Blood gases

What is most likely to be wrong with the patient and how will

you manage them?

Case 1: 75F

Arterial

FIO2 0.5

pH 7.289 7.35-7.43

pO2 147 69-116

pCO2 26.4 32-45

BXS 13.1 -2 - +2

HCO3 12.3 22-26

Na 155 136-146

K 4.4 3.5-5.0

Cl 120 99-106

Glucose 46 3.9-5.8

Lactate 4.3 0.5-1.6

Hb 163 130-180

Case 1: 75F

Arterial

FIO2 0.5

pH 7.289 7.35-7.43

pO2 147 69-116

pCO2 26.4 32-45

BXS 13.1 -2 - +2

HCO3 12.3 22-26

Na 155 136-146

K 4.4 3.5-5.0

Cl 120 99-106

Glucose 46 3.9-5.8

Lactate 4.3 0.5-1.6

Hb 163 130-180

Give me a couple of diagnoses and tell me your management

Case 1: 75F

Arterial

FIO2 0.5

pH 7.289 7.35-7.43

pO2 147 69-116

pCO2 26.4 32-45

BXS 13.1 -2 - +2

HCO3 12.3 22-26

Na 155 136-146

K 4.4 3.5-5.0

Cl 120 99-106

Glucose 46 3.9-5.8

Lactate 4.3 0.5-1.6

Hb 163 130-180

DKA or HHS + relative

hypoxia + hypoperfusion ?

septic

Rehydrate slowly

Add insulin and K+

replacement once K+

known

Seek and treat source

CXR

Case 2 85F

Arterial

FIO2 1.0

pH 7.186 7.35-7.43

pO2 87.5 69-116

pCO2 37.8 32-45

BXS -12.9 -2 - +2

HCO3 13.7 22-26

Na 139 136-146

K 9.4 3.5-5.0

Cl 117 99-106

Glucose 8.6 3.9-5.8

Lactate 0.6 0.5-1.6

Hb 124 130-180

Case 2 85F

Arterial

FIO2 1.0

pH 7.186 7.35-7.43

pO2 87.5 69-116

pCO2 37.8 32-45

BXS -12.9 -2 - +2

HCO3 13.7 22-26

Na 139 136-146

K 9.4 3.5-5.0

Cl 117 99-106

Glucose 8.6 3.9-5.8

Lactate 0.6 0.5-1.6

Hb 124 130-180

Give me a couple of diagnoses and tell me your

management

Case 2 85F

Arterial

FIO2 1.0

pH 7.186 7.35-7.43

pO2 87.5 69-116

pCO2 37.8 32-45

BXS -12.9 -2 - +2

HCO3 13.7 22-26

Na 139 136-146

K 9.4 3.5-5.0

Cl 117 99-106

Glucose 8.6 3.9-5.8

Lactate 0.6 0.5-1.6

Hb 124 130-180

Life threatening

hyperkalaemia

Hypoxia

Severe acidosis with poor

respiratory compensation ?

Decr LOC

Salbutamol

Calcium gluconate

ECG

Repeat K+ sample

Find the cause

? Candidate for dialysis

Case 3: 3 year old with tachypnoea,

floppy, parents don’t speak local

languagesVenous

FIO2 0.21

pH 7.22 7.35-7.43

pO2 48 69-116

pCO2 24 32-45

BXS -2 - +2

HCO3 10 22-26

Na 139 136-146

K 1.9 3.5-5.0

Cl 118 99-106

Glucose 4.1 3.9-5.8

Lactate 2.5 0.5-1.6

Hb 107 130-180

Case 3: 3 year old with tachypnoea

Venous

FIO2 0.21

pH 7.22 7.35-7.43

pO2 48 69-116

pCO2 24 32-45

BXS -2 - +2

HCO3 10 22-26

Na 139 136-146

K 1.9 3.5-5.0

Cl 118 99-106

Glucose 4.1 3.9-5.8

Lactate 2.5 0.5-1.6

Hb 107 130-180

NB venous

Severe hypokalaemia

? diarrhoeal illness

What's going on and what are you going to do?

Probable gastroenteritis with life threatening hypokalaemia.

Mx (lots of ways to do it)

If really shocked IV boluses eg Hartmann's (K = 5mmol/L) 20mmol/kg boluses

till clinically intravascularly euvolaemic.

Then

Eg 20mmolKCL in 1/2NS + 5% dextrose run at double maintenance

(Maintenance = 4ml/kg for 1st 10kg + 2ml/kg for next 10kg + 1ml/kg

thereafter, (but in Alice they use 5ml/kg if under ) 40 + 8 ml/hour. Double

maintenance = 96ml/hour

Alternatively (RCH): 250ml/hour NS + KCL 20mmol/L for first 6 hours

if severely dehydrated (=5mmolKCL/hour), or 150ml/kg thereafter

Alternatively (CC) 280ml boluses of Hartmann's if shocked. Then or

otherwise: 250 0r 150ml/hour (depending on severity) NS + 5%

Dextrose + KCL 20mmol/L. Offer ORS. Stop IV fluid when taking >

10ml/kg/hour ORS.

ORS (liquid or icy pole) contains KCL 20mmol/kg.

Ondansetron 2mg SL wafer or IV

Case 4 78F SOB

Arterial

FIO2 0.21

pH 7.421 7.35-7.43

pO2 41.9 69-116

pCO2 50.8 32-45

BXS 7.8 -2 - +2

HCO3 32.4 22-26

Na 140 136-146

K 2.7 3.5-5.0

Cl 99 99-106

Glucose 6.0 3.9-5.8

Lactate 0.9 0.5-1.6

Hb 104 130-180

Is there an acid base disorder present? If so what?

No acidaemia or alkalaemia but probably respiratory acidosis (low HCO3, high CO2 and

hypoxia (or could be metabolic alkalosis with full compensation - but hypoxia

suggests respiratory process and don't usually get full compensation for metabolic

acidosis).

HypoK

Most likley secondary to any or all of:

●Alkalosis

●Salbutamol

●Diuretics

●Vomiting

Conclusion

Severely unwell patient who requires oxygen.

She has hypoxic and hypercapnic respiratory failure.

She is not acidaemic or alkalaemic probably on the basis of a compensated

chronic respiratory acidosis + another process eg

●metabolic alkalosis from vomiting or diuretics (also causing hypo K)

●acute respiratory acidosis

She is hypokalaemic from eg

●vomiting

●diuretics

●alkalosis

●salbutamol

She needs urgent correction of her hypoxia as first line therapy. She is likely

to require ventilatory support. Her K needs to be corrected.

Case 5. 71F with persistent vomiting

Arterial

FIO2 0.21

pH 7.671 7.35-7.43

pO2 28.2 69-116

pCO2 43 32-45

BXS 25.7 -2 - +2

HCO3 49.1 22-26

Na 129 136-146

K 1.9 3.5-5.0

Cl 71 99-106

Glucose 6.0 3.9-5.8

Lactate 1.8 0.5-1.6

Hb 136 130-180

Acid base disorder

Hypoxic +

Metabolic alkalosis

Causes

Most common GIT loss (vomiting) or diuretics

Chloride responsive

● GI loss

●Diuretics

●Chloride wasting disease

o cystic fibrosis

Non-chloride responsive

●hyperaldosteronism

oExpect hyperNa and hypoK

oeg renal artery stenosis, CCF, liver failure, nephrotic syndrome

Severe hypoK: 1.9

Likely to be as a result of vomiting

●Kidneys retain H at expense of K

Needs urgent correction and cardiac monitoring

Conclusion

Severe hypoxaemia requiring oxygen and probably ventilatory

support.

Hypoxaemia may be as a result of aspiration from vomiting

and exacerbated by respiratory compensation for metabolic

alkalosis

Given Hx of persistent vomiting, vomiting is probable cause of

metabolic alkalosis.

Needs volume, Na, Cl and K replacement eg NS + 40mmolKCL/

1 hour with cardiac monitoring

Case 6 74M SOB

Arterial

FIO2 0.21

pH 7.49 7.35-7.43

pO2 38.4 69-116

pCO2 26.7 32-45

BXS -2.8 -2 - +2

HCO3 20.1 22-26

Na 139 136-146

K 4.2 3.5-5.0

Cl 108 99-106

Glucose 6.2 3.9-5.8

Lactate 1.4 0.5-1.6

Hb 121 130-180

Conclusion

Severe hypoxic respiratory failure.

Patient requires oxygen and treatment of underlying process