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:

Intravenous lidocaine does not cause shivering-like tremor or alter thermoregulation . We tested the hypotheses that systemic absorption of epidural lidocaine : ( 1 ) contributes to the shivering-like tremor seen during epidural anesthesia by causing central nervous system disinhibition of spinal reflexes , or ( 2 ) activates or alters thermoregulatory mechanisms . In a double-blind , placebo , cross-over study , nine healthy volunteers were given intravenous lidocaine ( or saline ) to approximate the plasma levels of lidocaine achieved during epidural anesthesia for major abdominal surgery . Five volunteers were studied in a warm room ( to test for nonthermoregulatory tremor ) , and four volunteers were studied in a cold room ( to test the effects of lidocaine on normal thermoregulation ) . Central temperatures , peripheral vasoconstriction , tremor and clonus were unaffected by intravenous lidocaine . We conclude that the systemic absorption of epidural lidocaine does not contribute to tremor or shivering by these mechanisms .
{"Intervention": ["lidocaine", "placebo", "lidocaine :", "saline", "intravenous lidocaine"], "Outcome": ["activates or alters thermoregulatory mechanisms", "alter thermoregulation", ".", "Central temperatures , peripheral vasoconstriction , tremor and clonus", ")", "normal thermoregulation", "nonthermoregulatory tremor", "shivering-like tremor seen during epidural anesthesia", "tremor or shivering", "shivering-like tremor"], "Participant": ["major abdominal surgery ."]}