CCP 331 Bariatrics 🍩 Flashcards

1
Q

How to dose paralytics in obesity

πŸ’΅πŸ’΅πŸ’΅ MONEY SLIDE πŸ’΅πŸ’΅πŸ’΅

A
  1. Roc = ideal body weight (IBW)

2. Suxx = total body weight (TBW)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Overweight definition (BMI)

A

BMI 25-30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

obesity definition

A

BMI of β‰₯30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

severe obesity definition

A

BMI β‰₯40 (or β‰₯35 in presence of comorbidities)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define Body mass index

A
  1. simple calculation using a person’s height and weight

2. BMI = kg/m2 (weight in kg / height in metres squared)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

prevalence of obesity in Canada

A
  1. 40% adults overweight
  2. 30% adults obese
  3. 3% adults β€œmorbidly obese”
  4. 27% adults normal/healthy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Vital Signs in Obesity Emergency Management

πŸ’ŽπŸ’ŽπŸ’ŽMEGA PEARLπŸ’ŽπŸ’ŽπŸ’Ž

A
  1. NIBP readings can be falsely elevated in obese patients as improperly placed small cuff size often overestimates BP
  2. A β€˜normal’ NIBP could represent a shock state in an obese adult
  3. Consider placing an early arterial line to obtain and trend accurate BP readings over time
  4. The Shock Index can be helpful in making a diagnosis of occult shock in obese and non-obese patients. Shock Index = HR/SBP; Any number > 1 suggests occult shock
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

ECG Alterations in Obesity Emergency Management

A
  1. Low voltages – d/t size of their chest wall
  2. Longer QT intervals sometimes >500ms as a result of obesity alone
  3. Signs of LVH – (consider obesity-associated cardiomyopathy)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Important Pulmonary Physiology changes in Obesity

πŸ’΅πŸ’΅πŸ’΅ MONEY SLIDE πŸ’΅πŸ’΅πŸ’΅

A
  1. ↓ respiratory reserve is 2Β° to ↓ total lung capacity and ↓ FRC. The ↓ reserve compromises an obese patient’s ability to tolerate respiratory insults such as pneumonia
  2. ↑ airway pressures are a result of ↑ airway resistance (heavier chest walls, ↑ abdominal girth, atelactatic lung bases). The ↑ pressures lead to: Smaller oxygen reserves at baseline, ↑ WOB, Shorter time to desaturation during induction and a shorter Safe Apnea Time
  3. ↑ incidence of hypoxemia and hypercapnia at baseline
  4. ↑ risk of aspiration pneumonitis
  5. More difficult to ventilate with BMV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

V.A.P.O.R.S mnemonic for factors that need to be considered in planning and executing a safe and successful intubation for critically ill obese patients

A

Ventilation (can you bag mask this patient?)

Acidosis

Pressures (BP, peak pressures, plateau pressures etc)

Oxygenation (safe apnea time)

Regurgitation

Shock Index (see above)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Pharmacologic Adjustments in Obesity Emergency Management

πŸ’΅πŸ’΅πŸ’΅ MONEY SLIDE πŸ’΅πŸ’΅πŸ’΅

A
  1. Lipophilic drugs (eg. Propofol) need to be dosed based on TBW
  2. Hydrophilic drugs (eg. Ketamine) are dosed based on IBW
  3. ABX also have different dosing profiles based on their class
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Radiology/Imaging in Obesity Emergency Management

πŸ’΅πŸ’΅πŸ’΅ MONEY SLIDE πŸ’΅πŸ’΅πŸ’΅

A
  1. The FAST scan may be indeterminate or falsely negative given the depth of penetration required to visualize Morrison’s pouch
  2. The chest x-ray will be under-penetrated
  3. CT images will be more difficult for the radiologist to interpret and as a result, injuries are more often missed.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe β€œramping” in Obesity Emergency Management

A
  1. Build a big ramp behind the patient’s head and torso to achieve an ear-to-sternal-notch configuration with towels/blankets or commercially available products
  2. position the patient in reverse Trendelenburg to take the weight of the panus off the chest
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

ANATOMIC changes to the airway/respiratory system of the obese patient

πŸ’΅πŸ’΅πŸ’΅ MONEY SLIDE πŸ’΅πŸ’΅πŸ’΅

A
  1. ↑ neck circumference d/t excess cervical adipose tissue β†’ upper airway collapse
  2. ↑ soft tissue deposition in the relatively closed space of the oropharyngeal cavity β†’ pharyngeal airway narrowing
  3. ↑ neck circumference + dorsocervical fat deposition β†’ limited neck extension
  4. Fat, obese neck β†’ difficult access for a surgical airway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

PHYSIOLOGIC changes to the airway/respiratory system of the obese patient

πŸ’΅πŸ’΅πŸ’΅ MONEY SLIDE πŸ’΅πŸ’΅πŸ’΅

A
  1. obese patients have markedly ↓ lung volumes
  2. for each unit ↑ in BMI, FRC, expiratory reserve volume, VC, TLC, and residual capacity ↓ 0.5% to 5%
  3. ↓ FRC β†’ closure of small airways and an ↑ in airway resistance β†’ under-ventilated areas of lung, atelectasis, and intrapulmonary shunting β†’ decreased safe apnea time
  4. obese patients develop VQ mismatch d/t their upper lung zones aerated preferentially, with lower lung zones perfused preferentially
  5. chest wall compliance is ↓ d/t increase in adipose tissue in the thoracic cage
  6. Oxygen consumption is ~1.5x higher in the obese patient than in non-obese patient
  7. d/t the ↑ in O2 consumption and WOB, obese patients CO2 production is also increased
  8. ↓ pulmonary reserve β†’ rapid onset of hypoxemia during RSI β†’ potential peri-intubation cardiac arrest πŸ’€πŸ’€πŸ’€
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

discuss Preoxygenation in the bariatric RSI

πŸ§™πŸ§™πŸ§™ ESOTERIC WISDOM πŸ§™πŸ§™πŸ§™

A
  1. obese patients have ↓ cardiopulmonary reserve and desaturate rapidly during intubation
  2. Often, traditional methods of preoxygenation using a NRB or BVM are insufficient in the critically ill obese patient
  3. NIV is the preferred preoxygenation method. CPAP at 10cmH2O has been shown to ↓ atelectasis, ↑ oxygenation, and ↑ safe apnea time in the obese patient
  4. BiPAP can also be used to preoxygenate obese patients, but is less well studied than CPAP
  5. CPAP or BiPAP should be maintained for at least five minutes during the preoxygenation period
  6. HFNC provides minimal CPAP, no evidence of benefit in preoxygenation prior to RSI for obesity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

discuss Patient Positioning in the bariatric RSI

A
  1. d/t alterations in respiratory physiology, positioning is critical for success in both preoxygenation and intubation of the obese patient.
  2. obese patients should be placed in either a HOB 45Β° or sitting position during preoxygenation
  3. patients should be placed in a head up/ramped position to optimize laryngoscopic view during intubation. patient’s sternal notch should align with his or her external auditory meatus
18
Q

discuss medication dosing in the bariatric RSI

A
  1. obese patients often receive inappropriate doses of sedative and paralytic medications during RSI
  2. Rocuronium should be dosed according to the patient’s ideal body weight (IBW)
  3. Succinylcholine should be dosed according to the patient’s total body weight (TBW)
  4. Lipophilic drugs (eg. Propofol) need to be dosed based on TBW. Therefore these doses will be much higher than in average adults (BE CAREFUL THOUGH DON’T GIVE A MASSIVE FUCK OFF DOSE OF PROPOFOL OR YOU’LL KILL THE PATIENT).
  5. Hydrophilic drugs (eg. Ketamine) are dosed based on IBW
19
Q

discuss mechanical ventilation in the bariatric patient

πŸ’΅πŸ’΅πŸ’΅ MONEY SLIDE πŸ’΅πŸ’΅πŸ’΅

A
  1. Vt must be calculated using IBW rather than TBW.
  2. This is important for the intubated obese patient, for whom the use of TBW to determine the Vt can lead to injurious lung volumes, barotrauma, and VILI
  3. obese patients produce ↑ amounts of CO2 d/t ↑ metabolic demand, ↑ oxygen consumption, and ↑ WOB. D/t this, they adopt a rapid, shallow breathing pattern and have a baseline RR that ranges from 15–21 bpm. You must account for this altered physiology and set a higher RR than for the non-obese patient.
  4. Obese patients demonstrate improved respiratory mechanics and alveolar recruitment when provided PEEP. PEEP reverses airflow limitations and helps to prevent alveolar derecruitment caused by the ↓ in FRC
20
Q

Challenges in ventilating the morbidly obese patient

A
  1. Lung volumes (eg. FRC) are decreased.
  2. Work of breathing, O2 consumption and CO2 production are increased
  3. Airway resistance is ↑ (until you ↑ the FRC with PEEP)
21
Q

problems with lung mechanics in morbid obesity

A
  1. Expiratory reserve volume is decreased
  2. FEV1 to FVC ratio is increased.
  3. VC, TLC and FRC are decreased.
  4. Work of breathing is increased
  5. The weight of the chest wall contributes to a decreased respiratory compliance
  6. Airway resistance is ↑ (until you ↑ the FRC with PEEP)
22
Q

discuss the balance of oxygen supply and demand in the bariatric patient

A
  1. O2 consumption and CO2 production is ↑ (more tissue metabolising), thus ventilatory needs are ↑
  2. Because of their ↑ abdominal and chest wall mass, morbidly obese patients β€œdedicate a disproportionately high percentage of total VO2 to conduct respiratory work, even during quiet breathing”
  3. The amount of additional O2 / CO2 flux to be expected is something like 150% of the normal values.
23
Q

Discuss strategies for Invasive mechanical ventilation in morbid obesity

A
  1. no difference between PCV and VCV in terms of outcome data.
  2. some sources recommended PCV d/t benefits of the constant pressure (better flow distribution and β€œtime under the curve”) and decelerating flow pattern (better patient-vent compliance, lower sedation requirements, better flow distribution)
  3. Calculate tidal volume based on patient’s height (IBW). JUST BECAUSE THEY ARE FAT DOESN’T MEAN THEIR LUNGS ARE ANY BIGGER
  4. A higher PEEP and Paw is generally required
  5. keep the Pplat under 30-35 cmH2O, using driving pressure as a backup surrogate of safety
  6. Esophageal balloon may help to calculate the actual Ptp and account for the resistive contribution from the chest wall
  7. You need a higher PEEP than you think.
  8. Post-intubation recruitment manoeuvre may be necessary to ↑ oxygenation and maintain lung volume
  9. You need a higher RR than you think d/t their inherent ↑ in VO2, and ↑ CO2 production d/t ↑ basal metabolism from being fat
24
Q

cardiovascular changes in the bariatric patient

A
  1. Cardiac output is ↑
  2. Total blood volume is ↑
  3. LV contractility is impaired
  4. LV size and wall thickness are ↑
  5. Hypertension is common
  6. LV diastolic pressure is ↑, and fluid loading is poorly tolerated
  7. The RV is likely failing or completely decompensated.
25
Q

hematologic changes in the bariatric patient

A
  1. polycythaemia, associated with chronic hypoxia β†’ hyperviscosity, and ↑ risk of thrombosis
  2. chronic immobility leads to ↑ risk of DVT/PE
26
Q

Pharmacokinetic changes in the bariatric patient

A
  1. Volume of distribution is ↑ for many lipophilic drugs
  2. Hepatic clearance may be ↓
  3. Renal clearance may be ↓
  4. It is unclear whether all drugs (or most?) must be dosed to IBW
  5. Drugs dosed to TBW may easily achieve toxic doses (propofol!!)
  6. Fatty acids may compete with drugs for protein binding, displacing free drug into the circulation.
  7. Conversely, Ξ±1-acid glycoprotein levels may ↑, leading to ↑ protein binding
  8. Metabolism of some pathways (eg. Phase 1 hepatic reactions such as oxidation, reduction and hydrolysis) are consistently ↑ in the morbidly obese.
27
Q

Metabolic changes in the bariatric patient

A
  1. ↑ resting energy expenditure
  2. A chronic proinflammatory state
  3. Insulin resistance β†’ DM1/DM2
  4. ↑ fatty acid mobilization, and hypetriglyceridaemia
  5. Accelerated protein degradation
  6. More rapid depletion of lean body mass
28
Q

changes in the bariatric patient leading to Difficulty in physical examination

A
  1. Respiratory examination is limited d/t difficult auscultation: you can’t hear anything, nor is it easy to get behind the patient to listen to their back.
  2. Cardiovascular examination is limited by difficult auscultation (heart sounds may be inaudible) and difficult palpation.
  3. Abdominal examination (eg. for organomegaly) is frustrating
29
Q

weight limit of Helijet stretcher (Sikorsky S-76)

A

500lbs

30
Q

Weight limit AND device weight for Bariatric #9 (Ferno #9B)

what are the implications of this

A

Ferno #9B is rated for 227kg/500lbs

Ferno #9B device weighs 22lbs

What this means is if your LifePort system is rated to 450lbs, your TOTAL PACKAGE WEIGHT is 450lbs. This includes patient weight, weight of #9 (22lbs), and gear/equipment weight (fully loaded CCP tray can be ~45lbs)

Eg: Add ~70lbs for #9B + tray and you are now only rated for a ~380lb patient

31
Q

weight limit of LifePort Sled System (Beechcraft Super King Air B350 and Cessna Citation C560 Jet)

what are the implications of this

A

450lbs

What this means is if your LifePort system is rated to 450lbs, your TOTAL PACKAGE WEIGHT is 450lbs. This includes patient weight, weight of #9, and gear/equipment weight.

32
Q

Beechcraft King Air B350 maximum allowable loading width (patient/equipment)

A

26in/66cm

33
Q

Cessna Citation C560 Jet maximum allowable loading width (patient/equipment)

A

29in/73.5cm

34
Q

Ferno CCP β€œTray” weight (empty)

A

10lb/4.5kg

35
Q

Average weight of fully loaded CCP β€œtray” with vent/pumps/monitor/meds

A

45lb/ 20.5kg

36
Q

Weight of LTV 1200

A

14.5lbs/6.5kg

37
Q

Standard Ferno #9 Weight limit AND device weight

A

Load Limit 350lb/159kg

Device Weight 17lb/8kg

38
Q

common Radiology problems associated with the bariatric patient

A
  1. Chest Xrays may be of poor quality
  2. some patients are too fat to fit into CT or MRI scanners.
  3. Ultrasonography is limited by thick abdominal / chest wall / leg fat
  4. CT/MRI table weight restrictions are typically 160-180kg when fully extended
39
Q

What is BMI calculated from?

A

Height and weight

40
Q

What is a normal BMI?

A

18.5 to 25