You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Successful difficult intubation . Tracheal tube placement over a gum-elastic bougie . A randomised study was carried out to assess the effect of tracheal tube rotation on the passage of a tube over a gum-elastic bougie into the trachea in 100 patients . The effect of the presence or absence of a laryngoscope on successful tube placement was also assessed . A grade 3 difficult intubation was simulated in patients with a laryngoscope . There was a significant difference in the rates for successful first-time intubation in those patients with tube orientation of -90 degrees ( with the bevel facing posteriorly ) as compared with a tube orientation of 0 degrees ( the normal orientation with the bevel facing left ) . The unsuccessful first-time intubations with a 0 degree orientation were frequently converted to successful intubations with the -90 degrees position at a second attempt . The presence of a laryngoscope in the mouth while rail-roading a tube over the bougie also made a significant difference to the rate of successful first-time intubations . The most successful method was to leave the laryngoscope in the mouth and rotate the tube to -90 degrees .
{"Intervention": ["first-time intubation", "simulated", "intubation", "Tracheal tube placement", "tracheal tube rotation", "intubations", "laryngoscope", "gum-elastic bougie"], "Outcome": ["unsuccessful first-time intubations", "presence of a laryngoscope", "successful intubations", "successful first-time intubation", "successful", "rate of successful first-time intubations"], "Participant": ["patients with a laryngoscope ."]}