272 Impact of a Novel Multiparameter Decision Support System on Intraoperative Processes of Care and Postoperative Outcomes
The hypothesis that an intraoperative multiparameter decision support system integrating electronic health records, real-time physiologic data, and evidence-based medicine practice guidelines may improve processes of care and postoperative outcomes was evaluated in 26,796 high-risk patients undergoing major inpatient surgery. The processes of care (hypotension, inappropriate ventilation, and fluid resuscitation rate) and postoperative outcomes of 7,954 patients for whom the decision support system was viewed for more than 75% of the cases were compared with those of 10,933 parallel and 7,882 historical control patients. Implementation of the novel decision support system was associated with small risk-adjusted improvements in processes of care compared with parallel controls. There was no effect on myocardial injury, acute kidney injury, mortality, length of stay, and encounter charges. See the accompanying Editorial Views on pages 241 and 247.
283 Defining the Intrinsic Cardiac Risks of Operations to Improve Preoperative Cardiac Risk Assessments
Accurate preoperative risk stratification allows for appropriate preoperative medical optimization, timely cardiac- specific interventions, and guidance regarding perioperative management. Operations carry risks for adverse outcomes beyond the influence of patient comorbidities for a variety of reasons. Broad groupings of operations, as has been conventionally done, can be misleading because they do not consider the continuum of intrinsic cardiac risk that exists for each operation. To improve on current preoperative cardiac risk assessment strategies and to facilitate interdisciplinary communication, the intrinsic risks of individual operations for perioperative adverse cardiac events were empirically derived using high-quality clinical data from 3,247,537 elective, noncardiac operations from the American College of Surgeons National Surgical Quality Improvement Program Essentials data between 2010 and 2015, encompassing 1,880 unique Common Procedural Terminology codes. There were 66 low-, 30 intermediate-, and 106 high-risk operations identified that accounted for most of the operations performed in each risk category. See the accompanying Editorial Views on pages 244 and 247.
293 Incidence of Artifacts and Deviating Values in Research Data Obtained from an Anesthesia Information Management System in Children
Anesthesia information management systems (AIMSs) are being used increasingly for anesthesiology record-keeping. The validity of AIMS data was assessed in an observational cohort study of 136 anesthetics in 132 pediatric patients who underwent general anesthesia for noncardiac surgical or diagnostic procedures during a cumulative anesthetic time of 10,236 min. Values on the monitor were compared with those stored in the AIMS and assessed as being an artifact or a valid value by an investigator in the operating room. An artifact was defined as any value that was judged invalid or not reflecting the patient’s current physiologic state. Artifacts were present in a substantial number of recordings. Heart rate and oxygen saturation had low incidences of artifacts, while mean noninvasive blood pressure, mean invasive blood pressure, and end-tidal carbon dioxide had higher incidences of artifacts. Artifacts were associated with deviating status of the measurement, phase of anesthesia, and anesthetic technique. Not all values in AIMS are valid. See the accompanying Editorial View on page 250.
328 Cost-effectiveness Analysis of Intraoperative Cell Salvage for Obstetric Hemorrhage
Intraoperative cell salvage in obstetrics can reduce the need for allogeneic blood transfusion and mitigate postpartum anemia after cesarean delivery. The circumstances under which use of cell salvage strategies in obstetric hemorrhage during cesarean delivery is cost-effective, from a societal perspective and over the reproductive lifespan, were determined using data from the National Vital Statistics Reports on births (2013) as the foundation of the base case and cohort. The cohort consisted of women requiring cesarean delivery, with an average age at first pregnancy of 26 yr and a reproductive lifespan of 19 yr. The use of cell salvage for cases at high risk for hemorrhage was cost-effective, with an incremental cost-effectiveness ratio of $34,881 per quality-adjusted life-year gained. The routine use of cell salvage for all cesarean deliveries was not cost-effective, with an incremental cost-effectiveness ratio of $415,488 per quality-adjusted life-year gained.
352 Microvascular Permeability after an Acute and Chronic Salt Load in Healthy Subjects: A Randomized Open-label Crossover Intervention Study
Tissue glycosaminoglycans influence sodium homeostasis via nonosmotic storage of sodium. Impairment of the microcirculatory endothelial surface layer, which consists of different glycosaminoglycans, decreases its vascular barrier function. The hypothesis that an acute intravenous sodium load and a chronic dietary sodium load differently affect blood pressure, the endothelial surface layer, and microcirculation was tested in 12 healthy males who followed both a low-sodium diet and a high-sodium diet for eight days each in a randomized crossover study. Despite similar increases in plasma sodium, chloride, and osmolality, chronic dietary sodium loading did not affect microvascular permeability but an intravenous infusion of more than 500 ml of hypertonic saline over 30 min after the low-salt diet increased it. Increased microvascular permeability after saline infusion coincided with decreased urinary glycosaminoglycan excretion, indicating damage to the endothelial surface layer. Neither sodium intervention affected blood pressure.
361 Vasculotide, an Angiopoietin-1 Mimetic, Restores Microcirculatory Perfusion and Microvascular Leakage and Decreases Fluid Resuscitation Requirements in Hemorrhagic Shock
One of the molecular systems involved in maintenance of microvascular integrity is the angiopoietin/Tie2 system, which plays an important role in the protection of microvascular integrity and microcirculatory perfusion during hemorrhagic shock. The hypothesis that therapeutically targeting the endothelial angiopoietin/Tie2 system with an angiopoietin-1 mimetic, vasculotide, would decrease microvascular leakage and improve microcirculatory perfusion was tested in a rat model of hemorrhagic shock. Rats were allocated to undergo hemorrhagic shock, hemorrhagic shock with fluid resuscitation, or a sham protocol. They were treated with vasculotide or phosphate-buffered saline at either baseline or, in the posttreatment group, after resuscitation with Ringer’s lactate. Severe hemorrhagic shock resulted in microcirculatory perfusion disturbances and microvascular leakage, which were not restored by fluid resuscitation. Targeting Tie2 with vasculotide reversed the microcirculatory perfusion disturbances during fluid resuscitation, reduced microvascular leakage, and reduced the fluid volume necessary to restore systemic hemodynamics. See the accompanying Editorial View on page 252.
390 Argatroban and Bivalirudin for Perioperative Anticoagulation in Cardiac Surgery (Clinical Focus Review)
Argatroban and bivalirudin are parenteral direct thrombin inhibitors. They are first-line alternatives for patients with contraindications to heparin, especially for patients with heparin-induced thrombocytopenia. They reversibly inhibit thrombin, but no specific reversal agents are available. Heparin, the standard anticoagulant for cardiovascular surgery or high-risk patients, is easily monitored and completely and rapidly reversed with protamine. Argatroban undergoes hepatic elimination, and its elimination is independent of renal function. Bivalirudin is cleaved by proteases, which accounts for 80% of its elimination with the remainder renally excreted. Effects are monitored with activated clotting time and partial thromboplastin time, although they may not be reliable with cardiopulmonary bypass. Neither drug is approved for use perioperatively or in cardiac surgery, although the American College of Chest Physicians recommends that bivalirudin is preferred for patients with heparin-induced thrombocytopenia. This review summarizes the existing data on argatroban and bivalirudin use in the intensive care unit and during cardiovascular surgery.
401 Multimodality Neuromonitoring in Adult Traumatic Brain Injury: A Narrative Review (Review Article)
Traumatic brain injury is a heterogeneous disease with temporal and regional variability. Multimodal neuromonitoring provides a comprehensive picture of pathophysiology in traumatic brain injury and is used to guide interventions to prevent or minimize secondary injury. The Glasgow coma score is the most popular clinical assessment tool, but it cannot test brainstem function or be applied to sedated or paralyzed patients. Intracranial pressure is measured invasively and is paramount for individualized optimization of cerebral perfusion pressure. Transcranial doppler ultrasound can noninvasively detect inadequate cerebral hemodynamics continuously. Brain oxygenation can be measured locally with a probe or indirectly assessed from mixed venous oxygen saturation or near-infrared brain spectroscopy. Continuous electroencephalography monitoring is recommended for the detection of posttraumatic seizures and to guide anticonvulsant therapy. Early detection of focal brain tissue energy imbalance is possible with invasively placed microdialysis catheters. The effects of brain tissue oxygenation partial pressure in combination with intracranial pressure monitoring are yet to be proven.