Question

1. Patient is on a ventilator; explain how you would fix the following ABG:

7.25

69

70

24

-2.3

2) What does compliance have to do with the lungs?

3)What does the static compliance formula use that dynamic compliance does not?

Answer 1

1. ABG VALUE

Arterial blood PH - 7.25 ( 7.35-7.45)

PCO2 - 69 ( 3.5-4.5)

PO2 - 70 ( > 90 % )

HCO3 - 24 ( 22-36 )

Base Excess - -2.3 ( -2- +2 )

From the above ABG values,

Finding is RESPIRATORY ACIDOSIS ( decreased arterial PH and increased PCO2 )

2. Alveolar pressure is the air pressure inside the alveoli. Pleural pressure is the pressure of the fluid present inside the space between visceral pleura and parietal pleura. Normally the total compliance of both lungs in an adult is about 100 ml/cm of H2O. This means that in a normal lung, the administration of 500ml of air via positive pressure ventilation will increase the alveolar pressure by 5 cm H2O . Conversely ,the administration of a positive pressure of 5 cm H2O will generate an increase in lung volume of 500 ml

3.

Dynamic compliance is always lower than static compliance. The reason for this is that dynamic compliance also incorporates airflow resistance, in addition to usual chest wall pressure and lung pressure.m