Arterial Blood Gas Reports

Question 1

when reading gas reports

Answer 1

ALWAYS START AT CO2 BECAUSE PCO2 IN BLOOD IS INVERSELY PROPORTIONAL TO VENTILATION

Question 2

Hyperventilation causing alkalosis

Answer 2

PCO2= high ( more co2> blood becomes acidic so pH lowers)
pH= more basic
PA-aO2 = small difference in PP due to anatomical right to left shunting
Bicarb = same

Question 3

Ventilatory failure causes acute respiratory acidosis

Answer 3

PCO2= way above normal = hypoventilation
pH= more acidic
PA-aO2 =
Bicarb = no change therefore - Aacute because NO CHANGE IN BICARB/
BROUGHT ON BY RESPIRATORY FAILURE

Question 4

Compensated ventilatory failure

Answer 4

PCO2= above, - hypoventilation
pH= normal
PA-aO2 = way lower
Bicarb =BICARB IS HIGHER = RENAL COMPENSATION

PATIENT IN DANGER BECAUSE MAY BECOME DEPENDANT ON HYPOXIC DRIVE TO BREATHE
COMPENSATION BETWEEN BLOOD AND BRAIN ECF

Question 5

Acute V/Q mismatch (asthma)

Answer 5

PCO2= below - hyperventilation
pH= RESPIRATORY ALKAHOLSIS
PA-aO2 = way greater (LOTS OF PHYSIOLOGICAL SHUNTING > ASTHMA)
Bicarb = same

Question 6

Acute asthma attack

Answer 6

 During an acute severe asthma attack, parts of the lungs are totally blocked of. Patients start to hyperventilate the still open parts of the lung. PCO2 below 40mmHg due to hyperventilation of still ventilated alveoli and the high diffusion coefficient of CO2; pH above 7.45 due to reduced CO2-induced [H+]; PO2 well below predicted range of 100 mmHg due to the large Ventilation/Perfusion mismatch (V/Q<1). After several hours patients’ respiratory muscles start to fatigue and ventilation decreases. This would lead to an increase in PCO2 to normal values leading to a normal pH but an even further decrease in PO2.

Question 7

Compensated V/Q mismatch

Answer 7

PCO2= below - hyperventilation
pH= normal (slightly higher)
PA-aO2 = way greater (LOTS OF PHYSIOLOGICAL SHUNTING > ASTHMA)
Bicarb = low

Question 8

Mixed ventilation failure and V/Q mismatch

Answer 8

PCO2= hypo.
pH= normal (slightly higher)
PA-aO2 = <10 35mm
SHUNTING > ASTHMA)
Bicarb = slightly higher

Question 9

Metabolic acidosis causing hyperventilation

Answer 9

PCO2= hyper.
pH=acidic - therefore CAN’T BE LINKED TO RESPIRATORY SYSTEM SO METABOLIC ACIDOSIS
PA-aO2 = below norm
Bicarb = very low

Question 10

Mixing high and low V/Q regions

Answer 10

Mixed blood
PO2 below normal
PCO2 below normal