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

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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.

Third Example – ABG Report of the Patient

Example:- (3)

Third Example - ABG Report of the Patient
Third Example – ABG Report of the Patient

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

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 .

2nd Example – ABG Report of the Patient

Example: (2)

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 Report of the patient

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.

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(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.

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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.

 

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.