Figure 4.

$\text{P}{\text{a}}_{\text{C}\text{O}}{}_{{}_2}$ at indicative baselines (resting nonimmersed and postpredive respiratory routine—referred to as “end of packing”) and the specimens taken during the two dives and at equivalent times during static surface apnea. Use of dotted lines represents an acknowledgment that the baseline measurements were indicative (not immediately before each dive or the static surface apnea). The solid lines link measurements made on the same dive and during surface apnea. $\text{P}{\text{a}}_{\text{C}\text{O}}{}_{{}_2}$, arterial partial pressure of carbon dioxide.