Generalizability of COBRA: A Parsimonious Perioperative Venous Thromboembolism Risk Assessment Model

INTRODUCTION

Standardized use of venous thromboembolism (VTE) risk assessment models (RAMs) in surgical patients has been limited, in part due to the cumbersome workflow addition required to use available models. The COBRA score-capturing cancer diagnosis, (old) age, body mass index, race, and American Society of Anesthesiologists Physical Status score-has been reported as a potentially automatable VTE RAM that circumvents the cumbersome workflow addition that most RAMs represent. We aimed to test the ability of the COBRA model to effectively risk-stratify patients across various populations.

METHODS

Patients were included from the 2014-2019 American College of Surgeons National Surgical Quality Improvement Program (NSQIP) Participant Use Data File for two hospitals, representing colorectal, endocrine, breast, transplant, plastic, and general surgery services. COBRA score was calculated for each patient using preoperative characteristics. We calculated negative predictive value (NPV) for VTE outcomes and compared the COBRA score to NSQIP's expected VTE rate for all patients, between the two hospitals, and between subspecialty service lines.

RESULTS

Of the 10,711 patients included, those with COBRA <4 (31%) had projected median VTE rate of 0.21% (interquartile range, 0.09-0.68%; mean, 0.54%). Patients with higher scores (69%) had median rate of 0.88% (0.26-2.07%; 1.46%); relative rate 2.7. The median projected VTE rates for patients identified as low risk were 0.21% and 0.16% and as high risk were 0.87% and 0.89% at hospitals one and 2, respectively. The median projected VTE rates for patients identified as low risk were 0.17%, 0.61%, and 0.08% and as high risk were 0.52%, 1.43%, and 0.18% among general, colorectal, and endocrine surgery patients, respectively. COBRA had NPV of 0.995 and sensitivity of 0.871 as compared to NPV 0.997 and sensitivity 0.857 of the NSQIP model.

CONCLUSIONS

The COBRA score is concordant with the traditional gold standard NSQIP VTE RAM and demonstrates interhospital and service-specific generalizability, although performance was limited in especially low-risk patients. The model adequately risk-stratifies surgical patients preoperatively, potentially providing clinical decision support for perioperative workflows.

Obstetric operating room staffing and operating efficiency using queueing theory

INTRODUCTION

Strategies to achieve efficiency in non-operating room locations have been described, but emergencies and competing priorities in a birth unit can make setting optimal staffing and operation benchmarks challenging. This study used Queuing Theory Analysis (QTA) to identify optimal birth center operating room (OR) and staffing resources using real-world data.

METHODS

Data from a Level 4 Maternity Center (9,626 births/year, cesarean delivery (CD) rate 32%) were abstracted for all labor and delivery operating room activity from July 2019-June 2020. QTA has two variables: Mean Arrival Rate, λ and Mean Service Rate µ. QTA formulas computed probabilities: P0 = 1-(λ/ µ) and Pn = P0 (λ/µ)n where n = number of patients. P0…n is the probability there are zero patients in the queue at a given time. Multiphase multichannel analysis was used to gain insights on optimal staff and space utilization assuming a priori safety parameters (i.e., 30 min decision to incision in unscheduled CD; ≤ 5 min for emergent CD; no greater than 8 h for nil per os time). To achieve these safety targets, a < 0.5% probability that a patient would need to wait was assumed.

RESULTS

There were 4,017 total activities in the operating room and 3,092 CD in the study period. Arrival rate λ was 0.45 (patients per hour) at peak hours 07:00-19:00 while λ was 0.34 over all 24 h. The service rate per OR team (µ) was 0.87 (patients per hour) regardless of peak or overall hours. The number of server teams (s) dedicated to OR activity was varied between two and five. Over 24 h, the probability of no patients in the system was P0 = 0.61, while the probability of 1 patient in the system was P1 = 0.23, and the probability of 2 or more patients in the system was P≥2 = 0.05 (P3 = 0.006). However, between peak hours 07:00-19:00, λ was 0.45, µ was 0.87, s was 3, P0 was 0.48; P1 was 0.25; and P≥2 was 0.07 (P3 = 0.01, P4 = 0.002, P5 = 0.0003).

CONCLUSION

QTA is a useful tool to inform birth center OR efficiency while upholding assumed safety standards and factoring peaks and troughs of daily activity. Our findings suggest QTA is feasible to guide staffing for maternity centers of all volumes through varying model parameters. QTA can inform individual hospital-level decisions in setting staffing and space requirements to achieve safe and efficient maternity perioperative care.

A Self-Sustaining Antibiotic Prophylaxis Program to Reduce Surgical Site Infections

Background: Our multi-institutional healthcare system had a higher-than-expected surgical site infection (SSI) rate. We aimed to improve our peri-operative antibiotic administration process. Gap analysis identified three opportunities for process improvement: standardized antibiotic selection, standardized second-line antibiotic agents for patients with allergies, and feedback regarding antibiotic administration compliance. Hypothesis: Implementation of a multifaceted quality improvement initiative including a near-real-time pre-operative antibiotic compliance feedback tool will improve compliance with antibiotic administration protocols, subsequently lowering SSI rate. Methods: A compliance feedback tool designed to provide monthly reports to all anesthesia and surgical personnel was implemented at two facilities, in September 2017 and December 2018. Internal case data were tracked for antibiotic compliance through June 2021, and these data were merged with American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) data at the case level to provide process and outcome measures for SSIs. Implementation success was evaluated by comparing protocol compliance and risk-adjusted rates of superficial and deep SSI before and after the quality improvement implementation. Results: A total of 20,385 patients were included in this study; 11,548 patients in the pre-implementation and 8,837 in the post-implementation groups. Baseline patient and operative characteristics were similar between groups, except the post-implementation group had a higher median expected SSI rate (2.2% vs. 1.6%). Post-implementation, antibiotic protocol compliance increased from 86.3% to 97.6%, and superficial and deep SSIs decreased from 2.8% to 1.9% (p < 0.001). The odds of superficial and deep SSI in patients in the post-implementation group was 0.69 (0.57, 0.83) times the odds of superficial and deep SSI in pre-implementation patients while adjusting for age, gender, diabetes mellitus, American Society of Anesthesiologists Physical Status (ASA) classification, wound class, smoking, and chronic obstructive pulmonary disease (COPD). Observed-to-expected ratios of superficial and deep SSI decreased from 0.82 to 0.48 after the intervention. Conclusions: Surgical antibiotic prophylaxis standardization and providing near-real-time individualized feedback resulted in sustained improvement in peri-operative antibiotic compliance rates and reduced superficial and deep SSIs.

Timing is Everything: Surgical Outcomes for SARS-CoV-2 Positive Patients

BACKGROUND

A debate remains on how long to postpone surgery after testing positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We aimed to determine surgical outcomes at different time points after a positive SARS-CoV-2 test.

METHODS

This cohort study included non-preoperative critically ill adult surgical patients from 5/2020-5/2021 and a subset of SARS-CoV-2 positive patients 15-30 days before surgery from 5/2020-12/2021. Demographics, comorbidities, surgical variables, and outcomes were compared between SARS-CoV-2 positive patients within 50 days before surgery to SARS-CoV-2 negative surgical patients. Cases were stratified based on the timing of SARS-CoV-2 positivity before surgery in days (< 15, 15-30, > 30). Outcomes were compared between strata and against SARS-CoV-2 negative controls. A multivariable model was built to determine the association that the timing of SARS-CoV-2 positivity has on the odds of a major complication.

RESULTS

The SARS-CoV-2 positive cohort had 262 patients compared to 1,840 SARS-CoV-2 negative patients. Timing strata contained 145 (< 15 days), 53 (15-30 days), and 64 (> 30 days). The SARS-CoV-2 positive group had a higher incidence of comorbidities (87.4% vs. 57.2%) and underwent more emergent surgery (45.7% vs. 9.3%). The odds of major complications in patients positive for SARS-CoV-2 before surgery were 1.88 (1.13-3.15) (< 15 days), 0.43 (0.14-1.30) (15-30 days), and 0.98 (0.44-2.21) (31-50 days) times the odds in SARS-CoV-2 negative surgery patients when controlling for other variables.

CONCLUSION

Timing of SARS-CoV-2 positivity before surgery has an impact on major complications. In certain cases, it may be appropriate to postpone surgery 14 days after SARS-CoV-2 positivity.

Approach to Perioperative Anaphylaxis in 2020: Updates in Diagnosis and Management

PURPOSE OF REVIEW

The goal of the paper is to review the epidemiology, pathogenesis, diagnosis, and manifestations of perioperative anaphylaxis (POA). We seek to review the most common culprits of POA and different diagnostic modalities for evaluation.

RECENT FINDINGS

Specific IgE testing has a limited role in POA evaluation due to lack of widespread availability and low sensitivity. Basophil activation testing is complementary to skin tests and can assist NMBA sensitivity diagnosis in complex cases. In the past years, there has been an exponential increase in suspected teicoplanin allergic reactions in the European Union. Chlorhexidine is also being increasingly implicated as a culprit in POA. Multiple classes of perioperative medications cause POA. Diagnostic modalities available include skin testing with nonirritating concentrations, basophil activation tests, specific IgE, and drug provocation testing. An accurate record and critical analysis of perioperative events is more important than isolated test results. Future studies evaluating the pathophysiology of these reactions and other therapeutic strategies, such as targeting the MRGPRX2 receptor, are needed.

Development of a Novel Preoperative Venous Thromboembolism Risk Assessment Model

INTRODUCTION

Standardization of preoperative venous thromboembolism (VTE) risk assessment remains challenging due to variation in risk assessment models (RAMs) and the cumbersome workflow addition that most RAMs represent. We aimed to develop a parsimonious RAM that is automatable and actionable within the preoperative workflow.

METHODS

We performed a case-controlled review of all 18 VTE cases reported over a 12-month period and 171 matched controls included in an institutional National Surgical Quality Improvement Project (NSQIP) data set. We examined the predictive value of the Caprini, Padua, and NSQIP RAMs. We identified the 5 most impactful risk factors in VTE development by contribution to the known RAMs. We compared the predictive ability of cancer, age, body mass index, black race, and American Society of Anesthesiologists Physical Status (ASA-PS) score, to the Caprini, Padua, and NSQIP RAMs for VTE outcomes. Finally, we evaluated concordance between each of the models.

RESULTS

The Caprini Score was found to be 88.9% sensitive and 32.7% specific using a threshold of 5. The Padua score was found to be 61.1% sensitive and 47.4% specific using a threshold of 4. The novel 5-factor RAM was found to be 94.4% sensitive and 38.0% specific using a threshold of 4. The Caprini and Padua models were discordant in 26% of patients.

DISCUSSION

Cumbersome manual data entry contributes to the ongoing challenge of standardized VTE risk assessment and prophylaxis. Universally documented information and patient demographics can be utilized to create clinical decision support tools that can improve the efficiency of perioperative workflow and improve the quality of care.

Management of Coronavirus Disease 2019 Intubation Teams

Some patients infected with the Coronavirus Disease 2019 (COVID-19) require endotracheal intubation, an aerosol-generating procedure that is believed to result in viral transmission to personnel performing the procedure. Additionally, donning and doffing personal protective equipment can be time consuming. In particular, doffing requires strict protocol adherence to avoid exposure. We describe the Emory Healthcare intubation team approach during the COVID-19 pandemic. This structure resulted in only 1 team member testing positive for COVID-19 despite 253 patient intubations over a 6-week period with 153 anesthesia providers on service.

Determination of ED50 and time to effectiveness for intrathecal hydromorphone in laboring patients using Dixon's up-and-down sequential allocation method

Background

With the increasing occurrence of drug shortages, understanding the pharmacokinetics of alternative intrathecal opioid administration has gained importance. In particular, additional data are needed to comprehensively evaluate the analgesic properties of intrathecal hydromorphone in the laboring patient. In a phase 2 clinical trial, we set out to determine the median effective dose (ED₅₀) and time to effectiveness for this drug in this population.

Methods

Using Dixon’s up-and-down sequential allocation method, twenty women presenting for labor analgesia were prospectively enrolled. A combined spinal-epidural technique was used to deliver the determined dose of intrathecal hydromorphone. Visual analog pain scores were obtained assessing peak pain scores during serial uterine contractions. Effective pain relief was defined as achieving a pain score of less than or equal to 3 out of 10. The dose was deemed to be ineffective if the patient failed to achieve this level of relief after 30 min.

Results

The ED₅₀ of hydromorphone in our population was 10.9 μg (95% confidence interval 5.6–16.2 μg). Amongst patients for whom the dose was effective, the median time to pain relief was 24 min. One patient experienced both nausea and pruritus. No other complications were noted.

Conclusion

Due to the prolonged time to onset, hydromorphone cannot be recommended in favor of substantively better alternatives such as sufentanil and fentanyl.

Trial registration

Clinicaltrials.gov registration number: NCT01598506.

Highly visible sepsis publications from 2012 to 2017: Analysis and comparison of altmetrics and bibliometrics

PURPOSE

We sought to delineate highly visible publications related to sepsis. Within these subsets, elements of altmetrics performance, including mentions on Twitter, and the correlation between altmetrics and conventional citation counts were ascertained.

MATERIALS AND METHODS

Three subsets of sepsis publications from 2012 to 2017 were synthesized by the overall Altmetric.com attention score, number of mentions by unique Twitter users, and conventional citation counts. For these subsets, geolocated Twitter activity was plotted on a choropleth, the lag between publication date and altmetrics mentions was characterized, and correlations were examined between altmetrics performance and normalized conventional citation counts.

RESULTS

Of 57,152 PubMed query results, Altmetric.com data was available for 28,344 (49.6%). The top 50 publications by Altmetric.com attention score and Twitter attention represented a mix of original research and other types of work, garnering attention from Twitter users in 143 countries that was highly contemporaneous with publication. Altmetrics performance and conventional citation counts were poorly correlated.

CONCLUSIONS

While unreliable to gauge impact or future citation potential, altmetrics may be valuable for parties who wish to detect and drive public awareness of research findings and may enable researchers to dynamically explore the reach of their work in novel dimensions.

Initial experience with the unrestricted introduction of sugammadex at a large academic medical center: a retrospective observational study examining postoperative mechanical ventilation and efficiency outcomes

Background

Sugammadex rapidly reverses deep neuromuscular blockade, but owing to cost, questions remain about its optimal utilization. After the unrestricted introduction of sugammadex at Emory University Hospital, we hypothesized that reductions would be demonstrated in the primary outcome of post-anesthesia care unit (PACU) mechanical ventilation (MV) and secondary outcomes of PACU length of stay (LOS) and emergence time (surgery end to anesthesia end time in the PACU).

Methods

This retrospective observational study included patients undergoing general anesthesia over a 12-month period. Using multiple variable penalized logistic regression in a one-group before-and-after design, we compared the categorized rates of PACU MV to examine the effect of sugammadex introduction following a post-hoc chart review to ascertain the reason for postoperative MV. Additionally, multiple variable linear regression was used to assess for differences in PACU LOS and emergence time within a propensity-matched set of patients receiving neostigmine or sugammadex.

Results

In total, 7,217 surgical cases met the inclusion criteria: 3,798 before and 3,419 after sugammadex introduction. The incidence of PACU MV was 2.3% before and 1.8% after (P = 0.118) sugammadex introduction. PACU MV due to residual neuromuscular blockade (rNMB) decreased from 0.63% to 0.20% (P = 0.005). Ventilation because of other causes was unchanged. PACU LOS and emergence time were unchanged in the propensity-matched set of 1,444 patients.

Conclusions

rNMB was an important contributor to PACU MV utilization and its incidence significantly decreased after sugammadex introduction. The selected efficiency measures may not have been sufficiently granular to identify improvements following introduction.

Variable effectiveness of stepwise implementation of nudge-type interventions to improve provider compliance with intraoperative low tidal volume ventilation

BACKGROUND

Identifying mechanisms to improve provider compliance with quality metrics is a common goal across medical disciplines. Nudge interventions are minimally invasive strategies that can influence behavioural changes and are increasingly used within healthcare settings. We hypothesised that nudge interventions may improve provider compliance with lung-protective ventilation (LPV) strategies during general anaesthesia.

METHODS

We developed an audit and feedback dashboard that included information on both provider-level and department-level compliance with LPV strategies in two academic hospitals, two non-academic hospitals and two academic surgery centres affiliated with a single healthcare system. Dashboards were emailed to providers four times over the course of the 9-month study. Additionally, the default setting on anaesthesia machines for tidal volume was decreased from 700 mL to 400 mL. Data on surgical cases performed between 1 September 2016 and 31 May 2017 were examined for compliance with LPV. The impact of the interventions was assessed via pairwise logistic regression analysis corrected for multiple comparisons.

RESULTS

A total of 14 793 anaesthesia records were analysed. Absolute compliance rates increased from 59.3% to 87.8%preintervention to postintervention. Introduction of attending physician dashboards resulted in a 41% increase in the odds of compliance (OR 1.41, 95% CI 1.17 to 1.69, p=0.002). Subsequently, the addition of advanced practice provider and resident dashboards lead to an additional 93% increase in the odds of compliance (OR 1.93, 95% CI 1.52 to 2.46, p<0.001). Lastly, modifying ventilator defaults led to a 376% increase in the odds of compliance (OR 3.76, 95% CI 3.1 to 4.57, p<0.001).

CONCLUSION

Audit and feedback tools in conjunction with default changes improve provider compliance.

Crowdsourcing sugammadex adverse event rates using an in-app survey: feasibility assessment from an observational study

Background

Mobile applications (apps) have become a ubiquitous source of clinical decision support. We sought to ascertain the feasibility of using an app platform to obtain a crowdsourced measure of adverse drug reaction reporting rates associated with sugammadex administration and compare it with traditionally-derived estimates.

Methods

Using the widely-distributed anesthesia calculator app, 'Anesthesiologist', we surveyed anesthesia providers regarding their experience with adverse drug reactions associated with sugammadex administration.

Results

Data were analyzed from 2770 participants in 119 countries responding between March 2016 and May 2017, who were estimated to have administered between 1.6-2.9 million doses (588-1040 administrations per participant). A low and high-end reporting rate of adverse events was estimated based on respondents' reported frequency and duration of sugammadex use. The estimated reporting rate of anaphylaxis due to sugammadex was 0.0055-0.098%, similar in range to previously published estimates.

Conclusions

Use of an in-app survey facilitated a global assessment of anesthesia providers and could have useful applications in monitoring adverse events and estimating their rates. Further work is needed to validate this approach for other medications and clinical domains.

Evidence for increased use of the Society of Pediatric Anesthesia Critical Events Checklist in resource-limited environments: A retrospective observational study of app data

BACKGROUND

Electronic decision support tools in anesthesiology practice have great value, including the potential for mobile applications to simplify delivery of best-practice guidelines.

AIMS

We sought to combine demographics with usage information to elucidate important patterns in the rate of use of the Society of Pediatric Anesthesia Critical Events Checklist, as measured by in-app accesses of the checklist via the freely available anesthesia calculator app anesthesiologist.

METHODS

We performed a retrospective analytic observational case-control study using analytics and survey data collected from the app. Users of the app were classified on the basis of whether or not they had accessed the checklist. This classification was used to perform logistic regression against a number of independent variables, including frequency of app use, country income level, professional role, rating of app importance, length of time in practice, group size, practice model, community served, and primary practice environment.

RESULTS

Individual app users practicing in low- and middle-income countries have a significantly higher rate of Society for Pediatric Anesthesia Critical Events Checklist utilization as compared with high-income countries. Rural practitioners had higher utilization of the checklist. Practice size did not affect the utilization of the checklist. The checklist was used for both provider learning and for just-in-time patient care.

CONCLUSION

mHealth apps are invaluable resource in everyday clinical practice. Mobile app analytics and in-app survey data reveal variable penetration and applicability of such technology worldwide. mHealth apps may be particularly impactful in limited-resource areas, such as lower-income environments and rural communities.

Update in the Management of Patients with Preeclampsia

Hypertensive disorders of pregnancy complicate approximately 10% of all deliveries in the United States and are a leading cause of maternal and fetal morbidity and mortality. Preeclampsia is defined as hypertension in association with proteinuria, thrombocytopenia, impaired liver function, renal insufficiency, pulmonary edema, or new-onset cerebral or visual disturbances. The greatest risk factor for the development of preeclampsia is a history of preeclampsia. There currently is no effective means for the prevention of preeclampsia. Approximately 39% of patients diagnosed with preeclampsia have hypertension and approximately 20% have proteinuria 3 months postpartum. Preeclampsia increases the risk of patients developing hypertension later in life.

Determination of ED50 of hydromorphone for postoperative analgesia following cesarean delivery

BACKGROUND

Morphine is the most common opioid injected into the intrathecal space for postoperative analgesia following cesarean delivery, but ongoing medication shortages have resulted in limited availability. One proposed morphine alternative is hydromorphone. Studies investigating its use in post-cesarean analgesia are limited. This study was conducted to determine the median effective dose of intrathecal hydromorphone 12h postpartum.

METHODS

Twenty healthy women undergoing elective cesarean delivery were recruited into this study. Hydromorphone doses were determined using the up-down sequential method. The study dose of hydromorphone started at 6μg and was raised or lowered by 2μg depending on the 12-h efficacy of the preceding participant's dose. Pain scores of <3/10 were considered successful and the subsequent patient received a lower dose. Participants received 0.5% bupivacaine 12.5mg, fentanyl 25μg, and the study dose of hydromorphone as a single intrathecal injection.

RESULTS

Ten of 20 participants reported an effective hydromorphone dosage 12h post-injection. The median effective hydromorphone dosage was 4.6μg (95% CI 3.72 to 5.48μg) based on participants' reported visual analog pain scores of <3/10. No significant side effects or adverse outcomes were observed.

CONCLUSION

Intrathecal hydromorphone may be an effective alternative to morphine for post-cesarean pain management. The amount of intrathecal hydromorphone necessary to provide analgesia at 12h postoperatively may be significantly lower than doses currently in use. Further research should be performed to identify the optimal dose of intrathecal hydromorphone for post-surgical pain relief.