Postoperative Fluid Management for Diabetic Patient After Appendectomy with Spinal Anesthesia

NPO Status Post-Operatively

This patient should NOT remain NPO post-operatively and should begin oral intake as soon as she is awake and free of nausea. 1

For most patients undergoing elective surgery, intravenous fluid therapy is unnecessary beyond the day of operation, with exceptions being upper gastrointestinal and pancreatic procedures (which appendectomy is not). 1
Patients should be encouraged to drink as soon as they are awake and free of nausea after the operation, with oral diet typically started the morning after surgery. 1
Once adequate oral fluid intake is tolerated, discontinue intravenous fluids immediately and restart only if required to maintain fluid and electrolyte balance. 1
Resume oral feeding as soon as possible and continue blood glucose monitoring until stable. 2, 3

Use balanced crystalloid solution (Lactated Ringer's) rather than D5NSS or normal saline for this diabetic patient.

Balanced crystalloids like Lactated Ringer's prevent hyperchloremic metabolic acidosis that occurs with normal saline (0.9% NaCl), which decreases gastric blood flow, reduces gastric intramucosal pH, and impairs gastric motility. 1
Excess normal saline causes hyperosmolar states, hyperchloremic acidosis, decreased renal blood flow and glomerular filtration rate, which exacerbates sodium retention and compromises microvascular perfusion. 1
In diabetic patients specifically, balanced crystalloids (Lactated Ringer's) are associated with faster resolution of metabolic acidosis compared to normal saline. 4
Lactated Ringer's does not cause hyperchloremic acidosis and probably less often leads to renal insufficiency than normal saline. 5

D5NSS (dextrose-containing solutions) should be avoided in diabetic patients unless specifically treating hypoglycemia, as it will worsen hyperglycemia and complicate glucose management. 1, 2
The patient's current BP is 154/71 with HR 59, indicating hemodynamic stability without need for glucose supplementation. 1

If IV fluids are still required postoperatively:

Use Lactated Ringer's solution as maintenance fluid at 25-30 mL/kg/day (approximately 1,375-1,650 mL/day for this 55 kg patient). 1
Provide no more than 70-100 mmol sodium/day, along with potassium supplements up to 1 mmol/kg/day. 1
Replace any ongoing losses (vomiting, drain output) on a like-for-like basis in addition to maintenance requirements. 1
Avoid fluid overload: even 2.5 L excess can cause increased postoperative complications, prolonged hospital stay, and impaired tissue oxygenation. 1

Monitor capillary blood glucose every 1-2 hours initially, targeting 100-180 mg/dL (5.6-10.0 mmol/L). 2, 3

If blood glucose >180 mg/dL (10 mmol/L), administer corrective subcutaneous rapid-acting insulin boluses. 2, 3
If blood glucose >300 mg/dL (16.5 mmol/L), check for ketosis immediately and consider hospitalization for IV insulin therapy. 2, 6
Resume regular diabetes medications when blood glucose is 90-180 mg/dL and patient is eating. 2

Do not use normal saline or D5NSS as primary fluid in this diabetic patient—both cause complications (hyperchloremic acidosis and hyperglycemia respectively). 1, 4
Do not keep patient NPO unnecessarily—this increases risk of hypoglycemia and delays return to normal diabetes medication regimen. 1
Do not give indiscriminate fluid boluses for hypotension in a patient with spinal anesthesia—use vasopressors instead after ensuring normovolemia. 1