Fluid Resuscitation in Sepsis by Different Weight Calculations and In-Hospital Mortality

Abstract

Obese patients receive less volume by body weight compared to normal weight classes in shock models yet have improved mortality outcomes. We describe the variation in volume and vasopressor resuscitation in septic shock by BMI (Body Mass Index). We aim to determine the optimal weight: actual, adjusted and ideal to calculate 30ml/kg fluid administration in sepsis resuscitation in association with in-hospital mortality. Methods: We included septic shock patients from VOLUME-CHASERS cohort between September 2017 to February 2018. Patients were subdivided into BMI categories of underweight <19, normal 19-25, overweight 25-30, obese 30-35, severe-morbidly obese >35. We calculated how many patients received 30ml/kg fluid resuscitation in a time period 12 hours prior and 3 hours following onset of shock by actual body weight, ideal body weight -IBW = 50 + 2.3 (height in inches -60), and adjusted body weight AjBW = IBW + 0.4 (ABW-IBW). Kruskal-Wallis test was used for continuous variables and Chi-square test for categorical variables. We performed multivariable logistic regression to determine the association between actual body weight, IBW and AjBW receiving 30ml/kg resuscitation for in-hospital mortality adjusting for age, APACHE score, race, gender and vasopressor use. Results: Of the 1,639 patients from VOLUME-CHASERS, 977 (59.6%) had septic shock. Fluid and vasopressor given in time intervals prior and after shock did not differ between BMI categories. 347 (35.5%) patients received 30ml/kg fluid resuscitation by actual body weight with highest proportion in underweight (59.5%) and lowest in Severe-Morbid (20%) BMI (p=0.0001, Figure 1). 396 (40.5%) patients received 30ml/kg resuscitation by AjBW with an increase in proportion of Severe-Morbid BMI category to 35.7% (P=0.012, Figure 1). 422 (43.2%) patients received 30ml/kg resuscitation by IBW with increase in proportion of Severe-Morbid BMI to 44.4% (P=0.686, Figure 1). There was no association with in-hospital mortality based on body weight used to calculate 30ml/kg fluid resuscitation by actual -Adjusted OR (odds ratio) 1.5 (95% CI (Confidence interval) 0.53-4.32, IBW -Adjusted OR 0.812 (95% CI 0.596-1.10), AjBW -Adjusted OR 0.760 (95% CI 0.55-1.04). Conclusion: In obese and severe-morbid BMI categories, patients were more likely to receive 30ml/kg using either AjBW and IBW. Our sample size is potentially small to detect protective effect of AjBW and IBW fluid resuscitation but could indicate differences in guideline fluid resuscitation versus actual practice for patients with higher BMI.

Evidence-based updates to the 2021 Surviving Sepsis Campaign guidelines Part 2

“…Given MV's hypotension, the ED NP was correct in prescribing the rest of the bolus, which subsequently was given within 3 hours of recognition. With a body mass index over 30, it is acceptable to prescribe crystalloids based on ideal body weight, and studies to date have not shown any significant difference in mortality in patients who receive an adjusted fluid bolus 35-38. However, the selection of crystalloid did not reflect the updated guidelines 1.…”

“…With a body mass index over 30, it is acceptable to prescribe crystalloids based on ideal body weight, and studies to date have not shown any signifi cant difference in mortality in patients who receive an adjusted fl uid bolus. [35][36][37][38] However, the selection of crystalloid did not refl ect the updated guidelines. 1 Rather, the ED NP prescribed 0.9% sodium chloride solution, which echoed the hospital culture norms.…”