Exploring phenotype-based ventilator parameter optimization to mitigate postoperative pulmonary complications: a retrospective observational cohort study.

PURPOSE: To identify tidal volume (VT) and positive end-expiratory pressure (PEEP) associated with the lowest incidence and severity of postoperative pulmonary complications (PPCs) for each phenotype based on preoperative characteristics. METHODS: The subjects of this retrospective observational cohort study were 34,910 adults who underwent surgery, using general anesthesia with mechanical ventilation. Initially, the least absolute shrinkage and selection operator regression was employed to select relevant preoperative characteristics. Then, the classification and regression tree (CART) was built to identify phenotypes. Finally, we computed the area under the receiver operating characteristic curves from logistic regressions to identify VT and PEEP associated with the lowest incidence and severity of PPCs for each phenotype. RESULTS: CARTs classified seven phenotypes for each outcome. A probability of the development of PPCs ranged from the lowest (3.51%) to the highest (68.57%), whereas the probability of the development of the highest level of PPC severity ranged from 3.3% to 91.0%. Across all phenotypes, the VT and PEEP associated with the most desirable outcomes were within a small range of VT 7-8 ml/kg predicted body weight with PEEP of between 6 and 8 cmH2O. CONCLUSIONS: The ranges of optimal VT and PEEP were small, regardless of the phenotypes, which had a wide range of risk profiles.

Fast-Tracking Patients in an Academic Hospital to Increase Efficiency and Decrease Discharge Delays: A Process Improvement Plan.

PURPOSE: The purpose of this quality improvement project was to determine if implementing a Phase II postanesthesia care unit (PACU II) to fast-track patients following surgery in an academic hospital would decrease OR hold times and increase patient flow efficiency. DESIGN: An observational pre-post design was used to compare PACU bypass rates and recovery times for ambulatory surgery (AS) patients before and after implementation of a patient fast-tracking program. METHODS: A PACU II was instituted and a fast-tracking program using the White Fast-Track Scoring tool was adopted. Nursing staff as well as anesthesia providers were educated to assess patients using the tool as well as the appropriate patient population to be transferred to the new PACU II. FINDINGS: Following implementation of the new unit and the fast-tracking program, a PACU bypass rate of 30% was achieved and there was a significant decrease in PACU length of stay for AS patients. CONCLUSIONS: The results suggest that fast-tracking is a suitable intervention to decrease inefficiencies in an academic setting despite higher acuity patient populations.

Lung-protective ventilation for the surgical patient: international expert panel-based consensus recommendations.

Postoperative pulmonary complications (PPCs) occur frequently and are associated with substantial morbidity and mortality. Evidence suggests that reduction of PPCs can be accomplished by using lung-protective ventilation strategies intraoperatively, but a consensus on perioperative management has not been established. We sought to determine recommendations for lung protection for the surgical patient at an international consensus development conference. Seven experts produced 24 questions concerning preoperative assessment and intraoperative mechanical ventilation for patients at risk of developing PPCs. Six researchers assessed the literature using questions as a framework for their review. The modified Delphi method was utilised by a team of experts to produce recommendations and statements from study questions. An expert consensus was reached for 22 recommendations and four statements. The following are the highlights: (i) a dedicated score should be used for preoperative pulmonary risk evaluation; and (ii) an individualised mechanical ventilation may improve the mechanics of breathing and respiratory function, and prevent PPCs. The ventilator should initially be set to a tidal volume of 6-8 ml kg-1 predicted body weight and positive end-expiratory pressure (PEEP) 5 cm H2O. PEEP should be individualised thereafter. When recruitment manoeuvres are performed, the lowest effective pressure and shortest effective time or fewest number of breaths should be used.

Nursing Perceptions and Workload Impact of a Standardized Emergence Delirium Assessment Scale in a Postanesthesia Care Unit.

PURPOSE: Emergence delirium (EDL) is a psychomotor behavioral phenomenon that occurs immediately after emergence from general anesthesia. EDL is nearly 1.5 times more common among military than nonmilitary patients. Indirect delirium scales have precluded understanding of EDL in military patients. This quality improvement project assesses the feasibility of adopting a population-specific scale, the Emergence Delirium in the Wounded Warrior (ED-WW) Tool. DESIGN: Pre-post implementation design. METHODS: Postanesthesia care unit (PACU) nurses were surveyed on the clinical utility of the ED-WW Tool and its impact on their workload. The incidence of EDL behaviors in a Veterans Administration PACU was also recorded using the ED-WW Tool. FINDINGS: PACU nurses agreed the ED-WW Tool was of clinical value to military patients and had a very low workload impact. Twenty-one percent of patients demonstrated at least one behavior associated with EDL. CONCLUSIONS: ED-WW Tool adoption is clinically feasible and recommended for practice.

Enhancing the Quality of the Anesthesia to Postanesthesia Care Unit Patient Transfer Through Use of an Electronic Medical Record-Based Handoff Tool.

PURPOSE: Anesthesia to postanesthesia care unit (PACU) handoffs are often incomplete, imprecise, and highly variable with respect to information transfer, and therefore can jeopardize patient safety. A standardized anesthesia to PACU electronic medical record (EMR)-based patient handoff checklist was implemented and evaluated for its effect on the information transfer. DESIGN: An observational preimplementation and postimplementation design was used. METHODS: Assessment of the completeness and accuracy of information transfer during the PACU handoff was performed for a convenience samples of 100 patients preimplementation, 3 weeks postimplementation, and 3 months postimplementation. FINDINGS: The mean percentage of total handoff checklist items addressed significantly increased 3 weeks and 3 months postimplementation compared with baseline. CONCLUSIONS: The use of a standardized anesthesia to PACU EMR-based handoff checklist significantly increased the percent of accurate information transferred without considerably affecting the duration of the PACU handoff process.

Characterization of bilateral frontal lobe cerebral oxygen saturation in patients with mild traumatic brain injury.

BACKGROUND: There is clear evidence of the potential for long-term neuro behavioral and cognitive sequelae following a mild traumatic brain injury (mTBI). Although the source of these persistent behavioral and cognitive issues is unclear, several studies have suggested a cerebral vascular disorder is a likely contributor. PURPOSE: Measure and compare cerebral blood oxygen saturation values in frontal brain lobes of subjects with and without a history of mTBI. METHODS: Bilateral frontal brain lobe blood oxygen saturation was measured using near-infrared spectroscopy in mTBI and non-brain injured subjects while alternately breathing room air and a mildly hypoxic gas mixture. RESULTS: Subjects with a history of mTBI displayed a significantly different trajectory of change in their cerebral oxygen saturation values during exposure to mild hypoxia compared to controls. DISCUSSION: The finding confirms and adds to previous research that indicates there is likely a vascular component to this mild form of brain injury.

Fast-tracking ambulatory surgery patients following anesthesia.

PURPOSE: The purpose of this process improvement project was to introduce and evaluate the efficacy of fast-tracking ambulatory surgical patients in a community hospital. DESIGN: An observational pre-post design was used, in which patient data from a reference period (pre-fast-tracking) was compared with patient data collected during an implementation period (post-fast-tracking). METHODS: Anesthesia providers were trained to use a tool to assess patients for eligibility to bypass the postanesthesia care unit (PACU). Fifty-nine patients met the fast-track criteria during the implementation period and were transferred directly to the ambulatory care unit from the operating room. FINDING: During the fast-track implementation period, a PACU-bypass rate of 79% was achieved, and a significant decrease in the total number of patients held in the operating room and in total length of stay was noted. CONCLUSIONS: Results suggest that fast-tracking is a suitable intervention to increase work flow efficiency and decrease both patient and hospital costs while promoting a more rapid discharge from the facility.

The accuracy of a near-infrared spectroscopy cerebral oximetry device and its potential value for estimating jugular venous oxygen saturation.

BACKGROUND: An intriguing potential clinical use of cerebral oximeter measurements (SctO2) is the ability to noninvasively estimate jugular bulb venous oxygen saturation (SjvO2). Our purpose in this study was to determine the accuracy of the FORE-SIGHT(®) (CAS Medical Systems, Branford, CT), which is calibrated to a weighted average of 70% (SjvO2) and 30% arterial saturation, for Food and Drug Administration pre-market approval 510(k) certification by adapting an industry standard protocol, ISO 9919:2005 (www.ISO.org) (used for pulse oximeters), and to evaluate the use of SctO2 and SpO2 measurements to noninvasively estimate jugular venous oxygen saturation (SnvO2). METHODS: Paired blood gas samples from the radial artery and the jugular venous bulb were collected from 20 healthy volunteers undergoing progressive oxygen desaturation from 100% to 70%. The blood sample pairs were analyzed via co-oximetry and used to calculate the approximate mixed vascular cerebral blood oxygen saturation, or reference SctO2 values (refSctO2), during increasing hypoxia. These reference values were compared to bilateral FORE-SIGHT SctO2 values recorded simultaneously with the blood gas draws to determine its accuracy. Bilateral SctO2 and SpO2 measurements were then used to calculate SnvO2 values which were compared to SjvO2. RESULTS: Two hundred forty-six arterial and 253 venous samples from 18 subjects were used in the analysis. The ipsilateral FORE-SIGHT SctO2 values showed a tolerance interval (TI) of [-10.72 to 10.90] and Lin concordance correlation coefficient (CCC) with standard error (SE) of 0.83 ± 0.073 with the refSctO2 values calculated using arterial and venous blood gases. The ipsilateral data had a CCC of 0.81 + 0.059 with TI of [-9.22 to 9.40] with overall bias of 0.09%, and amplitude of the root mean square of error after it was corrected with random effects analysis was 2.92%. The bias and variability values between the ipsilateral and the contralateral FORE-SIGHT SctO2 measurements varied from person to person. The SnvO2 calculated from the ipsilateral SctO2 and SpO2 data showed a CCC ± SE of 0.79 ± 0.088, TI = [-14.93 to 15.33], slope of 0.98, y-intercept of 1.14% with SjvO2 values with a bias of 0.20% and an Arms of 4.08%. The SnvO2 values calculated independently from contralateral forehead FORE-SIGHT SctO2 values were not as correlated with the SjvO2 values (contralateral side CCC + SE = 0.72 ± 0.118, TI = [-14.86 to 15.20], slope of 0.66, and y-intercept of 20.36%). CONCLUSIONS: The FORE-SIGHT cerebral oximeter was able to estimate oxygen saturation within the tissues of the frontal lobe under conditions of normocapnia and varying degrees of hypoxia (with 95% confidence interval of [-5.60 to 5.78] with ipsilateral blood sample data). These findings from healthy volunteers also suggest that the use of the calculated SnvO2 derived from SctO2 and SpO2 values may be a reasonable noninvasive method of estimating SjvO2 and therefore global cerebral oxygen consumption in the clinical setting. Further laboratory and clinical research is required to define the clinical utility of near-infrared spectroscopy determination of SctO2 and SnvO2 in the operating room setting.

Exploration of specialty certification for nurse anesthetists: nonsurgical pain management as a test case.

Certification is the outcome of the demonstration of knowledge and skills, which is an important link to licensing and credentialing. Considering the essential role that Certified Registered Nurse Anesthetists play in the practice of nonsurgical pain management, it is important that a certification process be developed that provides the necessary support to licensing and credentialing at the local, state, and federal levels. The goal of this project was to develop the foundational elements for a specialty certification in nonsurgical pain management. The Delphi method for the systematic solicitation and collation of information was used to query experts in the field of nonsurgical pain management regarding the elements necessary to establish such a specialty certification. Results of the query were compiled, analyzed, and compared to feedback about the elements from a sample of certified registered nurse anesthetists involved in nonsurgical pain management to assess reliability. The results provided identification of a target population for competency evaluation, tools for evaluation, resources for knowledge and skills testing, and a table of specifications for testing. A valid process to develop a specialty certification for nurse anesthetists with demonstration of knowledge and skills will help bridge the gap between continuing education and an actual demonstration that an individual practitioner possesses the necessary knowledge and skills to practice nonsurgical pain management.

Chapter 1 posttraumatic stress disorder: a view from the operating theater.

Posttraumatic stress disorder (PTSD) is an anxiety disorder that develops following exposure to a traumatic event. The prevalence and symptom severity of PTSD is greater in military combat Veterans than the civilian population. Although PTSD is a psychiatric disorder, in Veterans, it is associated with several physical comorbidities, chronic pain, substance abuse, and worse self-reported health status which may predispose them to greater perioperative morbidity and mortality. At present, the effect of surgery on the severity of PTSD is largely unknown. However, the perioperative clinician should consider PTSD a chronic illness associated with the accumulation of risk factors across the life span.

Reexamining traditional intraoperative fluid administration: evolving views in the age of goal-directed therapy.

Intraoperative volume administration has long been a topic of debate in the field of anesthesia. Only recently, however, has the conversation shifted to a discussion of appropriate intraoperative volume. A thorough review of the literature explores the history of today's widely accepted fluid administration equation and discusses possible explanations and consequences of iatrogenically induced hypervolemia. Current studies exploring various volume administration techniques are reviewed, as are emerging technologies available to help guide anesthesia providers with intraoperative fluid management.

Effect of elective surgery on subjective health in veterans with chronic posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) is common, is often chronic, and has been associated with greater risk of postoperative mortality in veterans. The purpose of this study was to determine if elective outpatient surgery had a persistent effect on the physical or mental health of veterans with chronic PTSD. A longitudinal, quasi-experimental study was conducted that followed up 60 veterans with chronic PTSD over 12 weeks. Self-reported physical and mental health, depressive symptom severity, and posttraumatic symptom severity were measured in 29 veterans undergoing outpatient elective surgery and 31 veterans not having elective surgery (controls). Data collection was performed at baseline and repeated 1, 4, and 12 weeks after surgery or enrollment. At baseline, both surgical and control subjects reported poor physical and mental subjective health status. After surgery, surgical group subjects reported mean age- and gender-adjusted reductions of 3.9 points on the Physical Component Summary score and 2.9 points on the Mental Component Summary score of the Veterans Rand 36-item Health Survey, which resolved by 4 weeks after surgery. These findings suggest that veterans with PTSD were at greater risk of mortality because of poor baseline health, but did not demonstrate persistent decline in health following common elective surgical procedures.

Development and validation of a cerebral oximeter capable of absolute accuracy.

OBJECTIVE: Cerebral oximetry may be a valuable monitor, but few validation data are available, and most report the change from baseline rather than absolute accuracy, which may be affected by individuals whose oximetric values are outside the expected range. The authors sought to develop and validate a cerebral oximeter capable of absolute accuracy. DESIGN: An in vivo research study. SETTING: A university human physiology laboratory. PARTICIPANTS: Healthy human volunteers were enrolled in calibration and validation studies of 2 cerebral oximetric sensors, the Nonin 8000CA and 8004CA. The 8000CA validation study identified 5 individuals with atypical cerebral oxygenation values; their data were used to design the 8004CA sensor, which subsequently underwent calibration and validation. INTERVENTIONS: Volunteers were taken through a stepwise hypoxia protocol to a minimum saturation of peripheral oxygen. Arteriovenous saturation (70% jugular bulb venous saturation and 30% arterial saturation) at 6 hypoxic plateaus was used as the reference value for the cerebral oximeter. Absolute accuracy was defined using a combination of the bias and precision of the paired saturations (A(RMS)). MEASUREMENTS AND MAIN RESULTS: In the validation study for the 8000CA sensor (n = 9, 106 plateaus), relative accuracy was an A(RMS) of 2.7, with an absolute accuracy of 8.1, meeting the criteria for a relative (trend) monitor, but not an absolute monitor. In the validation study for the 8004CA sensor (n = 11, 119 plateaus), the A(RMS) of the 8004CA was 4.1, meeting the prespecified success criterion of <5.0. CONCLUSIONS: The Nonin cerebral oximeter using the 8004CA sensor can provide absolute data on regional cerebral saturation compared with arteriovenous saturation, even in subjects previously shown to have values outside the normal population distribution curves.

Focused anesthesia interview resource to improve efficiency and quality.

In an effort to reduce costs, many hospitals may use registered nurses (RNs) with little to no formal education or training in anesthetic or surgical risk to perform anesthesia preoperative interviews (APIs). This lack of education and training can result in day of surgery delays and cancellations because of suboptimal preparation of patients for anesthesia and surgery. The Focused Anesthesia Interview Resource (FAIR) establishes minimum educational preparation for conducting APIs through educational modules and electronic triggers that prompt further questions and consultation flags or comorbidities for which an anesthesia provider is consulted. The goal of this process improvement project was to determine if fidelity to the FAIR tool enhanced the ability of RNs to perform preoperative anesthesia interviews and, if so, did this result in decreased surgical cancellations and delays? Retrospectively, we assessed completion rates of the training modules and anesthesia preoperative records as well as day of surgery cancellation and delay rates before and after the implementation of the FAIR tool. All RNs who might rotate to the API clinic (n=33) were included in the sample. Nurse fidelity to completion of the training modules was high (91%). Five hundred anesthesia interview records were randomly selected, reviewed, and completion rates scored. Our pre-/post-quasi-experimental design compared record completion rates. After the implementation of FAIR, significant improvement in identification of patients with hypertension (P<.01) and cardiac disease (P<.05) was noted. In addition, cancellation rates declined from 3.33% to 2.31% (P<.05) and first case delays decreased from 7.54% to 6.99%, although this was not statistically significant. FAIR improved preoperative record completion rates and decreased surgical cancellations, which improved perioperative quality and efficiency.

The perioperative implications of posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) is an anxiety disorder that develops after exposure to a traumatic event and is characterized by symptoms of reexperiencing, emotional numbing, persistent arousal, and avoidance. Approximately 6.8% of the people in the United States will be diagnosed with PTSD at some point in their lives. The presence of PTSD in a surgical patient can be important because PTSD is associated with the use of psychoactive medications, risky health behaviors, cardiovascular comorbidities, depression, chronic pain, and cognitive dysfunction, all of which may influence the risk of perioperative morbidity and mortality. In addition, patients with PTSD are anxious around unfamiliar people and in unfamiliar environments. The purposes of this journal course are to provide anesthetists with a working knowledge of the symptoms, treatments, and comorbidities associated with PTSD and to suggest ways of interacting with patients with the disorder that increase trust and decrease the risk of evoking posttraumatic symptoms in the perioperative environment.

Combined lipid emulsion and ACLS resuscitation following bupivacaine- and hypoxia-induced cardiovascular collapse in unanesthetized swine.

This study examined whether combining lipid emulsion and advanced cardiac life support (ACLS) improves survival in an unanesthetized swine model of bupivacaine- and hypoxia-induced cardiovascular collapse. Arterial and venous catheters and a tracheostomy were surgically placed in 26 swine receiving inhalation anesthesia. After a 1-hour recovery period, bupivacaine (5 mg/kg) was administered intravenously over 15 seconds. Following 1 minute of observation and 3 minutes of mechanical airway obstruction, during which all animals exhibited complete cardiovascular collapse, ACLS was initiated. Animals were randomized to receive either intravenous saline or 20% lipid emulsion commencing with the initiation ofACLS. Survival was defined as a return of spontaneous circulation (ROSC) with unsupported blood pressure greater than 60 mm Hg for 10 minutes after 25 minutes of resuscitation effort. Data collection included electrocardiogram, arterial blood pressure, and arterial and mixed venous oxygen saturations. There was no significant difference in survival between the saline group (4/12, 33%) and lipid emulsion group (6/12, 50%; P > .05). Additionally, there was no significant difference between groups of surviving animals in the time to ROSC (P > .05). The combination of lipid emulsion and ACLS did not improve survival from bupivacaine- and hypoxia-induced cardiovascular collapse in unanesthetized swine.

Review of the Mechanisms of Ventilator Induced Lung Injury and the Principles of Intraoperative Lung Protective Ventilation.

Intraoperative ventilator induced lung injury is associated with development of postoperative pulmonary complications. Despite advances in modes and methods of mechanical ventilation, postoperative pulmonary complications remain as one of the leading causes of adverse outcomes following surgery and anesthesia. In an attempt to reduce the incidence of postoperative pulmonary complications, the use of an intraoperative ventilatory technique to minimize lung injury has been introduced. Lung protective ventilation typically entails the use of a physiologic tidal volume, positive end expiratory pressure, extended inspiratory time, and an alveolar recruitment maneuver. The goal of intraoperative lung protective ventilation is to prevent or at least minimize development of ventilator induced lung injury by maintaining a homogeneous lung and alveolar stability during and after a surgical procedure. To appreciate the value of the application of an intraoperative lung protective ventilation strategy, the pathophysiology and developmental processes of ventilator induced lung injury must first be understood. The primary purpose of this paper is to provide a basic understanding of the relationship between conventional intraoperative mechanical ventilation, pulmonary derangement and lung injury as well as a rationale for the use of individualized lung protective ventilation to optimize surgical patient pulmonary outcomes.

Optimizing Intraoperative Fluid Replacement for Patients Receiving Mannitol During Neurosurgical Procedures: A Quality Improvement Initiative.

Patients undergoing craniotomy are at increased risk of intravascular volume changes due to the use of mannitol. This quality improvement project was conducted to implement a standardized goal-directed fluid therapy (GDFT) protocol using a dynamic physiologic measure in an attempt to maintain euvolemia in patients undergoing craniotomy with mannitol administration. An evidence-based GDFT protocol was integrated into an existing neurosurgical protocol. Anesthesia providers were asked to implement the protocol in patients who met the screening criteria. A preimplementation and postimplementation record review was conducted to compare outcomes of the intervention with standard practice. Primary outcomes included intensive care unit (ICU) length of stay (LOS), hospital LOS, serum lactate levels, and the total amounts of intraoperative crystalloid and colloid administered between the preimplementation and postimplementation groups. Of 95 patients who met the screening criteria, 51 (54%) had full protocol compliance. There was no significant difference between groups in ICU LOS (P=.700), hospital LOS (P=.948), serum lactate levels (P=.484), or the total amount of intraoperative crystalloid administered (P=.122). The postimplementation group had significantly more colloid administered than the preimplementation group (P=.004). A lack of provider compliance with the protocol may have affected these results. Further refined quality improvement cycles are warranted.

Does Ultrasonographic Measurement of Gastric Content Influence Airway Management Decisions?

The presence of gastric content before induction of general anesthesia is the primary modifiable risk factor in the prevention of pulmonary aspiration. The purpose of this project was to determine if ultrasonography could be routinely used to measure gastric content and assign aspiration risk in patients undergoing general anesthesia. Preoperative gastric ultrasonography was performed in a convenience sample of 100 patients. A group of Certified Registered Nurse Anesthetists, anesthesia residents, and anesthesiologists were asked their plan for airway management before and after receiving the results of the patients' gastric ultrasonogram, to determine if the scan would alter the plan. In 14% of patients scanned, solid gastric content was observed, 7% had clear liquids present, and 79% had an empty stomach. Of the patients with clear liquids present, 3 had substantial (> 100 mL) gastric content despite following fasting guidelines. Overall, there was a 9% change in airway management from standard induction: 6% changed to modified rapid sequence intubation (no ventilation, no cricoid pressure), and 3% changed to rapid sequence intubation with cricoid pressure. The number of changes to the airway management plan and identification of several patients with substantial gastric content demonstrate the value of preoperative gastric ultrasonography in airway management decision making.