Avery Tung

Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit

Objective:To revise the “Clinical Practice Guidelines for the Sustained Use of Sedatives and Analgesics in the Critically Ill Adult” published in Critical Care Medicine in 2002. Methods:The American College of Critical Care Medicine assembled a 20-person, multidisciplinary, multi-institutional task force with expertise in guideline development, pain, agitation and sedation, delirium management, and associated outcomes in adult critically ill patients. The task force, divided into four subcommittees, collaborated over 6 yr in person, via teleconferences, and via electronic communication. Subcommittees were responsible for developing relevant clinical questions, using the Grading of Recommendations Assessment, Development and Evaluation method (http://www.gradeworkinggroup.org) to review, evaluate, and summarize the literature, and to develop clinical statements (descriptive) and recommendations (actionable). With the help of a professional librarian and Refworks® database software, they developed a Web-based electronic database of over 19,000 references extracted from eight clinical search engines, related to pain and analgesia, agitation and sedation, delirium, and related clinical outcomes in adult ICU patients. The group also used psychometric analyses to evaluate and compare pain, agitation/sedation, and delirium assessment tools. All task force members were allowed to review the literature supporting each statement and recommendation and provided feedback to the subcommittees. Group consensus was achieved for all statements and recommendations using the nominal group technique and the modified Delphi method, with anonymous voting by all task force members using E-Survey (http://www.esurvey.com). All voting was completed in December 2010. Relevant studies published after this date and prior to publication of these guidelines were referenced in the text. The quality of evidence for each statement and recommendation was ranked as high (A), moderate (B), or low/very low (C). The strength of recommendations was ranked as strong (1) or weak (2), and either in favor of (+) or against (–) an intervention. A strong recommendation (either for or against) indicated that the intervention’s desirable effects either clearly outweighed its undesirable effects (risks, burdens, and costs) or it did not. For all strong recommendations, the phrase “We recommend …” is used throughout. A weak recommendation, either for or against an intervention, indicated that the trade-off between desirable and undesirable effects was less clear. For all weak recommendations, the phrase “We suggest …” is used throughout. In the absence of sufficient evidence, or when group consensus could not be achieved, no recommendation (0) was made. Consensus based on expert opinion was not used as a substitute for a lack of evidence. A consistent method for addressing potential conflict of interest was followed if task force members were coauthors of related research. The development of this guideline was independent of any industry funding. Conclusion:These guidelines provide a roadmap for developing integrated, evidence-based, and patient-centered protocols for preventing and treating pain, agitation, and delirium in critically ill patients.

Practice Guidelines for Central Venous Access A Report by the American Society of Anesthesiologists Task Force on Central Venous Access

P RACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints, and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open forum commentary, and clinical feasibility data.

Preoperative Clinic Visits Reduce Operating Room Cancellations and Delays

Background: Anesthesiologist-directed preoperative medicine clinics are used to prepare patients for the administration of anesthesia and surgery. Studies have shown that such a clinic reduces preoperative testing and consults, but few studies have examined the impact of the clinic on the day of surgery. The authors tested whether a visit to an anesthesia preoperative medicine clinic (APMC) would reduce day-of-surgery case cancellations and/or case delays. Methods: The authors conducted a retrospective chart review of all surgical cases during a 6-month period at the University of Chicago Hospitals. Case cancellations and rates of first-start case delay over the 6-month period were cross-referenced with a database of APMC attendees in both the general operating rooms and the same-day surgery suite. The impact of a clinic visit on case cancellation and delay in both sites were analyzed separately. Results: A total of 6,524 eligible cases were included. In the same-day surgery suite, 98 of 1,164 (8.4%) APMC-evaluated patients were cancelled, as compared with 366 of 2,252 (16.2%) in the non-APMC group (P < 0.001). In the general operating rooms, 87 of 1,631 (5.3%) APMC-evaluated patients were cancelled, as compared with 192 of 1,477 (13.0%) patients without a clinic visit (P < 0.001). For both operating areas, APMC patients had a significantly earlier room entry time than patients not evaluated in the APMC. Conclusions: An evaluation in the APMC can significantly impact case cancellations and delays on the day of surgery.

BIS monitoring to prevent awareness during general anesthesia.

Background Unexpected awareness is a rare but well-described complication of general anesthesia that has received increased scientific and media attention in the past few years. Transformed electroencephalogram monitors, such as the Bispectral Index monitor, have been advocated as tools to prevent unexpected recall. Methods The authors conducted a power analysis to estimate how many patients would be needed in an appropriately powered study to demonstrate the Bispectral Index monitor reduces awareness, as well as a cost analysis to assess the cost of using the monitor for this purpose alone. Results If unexpected recall is rare (1 in 20,000), it will require a large study to demonstrate that the monitor reduces awareness (200,000–800,000 patients), and the cost of using it for this purpose alone would be high (

Recovery from Sleep Deprivation Occurs during Propofol Anesthesia

400,000 per case prevented). If awareness is common (1 in 100), then the number of patients needed in a study to demonstrate that the monitor works becomes tractable (1,000–4,000 patients), and the cost of using the monitor for this purpose alone becomes lower (

Sleep Deprivation Potentiates the Onset and Duration of Loss of Righting Reflex Induced by Propofol and Isoflurane

2,000 per case prevented). Because there are reported cases of awareness despite Bispectral Index monitoring, the authors are certain that the effectiveness of the monitor is less than 100%. As the performance of the monitor decreases from 100%, the size of the study needed to demonstrate that it works increases, as does the cost of using it to prevent awareness. Conclusion The contention that Bispectral Index monitoring reduces the risk of awareness is unproven, and the cost of using it for this indication is currently unknown.

The relationship of sedation to deliberate self-extubation

Background: Some neurophysiologic similarities between sleep and anesthesia suggest that an anesthetized state may reverse effects of sleep deprivation. The effect of anesthesia on sleep homeostasis, however, is unknown. To test the hypothesis that recovery from sleep deprivation occurs during anesthesia, the authors followed 24 h of sleep deprivation in the rat with a 6-h period of either ad libitum sleep or propofol anesthesia, and compared subsequent sleep characteristics. Methods: With animal care committee approval, electroencephalographic/electromyographic electrodes and intrajugular cannulae were implanted in 32 rats. After a 7-day recovery and 24-h baseline electroencephalographic/electromyographic recording period, rats were sleep deprived for 24 h by the disk-over-water method. Rats then underwent 6 h of either propofol anesthesia (n = 16) or ad libitum sleep with intralipid administration (n = 16), followed by electroencephalographic/electromyographic monitoring for 72 h. Results: In control rats, increases above baseline in non–rapid eye movement sleep, rapid eye movement sleep, and non–rapid eye movement delta power persisted for 12 h after 24 h of sleep deprivation. Recovery from sleep deprivation in anesthetized rats was similar in timing to that of controls. No delayed rebound effects were observed in either group for 72 h after deprivation. Conclusion: These data show that a recovery process similar to that occurring during naturally occurring sleep also takes place during anesthesia and suggest that sleep and anesthesia share common regulatory mechanisms. Such interactions between sleep and anesthesia may allow anesthesiologists to better understand a potentially important source of variability in anesthetic action and raise the possibility that anesthetics may facilitate sleep in environments where sleep deprivation is common.

Prolonged sedation with propofol in the rat does not result in sleep deprivation.

Background Sleep and anesthesia differ physiologically but produce a similar loss of responsiveness to environmental stimuli. Recent data suggest that neuronal networks active in naturally occurring sleep also play a role in the anesthetized state. Changes in the propensity to sleep may then modify the response to anesthetic agents. The authors tested the hypothesis that sleep-deprived rats would require less anesthetic than rested rats to achieve a similar loss of responsiveness. Methods Rats were subjected to a 24-h period of either sleep deprivation or ad libitum activity. Sleep deprivation was produced by placing rats on a disk that rotated when sleep was detected by electroencephalographic and electromyographic (EEG, EMG) monitoring. A fixed dose of anesthetic agent was then administered, and the time required to induce loss of righting reflex was measured. Anesthetic administration was then stopped, and the time to recovery measured. All rats received both treatments separated by 7 days. Results Sleep deprivation reduced the time to loss of righting reflex by 40% for propofol (P < 0.025) and 55% for isoflurane (P < 0.025) and prolonged the time to recovery. In a separate control experiment, exposure to the deprivation environment but with disk rotation modified to allow adequate sleep did not affect the response to anesthetic administration. Conclusions Sleep deprivation significantly potentiated the ability of inhaled and intravenous anesthetic agents to induce a loss of righting reflex. These results support the hypothesis that neuronal networks active in sleep are also involved in the anesthetized state and suggest that sleep deprivation may partly explain the variability in patient response to anesthesia.

Complete airway obstruction during arthroscopic shoulder surgery

STUDY OBJECTIVES To evaluate the relationship between sedative therapy and self-extubation in a large medical-surgical intensive care unit (ICU). DESIGN Retrospective, case-controlled study. SETTING Large teaching hospital. PATIENTS All adult patients who underwent unplanned self-extubation during a 12-month period (n = 50). Each patient was matched to two control patients who did not self-extubate based on age, gender, dates in hospital and diagnosis. INTERVENTIONS none. MEASUREMENTS Data collected included time to self extubation, dosages and types of benzodiazepines, opioid analgesics, antipsychotics, and hypnotics. Data on the degree of agitation as assessed by nursing staff also were obtained. MAIN RESULTS When compared to controls, patients in the self-extubation group were more likely to have received benzodiazepines (59% vs. 35%; p < 0.05), but equally likely to have received opioids and/or paralytic drugs. Patients who self-extubated were twice as likely as controls to be agitated (54% vs. 22%; p < 0.05). Use of benzodiazepines was more common in agitated patients than in nonagitated patients (62% vs. 35%; p < 0.02). Among nonagitated patients who self-extubated, increased use of benzodiazepines (57% vs. 29%; p < 0.05) was noted when compared to nonagitated controls. CONCLUSIONS In intubated ICU patients, benzodiazepines may not consistently treat agitation effectively or prevent self-extubation. Such an effect may be due to paradoxical excitation, disorientation during long-term administration, or differences in drug administration between ICU and operating room (OR) environments.

Sleep inducing effects of propofol microinjection into the medial preoptic area are blocked by flumazenil.

The use of propofol provides sedation without prolonging emergence in patients in the Intensive Care Unit. When prolonged, however, continuous sedation may overlap with naturally occurring sleep periods and potentially increase the risk of sleep deprivation. We modified an established rat model of sleep to determine whether prolonged, continuous sedation results in sleep deprivation. Rats were continuously sedated for a 12-h period overlapping completely with their normal sleep phase. Electroencephalogram (EEG) and movement data were collected before and after the sedation period. Rats were evaluated for EEG and movement evidence of sleep deprivation after sedation. When compared with baseline, the time spent in rapid eye movement (REM) and non-REM sleep was decreased during the first 4 h after sedation. The duration of non-REM sleep bouts was not altered. Power in the &dgr; band (0.5–4 Hz) during non-REM sleep was diminished during the first 2 h only. Movements were reduced during the first hour after emergence from sedation only. In summary, no EEG or behavioral evidence of sleep deprivation was observed on emergence from sedation. These results imply that sedation is associated with a restorative process reversing the na-tural accumulation of sleep need that occurs during wakefulness.