Variability in usual care fluid resuscitation and risk-adjusted outcomes for mechanically ventilated patients in shock

Abstract

Rationale: There remains significant controversy regarding the optimal approach to fluid resuscitation for patients in shock. The magnitude of care variability in shock resuscitation, the confounding effects of disease severity and comorbidity, and the relative impact on sepsis survival are poorly understood. Objective: To evaluate usual care variability and determine the differential effect of observed and predicted fluid resuscitation volumes on risk-adjusted hospital mortality for mechanically ventilated patients in shock. Methods: We performed a retrospective outcome analysis of mechanically ventilated patients admitted to intensive care units using the 2013 Premier Hospital Database (Premier, Inc.). Observed and predicted hospital mortality were evaluated by observed and predicted day 1 fluid administration, using the difference in predicted and observed outcomes to adjust for disease severity between groups. Both predictive models were validated using a second large administrative database (Truven Health Analytics Inc.). Secondary outcomes included duration of mechanical ventilation, hospital and ICU length of stay, and cost. Results: Among 33,831 patients, observed hospital mortality was incrementally higher than predicted for each additional liter of day 1 fluid beginning at 7 L (40.9% vs. 37.2%, p = 0.008). Compared to patients that received expected (± 1.5 L predicted) day 1 fluid volumes, greater-than-expected fluid resuscitation was associated with increased risk-adjusted hospital mortality (52.3% vs. 45.0%, p < 0.0001) among all patients with shock and among a subgroup of shock patients with comorbid conditions predictive of lower fluid volume administration (47.1% vs. 41.5%, p < 0.0001). However, in patients with shock but without such conditions, both greater-than-expected (57.5% vs. 49.2%, p < 0.0001) and less-than-expected (52.1% vs. 49.2%, p = 0.037) day 1 fluid resuscitation were associated with increased risk-adjusted hospital mortality. Conclusions: Highly variable day 1 fluid resuscitation was associated with a non-uniform impact on risk-adjusted hospital mortality among distinct subgroups of mechanically ventilated patients with shock. These findings support closer evaluation of fluid resuscitation strategies that include broadly applied fluid volume targets in the early phase of shock resuscitation.

The Impact of Choice Architecture on Sepsis Fluid Resuscitation Decisions: An Exploratory Survey-Based Study

“… 5 , 6 Despite increasing hospital and institutional mandates for sepsis guideline compliance, however, overall concordance remains generally low, 5 , 6 including widely variable fluid resuscitation practices. 7 , 8 …”

“… 9 , 10 For example, clinicians commonly prescribe less fluid volumes to patients with comorbid conditions that increase risk for developing harmful fluid overload, such as a history of heart, liver, or renal failure. 7 , 8 …”

“…This highlights the challenge and complexity of prescribing optimal fluid volumes for patients with septic shock and why many patients receive either insufficient fluid volumes early in their disease course or excessive fluid volumes throughout the entirety of their hospitalization. 7 , 8 , 12 - 14 …”

“…5,6 Despite increasing hospital and institutional mandates for sepsis guideline compliance, however, overall concordance remains generally low, 5,6 including widely variable fluid resuscitation practices. 7,8 For providers, the clinical decision-making processes and rationales for choosing how much fluid to prescribe are poorly understood. One possibility is that variations in fluid resuscitation are warranted due to differences in patient conditions and disease severity and that clinicians may sometimes reasonably discount current guidelines.…”

“…9,10 For example, clinicians commonly prescribe less fluid volumes to patients with comorbid conditions that increase risk for developing harmful fluid overload, such as a history of heart, liver, or renal failure. 7,8 While clinical judgments based on case mix certainly contribute to variability, patient and hospital factors only partially explain frequent and potentially harmful under or overresuscitation. 8 At the bedside, resuscitation targets for individual patients are often unclear.…”