Is it safe to administer colloids (colloidal solutions) to an adult or elderly patient with possible comorbidities undergoing endoscopic spine surgery under Total Intravenous Anesthesia (TIVA), considering the risk of anaphylaxis, Impaired renal function, and coagulopathy, and the potential contribution to electrolyte imbalance?

Colloid Use in Endoscopic Spine Surgery Under TIVA

Colloids should generally be avoided in patients undergoing endoscopic spine surgery under TIVA, with balanced crystalloids being the preferred first-line fluid therapy. If colloids are considered, they should only be used as a second-line option when crystalloids combined with vasopressors fail to maintain adequate tissue perfusion, and must be administered within strict dose limits. 1, 2

Primary Recommendation: Crystalloids First

• Balanced crystalloids (such as Ringer's lactate or Plasma-Lyte) are the recommended first-line fluid for intraoperative volume replacement in spine surgery patients, as they provide equivalent hemodynamic support with significantly lower risk profiles compared to colloids. 1

• Aim for a mildly positive fluid balance of 1-2 liters by the end of surgery to protect kidney function while avoiding excessive hemodilution. 1

• If using 0.9% sodium chloride, limit administration to a maximum of 1-1.5 liters to minimize risk of hyperchloremic acidosis. 1

Why Colloids Are Problematic

Renal Toxicity Risk

• Hydroxyethyl starch (HES) solutions are associated with increased risk of acute kidney injury and need for renal replacement therapy, particularly in surgical patients receiving higher doses. 1, 3

• The FLASH study demonstrated significantly more frequent renal failure in patients receiving HES during major abdominal surgery (relative risk 1.34, p=0.05). 1

Coagulopathy Concerns

• All synthetic colloids (HES, gelatins, dextrans) impair coagulation and platelet function, which is particularly problematic in spine surgery where even minor bleeding can have serious consequences. 1, 3

• HES causes an acquired, reversible von Willebrand's-like syndrome and Factor VIII deficiency that may take several days to resolve. 3

• Higher bleeding risk and increased transfusion requirements have been documented with HES use during major non-cardiovascular surgery. 1

No Mortality Benefit

• Multiple meta-analyses demonstrate no mortality benefit from colloids compared to crystalloids in surgical patients, despite colloids' superior volume expansion properties. 1, 4, 5

• The volume-sparing effect of colloids (crystalloid to colloid ratio of approximately 1.5:1) does not translate into improved clinical outcomes. 1

Electrolyte Imbalance Considerations

Crystalloid-Related Issues

• Large volumes of 0.9% sodium chloride can cause hyperchloremic metabolic acidosis, which is why balanced crystalloids are preferred. 1

• Balanced crystalloids maintain more physiologic electrolyte composition and reduce risk of acid-base disturbances. 1

Colloid-Related Issues

• Colloids themselves do not directly cause electrolyte imbalances, but hemodilution from volume expansion can decrease total protein, albumin, calcium, and fibrinogen levels. 3

• The primary concern with colloids is not electrolyte disturbance but rather renal dysfunction, coagulopathy, and lack of clinical benefit. 1, 5

When Colloids Might Be Considered (Rarely)

• Only consider colloids as a second-line option if crystalloids combined with vasopressors fail to maintain adequate tissue perfusion in the setting of significant ongoing blood loss. 1, 6

• If colloids must be used, modern HES solutions in balanced formulations are preferred over older preparations, though safety concerns remain. 7

• Never exceed maximum daily dose limits (typically 50 mL/kg for HES), and avoid use in patients with pre-existing renal impairment or coagulopathy. 3, 5

• Albumin offers no benefit over crystalloids in surgical patients and is significantly more expensive without improved outcomes. 1

Specific Considerations for Spine Surgery

• Endoscopic spine surgery typically involves minimal blood loss, making crystalloid-only resuscitation entirely appropriate for most cases. 1

• One case-control study in spine surgery found that higher colloid percentage of total non-blood replacement was associated with reduced risk of ischemic optic neuropathy, but this finding is not sufficient to recommend routine colloid use given the overall safety profile. 1

• Monitor hemoglobin/hematocrit periodically during surgery if substantial blood loss occurs (>800 mL), and transfuse blood products as appropriate rather than relying on colloids. 1

Critical Pitfalls to Avoid

• Do not use colloids routinely for "better volume expansion" – this rationale is not supported by clinical outcomes data and exposes patients to unnecessary risks. 4, 5

• Avoid HES in patients with sepsis, severe bleeding disorders, or pre-existing renal dysfunction, as these populations have demonstrated increased mortality and renal failure rates. 3, 5

• Do not assume third-generation HES (130/0.4) is safe based on limited evidence – most studies used short observation periods, low cumulative doses, and inappropriate control groups. 5

• Monitor coagulation parameters (PT, PTT, platelet count) if colloids are administered, as coagulopathy may develop and persist for several days. 3