Takeaway

"approximately 2 L of net fluid can be a turning point for patients’ postoperative outcomes after complex spine surgeries that can serve as a guide for intraoperative fluid management"

Key Points

• Investigated the effects of excessive fluid administration and Intraoperative Hypotension (IOH) on postoperative complications in complex spine surgeries (fusion involving 2 or more spinal levels) such as stroke, MI (myocardial infarction), AKI (acute kidney injury), and ICU (intensive care unit) admissions and aimed to identify a change point in net fluid administration that increased postoperative complications
• Patients 18 years or older undergoing spine surgeries involving 2 or more spinal levels with or without instrumentation and having at least 48 hours of postoperative hospitalization were included in the study.
• Included a total of 6998 complex spinal surgery cases from 6243 patients between 2012 and 2022
• Change point of net fluid administration related to the postoperative complications was found to be 1865 mL (95% CI, 1228–4710 mL). For every 500 mL increase in fluid administered above the changing point, the odds ratio for postoperative complications was 1.16 ( P < .0001).
• A balanced fluid management approach improved intraoperative blood pressure control and reduced postoperative complications.

Excerpts

The optimal way to characterize intraoperative hypotension remains uncertain. It can be defined by the lowest mean arterial pressure (MAP) below various absolute and relative thresholds for cumulative durations or as a time-weighted average below these thresholds.Although there is no universal definition for IOH, it has been defined by absolute thresholds such as systolic blood pressure <80 mm Hg and MAP < 65 mm Hg.,Relative thresholds such as MAP reduction >20% to 30% from baseline has also been used across literature

the gold standard for intraoperative fluid management utilizes goal-directed fluid therapy (GDT) of the Enhanced Recovery After Surgery (ERAS) protocol which has shown great success across multiple specialties, including spine surgery.

Our change point of net fluid administration related to the postoperative complications was found to be 1865 mL (95% CI, 1228–4710 mL). For every 500 mL increase in fluid administered above the changing point, the odds ratio for postoperative complications was 1.16 ( P < .0001). The odds ratio for developing composite postoperative complications below the change point was 0.87 ( P = .026)

Based on our data, patients who received net fluid volumes exceeding this threshold showed a higher likelihood of complications, though this correlation does not imply a direct causal relationship.

with every 500 mL increase in net fluid administration, the odds ratio of developing postoperative pulmonary complications was 1.12 ( P < .0001)

the relationship between intraoperative hypotension and developing postoperative AKI and MI/stroke was not significant.

excessive fluid administration was shown to have deleterious effects on multiple organ systems (including pneumonia, ileus, and impaired cardiac function) and incur high risk of postoperative morbidity.

Yokoi et al performed a single-center trial comparing the postoperative complications before and after implementing a standardized blood & fluid protocol in major and complex spine surgeries. The protocol consisted of 3 components utilizing both a restrictive fluid regimen as well as GDFT: (1) Preoperative optimization of hemoglobin levels to 13 g/dL (2) use of tranexamic acid and lastly (3) GDFT with systolic pressure variation (SPV) and positive pressure variation (PPV) to guide fluid management while limiting total amount of crystalloids to 2L before administering 5% albumin. The outcomes were decreased intraoperative crystalloid administration, blood loss, transfusion, ICU admissions, and extubation in the OR after the surgery.

Physiology Review:

Fluid Management and Blood Pressure:

• Intravascular Volume: Maintaining optimal volume supports cardiac output and tissue perfusion, preventing hypotension or hypoperfusion.
• Over-resuscitation Risks: Excessive fluids can cause tissue edema, impair oxygen delivery, and worsen respiratory outcomes.
• Under-resuscitation Risks: Insufficient fluids lead to hypovolemia, reduced perfusion, and increased risk of organ dysfunction.

Abstract

BACKGROUND:

Both intraoperative hypotension and excessive fluid administration can lead to detrimental perioperative complications. However, how much fluid is considered excessive and how is intraoperative hypotension related to major postoperative complications?

METHODS:

We conducted a single-center retrospective cohort study in 6243 patients undergoing complex spine surgery at the Cleveland Clinic Foundation between 2012 and 2022 and studied the relationship between intraoperative net fluid administration and intraoperative hypotension with major postoperative complications. The primary outcome was a collapsed composite of postoperative complications including acute kidney injury (AKI), myocardial infarction (MI), stroke, and intensive care unit (ICU) admissions. Secondary outcomes were in-hospital postoperative pulmonary complications, surgical site infections (SSI), and mortality.

RESULTS:

The study consisted of 6998 complex spinal surgery cases from 6243 patients. The median net fluid administration was 2100 mL (Interquartile range: 1450 to 3020 mL), and we found a change point in net fluid administration of 1865 mL (95% Confidence Interval: 1228 to 4710 mL). The odds ratio of developing postoperative complications for every 500 mL increase in net fluid administration was 1.16 (95% confidence interval [CI], 1.11–1.21;P < .0001) above and 0.87 (95% CI, 0.77–0.98;P = .026) below the change point. The odds ratio of developing postoperative pulmonary complications was 1.12 (95% CI, 1.07–1.18;P < .0001) for every 500 mL increase in net fluid administration.Intraoperative hypotension was detected in 2052 complex spine surgeries (29%). The odds ratio of developing any postoperative complication was 1.57 (95% CI, 1.37–1.80;P < .0001) and 1.30 (95% CI, 1.04–1.61;P = .019) for postoperative pulmonary complications.

CONCLUSIONS:

We discovered a change point in net fluid administration of 1,865mL. Above this change point, higher net fluid administration is associated with increased odds of developing postoperative complications. Intraoperative hypotension in complex spine surgeries was associated with increased postoperative complications.

Citation

Koh, Y. , Li, Y. , Koh, J. , Ekrami, E. , Liu, X. , Argalious, M. , Manlapaz, M. , Troianos, C. , Steinmetz, M. & Farag, E. (9900). The Association Between Fluid Management and Intraoperative Blood Pressure and Patients’ Outcome After Complex Spine Surgeries. Anesthesia & Analgesia, Publish Ahead of Print , doi: 10.1213/ANE.0000000000007358.

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