pharm/physiology question

[jbro]

my teachers have described autonamic breathing reached during stage 3 of aneshtesia, as regular, rapid, and shallow, all of the literature i have read says that IAs decrease the ventilatory response to hypercarbia and hypoxia, my question is why is the respiratory rate increasing if the stimulus to breathe decreasing, and is this an acurate clinical picture.

[gaspassah]

as posted on another thread by passin gas.

Stage three anesthesia: Split into four planes--

Plane 1--regular breathing, active ocular muscles

Plane 2--eyes immobile, respiratory patterns change to decreased tidal volumes and increased rate, eyes become immobile

Plane 3--Surgical plane/stage of anesthesia--diaphragmatic breathing due to loss of intercostal muscles (muscle relaxant effect of inhaled anesthetics) further decrease in tidal volume with a less than compensatory increase in respiratory rate; end result is arterial carbon dioxide levels will increase; plus there is a diminished response by the chemoreceptors to increase ventilation in response to an increased arterial carbon dioxide level

Plane 4--Dilated pupils, irregular breathing

Stage four anesthesia: cardiovascular and respiratory collapse; don't go here.