Optimal Perioperative Fluid Management H Yang Professor & Chair Department of Anesthesia

Conflict of Interest No payment by industry No shares in industry

Objectives Review fluid management principles over the years & decades Understand the variability of fluid shifts Describe the physiology behind fluid management Discuss management principles

THE PENDULUM SWINGS

Perioperative Fluid Management Maintenance – 4:2:1 Rule Replacement – Previous losses: fasting; NG; pyloric stenosis; bleeding – Previously 1 – 2 L at start of Sx On-going Losses – Bleeding – Ascites – 3 rd space: 1 – 2 L/hr – Sepsis

Ann Surg 1961;154:803-10

Fluid Restriction Lobo – 20 elective colonic resection – Restriction resulted in earlier return of bowel function Brainstrup – 141 colorectal surgery – Restriction reduced incidence of anastomic leakage, pulmonary edema, & wound infection Holte & Kehlet – systematic review of 80 clinical trials – Avoid “fluid overload in major surgical procedures”

WE ARE NOT BUILT THE SAME!

Ann Surg 1961;154:803-10

Lindenauer et al. NEJM 2005; 353: Fluid Requirements # of Patients Elective Major fluid shift or blood loss

3rd Space: fact or fiction? Tissue injury & swelling Isotope measurements now called into question due to kinetics of fluid shifts Difficult to measure Common sense: just because it is hard to measure does not mean it doesn’t exist

PHYSIOLOGY

Total Body Water ICF 40% (28 L) ICF 40% (28 L) PV 5% (3.5 L) PV 5% (3.5 L) ISV 15% (10.5 L) ISV 15% (10.5 L) 3 rd space loss – 4cc/kg/hr x 4 hr = 280cc/hr x 4 = 1120 cc Maintenance – 120 cc/hr

Total Body Water ICF 40% (28 L) ICF 40% (28 L) PV 5% (3.5 L) PV 5% (3.5 L) ISF 15% (10.5 L) ISF 15% (10.5 L) Hypervolemia Increases leakage into ISF (endothelial glycocalyx)

Why worry about fluid replacement? Hemodynamic stability Tissue perfusion – Renal (urine output) – Surgical Site (not measureable)

It is dynamic, not static! PAOP, CVP, & formula for replacement are all assuming static kinetics Preop – elective versus non-routine, bowel prep Intraop - anesthetic, epidural, phenylephrine infusions, inotropes, surgical trauma, ascites, cardiac function (ischemia, diastolic dysfunction, systolic heart failure)

MANAGEMENT PRINCIPLES

Complex TEE – IVC, hepatic vein, RWMA, Non-Routine NICOM, fluid challenge Routine (elective) Fluid restriction, monitor component losses diastolic function

Dynamic Fluid restriction works for most routine cases Be alert to the non-routine cases – Keep track of component losses – Be ready to move up the intervention ladder: NICOM, TEE, TTE Be a little behind but not too much Keep track of the pharmacology (anesthetics, regional, vasoprressors)

Take care of the endothelial glycocalyx!