Protocol for a prospective, observational cohort study of awareness in mechanically ventilated patients admitted from the emergency department: the ED-AWARENESS study

IntroductionAwareness with paralysis is a complication with potentially devastating psychological consequences for mechanically ventilated patients. While rigorous investigation into awareness has occurred for operating room patients, little attention has been paid outside of this domain. Mechanically ventilated patients in the emergency department (ED) have been historically managed in a way that predisposes them to awareness events: high incidence of neuromuscular blockade use, underdosing of analgesia and sedation, delayed administration of analgesia and sedation after intubation, and a lack of monitoring of sedation targets and depth. These practice patterns are discordant to recommendations for reducing the incidence of awareness, suggesting there is significant rationale to examine awareness in the ED population.Methods and analysisThis is a single centre, prospective cohort study examining the incidence of awareness in mechanically ventilated ED patients. A cohort of 383 mechanically ventilated ED patients will be included. The primary outcome is awareness with paralysis. Qualitative reports of all awareness events will be provided. Recognising the potential problem with conventional multivariable analysis arising from a small number of events (expected less than 10—phenomenon of separation), Firth penalised method, exact logistic regression model or penalised maximum likelihood estimation shrinkage (Ridge, LASSO) will be used to assess for predictors of awareness.Ethics and disseminationApproval of the study by the Human Research Protection Office has been obtained. This work will be disseminated by publication of peer-reviewed manuscripts, presentation in abstract form at scientific meetings and data sharing with other investigators through academically established means.

SPECTRAL ENTROPY FOR ASSESSING THE PATIENT RESPONSIVENESS DURING PROPOFOL/FENTANYL SEDATION IN DAY CARE SURGERIES

Background: For day care surgery under monitored anesthetic care, precise monitoring of sedation depth facilitates optimization of dosage and prevents adverse complications from over sedation. Conventionally subjective sedation scales, such as the Modified observer’s assessment of alertness/ sedation scale (MOAA/S) have been widely utilized for sedation monitoring. The newer monitoring called entropy is considered to be beneficial for objective assessment with combined use of opioids and hypnotics if applied. The primary objective is to determine measurement of entropy as a marker for measuring depth of anaesthesia. Methods: Two groups P and PF ( with 25 patients each) received either propofol 1mg/kg followed by maintenance infusion of 250 mic/ kg/hr whereas “PF”group received additional single dose of fentanyl 2 mic/kg respectively. The values of response entropy (RE) and state entropy (SE) corresponding to each MOAA/S (5 to 0) were determined. Results: The patient’s demographic profile and clinical characteristics were comparable in both the groups. No difference observed in duration of anaesthesia and surgery in both groups. No difference observed in MOAA/S in both groups. The results shows a highly significant differences in the observed means of SE, RE, MAP and HR with considerably higher mean values in group P (p<0.0001). However other parameter such as SPO2, ETCO2 and RR were almost comparable in both groups. Conclusion: The mean value of SE and RE in group P and PF indicates that deeper plane of anaesthesia is observed in PF group. It is concluded that in assessing the level of hypnosis during intra-operative sedation in MAC, entropy corresponds to MOAA/S and increases or decreases proportionately depending upon increase or decrease level of sedation. Hence from these results it is proposed that entropy monitoring is a reliable monitoring index of anaesthesia depth in MAC. Keywords: Entropy, Propofol, Sedation, Day care surgery, Observer’s assessment of alertness/ sedation scale, Monitored anaesthesia Care

3 Is it acceptable to use technical monitoring to assess palliative care patients’ level of consciousness? a qualitative exploration with patients and relatives

IntroductionBispectral Index (BIS) monitoring uses electroencephalographic data to objectively measure patients’ level of consciousness and might be a useful supplement to clinical observation when using sedative medication in palliative care. However its acceptability to UK palliative care service users is unknown.AimTo explore the acceptability of BIS technology with UK hospice patients and relatives.MethodsWe conducted focus groups and individual interviews with patients and relatives in a UK hospice and analysed data thematically.Results10 patients and 15 relatives participated in seven focus groups and three interviews. Responses from patient participants were similar to those from relatives and four themes emerged:Knowledge and experience of current monitoring of sedation/consciousnessAcceptable duration of monitoringReservations about using technological devices in palliative carePotential benefits of using BIS.Participants’ comments on potential benefits included that BIS alongside routine clinical practice might help ensure comfort at the end of life and serve to assure medical needs are being met particularly for people who cannot communicate. Participants generally felt that the duration of BIS monitoring should be informed by each patient’s individual needs while some expressed that patients and/or families should be consulted before using the monitor. Participants also noted that BIS while possibly obtrusive is not invasive.ConclusionsOur participants considered BIS acceptable for monitoring level of consciousness and possibly helpful at the end of life. We therefore initiated an observational study exploring use of this technology in the clinical care of UK hospice inpatients.