Fluids/Peri-op

Question 1

daily H2O requirements

Answer 1

1.5ml/kg/h(-2.5l)

Question 2

daily Na+ requirement

Answer 2

1mmol/kg

Question 3

daily K+ requirement

Answer 3

1mmol/kg

Question 4

typical fluid regime

Answer 4

The traditional regime = “1 salty + 2 sweet”: Saline 0.9% + 20mmol potassium chloride (over 8 hours) Dextrose 5% + 20mmol potassium chloride (over 8 hours) Dextrose 5% + 20mmol potassium chloride (over 8 hours) This gives 3L H20, 154mmol Na and 60mmol K. Note that this provides about 0.5L more water and more sodium than is required for an average patient; 2.5: per day is usually adequate

Question 5

saline components

Answer 5

154 Na, 154 Cl

Question 6

complication of giving too much saline

Answer 6

hyperchloaraemic acidosis (HCl H+Cl), causes renal vasoconstriction.

Question 7

hartmanns

Answer 7

131 Na, 111Cl, 5K, 29 HCO3 most physiological, good for plasma losses, too much sodium for maintenance.

Question 8

fluid distribution

Question 9

Drugs to stop pre-operatively

Answer 9

CHOW

Clopidogrel – stopped 7 days prior to surgery due to bleeding risk. Aspirin and other anti-platelets can often be continued and minimal effect on surgical bleeding

Hypoglycaemics

Oral contraceptive pill (OCP) or Hormone Replacement Therapy (HRT) – stopped 4 weeks before surgery due to DVT risk. Advise the patient to use alternative means of contraception during this time period.

Warfarin – usually stopped 5 days prior to surgery due to bleeding risk and commenced on therapeutic dose low molecular weight heparin

Surgery will often only go ahead if the INR <1.5, so you may have to reverse the warfarinisation with PO Vitamin K if the INR remains high on the evening before