Agitation Sedation Research Articles

Sedation monitoring in ICU

Summary Sedation monitoring in intensive care unit (ICU) is necessary to avoid the problems related to both under and over sedation but there is no gold standard. The aim of this article is to review the methods used for sedation monitoring in ICU. Each method should be evaluated in terms of validity, applicability, responsivity, intra-rater reliability and inter-rater reliability. Both subjective and objective methods for monitoring sedation are available. Subjective methods include clinical scales; the Ramsay Scale, the Glasgow Coma Scale modified by Cook and Palma, the Sedation Agitation Scale, the Richmond Agitation and Sedation Scale, the Adaptation to the Intensive Care Environment (ATICE) scale and the Comfort scale for paediatric patients. Objective methods include: pharmacokinetic methods, lower oesophageal sphincter contractility measurement, heart rate variability measurement and neurophysiologic methods. Recently technological developments use neurophysiology and these include evoked potentials, electroencephalography and derived parameters such as Bispectral Index, Entropy, Patient State Index and Narcotrend. When neuromuscular blockade or sedation is administered to patients objective methods are fundamental to assessment of the sedation level. Studies of objective methods produce controversial results suggesting the ideal method is not yet available.

Phenobarbital Provides Effective Sedation for a Select Cohort of Adult ICU Patients Intolerant of Standard Treatment: A Brief Report

Purpose Critically ill patients are occasionally resistant to, or become intolerant of, standard sedating agents. We describe our experience using phenobarbital (PB) as an alternative sedative in a select cohort of patients. Methods Medical records of adult patients treated with PB for sedation were retrospectively reviewed. Patients receiving barbiturates for seizures, brain injury, or drug withdrawal protocols were excluded. Data are presented as mean ± standard deviation or median (range). Results Seven patients were treated with PB after failing standard medications due to refractory agitation (five patients) or propylene glycol toxicity (two patients). Patients were 35 ± 10-years-old, six were female (86%), APACHE II was 16 ± 5, ICU stay was 16 (8 to 88) days, and all seven patients survived. Four patients were initially sedated with lorazepam (mean daily dose = 163 mg), two with propofol (mean dose = 51 mcg/kg/min), and one with both. All seven received fentanyl for analgesia. Patients were switched to PB on ICU day-6 (3 to 50) with 240 (60 to 490) mg given the first day in divided doses. Subsequent doses were titrated to desired response, typically Sedation Agitation Scale (SAS) 3. PB was continued for 6 (3 to 21) days. Quality of sedation appeared similar when assessed with average SAS of 3.5 pre vs 3.7 post, as well as, by the absence of both oversedation (SAS less 3) and medical device removal. Hemodynamic derangements were not noted, and four patients were extubated while receiving PB. Conclusions PB provides adequate sedation and may be an alternative for patients intolerant or unresponsive to standard agents.

Bispectral Index monitoring correlates with sedation scales in brain-injured patients*

Monitoring critically ill, brain-injured patients with a decreased level of consciousness is challenging. Our goal is to determine in this population the correlation between the Bispectral Index (BIS) and three commonly used sedation agitation scales: the Richmond Agitation-Sedation Scale (RASS), the Sedation-Agitation Scale (SAS) and the Glasgow Coma Scale (GCS) scores. Prospective, single-blinded observational study. Eight-bed neurology-neurosurgery intensive care unit at the Cleveland Clinic Foundation. Thirty critically ill patients admitted to the neurointensive care unit with primary brain injury and a decreased level of consciousness. Patients were prospectively evaluated for level of consciousness using the RASS, SAS, and GCS every hour and simultaneously were monitored continuously with a BIS monitor for 6 hrs. A Spearman's correlation coefficient was used to correlate the BIS scores with clinical scales. In 15 patients monitored with the newer BIS XP version, the BIS values correlated significantly with the RASS (R2 = .810; p < .0001), SAS (R2 = .725; p < .0001), and GCS (R2 = .655; p < .0001). In 15 patients monitored with the older BIS 2.1.1 software, the correlation was as follows: for RASS, R2 = .30 (p < .008), for SAS: R2 = .376 (p < .001), and for GCS: R2 = .274 (p < .015). This correlation was maintained in patients who received sedative medications. A statistically significant correlation existed between BIS values and the RASS, SAS, and GCS scores in critically ill brain-injured patients, with and without sedation. The newer BIS XP software package may be a useful adjunctive tool in objective assessment of level of consciousness in brain-injured patients.

Quantifying agitation in sedated ICU patients using heart rate and blood pressure

Agitation is a significant problem in the intensive care unit (ICU), affecting 71% of sedated adult patients during 58% of ICU patient-days (Fraser and Riker 2001 NY Health-Syst. Pharm. 20 17–24). Subjective scale-based assessment methods are currently used to assess the level of patient agitation, but are limited in their accuracy and resolution. This research develops an objective agitation measurement method using heart rate variability (HRV), systolic blood pressure (BP) and blood pressure variability (BPV) data, processed by wavelet transforms and autoregressive signal processing. A fuzzy inference system (FIS) is developed to classify changes in these signals that correlate with observed patient agitation, and combine them into a final agitation level. Proof of concept clinical trials on 13 normal subjects and 5 ICU patients has been performed to verify the validity of this approach in comparison with agitation graded by nursing staff using the Riker sedation–agitation scale (SAS). Results show good correlation with medical staff assessment with no false positive results during calm periods. Clinically, this initial agitation measurement method promises the ability to consistently and objectively quantify patient agitation to enable better management of sedation and agitation through optimized drug delivery leading to reduced length of stay.

Benzodiazepine Sedation in Critically Ill Patients

Agitation is a common phenomenon in critically ill patients. This multidimensional challenge can prolong illness, interfere with treatment, and harm the patient. The nurse must assess the cause of the agitation and provide effective, timely intervention. Agitation is defined as motor restlessness secondary to possible physiologic, psychologic, environmental, and pharmacologic causes. The nurse has many effective assessment tools to systematically determine the cause of the agitation, including an agitation algorithm and sedation scale. With astute assessment and intervention, agitation can be prevented and treated to enhance recovery from critical illness. Benzodiazepines are an effective treatment intervention for agitation. With thorough knowledge of the actions and potential effects of these drugs, the nurse can provide the best pharmacologic intervention to treat agitation in the critically ill patient.