« Combined: CO2 and HCO3- move in opposite directions
- 34. Interpretation (contâd) â«Compensation â«To return pH to near-normal, CO2/HCO3- play âTagâ â« pH rarely OVERcompensated ⊠approaches Normal only â« CO2 follows HCO3- and vice versa â« Breathing increases or slows â« Kidneys release or conserve HCO3- â«NO compensation â Acute condition â«Partial Compensation â« Some shift, but pH still outside of 7.35 â 7.45 range â«Fully compensated â« Driving condition still exists, but pH within 7.35 â 7.45 range
- 35. Interpretation (contâd) â«Beyond Classifications â«Identify what is abnormal â«Initial interpretation, only â«True Interpretation â«Relating data to: â« Patient condition / current symptoms, if any â« Current treatment: Spontaneous breathing vs MV â« Patient History â« Are current abnormal values additions to prior âbaselineâ abnormal values? â« eg. CO2 retainers with acute exacerbation of disease
- 36. Practice BG 1 CSICU HFOV Arterial FiO2 0.30 Classification? â« pH 7.48 â« pCO2 4.4 â« pO2 10.2 â« HCO3- 24.6 â« Na+ 138 â« K+ 2.9 â« Cl- 104 â« Ca2+ 1.24 â« Lactate 1.1 â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________
- 37. Practice BG 1 CSICU HFOV Arterial FiO2 0.30 Acute Respiratory Alkalosis with low K+ â« pH 7.48 â« pCO2 4.4 â« pO2 10.2 â« HCO3- 24.6 â« Na+ 138 â« K+ 2.9 â« Cl- 104 â« Ca2+ 1.24 â« Lactate 1.1 â« Moderately Alkalotic â« Slightly low - Driver â« Acceptable â« Normal â« Normal â« Low - Alert â« Normal â« Normal â« Normal
- 38. Practice BG 2 CSICU SIMV/PS Venous Rate â 15 FiO2 â 0.40 Classification? â« pH 7.44 â« pCO2 9.9 â« pO2 3.6 â« HCO3- 50.3 â« Na+ 142 â« K+ 2.9 â« Cl- 94 â« Ca2+ 1.22 â« Lactate 0.8 â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________
- 39. Practice BG 2 CSICU SIMV/PS Venous Rate â 15 FiO2 â 0.40 Fully-Compensated Metabolic Alkalosis * with low K+ â« pH 7.44 â« pCO2 9.9 â« pO2 3.6 â« HCO3- 50.3 â« Na+ 142 â« K+ 2.9 â« Cl- 94 â« Ca2+ 1.22 â« Lactate 0.8 â« Normal - Alkalotic â« High â Arterial will be lower â« Normal â« Very High - Driver â« Normal â« Low - Alert â« A bit low â« Normal â« Normal * Can be interpreted in different ways.
- 40. Practice BG 3 CSICU SPRVC Venous 30 x 18/+10 FiO2 â 1.0 Classification? â« pH 7.26 â« pCO2 12.1 â« pO2 7.8 â« HCO3- 40.8 â« Na+ 143 â« K+ 5.3 â« Cl- 100 â« Ca2+ 1.23 â« Lactate 2.5 â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________
- 41. Practice BG 3 CSICU SPRVC Venous 30 x 18/+10 FiO2 â 1.0 Partially-Compensated Respiratory Acidosis * With Mild Lactic Acidosis â« pH 7.26 â« pCO2 12.1 â« pO2 7.8 â« HCO3- 40.8 â« Na+ 143 â« K+ 5.3 â« Cl- 100 â« Ca2+ 1.23 â« Lactate 2.5 â« Acidotic â« Elevated - Driver â« Normal â« Elevated â Chronic Comp? â« Normal â« Normal + â« Normal â« Normal â« Slightly elevated * Can be interpreted in different ways.
- 42. Practice BG 4 SSCU-B PSV Venous 10/+5 FiO2 â 0.30 Classification? â« pH 7.40 â« pCO2 8.0 â« pO2 4.6 â« HCO3- 37.2 â« Na+ 128 â« K+ 4.5 â« Cl- 92 â« Ca2+ 1.16 â« Lactate 0.8 â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________
- 43. Practice BG 4 SSCU-B PSV Venous 10/+5 FiO2 â 0.30 Likely a Fully-Compensated Respiratory Acidosis with electrolyte disturbance â« pH 7.40 â« pCO2 8.0 â« pO2 4.6 â« HCO3- 37.2 â« Na+ 128 â« K+ 4.5 â« Cl- 92 â« Ca2+ 1.16 â« Lactate 0.8 â« Normal â Sl. overcompensated â« High (possibly low for this pt.) â« Normal â« High - Compensating â« Nearing Critical Low - Alert â« Normal â« A bit low â« Normal â« Normal â System NOT stressed
- 44. Practice BG 4 â 5 Same Patient SSCU-B PSV Venous 10/+5 FiO2 â 0.30 PCV 20/+5 FiO2 â 0.30 â« pH 7.40 â« pCO2 8.0 â« pO2 4.6 â« HCO3- 37.2 â« Na+ 128 â« K+ 4.5 â« Cl- 92 â« Ca2+ 1.16 â« Lactate 0.8 â« 7.51 ___________ â« 5.1 ___________ â« 4.4 ___________ â« 30.3 ___________ â« 126 ___________ â« 4.2 ___________ â« 93 ___________ â« 1.12 ___________ â« 1.3 ___________
- 45. Practice BG 4 â 5 Same Patient SSCU-B PSV Venous 10/+5 FiO2 â 0.30 PCV 20/+5 FiO2 â 0.30 â« pH 7.40 â« pCO2 8.0 â« pO2 4.6 â« HCO3- 37.2 â« Na+ 128 â« K+ 4.5 â« Cl- 92 â« Ca2+ 1.16 â« Lactate 0.8 â« 7.51 Alkalotic â« 5.1 Normal? â« 4.4 Normal â« 30.3 High, but falling ⊠⫠126 Lower â« 4.2 Normal â« 93 Low â« 1.12 Normal â« 1.3 Normal
- 46. Practice BG 6 SSCU-B Spont Arterial FiO2 = 0.21 (Room Air) Classification? â« pH 7.41 â« pCO2 5.2 â« pO2 19.4 â« HCO3- 24.6 â« Na+ 142 â« K+ 4.5 â« Cl- 106 â« Ca2+ 1.16 â« Lactate 0.8 â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________
- 47. Practice BG 6 SSCU-B Spont Arterial FiO2 = 0.21 (Room Air??) Normal Blood gas, but conflict with pO2 reading â« pH 7.41 â« pCO2 5.2 â« pO2 19.4 â« HCO3- 24.6 â« Na+ 142 â« K+ 4.5 â« Cl- 106 â« Ca2+ 1.16 â« Lactate 0.8 â« Normal â« Normal â« Not possible on R/A. Max 14 +/- â« Normal â« Normal â« Normal â« Normal â« Normal â« Normal
- 48. Impossible PaO2? â«If you suspect that a PaO2 is too high for the given FiO2: â«Verify if the patient is on supplemental O2, what level? â«To calculate a Maximum possible PaO2: â«MAX (mmHg) = FiO2(PB â 43) â PaCO2 â«For the previous BG: â« Max = 0.21 (710-43) â (5.2 x 7.5) â« = 0.21 (667) â 39.5 = 140 â 39 = 101 mmHg / 7.5 = 13.5 kPa kPa = mmHg / 7.5 mmHg = kPa x 7.5
- 49. Practice BG 7 SSCU-B PRVC Arterial 15 x 340 +5 FiO2 - 1.0 Classification? â« pH 7.11 â« pCO2 4.9 â« pO2 45.8 â« HCO3- 11.8 â« Na+ 143 â« K+ 4.1 â« Cl- 117 â« Ca2+ 1.35 â« Lactate 7.7 â« __________________ â« __________________ â« Possible? â« __________________ â« __________________ â« __________________ â« __________________ â« __________________ â« __________________
- 50. Practice BG 6 Post-Op Blood Gas #1 SSCU-B PRVC Arterial 15 x 340 +5 FiO2 - 1.0 Acute Metabolic Acidosis with Lactic Acidosis â« pH 7.11 â« pCO2 4.9 â« pO2 45.8 â« HCO3- 11.8 â« Na+ 143 â« K+ 4.1 â« Cl- 117 â« Ca2+ 1.35 â« Lactate 7.7 â« Critical Acidotic â« Low normal â no comp â« Appropriate for O2 given â« Critical Low â« Normal â« Normal â« Normal â« Normal â« Quite elevated
Editor's Notes
- Again, this is not your responsibility, but it IS a way you can make another important contribution to patient care.
- BG Analysis CAN be performed on non-human samples. RCS only accepts HUMAN BLOOD for analysis. Non-human blood or other types of fluids (eg. Urine, CSF) are NOT to be run on RCS analyzers. RCS only accepts blood samples contained in approved, heparinized containers (syringe or capillary tube) SAFE â no needle attached. Degradation: Blood is a living medium, continues to metabolize, consuming oxygen, outside of the body, but without the usual support. Degrades as it does so. Bubbles: A bubble as small as 0.01 ml can increase the PO2 value of a sample by as much as 10%. BGs contaminated with various flush or IV solutions can significantly alter electrolyte values. Medical treatment based on incorrect BG data can be disastrous.
- For some people, abnormal value are their normal values ⊠might not be reason for alarm / concern
- Acid-Base status is a measure of the BALANCE between Lung Function (elimination / regulation of CO2) and Kidney Function (regulation of HCO3-, elimination or conservation)
- âDriversâ â The CAUSE of the condition, either Alkalotic or Acidotic. Can have TWO Drivers.
- The first 3 values are apparent in the ARTERIAL blood, the last two in VENOUS blood. PmvO2 ⊠usually look at SvO2 as a gauge of Metabolic Rate
- In most cases, the Therapist should pick up on any abnormalities and pursue the appropriate therapy. For BGTâs, recognizing an ABNORMAL HIGH for the FiO2 given is likely the critical consideration. Most easily recognized with ROOM AIR gases. Any R/A PaO2 > 15 is virtually impossible. Either bubble contamination or given FiO2 is incorrect. WE LOOK VERY BAD if such a result is reported as true. Check sample for bubbles. Appropriate PO2 changes with AGE
- CO2 is formed at cellular level. Free Carbon molecules attaching to free Oxygen molecules (Oxygen is essentially a garbage truck, there to remove Carbon molecules freed up by cellular metabolism) No oxygen, is like the garbage guys going on strike. It piles up, our bodies go into anaerobic metabolism ⊠Lactic Acid buildup.
- Hyperventilation in Head Injury, for first 12-24 hrs
- Buffer â counter for CO2
- HCO3- is the BASE, H+ is the acid If BE is +4.5, there is 4.5 mmol/L bicarb than necessary.
- âNormalâ in CSICU varies widely, so Saturation is specific to each patient in that unit. Hb g/L or mg/dL same thing âAcceptableâ saturation is also specific to each patient. If very low arterial, then a concern. Can still have a good PO2 with a poor Hb. CONTENT will be low. O2 Content = (Hb x 1.39 x O2Hb) + (PaO2 x 0.0031)
- Heavy smokers or exposure to high level of car exhaust Serious symptoms: Headache, dizziness, fatigue, confusion, SOB, unconsciousness, death, etc. (in KSA, more often in Winter, due to charcoal heaters in tents) Potential high PO2, with very low measured O2Hb / High COHb You should NOT see higher COHb in the Units, as these patients cannot be smoking. ER only. Pulse Oximeters are NOT effective in detecting COHb-related hypoxia.
- Cation is a postively-charged ion. (Anions are negatively-charged) Typically from incorrect infusion therapy with K+-containing medications: (Digoxin, Heparin, Succinylcholine, K-saving diuretics) Diabetics: Uncontrolled diabetes with reckless consumption of bananas or other high-K foods. â Suicidal! Mineral corticoid deficiency (adrenal gland)
- Cell Destruction: Cell is damaged or dies with K+ release from cells, haemolysis MDI does not always work, but is worth a shot in cases of very high Potassium. 12-15 puffs
- Controlled by: Hormones (Parathormone, Calcitonin), Acid-Base metabolism, Vitamin D metabolism and Phosphate metabolism
- Hyperchloridemia: High water loss (Diabetes Mellitus.isipidus), inadequate fluid supply in very ill patients, Hypokalemia, serious febrile illness Associated with Metabolic Acidosis due to loss of bicarb ⊠accompanied by hyperventilation Hypochloridemia: Vomiting, diarrhea, Excessive sweating, inadequate supply during infusion, etc.
- Vicious circle ⊠tissue hypoxia âŠ. Lactic Acid ⊠organ damage ⊠less blood flow / elimination of Lactate âŠ. Worsening hypoxia, etc âŠ
- Female Hb Normals: 120 â 160 mg/dL Male Normal Hb: 140 â 180 mg/dL The BIG 5: The parameters where accuracy and early notice is most important. Lactate is closely examined by the docs and nurses, so less Important to point out elevated values. Never a bad idea, though.
- Acid-Base status is a measure of the BALANCE between Lung Function (elimination / regulation of CO2) and Kidney Function (regulation of HCO3-, elimination or conservation)
- âDriversâ â The CAUSE of the condition, either Alkalotic or Acidotic. Can have TWO Drivers.
- Report or hilight the K+, otherwise no real cause for alarm. (pH < 7.55)
- The BODY rarely overcompensates, but we can easily do so with MV, so Blood Gas âClassificationsâ have to be a fluid concept ⊠classifications can be artificially induced. A high VENOUS CO2 is less significant than a high arterial value. Assess with pH.
- Can be interpreted in many ways âŠ. Chronic Resp Acidosis with acute flare up. / Partially-compensated Resp Acidosis INDUCED Rep Acidosis, eg with weaning of ventilation âŠ
- Most likely a chronic CO2 retainer âŠ. High CO2, bicarb compensation. Now on PSV and probably hyperventilating slightly, driving CO2 down and completely normalizing pH.
- Patient was likely a chronic CO2 retainer, but dehydrated from sweating / vomiting. Now alkalotic due to imposition of MV. We have artificially lowered this patientâs CO2, leaving him alkalotic.
- Patient was likely a chronic CO2 retainer, but dehydrated from sweating / vomiting. Now alkalotic due to imposition of MV. We have artificially lowered this patientâs CO2, leaving him alkalotic. Straight classification is Acute Metabolic Alkalosis, but is actually a Respiratory Alkalosis, as the high HCO3- is likely normal for this patient.
- Either there was a large bubble in the sample, the sample was somehow otherwise contaminated with O2, or the patient is NOT on Room Air. If no bubble in sample, then check to see if the patient is on supplemental O2 PA = FiO2 (Pb â PH2O) â PaCO2 PaO2 can only approach PAO2.
- FiO2 is 0.21 to 1.0
- Ventilation is good. Oxygenation is good. Can we have a PO2 this high? 1.0(667) â (4.9 x 7.5) = 667 â 37 = 630 / 7.5 = 84 Yup. Cardiac output is likely VERY POOR ⊠low HCO3- and high Lactate. Get this BG to the Therapist ASAP.