The effects of hyperventilation on axonal excitability parameters in patients with diabetes mellitus and polyneuropathy.

AIMS: We aimed to explore axonal excitability parameters in patients with diabetes mellitus (DM) and polyneuropathy (PNP) as well as those without PNP.

METHODS

We used the short TROND protocol by QTRAC to measure axonal excitability parameters (strength-duration time constant (SDTC), rheobase, etc.) in 12 healthy subjects and 14 DM patients with PNP and 10 DM patients without PNP. The short TROND protocol was performed before and after 20min of deep hyperventilation in healthy subjects and patients with DM. Also, venous blood pH and partial pressure of O2 and CO2 were recorded before hyperventilation (HPV) and after 20min of HPV. A "hyperventilation score" was evaluated before and after HPV.

RESULTS

When the values of DM with PNP group and control group before HPV were compared, SDTC and latency were statistically significant. Comparing the values of the excitability parameters after HPV showed statistically significant changes in the SDTC, rheobase, and refractoriness at 2.5ms in controls and DM patients without PNP. HPV resulted in no changes in SDTC in DM patients with PNP.

CONCLUSION

The results of this study suggest that patients with DM and healthy subjects have different responses to HPV, and pH changes have different effects on diabetic PNP compared with healthy controls and DM patients without PNP.