766 Anesthesia-induced Suppression of Human Dorsal Anterior Insula Responsivity at Loss of Volitional Behavioral Response

Loss of behavioral responsiveness (LOBR) is often used to define anesthesia-induced loss of consciousness in both clinical and experimental settings. Fifteen healthy volunteers participated in two neuroimaging experiments, a laboratory-based electroencephalography study and a simultaneous electroencephalography–functional magnetic resonance imaging study, designed to identify changes in neural processing specifically associated with the LOBR transition during ultraslow induction of anesthesia with propofol. The results suggest that the dorsal anterior insula cortex could be a key cortical region that underpins LOBR under anesthesia because activity within this brain region in response to painful stimuli and to two types of auditory stimuli was commonly reduced around the time of LOBR. Suppression of dorsal anterior insula cortex activity was associated with reductions of its functional connectivity to frontoparietal brain regions and reduced electroencephalographic synchrony there around LOBR. See the accompanying Editorial View on page 747 and Infographics in Anesthesiology on page 21A.

815 Self-reported Mobility in Older Patients Predicts Early Postoperative Outcomes after Elective Noncardiac Surgery

Preoperative assessment of patient characteristics that can assist in the evaluation of risk for adverse postoperative outcomes is especially important for the elderly, in whom postoperative complications are more likely. Traditional risk factors and geriatric-specific assessments, including mobility and frailty, were assessed before elective noncardiac surgery in a cohort of 197 patients at least 69 yr of age. While frailty was associated with nursing home placement, preoperative self-reported mobility, as measured by the quick, reliable, and cost-effective mobility assessment tool–short form, was the only measure that consistently predicted early postoperative complications, time to discharge, and nursing home placement. Traditional risk assessments, such as American Society of Anesthesiologists physical status classification and Revised Cardiac Risk Index, may be too comprehensive or too focused on single organ systems.

785 Microbiological Contamination of Drugs during Their Administration for Anesthesia in the Operating Room

Postoperative infections represent a significant proportion of health care–associated infections. Anesthesiologists make an average of 10 bolus injections per case. Their aseptic technique when preparing and administering injected drugs may sometimes be deficient and could lead to postoperative infection. Twenty-three anesthesiologists were asked to make bolus injections of all drugs, except propofol and antibiotics, through a 0.2 micron filter unit in a prospective, open, microbiological audit of 300 cases in which patients underwent general anesthesia. Potentially pathogenic microorganisms were isolated from the 0.2 micron filters of 19 (6.3%) of the 300 cases. Microorganisms were also grown from residual drug in 55 (2.4%) of the 2,318 syringes collected at the end of the cases. The average rating of ease of use of the filter unit was 3.5/10 (0 being very easy). See the accompanying Editorial View on page 752.

795 A Human Factors Engineering Study of the Medication Delivery Process during an Anesthetic: Self-filled Syringes versus Prefilled Syringes

Prefilled syringes (PFS) have been implemented in the operating room as an alternative to traditional self-filled syringes (SFS). System vulnerabilities of PFS and SFS were compared to determine the effect of using PFS on medication safety and efficiency in the context of anesthesiology medication delivery using human factors engineering methods. Anesthesia providers were shadowed during eight general surgery cases using only SFS and during nine cases using only commercially available PFS to identify system vulnerabilities. A proactive risk assessment was then conducted by a six-member focus group to help understand the risk of each identified system vulnerability. PFS simplified work processes and reduced the number and associated risk of system vulnerabilities. However, PFS introduced complications that need to be addressed by improvements in PFS product design and organizational-level interventions. See the accompanying Editorial View on page 752.

899 Use of Intensive Care Services for Medicare Beneficiaries Undergoing Major Surgical Procedures

This retrospective study used data on all hospitalizations of Medicare beneficiaries 65 yr old or older undergoing one of five major surgical procedures from 2004 through 2008 to determine the variation in use of intensive care services and to assess hospital-level outcomes for patients cared for in low-, moderate-, and high-use hospitals. There was substantial variation across hospitals in use of intensive care services but there was no association between hospital use of intensive care and hospital mortality. There were also no consistent differences in length of hospital stay or in Medicare payments associated with systematically more or less use of intensive care due to higher payments for the fewer patients who received intensive care in low-use hospitals compared with those in high-use hospitals. See the accompanying Editorial View on page 761.

826 Cerebral Oximetry Monitoring to Maintain Normal Cerebral Oxygen Saturation during High-risk Cardiac Surgery: A Randomized Controlled Feasibility Trial

The feasibility of successfully using a near infrared–reflected spectroscopy–guided intervention algorithm to prevent decreases in regional cerebral oxygen saturation was determined at centers participating in a large multicenter randomized controlled trial designed to determine the effect of reversing decreases in regional cerebral oxygen saturation on postoperative outcomes. Eight sites randomly assigned 201 patients undergoing high-risk cardiac surgery with cardiopulmonary bypass to either control or intervention groups. Cerebral desaturation below 10% of baseline occurred in 71 of 102 intervention group patients and 56 of 99 control group patients. Desaturations were successfully reversed in 69 (97%) intervention group patients. Interventions at the 10% threshold apparently prevented progression of desaturations below 20% of baseline; 34 of 71 (48%) intervention patients had desaturations below 20% of baseline compared with 46 of 56 (82%) control patients.

923 Mitochondrial DNA: An Endogenous Trigger for Immune Paralysis

Tissue injury and destruction are associated with systemic immune suppression and early bacteremia. The complex sepsis syndrome is believed to result in initial hyperinflammation followed by “immune paralysis,” contributing to late morbidity and death. Due to its bacterial-like, unmethylated DNA structure, the hypothesis that mitochondrial DNA (mtDNA), an endogenous Toll-like receptor (TLR) 9-ligand, is a link from inflammation to immunosuppression in critically ill patients was tested in a prospective observational trial of 165 septic patients and 50 healthy volunteers and in wild-type and TLR9 knockout mice. Serum mtDNA concentrations were increased in critically ill patients with sepsis and were associated with increased 30-day mortality. Even a single mtDNA injection in wild-type mice caused profound, TLR9-mediated immune suppression with loss of antiviral T-cell cytotoxicity and induced a variety of immunosuppressive mechanisms.

960 Perioperative Opioids and Public Health (Clinical Concepts and Commentary)

The human and financial toll of nonmedical prescription opioid diversion, abuse, addiction, and overdose is substantial. The primary regulatory, medical, and scientific focus has been on the role of chronic opioid use in the rising epidemic of prescription opioid abuse, with little attention devoted to the contribution of opioids prescribed for postoperative pain. This Clinical Concepts and Commentary calls for development of research agendas to determine to what extent overprescription of postoperative opioids is creating a reservoir of unused drug, with the potential for opioid sharing, selling, and diversion. Such research should lead to a better understanding of patients’ pain experiences and actual opioid use after specific operations and development of best practices postoperative opioid prescription guidelines that are based on actual usage patterns.