Paraesthesia with lumbar epidural catheters. A comparison of air and saline in a loss-of-resistance technique. The epidural space was located in 32 obstetric patients using loss of resistance to air, while in a further 35 saline was used. The incidence of paraesthesia was 56% in the air group and 57% in the saline group. There was no significant difference between the groups in terms of other complications or in the quality of analgesia provided. 