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 Fio2.
Step:2
PAo2 = 135.3 mm of Hg – Above normal, due to high Fio2.
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

4th Example – ABG Report of the Patient

4th Example of ABG Analysis
4th Example of ABG Analysis

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
step-4H+ & HCo3 move in same direction. so, respiratory cause.
Step: 5
step-5So, 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.

1st Example – ABG Report of the Patient

Example: (1) 
A known case of chronic kidney disease admitted in EOPD, D.M.C.H. with the c/o Breathlessness with decreased urine output.

ABG Analysis:

ABG Report of the patient
ABG Report of the patient

(i) Gas Analysis
Step:1
PaO2 =36.9 mm of Hg.
SPO2 =52.4 %
Severe Hypoxemia.

Step: 2
PAO2 =114.9
 Normal.  

Step: 3
P(A-a)O2=(114.9-36.9)
=78 -> increased
Parenchymal lung disease.

Step: 4
PaCo2=30.2 mm of Hg -> low
So, Type 1 respiratory failure.

Step: 5
O2 therapy (6 L/m through C-PAP) for 2 hrs
Improved to some extent. So the causes may be
Ventilation / perfusion mismatch i.e.

  •  Airway disease .
  •  Interstitial lung disease.
  • Alveolar disease.
  • Pulmary vascular disease.

Step: 6
P/F=36.9/21 X 100
= 175.7 mm Hg.
ALI/ARDS to be decided by excluding, pneumonia or heart failure. There should be (progressive diffuse pulmonary infiltration in x-ray) and  arterial hypoxemia.

Step: 7  
Relation of PaO2 and SPO2 is normal.

Step: 8
CaO2 = 10X5.6(gm/L)X1.34X52.4/100+0.003X36.9 ml/L
= 39.32+0.11
= 39.43 ml/L
Wt. Of the patient is 58 kg.
So,expected CaO2 = 161.11 ml/L
Available CaO2   = 39.43 ml/L
So, Blood transfusion is also indicated.

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(ii) Electrolyte Analysis

S.Na    – Normal
S.Cl     – raised -> may be due to metabolic acidosis.
S.Ca++  – low    -> may be due to hypoalbuminemia.
S.K+        – high    -> may be due to acidosis/Renal Dysfunction
Anion Gap :-
AG = 140.5-[110.7+11.4]
= 140.5-122.1
= 18.4  but it is 25.6 as derived by machine. It may be due to hypoalbuminemia.
AG > 20 so, primary metabolic acidosis.

Delta Gap :-
Delta Gap = 25.6-12
= 13.6
Delta Gap + HCo3 = 13.6+11.4
= 25 -> Normal range

Gap-Gap Ratio :-
Gap/Gap ratio = 13.6/12.6 >1
But delta gap + HCo3 is normal.
So their is less chance of associated metabolic alkalosis.

BE :-
BE = 11.4-24
= -12.6  ->  Base deficit
So, Metabolic acidosis.

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(iii) Acid-Base Analysis
Step: 1
pH = 7.193
H+ = 64.1 nmol/L
So acidemia.
Step: 2
HCo3 = 11.4 mmol/L
(< 24 mmol/L) so, metabolic acidosis.

Step: 3
PaCo2 = 30.2 mm of Hg
(< 40 mm of Hg) so, respiratory alkalosis.

Step: 4

Step: 5

Step: 6
Compensation –
Expected, PaCo2 fall = 1.2 X (24-11.4 )
= 1.2 X 12.6
= 15.12
So, expected PaCo2  = 40-15.12
= 24.88
So, metabolic acidosis with incomplete compensatory respiratory alkalosis.

Step: 7
AG = 25.6
High anion gap metabolic acidosis.
Delta gap + HCo3 -> normal.
So, no normal anion gap metabolic acidosis and no metabolic alkalosis.

Step: 8

Final diagnosis – High anion gap metabolic acidosis with incomplete compensatory respiratory alkalosis with type 1 respiratory failure with Hyperkalaemia with Hypocalcaemia.

Causes of High Anion Gap Metabolic Acidosis

M – Methanol                    – No history in this patient
U – Uraemia                      – Present
D – Diabetes mellitus          – Not present
P – Paraldehyde                 – No history
I – Infection, Ischaemia, Isoniazide – Infection present, No Ischaemia , No H/O Isoniazide
L – S.lactate                     – Not done
E – Ethanol                       – No history
S – Starvation, Salicylate  – Starvation present, No H/O Salicylate intoxication
So, Acidosis is most probably due to Infection, Uraemia.

Cause of Type 1 RF

X – Ray chest suggest pneumonia.
Cause of Type 1 RF

Prognosis:- 
Since hypoxemia is severe and there is associated Anaemia, hyperkalaemia, pneumonia and uraemia, so prognosis is not good even with haemodialysis, blood transfusion and close monitoring of the patient.