Perioperative fluid management

Goals

• Maintenance of perfusion (and oxygenation)
• Avoid haemodilution
• Avoid coagulopathy
• Avoid hypothermia

 

By maintaining blood flow

Blood pressure

Good BP does NOT mean

Good blood flow

 

Normal volume

 

Essential for perfusion of

 

Brain

Kidney

 

Normal volume

 

Adequate cardiac function

 

Optimising cardiac preload

 

 

Decisions to make

 

Choice of fluid

 

Amount

 

Timing

 

Volume effects of colloids is context sensitive

 

90% volume effects during acute bleeding

 

40% volume effect when normovolemic

 

During acute bleeding, volume effect of colloids ≥ 90%

 

When normovolemic, volume effect of colloids ≈ 40%

 

Crystalloid preloading has no major effects

 

Monitoring

 

Perioperative weight gain

 

CVP

 

Pulmonary artery occlusion pressure (PAOP)

 

aka "wedge" pressure

 

Arterial line trace "swing"

 

Variation in systolic blood pressure and pulse pressure with positive pressure ventilation

 

≥5 mmHg during one positive pressure mechanical breath is significant

 

Strong predictor of positive response to a colloid volume challenge

 

Dynamic fluid challenge

 

A fixed volume of colloid (e.g. 100-200mL)

 

No change or decrease after fluid challenge

 

Covert hypovolaemia

 

Need more colloid

 

Sustained increased of ≥3 mmHg in CVP or PAOP

 

Intravascular compliance has been reached

 

Cease fluid challenge

 

TOE monitor

 

Repeated boluses of colloid to maximize stroke volume

 

SE of overhydration

 

PONV

 

May be worsened with dehydration

 

Overhydration does not improve PONV

 

Wound infection

 

Risk factors

 

Impaired tissue oxygenation

 

Mild hypothermia

 

Wound healing

 

Oedema adversely affct flap outcome in plastic and flap surgery

 

Intestinal oedema

 

Associated with

 

Delayed gut recovery

 

Risk of bacterial translocation

 

Risk of multiple organ dysfunction syndrome

 

Abdominal compartment syndrome

 

Recommendation

 

No more than 2.5 - 3L of crystalloids in the 24 hours post-op

 

Replace blood loss with colloid or blood

 

Avoid

 

No dextran in trauma

 

No albumin in traumatic head injury