Implementation and Evaluation of Weight-Based Vasopressors in Intensive Care Units

Background: Vasopressors, including norepinephrine, epinephrine, and phenylephrine are commonly used to maintain mean arterial pressure (MAP) in critically ill patients. Despite their frequent use, the optimal dosing strategy for vasopressors remains understudied. Objective: The purpose of this study is to evaluate the implementation of a weight-based (WB) dosing strategy using ideal body weight compared to a non-weight-based (NWB) dosing strategy for vasopressors in critically ill patients. Methods: This is a retrospective chart review of patients admitted to intensive care units receiving vasopressor medications for greater than or equal to 4 hours. Patients received either an NWB or a WB vasopressor dosing strategy. The primary endpoint was the time to achieve goal MAP. Results: This study included 153 patients in the NWB vasopressor dosing group and 183 in the WB dosing group. The median time to achieve goal MAP in the NWB group was 24 minutes versus 21 minutes in the WB group (P = 0.1713). There were no significant differences in secondary outcomes including number of vasoactive agents required, hospital length of stay, and duration of mechanical ventilation. Subgroup analysis of patients with extremes of body mass index did not show a difference in time to achieve goal MAP. In a subgroup analysis of patients with septic shock, a higher percentage of patients in the WB group received corticosteroids than the NWB group patients (14% vs. 54%; P ≤ 0.001). Conclusion and relevance: There was no difference in time to achieve goal MAP when using a WB or NWB vasopressor dosing approach. Institutions should employ a consistent dosing strategy for vasopressors with either an NWB or WB approach.

Continuous Renal Replacement Therapy and Mortality in Critically Ill Obese Adults

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.

Evaluation of Dose Requirements Using Weight-Based versus Non-Weight-Based Dosing of Norepinephrine to Achieve a Goal Mean Arterial Pressure in Patients with Septic Shock

No consensus exists regarding optimal dosing of norepinephrine in septic shock. We aimed to evaluate if weight-based dosing (WBD) lead to higher norepinephrine doses when achieving goal mean arterial pressure (MAP) than non-weight-based dosing (non-WBD). This was a retrospective cohort study conducted after standardization of norepinephrine dosing within a cardiopulmonary ICU. Patients received non-WBD prior to standardization (November 2018-October 2019) and WBD afterwards (November 2019-October 2020). The primary outcome was the norepinephrine dose needed to attain goal MAP. Secondary outcomes included time to goal MAP, duration of norepinephrine therapy, duration of mechanical ventilation, and treatment-related adverse effects. A total of 189 patients were included (WBD 97; non-WBD 92). There was a significantly lower norepinephrine dose at goal MAP (WBD 0.05, IQR 0.02, 0.07; non-WBD 0.07, IQR 0.05, 0.14; p < 0.005) and initial norepinephrine dose (WBD 0.02, IQR 0.01, 0.05; non-WBD 0.06, 0.04, 0.12; p < 0.005) in the WBD group. No difference was observed in achievement of goal MAP (WBD 73%; non-WBD 78%; p = 0.09) or time until goal MAP (WBD 18, IQR 0, 60; non-WBD 30, IQR 14, 60; p = 0.84). WBD may lead to lower norepinephrine doses. Both strategies achieved goal MAP with no significant difference in time to goal.

Beyond the bundle: Clinical controversies in the management of sepsis in emergency medicine patients

Sepsis is a condition characterized by life-threatening organ dysfunction caused by a dysregulated host response to infection. The emergency department (ED) serves as a crucial entry point for patients presenting with sepsis. Given the heterogeneous presentation and high mortality rate associated with sepsis and septic shock, several clinical controversies have emerged in the management of sepsis. These include the use of novel therapeutic agents like angiotensin II, hydrocortisone, ascorbic acid, thiamine ("HAT") therapy, and levosimendan, Additionally, controversies with current treatments in vasopressor dosing, and the use of and balanced or unbalanced crystalloid are crucial to consider. The purpose of this review is to discuss clinical controversies in the management of septic patients, including the use of novel medications and dosing strategies, to assist providers in appropriately determining what treatment strategy is best suited for patients.

Evaluation of Evidence, Pharmacology, and Interplay of Fluid Resuscitation and Vasoactive Therapy in Sepsis and Septic Shock

ABSTRACT

We sought to review the pharmacology of vasoactive therapy and fluid administration in sepsis and septic shock, with specific insight into the physiologic interplay of these agents. A PubMed/MEDLINE search was conducted using the following terms (vasopressor OR vasoactive OR inotrope) AND (crystalloid OR colloid OR fluid) AND (sepsis) AND (shock OR septic shock) from 1965 to October 2020. A total of 1,022 citations were reviewed with only relevant clinical data extracted. While physiologic rationale provides a hypothetical foundation for interaction between fluid and vasopressor administration, few studies have sought to evaluate the clinical impact of this synergy. Current guidelines are not in alignment with the data available, which suggests a potential benefit from low-dose fluid administration and early vasopressor exposure. Future data must account for the impact of both of these pharmacotherapies when assessing clinical outcomes and should assess personalization of therapy based on the possible interaction.

Practice Patterns in the Initiation of Secondary Vasopressors and Adjunctive Corticosteroids during Septic Shock in the US

RATIONALE

A central component of septic shock treatment is the infusion of vasopressors, most commonly starting with norepinephrine. However, the optimal approach and practice patterns to initiating adjunctive vasopressors and corticosteroids are unknown.

OBJECTIVES

To characterize practice pattern variation in the norepinephrine dose at which secondary vasopressors and adjunctive corticosteroids are initiated and to identify factors associated with a treatment strategy favoring secondary vasopressors to a treatment strategy favoring adjunctive corticosteroids among patients with septic shock on norepinephrine.

METHODS

We used a multicenter ICU database to identify patients with septic shock who were started on norepinephrine followed by an additional vasopressor or corticosteroids. We used multi-level models to determine the hospital risk-adjusted norepinephrine dose at which additional vasopressors and corticosteroids were started, the percentage of variation in norepinephrine dose at the time of adjunctive treatment associated with hospital of admission, and the factors associated with choosing an 'additional vasopressor first' strategy vs. a 'corticosteroid first' strategy.

RESULTS

Among 4,401 patients with septic shock on norepinephrine, 1940 (44.0%) were started on adjuncts (1357 received an 'additional vasopressor first' strategy and 583 received a "corticosteroid first strategy). The hospital risk-adjusted norepinephrine dose at which vasopressors were initiated ranged 6.4 mcg/min (95% CI 5.9-7.0 mcg/min) to 92.6 mcg/min (95% CI 72.8-113.0 mcg/min). The hospital risk-adjusted norepinephrine dose at which corticosteroids was initiated ranged 3.0 mcg/min (95% CI 2.4-3.8 mcg/min) to 32.7 mcg/min (95% CI 24.9-43.0 mcg/min). 25.1% (intraclass correlation coefficient 95% CI 24.8%, 25.5%) of the variation in norepinephrine dose at which additional vasopressors were initiated was explained by hospital site after adjusting for all hospital- and patient-level covariates. Hospital of admission was strongly associated with receiving an 'additional vasopressor first' over a 'corticosteroids first' strategy (median odds ratio 3.28 (95% CI 2.81-3.83)).

CONCLUSIONS

Practice patterns for adjunctive therapies to norepinephrine during septic shock are variable and are determined in large part by hospital of admission. These results inform several future studies seeking to improve septic shock management.

The Obese Patient: Facts, Fables, and Best Practices

The prevalence of obesity continues to rise worldwide, and anesthesiologists must be aware of current best practices in the perioperative management of the patient with obesity. Obesity alters anatomy and physiology, which complicates the evaluation and management of obese patients in the perioperative setting. Gastric point-of-care ultrasound (PoCUS) is a noninvasive tool that can be used to assess aspiration risk in the obese patient by evaluating the quantity and quality of gastric contents. An important perioperative goal is adequate end-organ perfusion. Standard noninvasive blood pressure (NIBP) is our best available routine surrogate measurement, but is vulnerable to greater inaccuracy in patients with obesity compared to the nonobese population. Current NIBP methodologies are discussed. Obese patients are at risk for wound and surgical site infections, but few studies conclusively guide the exact dosing of intraoperative prophylactic antibiotics for them. We review evidence for low-molecular-weight heparins and weight-based versus nonweight-based administration of vasoactive medications. Finally, intubation and extubation of the patient with obesity can be complicated, and evidence-based strategies are discussed to mitigate danger during intubation and extubation.

Prescribing of Pressor Agents in Septic Shock: A Survey of Critical Care Pharmacists

Background: Pressor agents are recognized as high-alert medications by the Institute for Safe Medication Practices, but little evidence is available to guide their use in septic shock. Objective: Characterize the use of pressor agents for septic shock in clinical practice. Methods: A cross-sectional electronic survey assessing demographics, institutional practices, and respondent perceptions related to pressor agents was distributed to the American College of Clinical Pharmacy Critical Care Practice and Research Network. The primary outcome was the use of a weight-based dosing (WBD) strategy versus non-WBD strategy for norepinephrine. Descriptive statistics were used to summarize survey results. Binary logistic regression was performed to determine variables associated with dosing strategies. Results: The survey was completed by 223 respondents. The typical respondent worked in a medical or mixed intensive care unit at a teaching hospital and had training and/or board certification beyond the Doctor of Pharmacy degree. Nearly all respondents (n = 221, 99%) reported norepinephrine as the first-line vasopressor for septic shock; however, 38% used WBD and 60% used non-WBD. In logistic regression, respondents located in the South and practicing at institutions with larger numbers of intensive care unit beds were more likely to use WBD for norepinephrine infusions. Similar findings were observed with epinephrine and phenylephrine. Conclusion: Wide variability exists in prescribing patterns of pressor agents and in pharmacist perceptions regarding best practices. The use of WBD varied based on institutional characteristics and resulted in higher maximum allowable infusion rates of pressor agents. Future research should compare dosing strategies to identify associations with patient outcomes.

Vasoactive Agent Use in Septic Shock: Beyond First-Line Recommendations

Septic shock is a life-threatening disorder associated with high mortality rates requiring rapid identification and intervention. Vasoactive agents are often required to maintain goal hemodynamics and preserve tissue perfusion. However, guidance regarding the proper administration of adjunct agents for the management of septic shock is limited in patients who are refractory to norepinephrine. This review summarizes vasopressor agents and describes the nuanced application of these agents in patients with septic shock, specifically focusing on clinical scenarios with limited guidance including patients who are nonresponsive to first-line agents and individuals with mixed shock states, tachyarrhythmias, obesity, valvular abnormalities, or other comorbid conditions.

Atrial fibrillation detected initially during acute medical illness: A systematic review

Objective:

There is uncertainty about the incidence of and prognosis associated with atrial fibrillation that is documented for the first time in the setting of an acute stressor, such as surgery or medical illness. Our objective was to perform a systematic review of the incidence and long-term recurrence rates for atrial fibrillation occurring transiently with stress in the setting of acute medical illness.

Data sources:

Medline, Embase and Cochrane Central to September 2017.

Study selection:

We included retrospective and prospective observational studies, and randomised controlled trials. The population of interest included patients hospitalised for medical (i.e. non-surgical) illness who developed newly diagnosed atrial fibrillation. Studies were included if they included data on either the incidence of atrial fibrillation or the rate of atrial fibrillation recurrence in atrial fibrillation occurring transiently with stress patients following hospital discharge.

Data extraction:

Two reviewers collected data independently and in duplicate. We characterised each study’s methodology for ascertainment of prior atrial fibrillation history, atrial fibrillation during hospitalisation and atrial fibrillation recurrence after hospital discharge.

Data synthesis:

Thirty-six studies reported the incidence of atrial fibrillation. Ten used a prospective design and included a period of continuous electrocardiographic (ECG) monitoring. Atrial fibrillation incidence ranged from 1% to 44%, which was too heterogeneous to justify meta-analysis ( I2=99%). In post-hoc meta-regression models, the use of continuous ECG monitoring explained 13% of the variance in atrial fibrillation incidence, while care in an intensive care unit explained none. Two studies reported the long-term rate of atrial fibrillation recurrence following atrial fibrillation occurring transiently with stress. Neither of these studies used prospective, systematic monitoring. Recurrence rates at 5 years ranged from 42% to 68%.

Conclusions:

The incidence of atrial fibrillation with medical illness may be as high as 44%, with higher estimates in reports using continuous ECG monitoring. Within 5 years following hospital discharge, atrial fibrillation recurrence is documented in approximately half of patients; however, the true rate may be higher.

Protocol registration

PROSPERO CRD42016043240

Clinical Outcomes of Weight-Based Norepinephrine Dosing in Underweight and Morbidly Obese Patients: A Propensity-Matched Analysis

BACKGROUND

Weight-based dosing strategy for norepinephrine in septic shock patients with extremes of body mass index has been lesser studied.

METHODS

This historical study of adult septic shock patients was conducted from January 1, 2010, to December 31, 2015, at all intensive care units (ICUs) in Mayo Clinic, Rochester. Patients with documented body mass index were classified into underweight (body mass index <18.5 kg/m²), normal weight (18.5-24.9 kg/m²), and morbidly obese (≥40 kg/m²) patients. Patients with repeat ICU admissions, ICU stay <1 day, and body mass index 25 to 39.9 kg/m² were excluded. The primary outcome was in-hospital mortality, and secondary outcomes included cumulative norepinephrine exposure acute kidney injury, cardiac arrhythmias, and 1-year mortality. Two-tailed P < .05 was considered statistically significant.

RESULTS

From 2010 to 2015, 2016 patients met inclusion-145, 1406, and 466 patients, respectively, in underweight, normal weight, and morbidly obese cohorts. Underweight patients used the highest peak dose and absolute exposure was greatest for morbidly obese patients. In-hospital mortality decreased with increasing log₁₀ body mass index: 41.4% (underweight), 28.4% (normal weight), and 24.7% (morbidly obese), respectively (P < .001); however, this relationship was not noted at 1 year. Unadjusted log₁₀ norepinephrine cumulative exposure (mg) was associated with higher in-hospital mortality, acute kidney injury, cardiac arrhythmias, and 1-year mortality. After adjustment for demographics, body mass index, comorbidity, and illness severity, log₁₀ norepinephrine exposure was an independent predictor of in-hospital mortality (odds ratio 2.4 [95% confidence interval, 2.0-2.8]; P < .001) and 1-year mortality (odds ratio 1.7 [95% confidence interval, 1.5-2.0]; P < .001). In a propensity-matched analysis of 1140 patients, log₁₀ norepinephrine was an independent predictor of in-hospital mortality (odds ratio 2.2 [95% confidence interval, 1.8-2.6]; P < .001).

CONCLUSIONS

Morbidly obese patients had lower in-hospital mortality but had higher 1-year mortality compared to normal weight and underweight patients. Cumulative norepinephrine exposure was highest in morbidly obese patients. Total norepinephrine exposure was an independent mortality predictor in septic shock.

Impact of Norepinephrine Weight-Based Dosing Compared With Non-Weight-Based Dosing in Achieving Time to Goal Mean Arterial Pressure in Obese Patients With Septic Shock

Obesity presents a growing challenge in critically ill patients because of variable medication pharmacokinetics and pharmacodynamics. Vasopressors used in the treatment of septic shock, including norepinephrine, are dosed using weight-based (WB) or non-weight-based (NWB) strategies. Retrospective research has evaluated the effect of total body weight and body mass index on vasopressor requirements, consequently finding that obese patients require less total vasopressor per kilogram to obtain clinical end points such as mean arterial pressure. Although this effect is not completely understood, this may suggest that a NWB dosing strategy is preferred over a WB strategy in obese patients to minimize potential for error.