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Abstract Background Critically ill patients, particularly those treated with extracorporeal devices or at extremes of weight, experience pharmacokinetic variability which can compromise beta-lactam (BL) antibiotic target attainment and treatment response. Therapeutic drug monitoring (TDM) for BL antibiotics can improve precision pharmacotherapy but has had limited implementation. The objective of this study was to evaluate the frequency of BL target attainment among adult intensive care unit (ICU) patients who underwent TDM. Methods This observational study evaluated adults treated with cefepime, piperacillin/tazobactam or meropenem in ICUs at the Mayo Clinic in Rochester, Minnesota who underwent TDM from June-September 2022. During the study timeframe, multidisciplinary teams were encouraged to perform BL TDM on patients requiring extracorporeal membrane oxygenation, continuous kidney replacement therapy, or at an extreme of body weight (weight < 40 kg or >120 kg or BMI < 18 kg/m2 or > 40 kg/m2). Percentage of patients with initial serum trough concentrations within the therapeutic range was calculated (Table 1). Results During the study timeframe, 59 trough concentrations were performed on critically ill patients, of which 5 were excluded due to uninterpretable results. Of the remaining 54 BL trough concentrations analyzed, 49 (91%) were initial troughs during the antibiotic course, and 5 (9%) were repeat troughs. Thirty-six (73%) of the initial trough concentrations were within the therapeutic range. Among the trough concentrations outside the therapeutic range, 10 (77%) were too high, and 3 (23%) were too low (Table 2). Dose adjustment occurred in 19 (39%) of initial trough evaluations, including 6 which were adjusted despite a level within the therapeutic range. All of the repeat trough concentrations drawn during the same antibiotic course were within the therapeutic range (n = 5/5; 100%). Conclusion One-fourth of initial BL trough concentrations were outside of the therapeutic range. BL levels outside the therapeutic range prompted dose adjustment to improve the potential for effectiveness or limit the potential for toxicity. BL TDM appears to be a promising strategy to enhance precision pharmacotherapy in the critically ill. Disclosures Sara Ausman, PharmD, Gilead: Honoraria Christina G. Rivera (O'Connor), Pharm.D, Gilead Sciences: Advisor/Consultant|Gilead Sciences: Board Member|Gilead Sciences: Grant/Research Support|Gilead Sciences: Honoraria

Abstract Background Hospital-acquired and ventilator-associated pneumonia (HAP/VAP) remain significant causes of morbidity and mortality among patients admitted to a medical facility. Consensus guidelines for the treatment of HAP/VAP recommend patients with certain risk factors be empirically treated with an anti-methicillin resistant Staphylococcus aureus (MRSA) and anti-pseudomonal antibiotic. The most commonly utilized anti-pseudomonal agents at BJC hospitals include cefepime, followed by piperacillin/tazobactam and meropenem. The purpose of this study is to determine if there is a difference in clinical outcomes between cefepime and the other most commonly used anti-pseudomonal antibiotics, piperacillin/tazobactam or meropenem, at these institutions for the treatment of HAP/VAP. Methods This retrospective, multicenter cohort study included adult patients with HAP/VAP who received cefepime, meropenem, or piperacillin/tazobactam. Major exclusion criteria included patients that received antibiotics within 48 hours of hospital admission or less than 48 hours of empiric antibiotics. The primary outcome was in-hospital mortality. Secondary outcomes included change in initial antibiotic, mechanical ventilation-free days, ICU length of stay, hospital length of stay, hospital readmission, and new C. difficile infection. Results Of 1,117 included patients, 1,008 patients received cefepime and 109 received meropenem or piperacillin/tazobactam. Incidence of in-hospital mortality was not observed to be significantly different among empiric Gram-negative regimens (cefepime group 19.4% vs. meropenem or piperacillin/tazobactam 22%, p=0.521. Change in initial antibiotic, ICU length of stay, and hospital length of stay were observed to be significantly higher in the cefepime group. Conclusion We observed no difference in in-hospital mortality between cefepime and piperacillin/tazobactam or meropenem. However, there was a significantly higher incidence of change in initial antibiotic, ICU length of stay, and hospital length of stay observed in the cefepime group, though additional research is needed to corroborate these observations. Disclosures Kevin Betthauser, PharmD, La Jolla Pharmaceutical Company: Advisor/Consultant|La Jolla Pharmaceutical Company: Grant/Research Support Paul Juang, Pharm.D., Merck & Co: Grant/Research Support

IMPORTANCE: The outcomes of critically ill adults with obesity on continuous renal replacement therapy (CRRT) are poorly characterized. The impact of CRRT dose on these outcomes is uncertain. OBJECTIVES: This study aimed to determine if obesity conferred a survival advantage for critically ill adults with acute kidney injury (AKI) on CRRT. Secondarily, we evaluated whether the dose of CRRT predicted mortality in this population. DESIGN, SETTING, AND PARTICIPANTS: A retrospective, observational cohort study performed at an academic medical center in Minnesota. The study population included critically ill adults with AKI managed with CRRT. MAIN OUTCOMES AND MEASURES: The primary outcome of 30-day mortality was compared between obese (body mass index [BMI] ≥ 30 kg/m2) and nonobese (BMI < 30 kg/m2) patients. Multivariable regression assessed was used to assess CRRT dose as a predictor of outcomes. An analysis included dose indexed according to actual body weight (ABW), adjusted body weight (AdjBW), or ideal body weight (IBW). RESULTS: Among 1033 included patients, the median (interquartile range) BMI was 26 kg/m2 (23–28 kg/m2) in the nonobese group and 36 kg/m2 (32–41 kg/m2) in the obese group. Mortality was similar between groups at 30 days (54% vs. 48%; p = 0.06) but lower in the obese group at 90 days (62% vs. 55%; p = 0.02). CRRT dose predicted an increase in mortality when indexed according to ABW or AdjBW (hazard ratio [HR], 1.2–1.16) but not IBW (HR, 1.04). CONCLUSIONS AND RELEVANCE: In critically ill adults with AKI requiring CRRT, short-term mortality appeared lower in obese patients compared with nonobese patients. Among weight calculations, IBW appears to be preferred to promote safe CRRT dosing in obese patients.

ABSTRACT Cefepime exhibits highly variable pharmacokinetics in critically ill patients. The purpose of this study was to develop and qualify a population pharmacokinetic model for use in the critically ill and investigate the impact of various estimated glomerular filtration rate (eGFR) equations using creatinine, cystatin C, or both on model parameters. This was a prospective study of critically ill adults hospitalized at an academic medical center treated with intravenous cefepime. Individuals with acute kidney injury or on kidney replacement therapy or extracorporeal membrane oxygenation were excluded. A nonlinear mixed-effects population pharmacokinetic model was developed using data collected from 2018 to 2022. The 120 included individuals contributed 379 serum samples for analysis. A two-compartment pharmacokinetic model with first-order elimination best described the data. The population mean parameters (standard error) in the final model were 7.84 (0.24) L/h for CL1 and 15.6 (1.45) L for V1. Q was fixed at 7.09 L/h and V2 was fixed at 10.6 L, due to low observed interindividual variation in these parameters. The final model included weight as a covariate for volume of distribution and the eGFR cr-cysC (mL/min) as a predictor of drug clearance. In summary, a population pharmacokinetic model for cefepime was created for critically ill adults. The study demonstrated the importance of cystatin C to prediction of cefepime clearance. Cefepime dosing models which use an eGFR equation inclusive of cystatin C are likely to exhibit improved accuracy and precision compared to dosing models which incorporate an eGFR equation with only creatinine.

IMPORTANCE: Protein binding of valproate varies among ICU patients, altering the biologically active free valproate concentration (VPAC). Free VPAC is measured at few laboratories and is often discordant with total VPAC. Existing equations to predict free VPAC are either not validated or are inaccurate in ICU patients. OBJECTIVES: We designed this study to derive and validate a novel equation to predict free VPAC using data from ICU patients and to compare its performance to published equations. DESIGN: Retrospective cohort study. SETTING: Two academic medical centers. PARTICIPANTS: Patients older than 18 years old with concomitant free and total VPACs measured in the ICU were included in the derivation cohort if admitted from 2014 to 2018, and the validation cohort if admitted from 2019 to 2022. MAIN OUTCOMES AND MEASURES: Multivariable linear regression was used to derive an equation to predict free VPAC. Modified Bland-Altman plots and the rate of therapeutic concordance between the measured and predicted free VPAC were compared. RESULTS: Demographics, median free and total VPACs, and valproate free fractions were similar among 115 patients in the derivation cohort and 147 patients in the validation cohort. The Bland-Altman plots showed the new equation performed better (bias, 0.3 [95% limits of agreement, –13.6 to 14.2]) than the Nasreddine (–9.2 [–26.5 to 8.2]), Kodama (–9.7 [–30.0 to 10.7]), Conde Giner (–7.9 [–24.9 to 9.1]), and Parent (–9.9 [–30.7 to 11.0]) equations, and similar to Doré (–2.0 [–16.0 to 11.9]). The Doré and new equations had the highest therapeutic concordance rate (73%). CONCLUSIONS AND RELEVANCE: For patients at risk of altered protein binding such as ICU patients, existing equations to predict free VPAC are discordant with measured free VPAC. A new equation had low bias but was imprecise. External validation should be performed to improve its precision and generalizability. Until then, monitoring free valproate is recommended during critical illness.

Background: Patients with pulmonary hypertension (PH) who undergo endotracheal intubation have an increased risk of adverse outcomes, but little is known regarding prognostic factors and there is limited evidence to guide management. We sought to define characteristics, prognostic factors, and outcomes of critically ill patients with PH who underwent intubation. Study Design: We performed a single-center retrospective cohort study of critically ill patients with group 1, 3 or 4 PH who underwent intubation. Results: Eighty-one patients were included. Patients had a median age of 56 years (interquartile range 44-65) and were predominantly female (n = 53, 65%) and Caucasian (n = 71, 88%). Forty-five (56%) had group 1 PH while 25 (31%) had group 3 PH and 11 (14%) had group 4 PH. Patients were admitted to the hospital for right ventricular failure (n = 21, 25.6%), sepsis (n = 18, 22.2%), and respiratory failure (n = 19, 23.1%). Hypoxemic respiratory failure (n = 54, 66.7%) was the most common indication for intubation. In-hospital mortality was 30.9% and 1-year mortality was 48.2% . All patients (11 of 11, 100%) intubated electively for intensive care unit procedures survived to hospital discharge while only 1 of 6 (16.7%) intubated in the setting of a cardiac arrest survived. After adjusting for right ventricular systolic pressure, pre-intubation PaO 2 (odds ratio [OR] = 0.99, 95% confidence interval [CI] 0.97-1.00, P = .02) and postintubation PaO 2 (OR = 0.97 per 1mm Hg, 95% CI 0.95 to 0.99, P = .003), pH (OR = 0.49 per 0.1 increase, 95% CI 0.29 to 0.80, P = .005) and PaCO 2 (OR = 1.08 per 1mm Hg, 95% CI 1.02 to 1.14, P = .005) were significantly associated with in-hospital mortality. Results were similar when we excluded patients intubated electively or in the setting of cardiac arrest. Conclusions: Intubation in critically ill patients with PH is associated with significant in-hospital mortality and nearly 50% 1-year mortality. Potentially modifiable factors, such as peri-intubation gas exchange, are associated with an increased risk of death while other demographic and hemodynamic variables are not.

Background: Cardiovascular instability occurring during endotracheal intubation (ETI) in the critically ill is a commonly recognized phenomenon. However, this complication has not been evaluated in terms of the physiological cause (ie, decreased preload, contractility, or afterload) leading to the instability. Thus, the aim of the current investigation was to describe the hemodynamics occurring during ETI with noninvasive physiologic monitoring and to collect preliminary data on the hemodynamic effects of induction agents and positive pressure ventilation. Methods: A multicenter prospective study enrolling adult (≥18 years) critically ill patients undergoing ETI with noninvasive cardiac output monitoring in a medical/surgical intensive care unit from June 2018 to May 2019 was conducted. This study used the Cheetah Medical noninvasive cardiac output monitor to collect hemodynamic data during the peri-intubation period. Additional data collected included baseline characteristics such as illness severity, peri-intubation pharmacologic administration, and mechanical ventilation settings. Results: From the original 27 patients, only 19 (70%) patients had complete data and were included in the final analysis. Propofol was the most common sedative 8 (42%) followed by ketamine 6 (32%) and etomidate 5 (26%). Patients given propofol demonstrated a decrease in total peripheral resistance index (delta change [dynes × s/cm −5 /m 2 ]: −2.7 ± 778.2) but stabilization in cardiac index (delta change (L/min/m 2 ]: 0.1 ± 1.5) while etomidate and ketamine demonstrated increases in total peripheral resistance index (etomidate delta change [dynes × s/cm −5 /m 2 ]: 302.1 ± 414.3; ketamine delta change [dynes × s/cm −5 /m 2 ]: 278.7 ± 418.9) but only etomidate resulted in a decrease in cardiac index (delta change [L/min/m 2 ]: −0.3 ± 0.5). Positive pressure ventilation resulted in minimal changes to hemodynamics during ETI. Conclusions: The current study demonstrates that although propofol administration leads to a decrease in total peripheral resistance index, cardiac index is maintained while etomidate leads to a decrease in cardiac index with both etomidate and ketamine increasing total peripheral resistance index. These hemodynamic profiles are minimally affected by positive pressure ventilation. Study registration: ClinicalTrials.gov ID, NCT03525743.

AbstractBeta‐lactam therapeutic drug monitoring (TDM) can improve precision dosing and clinical outcomes in critically ill patients, but has not been implemented widely in the United States. Mayo Clinic recently implemented a beta‐lactam TDM program. This single‐center experience forms the basis of the manuscript which outlines practical considerations involved with beta‐lactam TDM implementation, including the pharmacist's role as a leader. Our implementation effort focused on three primary domains. First, we aimed to ensure a supportive organizational infrastructure. Early leadership engagement by the pharmacist‐led core team facilitated advocacy for the clinical need, allocation of resources, and assay development. Second, core clinical workflows were developed that addressed the preferred patient population for use, desirable pharmacokinetic and pharmacodynamic targets, and the preferred sampling strategy. Clinical tools to guide pharmacists in interpreting the results (e.g., pharmacokinetics calculator) and documenting decisions were developed. Third, stakeholders were offered repeated exposure to evidence and expertise to facilitate understanding and application of the new practice. This act of ‘individual internalization’ seems to be uniquely important to beta‐lactam TDM implementation compared with the implementation of other antimicrobial TDM programs. Educational strategies and supportive materials that were developed were focused on providing substantive and varied information tailored to the stakeholders' role in the process. For pharmacists, this included both clinical and operational considerations. A continuous improvement plan to support management of the process was instituted to address necessary updates and changes that inevitably emerged. In summary, the described approach to implementation of a pharmacist‐led beta‐lactam TDM program could be used as a roadmap to aid other institutions that aim to develop such a program.