Hyperoxia: Current Practice of Oxygen Delivery During General Anesthesia

Background While supplemental oxygen is routinely administered during anesthesia to prevent oxygen desaturation and optimize tissue oxygenation, oxygen delivery practices after intubation are largely unknown. Compiled evidence suggests limiting intraoperative fraction of inspired oxygen (FiO2) to below 60%. The deleterious effects of hyperoxia and the mortality benefit of conservative oxygen administration are being demonstrated in contemporary critical care literature. The lack of consensus guidelines and high level evidence on the topic of intraoperative oxygen delivery begs the question to what degree are patients being exposed to hyperoxia during general anesthesia. The purpose of this evidence-based practice project was to better understand oxygen administration practices during general anesthesia and assess independent risk factors for hyperoxia for patients at Providence Sacred Heart Medical Center. Methods A comprehensive literature review was conducted • Institutional approval and IRB exemption determination granted • Relevant de-identified patient data was extracted from electronic health record • Encrypted data was stored in a HIPAA compliant REDCap database • Inclusion criteria: Adults 18 years of age or older who received general anesthesia at PHSMC during 2018 • Patients must have been intubated with an ETT or LMA and extubated at the end of the case • Additional exclusion criteria: ENT, thoracic, cardiac, pulmonary service lines and emergent procedures • Median FiO2 and SpO2 from intubation to extubation were measured and analyzed • Binary logistic regression analyzed the independent effects of hyperoxia (median FiO2 in excess of 60% while under anesthesia) • Level of significance set to 0.05 Discussion Of the cases reviewed for this project, 39% of the patients were exposed to median FiO2 in excess of 60% during anesthesia. Median FiO2 from intubation to extubation largely fell between 50% and 70% and SpO2 averaged 99%. Independent risk factors for median FiO2 in excess of 60% included higher ASA status, increasing age, and female gender. Case duration was inversely independently related. No effects were observed from smoking, COPD or BMI. Further studies are needed to evaluate the implications of oxygen exposure during general anesthesia and the safety and feasibility of more conservative intraoperative oxygen administration. The emerging evidence will likely prompt providers to be more mindful of oxygen delivery practices during anesthesia.https://digitalcommons.psjhealth.org/other_pubs/1116/thumbnail.jp

Comparison of Ondansetron, Dexamethasone, and its Combination in the Prevention of Postoperative Nausea and Vomiting

Background Postoperative nausea and vomiting remains a common and unpleasant side effect for patients following surgery. Uncontrolled PONV can result in prolonged hospital stays, unanticipated hospital readmissions, and decreased patient satisfaction. The Apfel score identifies and counts independent risk factors for PONV; females, non-smokers, postoperative opioid use, and history of PONV or motion sickness. Rates of PONV increases as the number of risk factors increase. The primary intervention to decrease PONV is administration of prophylactic antiemetics. Research supports the use of combination antiemetic therapy for patients with a high number of risk factors. The purpose of this evidence based practice (EBP) project was to report the rate of PONV among surgical patients who received general anesthesia, comparing combination prophylactic antiemetics of ondansetron and dexamethasone to single antiemetic administration. Methods A retrospective, EBP project was conducted at Providence Sacred Heart Medical Center (PSHMC) in Spokane, WA. • Permission was obtained by the facility and exemption determination was granted by the IRB. • Patient data was securely extracted and stored in a HIPPA compliant REDCap database. Patient data was fully de-identified. Data extraction included all surgeries in the 2018 calendar year. • Inclusion criteria: Adult patients \u3e 18 years old, non-emergent surgery, general anesthesia (ETT, LMA) using volatile inhalational agents or total intravenous anesthesia. • Exclusion criteria: Pediatric, obstetric, emergency surgery, direct admission to ICU. • PONV outcome determined by nursing documentation of PONV scale, intervention, reassessment or signs/symptoms or administration of antiemetic medication. • Descriptive data analysis completed and stratified by the number of Apfel risk factors. Independent risk factors determined using binary logistic regression. Level of significance set at 0.05. Discussion CONCLUSION When controlling for all literature reported PONV risk factors, this EBP project demonstrated that the odds of PONV reduction were similar for combination and individual antiemetic therapy. Similar to current research evidence, the identified independent risk factors for PONV were female gender, history of PONV or motion sickness, postoperative opioid administration, younger age, high risk procedures, and increased case duration. Non-smoking status and nitrous oxide use were not observed to be independent risk factors. As Apfel reported, this project similarly reported an increase rate in PONV as the number of PONV risk factors increased. The observed risk of PONV decreased among patients with at least one Apfel risk factor following prophylactic antiemetic administration. IMPLICATIONS Practice at PSHMC is demonstrating that combination prophylactic treatment is being used for patients with higher PONV risk factors. Practice is following current research evidence. Anesthetists should continue to tailor prophylactic antiemetic administration to patients based on presenting risk factors.https://digitalcommons.psjhealth.org/other_pubs/1118/thumbnail.jp

COMPARISONS OF PREOPERATIVE BLOOD PRESSURES IN SURGICAL PATIENTS

Background Surgical patients expect anesthesia providers to provide high quality care. Blood pressure variability must be mitigated by establishing the patient’s blood pressure baseline and sustaining it through surgery. A consensus has not been established on which blood pressure measurement should be used as the patient’s baseline. Blood pressures before surgery in multiple care settings have been shown to vary. This may result in differences in drug and fluid administration, depending on the blood pressure considered baseline by the anesthesia provider. The purpose of this observational evidence-based practice project was to compare mean blood pressures leading up to surgery among patients at Providence Sacred Heart Medical Center (PSHMC). Methods Literature review identified five high quality studies to inform this project. • Institutional approval sought and obtained. IRB determined exempt research. • Data on adult, elective surgical patients receiving a general anesthetic from 09/30/2017-10/1/2018 were extracted in an anonymized fashion. • Patients characterized by demographic and clinical characteristics (table 1). • Mean blood pressures calculated from three settings: ambulatory clinics in the 12 months prior to surgery, the surgical admit unit (SAU) and the “first on table” (FOT) or first pressure recorded in the operating room. Patients without blood pressures recorded in each care setting excluded. • Repeated measures ANOVA and multiple linear regression (α=0.05). Discussion SBP increased significantly from the pre-surgical ambulatory period to the first on table (FOT) blood pressure taken in the operating room. Changes in MAP were statistically, but not clinically, significant. A multivariable regression model revealed age, sex, heart failure, atrial fibrillation, hypertension, chronic kidney disease and peripheral vascular disease to be factors predictive of increasing FOT SBP. Our findings are consistent with current research evidence. Providence Sacred Heart Medical Center patients may experience over-treatment for hypotension if the first-ontable SBP is utilized as a baseline. This overtreatment may result in increased monetary and physical costs.https://digitalcommons.psjhealth.org/other_pubs/1119/thumbnail.jp

Intraoperative Hypotension in Non-Cardiac Surgery Patients at Providence Sacred Heart Medical Center

Background Intraoperative Hypotension (IOH) during non-cardiac surgery is a common side effect of anesthesia that is associated with acute kidney injury (AKI), myocardial injury (MI), mortality, and other adverse outcomes1,3,4. These risks increase as the duration and severity of IOH exposure increase3,4. Blood pressure is a modifiable risk factor of mortality and organ damage that can be readily treated by the anesthesia provider2 . Limiting IOH can improve patient outcomes and produce monetary savings5 . The objective of this project is to report the incidence of IOH at a large tertiary teaching hospital, and extrapolate the risks of mortality and organ damage among patients with IOH. This project also identifies IOH risk factors, and reports timing of IOH during surgery. Methods We conducted a retrospective analysis of secondary, observational data at Providence Sacred Heart Medical Center (PSHMC) • Eligibility Criteria. Inclusion: patients \u3e18 years of age who received general anesthesia for elective non cardiac surgery from October 1, 2017 to September 30, 2018 Exclusion: cardiopulmonary bypass, emergent, cesarean & pediatric surgical populations; persons with blood pressure frequency \u3e5 minutes • Patient demographic and surgical data from electronic medical records were extracted using a REDCap data collection tool • We defined IOH according to absolute mean arterial pressure thresholds described by Wesselink et al., 20184 • Descriptive analyses were conducted to examine baseline demographics, incidence and timing of IOH in the study population • Multivariable analyses using binary logistic regression were performed to examine risk factors associated with IOH ( = 0.5) • The risks of mortality, AKI & MI associated with each IOH definition were extrapolated based upon data from a 2018 systematic review4 • This project was approved by the PSHMC Clinical Innovation and Research Council, and deemed exempt from human subjects research by Providence Health Care institutional review board Discussion At a large tertiary teaching hospital, we found that 24% of our study population experienced IOH associated \u3e 50% increased risk of MI, while 8% and 6% of patients experienced IOH associated with a \u3e2 times greater risk for AKI and mortality, respectively. Female sex, longer case duration, and interventional radiology, cardiology, and plastics service lines were among the top IOH risk factors. 42% of IOH occurred between anesthesia induction and surgical incision, even though that time period only accounted for 19% of the intraoperative time. These findings suggest that up to one-quarter of non-cardiac surgical patients may be at elevated risk for organ damage, and as much as 6% patients may double their risk of mortality due to IOH. Given these risks, anesthesia providers should minimize IOH, and be aware of patient and surgical characteristics associated with higher IOH risk. The period between anesthesia induction and surgical incision may represent a time in which the anesthesia providers can work independently to reduce IOH exposure. Future projects should examine the utility of strategies for anesthesia providers to reduce IOH exposure in patients undergoing noncardiac surgery and reassess incidence rates.https://digitalcommons.psjhealth.org/other_pubs/1117/thumbnail.jp

Transfusion Ratios Following Activation of a Massive Transfusion Protocol: An Evidence Based Practice Project

Background Accidental injury is one of the leading causes of death in the United States and worldwide. Severe hemorrhage from injury is the leading cause of preventable death. Effective management of hemorrhaging trauma patients has been evolving since the early 1900’s. Recent studies have demonstrated the benefits of using a balanced resuscitation technique, revolving around the goal of recreating whole blood. The purpose of this project was to identify what ratios of blood products are being transfused at Providence Sacred Heart Medical Center (PSHMC) and Providence Holy Family Hospital (PHFH). Methods A literature review was performed identifying seven high quality peer-reviewed studies. • Institutional approval and IRB review for exemption determination completed. Human subjects were protected. • Registry data extraction in an anonymized fashion. • Patients who received no packed red blood cells or had no age specified were excluded. • Patients organized by demographic and clinical characteristics. • 24-hour mortality rates extracted from the electronic health record. • Post hoc power analysis was completed. • High ratio transfusion was defined as a ratio approaching or greater than 1:1 with packed red blood cells always being the denominator (i.e. FFP:PRBC, PLT:PRBC). Discussion Massive transfusion ratios among hemorrhaging patients at PSHMC and PHFH were observed at high ratio 35% of the time, when comparing fresh frozen plasma to packed red blood cells, and 49% of the time, when comparing platelets to packed red blood cells. Trauma patients account for 39% of all massive transfusions at PSHMC and PHFH. Though some cases of massive transfusions observed in this project did achieve high transfusion ratios, it is unclear what reasons prevented high transfusion ratios. Research evidence suggest that mortality risk is higher when lower ratios are utilized during massive transfusions. However, this project was not powered to detect mortality differences by ratios.https://digitalcommons.psjhealth.org/other_pubs/1121/thumbnail.jp

Intraoperative Opioid Administration Among Cancer Patients

Background Cancer prevalence continues to rise. In vitro and in vivo studies have demonstrated that opioid receptor agonists may be associated with poor outcomes for cancer patients. Laboratory studies have shown that opioids cause immunosuppression; tumor cell progression, recurrence and metastasis. The surgical environment further decreases immune function, causes an inflammatory response and promotes cancer cell mobilization. Anesthesia providers are in a unique position to influence postoperative outcomes. Opioid free anesthetic delivery is a growing trend amongst anesthesia providers and is supported by the literature. The purpose of this project is to compare intraoperative opioid administration rates for patients with a cancer diagnosis to those without a cancer diagnosis. Methods • Design: Observational, retrospective, descriptive study • Regulatory: CIRC approval and IRB exemption • Dates: October 1, 2017 to September 30, 2018 • Protection of human subjects: Deidentified patient data stored in HIPPA compliant Redcap Database • Setting: Providence Sacred Heart Medical Center • Participants: Adult, non-emergent surgical patients receiving IV and inhalational anesthesia • Event rates reported as risk and relative risk (RR) calculated • Analysis: Group differences in categorical variables tested by Chi-Square Discussion This project determined that rates of intraoperative opioid administration were similar for patients with or without a cancer diagnosis. Literature suggests the use of opioid free anesthesia should be considered for patients with a cancer diagnosis. Opioid administration is common practice. Reducing its use may provide improved short and long term outcomes. This project did not consider costs of various anesthesia techniques nor did it examine dosages of opioid administration. Future research should examine reductions in the use of opioid administration and the costs associated with the use of opioid free anesthesiahttps://digitalcommons.psjhealth.org/other_pubs/1113/thumbnail.jp

Ultrasound Simulation for Regional Anesthesia

Background Regional anesthesia is an essential skill in the practice of Nurse Anesthesia, and future employment demands expertise. Literature supports the addition of simulation training to existing didactic and apprenticeship education to improve clinical expertise. The purpose of this project was to trial simulation training, focused on anatomical visualization with ultrasound for regional anesthesia, as a means to improve student performance and confidence. Methods • Facility project approval and exemption determination by IRB. • Hands-On Test: Ultrasound to obtain visualization for axillary (cohort 1), interscalene (cohort 2) block on live-model. Expert CRNA observed performance to determine if image was clinically acceptable. Yes/No result, and time necessary for visualization recorded. • Written Test: Anatomical structures to be named, (fig. 1). • Expert led practice with visualization for interscalene, supraclavicular, axillary, TAP, adductor canal, popliteal and IPACK blocks. • Testing repeated after completion of training. Discussion Student performance in ultrasound demonstration and written anatomy identification improved after implementation of expert-led ultrasound training and simulation practice. Survey results demonstrated improvements in perceived confidence with the use of ultrasound following simulation training. Clinically significant improvement as demonstrated by this educational innovation project, provides a compelling statement to the University; additional simulation training should be integrated into the curriculum. Furthermore, this project opens dialogue about purchasing an ultrasound machine dedicated to the Nurse Anesthesia program.https://digitalcommons.psjhealth.org/other_pubs/1115/thumbnail.jp

Prophylactic Phenylephrine Infusion to Mitigate Intraoperative Hypotension after Spinal Anesthesia among Orthopedic Patients

Background Intraoperative Hypotension (IOH) is common after spinal anesthesia (SA) and is associated with an increased risk of end organ damage.1 2 3 The treatment regimen for IOH after SA varies in the orthopedic population. However, the current research literature suggests that a prophylactic infusion of phenylephrine significantly reduces the number of episodes and duration of hypotension.1 This EBP project aims to report the proportion of patients receiving prophylactic phenylephrine infusions and the incidence of hypotension following SA among orthopedic surgery patients at Providence Sacred Heart Medical Center (PSHMC) in Spokane, WA. Methods • A retrospective, observational EBP project was conducted at PSHMC. • Permission was obtained by PSHMC Clinical Innovation and Research Council and deemed exempt from human subjects research by the Providence Health Care Institutional Review Board. • Patient data was securely extracted, deidentified, and stored in a HIPPA compliant REDCap database. • Inclusion criteria: Adult patients ≥ 18 years old who received SA for non-emergent orthopedic surgery. • Exclusions: Pediatric, obstetric, emergency surgery, and surgery lines other than orthopedic. • IOH outcome determined by absolute mean arterial pressure (MAP) thresholds, as described in Wesselink et al. (2018) systematic review.4 • Descriptive analyses were conducted to examine baseline demographics and IOH treatment regimens utilized at PSHMC. • Independent risk factors determined using binary logistic regression and time-to-event (MAP \u3c60 mmHg) analyses determined using the Kaplan-Meier estimator (α = 0.05). Discussion The primary objective of this observational EBP project of 3,745 patients was to measure the use of prophylactic phenylephrine infusions among orthopedic surgery patients at PSHMC. Overall, we found that 16% of patients received a prophylactic phenylephrine infusion. The median infusion start time for a prophylactic infusion was 19 minutes following SA [IQR 10-29]. Patients who did not receive a prophylactic phenylephrine infusion following SA had significantly increased risk of MAP \u3c60mmHg for ≥ 10 minutes (RR 3.42, 2.55-4.62, p\u3c0.001). The observed median time to the first MAP \u3c60 mmHg was longer in patients who received prophylactic phenylephrine infusions (80 [41-99] vs 29 [16-57] minutes, p \u3c 0.0001). Patients who were male, advanced age, higher physical status scores and history of CVD were more likely to receive a prophylactic infusion. This project is the first to establish the utilization rate of prophylactic phenylephrine infusions and the incidence of IOH after SA among orthopedic patients at a large academic health center. However, due to the lack of prospective studies, further investigation is warranted.https://digitalcommons.psjhealth.org/other_pubs/1105/thumbnail.jp