ABSTRACT
BACKGROUND: Reduced mouth opening may be a major contributing factor to the deterioration in the view obtained at laryngoscopy when a semi-rigid cervical collar is in place. We set out to assess the degree to which mouth opening is restricted by a cervical collar. METHODS: We measured maximal inter-incisor distance in 52 volunteers. It was measured again after application of each of three appropriately sized semi-rigid cervical collars (Stifneck, Miami J, and Philadelphia). RESULTS: Inter-incisor distance was significantly reduced by the application of a cervical collar [No collar 41 (7) mm-mean (SD); Stifneck 26 (8) P<0.0001; Miami J 29 (9) P<0.0001; Philadelphia 29 (9) P<0.0001]. There was a wide and unpredictable variation between subjects in the reduction in mouth opening and a significant proportion had an inter-incisor distance of 20 mm or less (Stifneck, 25%; Miami J, 21%; Philadelphia, 21%). CONCLUSIONS: Application of a semi-rigid cervical collar can significantly reduce mouth opening. This could hinder definitive airway placement. Our results support removing the anterior portion of the collar before attempts at tracheal intubation.
Subject(s)
Mouth/physiopathology , Neck , Orthotic Devices , Anthropometry , Cervical Vertebrae/injuries , Equipment Design , Female , Humans , Immobilization , Incisor/pathology , Intubation, Intratracheal , MaleSubject(s)
Braces , Cervical Vertebrae/surgery , Laryngeal Masks , Emergencies , Humans , Immobilization , Intubation, Intratracheal/methodsABSTRACT
A postembedding immunogold study of type I synaptic glomeruli in lamina II of rat dorsal horn was carried out using antiserum to gamma-aminobutyric acid (GABA). Gold particles were concentrated over some peripheral axons and vesicle-containing dendrites within these glomeruli and both types of profile were presynaptic to central axons. These results suggest that GABA is involved in presynaptic inhibition of unmyelinated primary afferents and is released by some presynaptic dendrites within lamina II.
