intro to surgery

Question 1

Elective Surgery:

Answer 1

non-emergent which is scheduled at least 24 hours in advance

Question 2

Emergent Surgery:

Answer 2

Surgery for a condition which is immediately life-threatening. performed within a few hours

Question 3

Preparations that greatly improve outcome of surgery (elective vs. emergent)

Answer 3

• appropriate pre-op meds
• cardiac optimization
• pulm optimization
• empty stomach
• bowel prep

Question 4

Why is it optimal for a patient to have an empty stomach prior to surgery?

1. Decreases likelihood of gastric rupture
2. Decreases likelihood of aspiration pneumonia
3. Decreases postoperative nausea and vomiting
4. Increases absorption rate of preoperative anesthesia medications

Answer 4

2

Question 5

how long does emptying the stomach take?

Answer 5

• clear liquids = 2 hr
• breast milk = 4 hr
• infant formula= 4 (<3 mo), 6(>3 mo)
• nonhuman milk= 6
• light meal = 6 hour

Question 6

conditions that increase aspiration risk (elevate intra-abdominal pressure)

Answer 6

morbid obesity
prego
gastroparesis, abdominal trauma

Question 7

why would a pt need a pre-op bowel prep?

Answer 7

-decrease abdominal contamination in event of bowle entry

Question 8

pre-op questions (AMPLE)

Answer 8

• allergies
• meds
• pmh
• last meal
• events prior

Question 9

describe the distribution of water in the human body:

Answer 9

total body water is distributed with about 2/3 intracellular (25 L) and 1/3 is extra cellular (12 L)

Question 10

extra cellular water distribution:

Answer 10

interstitial= 25% (9 L)
Plasma= 8% (3 L)

Question 11

calculating blood volume=

Answer 11

TBV= 7% x Body Weight

Question 12

how many L = 1 kg

Answer 12

1

Question 13

why are surgical pos prone to disruptions of fluid and electrolytes?

Answer 13

• cant eat or drink for a while
• anesthesia causes increased pulmonary insensible loss
• postop fever increases insensible loss
• thrid spacing
• sepsis

Question 14

during and after surgery pt needs:

Answer 14

• maintenance volume fluid replacement
• maintenance electrolyte replacement
• replacement for ongoing losses in excess of maintenance
• replacement of pre-exisiting volume deficits
• replacement of pre-existing electrolyte deficits

Question 15

maintenance requirements:

Answer 15

• 0-10 kg = 100ml per kg/day
• 10-20 kg= 50 ml/kg/d
• all kg after that= 20 ml/kg/d
• divide by 24 for ml/hr

Question 16

best way to monitor fluid status

Answer 16

Despite all of the aforementioned, best way to monitor fluid status is to measure urine output you will measure it/follow it ALL THE TIME in an inpatient setting

Question 17

Na maintenance=

Answer 17

1-2 mEq/kg/d

Question 18

K maintenance=

Answer 18

.5-1 mEq/kg/d

-always infusion, never as bolus

Question 19

how fluid is lost:

Answer 19

*NG tube (gastric contents = H+, K+ and Cl- loss)
Evaporation via open incision
Operative bleeding 
Third space losses 
Drains 
Fistulae 
Burns

Question 20

how to recognize acute volume deficit:

Answer 20

Changes in vital signs
Blood pressure
Heart rate
CVP (central venous pressure)
Decreased urine output
Why a postop foley is so helpful
Tissue changes often are not obvious when there’s an acute volume loss!

Question 21

how to tell volume excess:

Answer 21

Over hydration can happen
Signs of volume excess:
weight gain
pulmonary edema
peripheral edema
S3 gallop

Third spacing Third-spacingoccurs when too much fluid moves from the intravascularspace(blood vessels) into the interstitial or “third”space, area between cells.
Third spaced fluids eventually will re-enter the intravascular space (mobilize)
Typically, third space mobilization happens around POD3.
Can get a very large urine output when mobilization begins

Question 22

time frame for fluid replacement:

Answer 22

Try to correct abnormalities over 24 hours– don’t go too fast.
For seriously ill patients and patients with tenuous lungs or cardiac status, calculate over shorter period and reassess more frequently (even q hour in some)
For large fluid deficits - correct over a longer period of time

Question 23

when does 3rd spacing fluid tend to mobilize after surgery?

Answer 23

POD3

Question 24

fevers after surgery:

Answer 24

Fever <38.5ºC (101.3 Fahrenheit) is common after surgery
It’s usually due to the inflammatory stimulus of surgery and resolves spontaneously
Fever = response to cytokine release
Fever-associated cytokines are released by tissue trauma and do not necessarily signal infection

Question 25

fever associated cytokines:

Answer 25

IL-1, IL-6, TNF-alpha, IFN-gamma

Question 26

What is the “mechanical” cause of the shaking chills that come before– or with-- a fever? What are these called?

Answer 26

Rigors not just chills, they are “shaking chills” can be quite violent Due to rapid, alternating muscle contractions which generate heat; body’s response to increased “set” temperature.

Question 27

post-op fever causes by days:

Answer 27

1. wind- Atelectasis 3. water- UTI 5. wound- surgical site infection 7. walking- dvt 9. wonder- drugs

Question 28

In general, early fever is not infectious with one critical exception:

Answer 28

Necrotizing fasciitis or soft tissue infection

Question 29

Atelectasis:

Answer 29

A partial collapse of the alveoli, often due to hypo-inflation. This partial collapse causes a decrease in lung compliance, making it tougher to re-inflate the lung. Atelectasis occurs in the most dependent parts of the lung in 90% of patients who are anesthetized.

Question 30

why hypo-inflation after surgery?

Answer 30

Lungs may not have been inflated completely during endotracheal anesthesia After surgery, patients may have trouble taking a deep inflating breath (pain, sedation) Pulmonary disease like COPD can contribute

Question 31

risk factors for atelectasis?

Answer 31

``` Painful abdominal or thoracic incision – decreases pulmonary excursion Smoking Pulmonary Disease (asthma, CF) Obesity Respiratory muscle weakness ```

Question 32

atelectasis tx?

Answer 32

incentive spirometry

Question 33

differentiating atelectasis and pneumonia?

Answer 33

Hint: Atelectasis will usually be bilateral! A unilateral infiltrate is most likely pneumonia This can be hard to differentiate from atelectasis. Look for sputum production, elevated WBC, and temp curve that progresses upward. In at-risk individuals, check CBC with Diff and CXR, and consider antibiotics earlier than in non-risk individuals.

Question 34

when do drugs tend to cause post-op fevers?

Answer 34

anytime!

Question 35

why UTI's post op?

Answer 35

Catheter use during surgery Delays in bladder emptying due to anesthesia Bladder manipulation during surgery ``` Risk is increased by: Female gender Older age Diabetes Immobilization ```

Question 36

what about surgery increases risk of DVT?

Answer 36

- immobility | - vascular damage

Question 37

virchows triad:

Answer 37

- stasis - vessel damage - hyper-coaguability

Question 38

fever things that could kill the pt:

Answer 38

Necrotizing infection (can kill rapidly) Clostridium perfringens, Group A β-hemolytic streptococcus Tx: Resuscitation, Pen G, surgical debridement Malignant hyperthermia Tx: Resuscitation, rapid cooling, IV *dantrolene (excitation-contraction decoupler) Anastomotic leak (GI) Place a drain or return to OR Other: Allergic rxn (to abx) or transfusion Look for hypotension, rash Tx: Stop the offending agent

Question 39

fever things that could kill the pt:

Answer 39

Necrotizing infection (can kill rapidly) Clostridium perfringens, Group A β-hemolytic streptococcus Tx: Resuscitation, Pen G, surgical debridement Malignant hyperthermia Tx: Resuscitation, rapid cooling, IV *dantrolene (excitation-contraction decoupler) Anastomotic leak (GI) Place a drain or return to OR Other: Allergic rxn (to abx) or transfusion Look for hypotension, rash Tx: Stop the offending agent Pulmonary embolism (can present with fever) MI (unusual but can also present with fever) Other things: ventilator-associated pneumonia aspiration pneumonia nosocomial infection EtOH withdrawal (day 3)

Question 40

delayed fever (5 days post-op):

Answer 40

``` #1: Wound infection (40%) #2: UTI (29%) especially if indwelling Foley #3: Pneumonia (12%) if on vent or COPD Also think of: C. difficile colitis line sepsis & bacteremia intra-abdominal abscess Rarer: Sinusitis Meningitis Acalculous cholecystitis Weeks out: Endocarditis Infected prostheses ```

Question 41

initial assessment of fever post-op:

Answer 41

If called for fever, get to the bedside, get the nurse/flowsheet and CBC with vitals Obtain a history. If the situation is worrisome, jump to the AMPLE format Type of surgery, meds or blood given, other symptoms (rash, cough, dyspnea, chest pain, dysuria, leg swelling, painful IV site, abd pain) Physical: #1 check the wound or surgical site #2 lung sounds, heart/abd/extremity exam #3 check IV sites, central line, Foley, tubes

Question 42

fever take home points:

Answer 42

Know the five Ws as a rough guide for most common causes & timing Learn to think of what can kill the patient Also think:“what did we do to cause this?” (iatrogenic) Targeted H&P / labs / imaging to rule out the killers, then confirm most likely cause Should have a working diagnosis before labs and imaging Know the dx & treatment of necrotizing fasciitis (future lecture)