Fluids, Postop Complications, and other periop management

Question 1

List the normal range of Na+, K+, Cl-, HCO3- in serum

Answer 1

Na+: 135-150
K+: 3.5-5.0
Cl-: 98-106
HCO3-: 22-30

Question 2

List the normal range of Na+, K+, Cl-, HCO3- in perspiration

Answer 2

Na+: 30-50
K+: 5
Cl-: 30-50
HCO3-: 0

Question 3

List the normal range of Na+, K+, Cl-, HCO3- in stomach contents

Answer 3

Na+: 10-150
K+: 4-12
Cl-: 120-160
HCO3-: 0

Question 4

List the normal range of Na+, K+, Cl-, HCO3- in bile

Answer 4

Na+: 120-170
K+: 3-12
Cl-: 80-120
HCO3-: 30-40

Question 5

List the normal range of Na+, K+, Cl-, HCO3- in ileostomy

Answer 5

?
using info for small intestine

Na+: 80-150
K+: 2-8
Cl-: 70-130
HCO3-: 20-40

Question 6

List at least four endogenous factors that affect renal control of sodium and water excretion.

Answer 6

• RAAS (renin, aldosterone, angiotensin, ACE)

Question 7

List least six symptoms or physical findings of dehydration.

Answer 7

• thirst
• dry axilla
• syncopal Sx, orthostasis
• low JVP
• dry mucous membranes
• skin tenting (peds)
• sunken fontanelles (peds)

Question 8

List the electrolyte composition of half normal saline (.45%)

Answer 8

Glucose (g/L): --
Na+ (mEq/L): 77
K+ (mEq/L): --
Cl− (mEq/L): 77
Lactate (mEq/L): --
Ca++ (mEq/L): --

Question 9

List the electrolyte composition of 5% dextrose in water

Answer 9

Glucose (g/L): 50
Na+ (mEq/L): --
K+ (mEq/L): --
Cl− (mEq/L): --
Lactate (mEq/L): --
Ca++ (mEq/L): --

Question 10

List the electrolyte composition of Ringer’s lactate

Answer 10

Glucose (g/L): --
Na+ (mEq/L): 130
K+ (mEq/L): 4.0
Cl− (mEq/L): 109
Lactate (mEq/L): 28
Ca++ (mEq/L): 3.0

Question 11

What is the most common cause of dilutional hyponatremia in surgical patients?

Answer 11

hypotonic fluids are used to replace significant isotonic gastrointestinal or third space losses

Question 12

What fluids should you use for volume resuscitation, and what should you keep in mind?

Answer 12

LR (minimal K+ … theoretically could overload but would be many litre)
NS (can induce acidosis bc of ion gradient)

Consider LR for larger volumes.
Consider NS if kidney pt (K+ a concern).
Bottom line: evidence is equivocal, both are fine

Question 13

What should you give for maintenance fluids?

Answer 13

1/4 NS, 1/4 NS D5, 1/2 NS, 1/2 NS D5 … any are reasonable options

Question 14

How do you calculate maintenance fluids?

Answer 14

4-2-1 rule!

or to re-arrange, total daily fluid req /24:
1500 + [(kg-20) * 20]
Then, /24 to get hourly rate
Range is generally 75-150cc/h

Question 15

What should you do for a pt who needs maintenance fluids who has had losses, or needs resuscitation?

Answer 15

Maintenance + resusc – remember that maintenance is just insensible losses

Question 16

How should you give free water?

Answer 16

PO, if at all possible (If not, NG; if not, G-tube)
250CC q6h

If you need IV, give D5W

Question 17

What is the max correction rate for sodium?

Answer 17

Severe symptomatic hyponatremia: the rate of sodium correction should be 6 to 12 mEq/L in the first 24 hours and 18 mEq/L or less in 48 hours. (ie to start, 0.25 mEq/L per hour)

A bolus of 100 to 150 mL of hypertonic 3% saline can be given to correct severe hyponatremia.

Question 18

What are the etiologies of post-op fever, and when do they occur?

Answer 18

Wind: atelectasis or pneumonia, POD 0
Water: UTI, POD 2-3
Wound: infection, POD 3-7
Weins/Walking: DVT/PE, POD 5-7
Wonder drugs/"What did we do?": drug fever, POD 7 or more

Any time: Waves (ECG) – MINS

Question 19

What is MINS?

Answer 19

Myocardial Injury after Noncardiac Surgery

Question 20

What should every pt get POD1 (cardiac)?

Answer 20

Trop & ECG: evaluate for MINS

• slight elevation: repeat next day
• dramatic elevation: treat as MI (aspirin, beta-blocker, statin)

Question 21

What should every pt get POD1 (cardiac)?

Answer 21

Trop & ECG: evaluate for MINS

• slight elevation: repeat next day
• dramatic elevation: treat as MI (aspirin, beta-blocker, statin)

Question 22

Name 2 common urinary/renal complications of surgery

Answer 22

• urinary retention

- oliguria/anuria

Question 23

Why does urinary retention occur post-op, and what is done for it?

Answer 23

• can occur after any Sx with GA or (more commonly) spinal anesthesia
• more likely in pt with BPH & pt on anticholinergics

Foley catheter to rest bladder, then TOV

Question 24

Why does oliguria/anuria occur post-op, and what is done for it?

Answer 24

pre/intra/post-renal
Most common cause post-op is prerenal + ischemic ATN
- external loss: hemorrhage, dehydration, diarrhea
- internal loss: 3rd spacing (2y to bowel obstruction), pancreatitis

Urine output < 0.5 ml/kg/h, rising Cr and BUN

Treat according to underlying cause (most commonly: give IVF)

Question 25

What respiratory complications may occur post-op?

Answer 25

Atelectasis Pneumonia/pneumonitis (eg if aspiration) PE Pulmonary edema

Question 26

What should you be suspicious of if an elderly pt has new shortness of breath and wheezing?

Answer 26

New onset “asthma” and wheezing in the elderly is cardiogenic until proven otherwise

Question 27

How do you manage fever in a postop pt?

Answer 27

Address cause | Antipyretics