75y old(single kidney,high creatinine,pressure ok),had dizziness since total colectomy surgery 6 months.co2 level is low(~114).may this be the reason?

Here are some ...: Has the dizziness been constant (24 hrs a day) or intermittent or just related with positioning? if constant, need to consider some change in central nerve system incurred in the recent past including drug use; if off & on or positioning-related, consider postural hypotention. In short, is there any problems in central nerve, drug effects (iatrogenic), or indeed low red blood cell count, etc.