Pain on i.v. injection of some anaesthetic agents is evoked by the unphysiological osmolality or pH of their formulations.
We have studied the intensity and time-course of pain during and after injection into an isolated vein segment in seven normal subjects of saline or glucose of different osmolalities (0-6 osmol kg-1) or pH (2-13). Pain scores were recorded continuously by a modified visual analogue scale apparatus. With osmolar stimulation, pain occurred at 1.0 osmol kg-1 during perfusion and 3.0 osmol kg-1 with rapid injection and increased with osmolar concentration of both saline and glucose solutions. Acidic and alkaline solutions evoked pain at a pH value less than 4 or greater than 11. We conclude that pain on i.v. injection of some sedative and hypnotic drugs is likely to be caused by formulations of extremely unphysiological osmolalities or pH values.
Klement
W
W
Department of Experimental Anaesthesiology, University of Düsseldorf, F.R.G.
Arndt
J O
JO
D000777:Anesthetics / Q000008:administration & dosage*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007275:Injections, Intravenous / Q000009:adverse effects*; D009994:Osmolar Concentration; D010146:Pain / Q000209:etiology*
D000777:Anesthetics