Fifth Example - ABG Report of the Patient

Fifth Example - ABG Report of the Patient

A 55 years obese patient admitted in emergency department of DMCH with the C/O breathlessness, pain abdomen, irritability. She was taking corticosteroid for longer period and had moon facie, obesity, hypertension and pateche. Before ABG she was give O2 inhalation 5 L/min, Diuretics, corticosteroid, nebulisation, Inhalation with salbair I. iv fluid, pantoprazole, antibiotics without improvement. Then after 48 hrs patient was transferred to ICU and ABG was done.

ABG Analysis

1. Gas Analysis :-

Step: 1

Pao₂ = 135.3 mm of Hg – Above normal, due to high Fio_2.

_{Step: 2}

PAo₂ = 135.3 mm of Hg – Above normal, due to high Fio_2.

_{Step: 3}

P(A-a)o₂ = (135.3-135.3) 

                = 0, below normal – no Parenchymal lung 

                                                 disease.

Step: 4

PaCo₂ = 15.7 mm of Hg – low – Hyperventilation.

     No, respiratory failure.

Step: 5

Patient has below normal PaCo₂ with no increase in 

P(A-a)o₂ and The Fio₂ is not less, so no respiratory 

cause of increased respiration.

Step: 6

P/F = 135.3/40X100    (Here Fio₂ = 50%)

      = 338.25                   No ALI

Step:7

The relation between Spo₂ and Pao₂ are normal.

Step: 8

Cao₂ = 5.5X10X1.34X99/100+0.003X135.3

         = 5.5X1.34X0.99+0.003X135.3

         = 72.963+0.4059

         = 73.369

         The weight of the patients is 65 kg.

         So expected normal Cao₂ in this patient = 180.6 ml 

         of O₂/L

         But it is  = 73.369

         So it is one cause of dyspnoea.

2. Electrolyte Analysis

Ca⁺⁺  - 0.166 mmol/L – Low -> Cause of Hypocalcaemia is needed to be 

                                                      searched.  

K⁺     - 1.25 mmol/L – Low  -> i.e. losses in gastrointinal or renal cause 

                                                      here probably due to diuretic  use.

Anion Gap :-

26.4 mmol/L -> So AG>20 mmol/L                                  

                       Support a primary metabolic acid base disturbance.

Delta Gap :-

Delta Gap = 26.4-12

                 = 14.4

Delta gap + HCo₃    = 14.4 + 10.5

                             = 24.9 falls in between 22-26 mmol/L,  Normal

           So no metabolic alkalosis and no non-anion gap metabolic acidosis.

Gap - Gap Ratio :-

Gap-Gap ratio = (26.4-12)/(24-10.5)

                     = 14.4/14.5 =approx 1

            Indication high AG metabolic acidosis.

Base Excess :-

Base Excess (BE) = -12.5 -> Metabolic acidosis.

                                               It also justified.

3. Acid - Base Analysis

Step: 1

Step: 2

HCo₃ = 10.5 mmol/L -> metabolic acidosis .

Step: 3

PaCo₂ = 15.7 mm of Hg (< 40 mm of Hg) so, respiratory alkalosis.

Step: 4

H⁺ & HCo₃^- move in same direction.

So, respiratory cause. So, Respiratory Alkalosis.

Step: 5

So, PaCo₂ & HCo₃^- move in same direction.

So, simple cause (fallacy of the formula, because there is metabolic acidosis confirmed).

So, other way to know about mixed disorder is to evaluate.

              Expected value of PaCo₂ = 46

              Actual value of PaCo₂      = 15.7

So, Expected value and actual value of PaCo₂ do not match -> So, mixed disorder present.

So, High Anion gap Metabolic acidosis with Respiratory alkalosis.

Step: 6     

Compensatory  change

Predicted comparative of PaCo₂ fall = 1.2 X (24-10.5)

                                                     = 1.2 X 13.5 = 16.20

                

So, Expected value of PaCo₂          = 40 - 16.20 = 23.80

The value of PaCo₂ is 15.7

       Much less than 23 – 80

So, Respiratory Alkalosis associated. 

Final diagnosis

The patient has mixed disorder of high anion gap metabolic acidosis with respiratory alkalosis 

with dehydration with hypokalaemia  with hypocalcaemia without ALI/ Parenchymal lung disease.

Causes of Respiratory Alkalosis 

                L – Liver disease – Increase SGPT

                E – Embolism – Not

                D – Drug

                A – Anxiety – Present

                V – Ventilator – Not

                P – Pregnancy – Not

                H – Hyperventilation - Present 

Causes of High Anion gap metabolic acidosis 

                M – Methanol                         - No history in this patient

                U – Uraemia                           - Not present

                D – Diabetes mellitus             - Not present

                P – Paraldehyde                      - No history

                I – Infection (CBC) Present , Ischaemia (ECG) Not Present

                L – S.lactate                            - Not done

                E – Ethanol                             - No history

                S – Starvation, Salicylate               

Fourth Example - ABG Report of the Patient

Fourth Example - ABG Report of the Patient

A male patient aged 65 years of COPD and cor pulmonale admitted with the complain of increase in Breathlessness. ABG was done before giving oxygen therapy on 12/02/2015 at 6.13 PM.

ABG Analysis 

1. Gas Analysis :- 

Step: 1 

PaO2 = 47.1 mm of Hg – Moderate Hypoxenia.

Step: 2

PAO2 = 72.5 – decrease Alveolar oxygen content.

Step: 3

P(A-a)O2 = 72.5-47.1

                 = 25.4 

Nearly Normal = age/4+4 

    = 65/4+4 = 16+4 = 20

Supposed to be no paregnel lup disease.

Step: 4

PaCo2 = 66.5 Increased more than 49.

              So, Hypoventilation.

              So, Hypoxemia with Hypercapnia 

              = Type 2  Respiratory failure.

Step: 5

Since PaCo2 is increased and P(A-a)O2 not increased so, hypo ventilation alone and important cause of it is decrease respiratory drive and neuromuscular disease.

Step: 6

 P/F = 224.3 – there are features of heart failure so is not an  indication of ALI.

   

Step: 7

PaO2 of (40 – 60) mm of Hg  Correspond to SPO2 of (75 – 91)%. 

Here, SPO2 69.7% & PaO2 47.1 mm of Hg.  

So, SPO2 a bit low. 

Step: 8

Cao2 = 17.1 X 10 X 1.34 X 69.7/100 + 0.003 X 47  ml/L

         = 159.71 + 0.1413

         = 159.85 ml/L

2. Electrolyte Analysis :-

Ca++ -> 0.561 – low – Cause, Pancreatis, hypoalbuminemia, Renal failure, Vit deficiency and alkalosis to be searched. 

K+     -> 4.90   – normal 

Anion Gap :-
AG = 12.5 – near normal

Delta Gap :- 
Delta gap = 12.5 – 12 = 0.5

Gap – Gap ratio :- 
Delta gap / HCo3 gap = 0.5/(30.6-24) = 0.5/6.6 = 0.08 <1  (to be taken in consideration if there is metabolic cause.)

Base Excess :- 
BE = 1.5 mm/L –> if metabolic cause it suggest metabolic alkalosis.

3. Acid Base Analysis :-

Step:1

Step: 2
HCo3 = 30.6 mmol/L (> 24 mmol/L) metabolic alkalosis .
       
Step: 3
PaCo2 = 66.5 mm of Hg (> 40 mm of Hg) so, respiratory acidosis.

Step: 4

H+ & HCo3- move in same direction.
so, respiratory cause. 

Step: 5

So, PaCo2 & HCo3- move in same direction.
so, simple cause. So, respiratory acidosis with compensatory metabolic alkalosis.


Step: 6  

Compensation in chronic cause of respiratory acidosis 

HCo3 rise = (2.62 X 66.5)/7.50 = 23.23

So, expected HCo3 = 40 + 23.23 = 63.23 , so fully compensatory.

So, chronic respiratory acidosis with fully compensatory metabolic acidosis with Type 2 respiratory failure due to decrease respiratory drive in a patient of COPD. 

Third Example - ABG Report of the Patient

Third Example - ABG Report of the Patient

Example:- (3)

A young adult of 30 Years suffering from Type 1 Diabetes mellitus from last 5 years, not taking insulin, admitted in emergency department of DMCH with the complain of vomiting, loose motion drowsiness and found tachycardia, hypotension, dehydration , increased rate of respiration (34/m). ABG was done on 12/02/15 at 4.36 PM.

ABG Analysis:

 (i) Gas Analysis

Step:1

   PaO₂ - 139.0 mm of Hg –> High due to use 

                                               of High Fio₂

Step:2

   PAO₂ - 139.0 mm of Hg –> Above normal

                                               alveolar oxygen 

                                               content due to

                                               high Fio₂ .

Step:3

   P(A-a)O₂   = (139.0-139.0) mm of Hg

                    = 0 mm of Hg –> No Parenchymal 

                                                lung disease.

Step:4

   PaCo₂ ->  11.3 mm of Hg –> Hyperventilation

Step:5
   No Hypoxemia/No respiratory failure.

Step:6
   P/F = 661.8 –> No ALI/ARDS –> gas exchange is very good.  

Step:7
   SPO₂^- = 96.5 –> Probably due to increase H⁺ there is Rt shift of the Hb dissociation curve. So, PaO₂ increase and SpO₂ relatively Low.

Step:8

   CaO₂ = 15.9X10X1.34X96.5/100+0.003X139.0
             = 205.60 + 0.417
             = 206.01 ml/L

Normal value for this 40 Mg adult man should be approximate  111 ml/L. So oxygen to be avoided to protect from oxygen toxicity.

(ii) Electrolyte Analysis

Upper limit – due to loss of body water content & Cl- is a bit high due to metabolic acidosis.

Ca++ -> 1.172 - High
K+     ->  4.18 - normal , but its value should be high due to decrease blood pH.
For 0.10 decrease of pH.
Increase of K⁺ should approximate 0.6 mmol/L.
So for 7.029 of pH –> K⁺ should have increased value upto (N⁺2.226)mmol/L.
Low level is due to GIT and / or Renal loss.

Anion Gap

AG = 144.9-(116.7+2.9)

      =144.9-119.6 = 25.3/29.5 (derived by machine)

Perhaps K⁺ is also taken in consideration by the machine.

Delta Gap

Delta gap+ measured HCo3 = 17.5 +2.9=20.4 –> low (normal 22-26 mmol/L)
                                             i.e. non anion gap metabolic acidosis.

Gap - Gap Ratio
Gap -gap ratio = (29.5-12) / (24-2.9) = 17.5 / 21.1 = 0.83 <1
i.e. normal AG metabolic acidosis and treatment with N/S (Hyperchloronic).
In this case patient had been gives 3L of N/S before the ABG was done.

Base Excess

BE = 2.9-24 = -21.1 (Derived value by machine -25.8)

Negative value suggestion metabolic acidosis. (So non respiratory cause of Acidosis).

(iii) Acid - Base Analysis

Step:1

        pH = 7.029

        H⁺ = 93.6 nmol/L

        So acidemia.

Step:2

        HCo₃ = 2.9 mmol/L (< 24 mmol/L) so, metabolic acidosis.

Step:3

        PaCo₂ = 11.3 mm of Hg (< 40 mm of Hg) so, respiratory alkalosis.

Step:4

H⁺ & HCo₃^- moves in opposite direction.

so, metabolic cause.

Step:5

So, PaCo₂ & HCo₃^- moves in same direction.

so, simple cause.

So, the patient have metabolic acidosis (primary cause) with compensatory  respiratory alkalosis.

Step:6    
      
 Compensation - Expected PaCo₂ fall = 1.2 X (24-2.9)

                                                            = 1.2 X 21.6

                                                             = 25.32

                            So, expected PaCo₂ = 40-25.32

                                                             = 14.68

       So, metabolic acidosis with fully compensatory respiratory alkalosis.

Final Diagnosis

High and normal AG metabolic acidosis with fully compensatory respiratory alkalosis with hyperventilation with low value of K⁺ is this condition.

Causes of high AG  metabolic acidosis

M – Methanol                        - No history in this patient

U – Uraemia                          - Blood urea/ s.creatinine/spot urinary ACR /                                                   Input- output chart. 

                                                                                     

D – Diabetes mellitus            - This is the cause

P – Paraldehyde                    - No history

I – Infection,Ischaemia,Isoniazide – CBC,ECG required

L – S.lactate                - to be estimated

E – Ethanol                            - No history

S – Starvation,                      - Present for 2 days

       Salicylat                        - No history.

Causes of Normal AG  metabolic acidosis 

• Gastrointestinal loss of HCO₃ in diarrhoea (which was presenting problem).
•  Renal Tubular Acidosis -> to be excluded by normal AG with no evidence of gastrointestinal disturbance and urinary pH is inappropriately high >5.5 .

Second Example - ABG Report of the Patient

Example: (2)

ABG Report of the patient

A patient of constrictive pericarditis, who had breathlessness on slight movement from one month admitted in stuporosed condition in emergency department of DMCH on 15/01/15.

ABG was done on 15/01/15 at 9.39 PM.

ABG Analysis: 

    (i) Gas Analysis

Step:1

   PaO₂ – 49.8 mm of Hg – Moderate  hypoxemia

   SPo₂ – 70.5 % - Severe hypoxemia

There is slight  left shift of the oxygen dissociation curve, most probably due to decrease in temperature.

Step:2

  PAO₂ - 49.8 mm Hg – low

So, either Fio2 low or PaCo2 high.

Step:3

  P(A-a)O2 = (49.8 – 49.8) mm Hg.

                  = 0 mm of Hg – normal

Step:4

  PaCo2 – 122.5 – Hypercapnea – hypoventilation

So, the patient has hypoxemia with Hypercapnea

 i.e. Type 2 Respiratory failure.   

Due to advanced stage of LVF.

Step:5

Here PaCo2 is increased, and P(A-a)O2 is not increased , so the cause is hypoventilation alone  and since the patient had no neuromuscular disease , so it is due to decreased respiratory drive due to critical illness.

Step:6

P/F index or hypoxemia index = 237.3

x-ray finding does not suggest progressive diffuse pulmonary infiltration , feature of

pneumonia . So it can be due to heart failure or arterial hypoxemia.    

Step:7

There is slight mismatch in the relation between SPo2 and PaO2.

Cause of mismatch is left shift of the oxygen dissociation curve most probably due to low temperature.

Step:8

Hemoglobin and HCT value are high indicating polycythaemia mosr probably due to hypercapnea . we calculate arterial oxygen content

                CaO2= 16.4X10(gm/L) X 1.34 X 70.5 / 100 + 0.003 X 49.8

                         = 154.93 + 0.149

                         = 155.08 ml/L

Expected CaO2 in a 70 Kg person is 194.44 ml/L.

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(ii) Electrolyte Analysis

               S.Na₊  - 130.7 mmol/L  – low

               S.Cl_-   - 86.5      mmol/l  – low

               S.iCa – 0.915 mmol/L  – normal

               S.K₊   - 5.31      mmol/L    – high

Decrease level of   s.Na+ and Cl-is due to fluid retention.high level of K+ matches with the change  in pH due to acidosis.

Anion Gap :-

            AG = [130.7]-[86.5+43.4]

                  = 130.7-129.9

                  = 0.8 mmol/l

Derived AG is 6.1 mmol/L

This increased level of AG is due to increased in unmeasured anion.

Delta Gap :-

              = 6.1-12

              =  -5.9

Delta gap + HCo3 = -5.9+43.4

                              = 37.5 – metabolic alkalosis.

Gap-Gap Ratio :-

               = -5.9 /(24-43.4)

               = -5.9/-19.4

               = 0.30 <1

BE :-

      BE= 43.4 – 24=19.4

So,metabolic alkalosis.

******************************************************************************************

(iii) Acid Base Analysis

Step:1

Step:2

  Hco3 – 43.4 mmol/L – Metabolic alkalosis

Step:3

  PaCo2- 122.5 – Respiratory acidosis

Step:4

Step:5





Expected cause of Acid-Base change in simple.

So, respiratory acidosis with compensated metabolic alkalosis.

Compensation of Hco3 In chronic condition

                        = 2.62 X 122.5/7.50 kpa=42.79

So, expected value of Hco3  = 24+42.79=66.70

Compensation of Hco3 In acute condition

                       = 0.75X 122.5/7.5 = 12.25

So, expected value of Hco3 = 24+12.25=36.25

So,respiratory acidosis with chronic compensated metabolic alkalosis.

******************************************************************************************

Final diagnosis

Respiratory acidosis with chronic compensated metabolic alkalosis with hypoxemia and dilutional huponatremia

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Causes of Respiratory Acidosis

In this case it is ventilatory failure due to decreased respiratory drive or due to respiratory muscle weakness.