Goldberg JS et al, 1990, UK | 62 men aged 18–70 years old, ASA I, II and III. Simulated difficult intubation drill, using laryngoscope to increase larynoscopy grade. | Prospective observational study | 3 separate observers recorded time to recognition of tracheal and oesophageal intubation, by observing IR capnography, FEF end-tidal colourimeter, and auscultaion respectively. | All three methods confirmed correct positioning in 100% (n=51) cases. Colourimeter and capnograph were faster than chest auscultation. All oesophageal intubations (n=11) confirmed by all 3 methods. One oesophageal intubation gave mild colour change but correctly interpreted. | Study only used haemodynamically stable patients |
| | | | | Observers were specialist anaesthetic staff as were those intubating |
| | | | | Observers not blinded to other detection methods |
Anton WR et al, 1991, USA | 60 emergency intubations, out with theatre – respiratory failure n=29, CPR n=9, self-extubation n=7, ET tube change n=6, airway protection n=3. ? other 6 | Prospective observational study | Observation of colour change in FEF colourimeter within 6 breaths post intubation. Observation of a positive signal from portable TRIMED IR CO2 detector within 6 breaths post intubation | Positive signal of exhaled CO2 produced within 6 breaths by 59 of 60 by FEF detector, and 58 of 60 by TRIMED. Of the 9 CPR patients 5 showed a colour change that was “subtle”, into the brown range. One patient receiving CPR took 20 breaths before a positive signal was received in either | Doctors were presumably anaesthetists |
| | | | | There were no oesophageal intubations |
Kelly JS et al, 1992, USA | 20 children age 6 months to 8 years undergoing elective anaesthesia | Prospective observational study | Colour change in Fenem CO2 detector versus IR capnographer reading in 1.spontaneous mask ventilation 2.post tracheal intubation10 breaths during each point were monitored | Of total 400 breaths, 398 registered yellow colour in the FEF colourimeter with expiration. This correlated with capnography readings.
2 breaths fell into brown range–both of these during mask ventilation, corrected by mask adjustment | All patients haemodynamically stable, with optimal intubating conditions |
| | | | | There were no oesophageal intubations |
| | | | | Participants were specialist anaesthetists |
Puntervoll SA et al, 2002, Norway | 14 female patients undergoing general anaesthesia | Experimental study | Detection of tracheal placement | 100% in both devices | Small numbers |
| | | | | Not emergency intubation |
| All had both tracheal and oesophageal tubes passed | | Detection of oesophageal misplacement | In 5 patients with expired air placed in the oesophagus the colourimeter changed colour | |
| CO2v capnography | | | | |