Norepinephrine Dosing in Obese and Nonobese Patients With Septic Shock

Abstract

Background Whether or not norepinephrine infusions for support of hemodynamic status in patients with septic shock should be weight based is unknown. This situation is particularly pertinent in patients who are extremely overweight or obese. Objective To compare dosing requirements and effect of norepinephrine on blood pressure in obese and nonobese patients with septic shock. Methods In a retrospective cohort study, data on adult patients with septic shock who received norepinephrine infusion for support of hemodynamic status in a tertiary care, academic medical center were analyzed. Patients were categorized as obese (body mass index ≥ 30) or nonobese (body mass index < 30). The primary outcome was dosing requirements of norepinephrine at 60 minutes after the start of the infusion. The secondary outcome was the log-transformed ratio of mean arterial pressure to norepinephrine. Results The final cohort consisted of 100 obese and 100 nonobese patients. Mean norepinephrine infusion rate at 60 minutes was 0.09 (SD, 0.08) μg/kg per minute in the obese group and 0.13 (SD, 0.14) μg/kg per minute in the nonobese group (P = .006). The non–weight-based dose at 60 minutes was 9 μg/min in obese patients and 8 μg/min in nonobese patients (P = .72). The log transformed mean arterial pressure to norepinephrine ratio at 60 minutes was 2.5 (SD, 0.9) in obese patients and 2.5 (SD, 0.8) in nonobese patients (P = .54) Conclusions Compared with nonobese patients, obese patients with septic shock require lower weight-based doses of norepinephrine and similar total norepinephrine doses.

Sepsis Patients in Critical Care Units with Obesity: Is Obesity Protective?

“…There is no guidance on whether vasopressors should be dosed based on weight (mcg/kg/min) or not (mcg/min) and both methods are used in practice and clinical trials [16]. In a study by Radosevich and colleagues, obese patients with septic shock required less weight-based doses of norepinephrine and similar total doses compared to non-obese patients with no decrease in mortality [42]. Interestingly, Arabi et al found that underweight and very obese patients with septic shock had fewer hemodynamic disturbances compared to normal weight patients with similar APACHE II scores and required lower amounts of norepinephrine and epinephrine [17].…”

Comparing the Use of Dopamine and Norepinephrine in Shock Treatment

“…There were more days that did not need trial drug and open-label vasopressors with the norepinephrine group of patients compared to the dopamine group [25]. On the other hand, there were insignificant disparities between the groups that did not need the ICU care and those that did not need organ support [26].…”

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

“…Additionally, critically ill obese patients receive less fluids (on ml/kg basis) and lower vasopressor doses (on μg/kg/min basis) than nonobese patients . However, when evaluating weight‐based dosing of NE versus non–weight‐based dosing in obese patients, no significant difference between goal MAP achievement was detected between dosing strategies . Despite the fact that initial doses will differ in obese patients, the ultimate result and clinical outcomes should be similar, regardless of the dosing strategy, because NE is titrated to goal MAP.…”

“…83 However, when evaluating weightbased dosing of NE versus non-weight-based dosing in obese patients, no significant difference between goal MAP achievement was detected between dosing strategies. 84,85 Despite the fact that initial doses will differ in obese patients, the ultimate result and clinical outcomes should be similar, regardless of the dosing strategy, because NE is titrated to goal MAP. With regard to vasopressin, a medication that is not commonly titrated and is typically administered at a fixed dose, one study showed lower serum vasopressin levels in obese patients 24 and 72 hours after its initiation.…”