The Safety of Ketamine versus Propofol in the Sedation of Acute Psychiatric/ Psychotic Patients requiring Aeromedical Retrieval - A Randomised Clinical trial

Final Updates Between 16th September 2016 and 2nd September 2020, a sample size of 1078 acute psychiatric patients were retrieved in the Top End of the NT by CareFlight. Of the sample 76.5% of patients identified as First Nations people. 731 patients met the primary inclusion criteria being >18 years of age, an involuntary patient who had been sectioned under the Mental Health and Related Services Act 1998, had a flight doctor present for the retrieval and did not have evidence of an organic delirium. Of these 177 patients met the secondary inclusion criteria of a Richmond Agitation Sedation Score (RASS) of +1 to +4, a GCS >8, an absence of a sedation infusion prior to CareFlight’s arrival and no evidence of an organic delirium on assessment. From the 177, and considering the initial and secondary inclusion criteria, 46 patients had a deviation from the study protocol and were excluded from the study. Twenty of these patients had ketamine commenced by the referring centre prior to CareFlight arriving. After randomisation to either ketamine or propofol, the flight doctor found 22% of patients were insufficiently sedated necessitating the introduction of secondary sedation. 82% of these patients were started on ketamine sedation and required the introduction of propofol to maintain the patient’s safety in flight. Two patients had recorded adverse reactions to ketamine, thus they received propofol. In other deviations the flight doctor did not feel comfortable administering the randomised drug and defaulted to the other trial drug. Of the 1078 patients retrieved, ten patients were intubated (<1%). 131 patients met the primary and secondary inclusion criteria and were randomised to receive Ketamine or Propofol for sedation. For all patients randomised to the trial, the flight doctors were not able to obtain verbal consent from the patient or their families at the referring centre. Delayed consent was required for 100% of the patients post retrieval. Six patients withdrew consent to participate in the study and they were excluded. 125 patients received either Ketamine (44%) or Propofol (56%) during flight. Of these, 116 patients were lost to follow up and nine patients gave delayed consent. Patients were lost to follow up as they were discharged from mental health services in Darwin and had not made it back to the community, there was no answer on phone numbers provided to the clinic or the clinic were not able to follow patient up in the community. 72.8% of the patients who were included in the trail identified as First Nations, 79% were less 40 years old and 64.8% were male. 46.4% of patients in the trial were diagnosed with acute psychosis, 23.2% with drug induced psychosis and 10.4% with suicidal ideation. Other diagnoses included attempted hanging, bipolar disorder, depression, mania and schizophrenia. SUMMARY: AIM Randomise 400 patients to either Ketamine or Propofol arms of the research. OUTCOME: 119 patients were randomised to and received either Propofol or Ketamine. The low number can be explained by the implementation of better pre-sedation administration and protocols over the lifetime of the study. AIM: To compare a Propofol administration protocol with a Ketamine administration protocol in terms of safety and flight crew satisfaction when used in the sedation of acute psychiatric/psychotic patients requiring aeromedical retrieval in Australia. OUTCOME: 5% of flight doctors were satisfied or strongly satisfied with the sedation provided by Propofol. 56% were satisfied or strongly satisfied with the sedation provided by Ketamine. AIM: To the use of investigate the use of airway, breathing and circulatory interventions when using either Ketamine or Propofol to sedate patients with an acute psychiatric/ psychotic illness/ event. OUTCOME: Airway interventions Suction was required by six patients and an oropharyngeal airway was required on three patients. An airway manoeuvre, either a jaw thrust or a chin lift, was required on 16 patients, of who 13 had received propofol. Eight patients require stimulation post sedation. Hypersalivation was seen in one patient who received ketamine. Breathing Interventions Nil patients required bag/ valve mask ventilation. Seventeen patients required oxygen via Hudson mask (4-12 Litres), 24 patients required oxygen via nasial prongs (2-4 Litres) and three patients required oxygen via a non-rebreather mask 9-15 Litres). 61% of patient who required oxygen were given propofol. Circulation Interventions Twelve patients required a fluid bolus of 500-1000mls of either Plasmalyte or Normal Saline 0.9%. Observations Five patients had a systolic blood pressure (SBP) <90mmHg; four of these patients received propofol and all five required fluid boluses to bring their SBP to >90mmHg. 36% of patients who received either ketamine or propofol during flight measured an end tidal carbon dioxide (ETCO2) level of <30mmHg and 26% had an oxygen saturation <95%. There were nil patients who had a respiratory rate (RR) <8 breaths per minute (bpm) and there were five patients with a RR >25 bpm. AIM: To investigate the presence/ absence of post flight complications after sedation with either Ketamine or Propofol when sedating patients with an acute psychiatric/ psychotic illness/ event. OUTCOME: Of the 125 patients who received ketamine or propofol none of the patient had any documented post flight complications. There were no patients discharge summaries or radiology reports that suggested there was any post flight complications (including aspiration pneumonia) experienced by any of the patients in the trial.