Table
1. Arterial Blood Gases in Open-Chest Mice
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ventilation
rate
|
|
|
|
(breaths/min)
|
|
|
|
|
|
|
|
Tidal
volume
|
|
|
|
(ml)
|
|
|
|
|
|
|
|
PaO2
|
|
|
|
(mmHg)
|
|
|
|
|
|
|
|
pH
|
|
|
|
|
|
|
|
PaCO2
|
|
|
|
(mmHg)
|
|
|
|
|
|
|
|
HCO3-
|
|
|
|
(mM/L)
|
|
|
|
|
|
|
|
Open-chest
mice (n=23) were ventilated using a tidal volume of 2.2±0.1 ml at
different rates in order to identify the optimal ventilation rate. The
mice were allowed to stabilize for 40 min after the chest was opened and
then arterial blood gases were measured in each animal. In mice ventilated
at a rate of 95±1 breaths/min (n=6), arterial pH was 7.30±0.02.
Increasing the ventilatory rate to 105±2 breaths/min (n=6)
resulted in a normal arterial pH (7.39±0.01) as well as in a higher
arterial pO2 (327±45 mmHg). A further increase in the
ventilatory rate to 121±1 breaths/min (n=11) caused the arterial
pH to be abnormally high (7.51±0.02) without any further increase
in arterial pO2 (321±36 mmHg). Accordingly, a ventilatory
rate of 105 breaths/min was used in the present study.
Data are means ± SEM. Reproduced from Ref. 2 with permission. |