Test 2: Obesity (pt 3/3)

Question 1

What are the S/sx of Cardiac Dz in obese patients?

Answer 1

-Dyspnea
-Pedal Edema
-JVD
-Hepatomegaly
-Exercise intolerance
-Body habitus complicates assessment

Question 2

Why are dysrhythmias common in the obese population?

Answer 2

Due to sinoatrial node dysfunction and fatty infiltration of the conduction system.
-ECG changes including Right-Axis deviation & RBB suggest pulmonary HTN and RV Hypertrophy

Question 3

True/False: A LBBB is common in obesity.

Answer 3

False: A LBB Is unusual in obesity and raises suspicion of occult CAD.
-Warrants a Transthoracic Echo (TTE)

Question 4

Patients with a BMI > ____ need increased doses of anticoagulants for their VTE prophylaxis.

Answer 4

> 50 kg/m2

Question 5

Increased BMI = ______ comorbidities = _______ risk!!

Answer 5

Bottom line: increased BMI = increased comorbidities = increased risk!!!

Question 6

What are some planning considerations to consider for the location and equipment needed in surgery for the obese patient?

Answer 6

-Appropriate for outpatient setting?
-Weight limits of OR Table
-BP cuffs may not fit; may require arterial line monitoring for accurate BP
-Difficult IV Access (US)
-Positioning needs
-Airway equipment (video laryngoscope; FOB)
-Additional trained personnel
-Postop monitoring of SPO2 with CPAP, possible ICU admission

Question 7

What are factors that potentiate injury complications related to positioning in obese patients?

Answer 7

-Hypothermia
-Hypotension
-Table positioning
-Pressure from adipose tissue on orthopedic and cardiopulmonary structures

Question 8

How do you prevent or mitigate risk of positioning injury in obese patients?

Answer 8

-Frequent palpation of pulses
-Generous padding
-Correct alignment
-Repeated inspection of extremities for color & temperature
-Treatment of the Panniculus

Question 9

True/False: You don’t have to worry about weight limits with OR tables.

Answer 9

False: Ensure the OR table can support the weight of the patient - high risk for falls and table failure!!!

Question 10

What are the pharmacokinetic changes associated with obesity?

Answer 10

-Increased fat mass
-Increased cardiac output
-Increased blood volume
-Increased lean body weight
-Changes in plasma protein binding
-Reduced total body water
-Increased renal clearance
-Increased volume of distribution of lipid-soluble drugs
-Abnormal liver function
-Decreased pulmonary function

Question 11

Give water-soluble drugs according to _____.

Answer 11

IBW

Question 12

Give lipid-soluble drugs according to ______.

Answer 12

TBW

Question 13

Can you give inhalational agents to obese patients?

Answer 13

Yes; newer inhalational agents (Des/Sevo) have excellent recovery profiles
-Des is less soluble than sevo; clinical differences are minimal

Question 14

True/False: You can never give Nitrous Oxide to an obese patient.

Answer 14

False: Nitrous oxide is being increasingly used in obese patients as a volatile-sparing adjunct.
-Can be used unless a high O2 requirement precludes its administration

Question 15

What are some benefits to using Nitrous Oxide in obese patients?

Answer 15

-Has the potential to reduce chronic postop pain
-The 2nd gas effect of N2O at induction & emergence can accelerate uptake and elimination of the volatile agent.

Question 16

Appropriate antiemetic prophylaxis should be administered whenever _______, especially _____ are used.

Answer 16

Anesthetic gases; Nitrous Oxide

Question 17

What is the induction dose and maintenance dose based on for propofol?

Answer 17

Induction: LBW (avoid hypotension)
Maintenance: TBW

Increased fat mass does not affect initial distribution/redistribution during induction; cardiac depression at high doses is a concern

Question 18

What is your intubating dose of succinylcholine based on?

Answer 18

TBW

Question 19

Why is succinylcholine dosing based on TBW?

Answer 19

Increased fluid compartment and pseudocholinesterase levels require higher doses to ensure adequate paralysis

Question 20

Dosing for Rocuronium/Vecuronium/Cisatracurium is based on:

Answer 20

IBW

Question 21

Why are NDMR given based on IBW?

Answer 21

Hydrophilic drugs given according to IBW will ensure shorter duration and a more predictable recovery in this respiratory-challenged population

Question 22

What are the Loading Dose and Maintenance Doses based on for Fentanyl/Sufentanil?

Answer 22

Loading Dose: TBW
Maintenance Dose: LBW
(remember: can always give more. Need them to be able to breathe)

Increased distribution volume and elimination time correlate with degree of obesity

Question 23

What is the infusion rate of Remifantanil based on?

Answer 23

IBW
Distribution volumes and elimination rates are similar to normal-sized individuals; fast offset requires planning for postoperative analgesia

Question 24

What is the infusion rate of dexmedetomidine?

Answer 24

Infusion rates of 0.2 mcg/kg per min

Useful as an adjunct; lower than usual infusion rates are recommended to minimize adverse cardiac side effects

Question 25

What is Sugammadex reversal dosing based on?

Answer 25

TBW; no change from normal dosing

Question 26

What are the objectives for the maintenance of anesthesia in the obese patient?

Answer 26

-strict maintenance of airway -adequate skeletal muscle relaxation -optimum oxygenation -avoidance of the residual effects of muscle relaxants -provision of appropriate intraoperative and postoperative tidal volume -effective postoperative analgesia

Question 27

Despite the augmentation of circulatory fluid that accompanies extreme obesity, the estimated blood volume is actually __________.

Answer 27

diminished.

Question 28

What should you do differently with volume replacement in obese patients to reduce the risk of cardiopulmonary compromise?

Answer 28

Use of reduced parameters for volume replacement and avoidance of rapid dehydration.

Question 29

How do you guide fluid management in the obese patient?

Answer 29

BP, HR, and UOP

Question 30

Fluid requirements for bariatric procedures may be ________ than anticipated to maintain renal perfusion.

Answer 30

greater

Question 31

True/False: No difference in the criteria between the administration of blood products in normal-weight patients versus severely obese patients has been identified.

Answer 31

True

Question 32

What are the things to know regarding mechanical ventilation in the obese population?

Answer 32

-Body weight is not the same as lung volume -Ventilate with 6-8 mL/kg -No specific ventilator mode is superior (Gegel likes pressure control) -Alveolar recruitment maneuvers are beneficial

Question 33

What is the only mechanical ventilation parameter shown to improve respiratory function?

Answer 33

PEEP

Question 34

What do you need to ensure before considering the use of regional anesthetic techniques?

Answer 34

That the patient can tolerate surgical positioning

Question 35

What are some difficulties associated with the use of regional anesthesia in obese patients?

Answer 35

Anatomic landmarks are difficult to find or palpate -Need US guidance

Question 36

What are the positioning recommendations for neuraxial anesthesia in the obese patient?

Answer 36

Sit upright: -Skin folds fall towards OR table -Improved visualization of landmarks -Respiratory mechanics enhanced -Generous use of LA and longer "finder" needles used -Catheters may migrate due to excess tissue -Lack of predictability of the LA spread, caution with high regional blockade due to risk of respiratory compromise.

Question 37

In general, patients with a BMI > ____ are not appropriate for Ambulatory Surgery Centers.

Answer 37

>/= 50