PT  - JOURNAL ARTICLE
AU  - Keil, V.C.
AU  - Eichhorn, L.
AU  - Mutsaerts, H.J.M.M.
AU  - Träber, F.
AU  - Block, W.
AU  - Mädler, B.
AU  - van de Ven, K.
AU  - Siero, J.C.W.
AU  - MacIntosh, B.J.
AU  - Petr, J.
AU  - Fimmers, R.
AU  - Schild, H.H.
AU  - Hattingen, E.
TI  - Cerebrovascular Reactivity during Prolonged Breath-Hold in Experienced Freedivers
AID  - 10.3174/ajnr.A5790
DP  - 2018 Oct 01
TA  - American Journal of Neuroradiology
PG  - 1839--1847
VI  - 39
IP  - 10
4099  - http://www.ajnr.org/content/39/10/1839.short
4100  - http://www.ajnr.org/content/39/10/1839.full
SO  - Am. J. Neuroradiol.2018 Oct 01; 39
AB  - BACKGROUND AND PURPOSE: Experienced freedivers can endure prolonged breath-holds despite severe hypoxemia and are therefore ideal subjects to study apnea-induced cerebrovascular reactivity. This multiparametric study investigated CBF, the spatial coefficient of variation as a correlate of arterial transit time and brain metabolism, dynamics during prolonged apnea.MATERIALS AND METHODS: Fifteen male freedivers (age range, 20–64 years; cumulative previous prolonged breath-holds >2 minutes and 30 seconds: 4–79,200) underwent repetitive 3T pseudocontinuous arterial spin-labeling and 31P-/1H-MR spectroscopy before, during, and after a 5-minute breath-hold (split into early and late phases) and gave temporally matching venous blood gas samples. Correlation of temporal and regional cerebrovascular reactivity to blood gases and cumulative previous breath-holds of >2 minutes and 30 seconds in a lifetime was assessed.RESULTS: The spatial coefficient of variation of CBF (by arterial spin-labeling) decreased during the early breath-hold phase (−30.0%, P = .002), whereas CBF remained almost stable during this phase and increased in the late phase (+51.8%, P = .001). CBF differed between the anterior and the posterior circulation during all phases (eg, during late breath-hold: MCA, 57.3 ± 14.2 versus posterior cerebral artery, 42.7 ± 10.8 mL/100 g/min; P = .001). There was an association between breath-hold experience and lower CBF (1000 previous breath-holds reduced WM CBF by 0.6 mL/100 g/min; 95% CI, 0.15–1.1 mL/100 g/min; P = .01). While breath-hold caused peripheral lactate rise (+18.5%) and hypoxemia (oxygen saturation, −24.0%), cerebral lactate and adenosine diphosphate remained within physiologic ranges despite early signs of oxidative stress [−6.4% phosphocreatine / (adenosine triphosphate + adenosine diphosphate); P = .02].CONCLUSIONS: This study revealed that the cerebral energy metabolism of trained freedivers withstands severe hypoxic hypercarbia in prolonged breath-hold due to a complex cerebrovascular hemodynamic response.ATPadenosine triphosphateASLarterial spin-labelingASL-sCoVspatial coefficient of variation of CBF (by ASL)ATTarterial transit timeCVRcerebrovascular reactivityHRheart ratePiinorganic phosphatesPCrphosphocreatinepO2partial pressure of oxygenSpO2oxygen saturation