OBESITY ANESTHESIA Flashcards
1
Q
When performing a spinal anesthetic on a morbidly obese individual, you know that you should
A
use a lower volume of local anesthetic
2
Q
What is the most reliable test for detecting an inadvertent intrathecal or intravascular epidural catheter placement in a laboring parturient?
A
Negative aspiration for CSF or blood
3
Q
**What is the only ventilator adjustment shown to improve respiratory function consistently in obese individuals? WAS on SEE EXAM
A
PEEP
4
Q
If a drug distributes primarily to lean tissues, then its loading dose should be based upon the patient’s
A
Lean body weight
5
Q
The recommended tidal volume for an obese patient should be estimated as
A
Predicted body weight
6
Q
Tubular renal tubular reabsorption and GFR in obesity
A
Increased
7
Q
Sodium excretion with obesity is
A
Decreased/ impaired
8
Q
Increase in direct proportion to body weight
A
Plasma cholinesterase activity
9
Q
FRC and obesity
A
Decreases exponentially as BMI increases
10
Q
2 warning sings of diminished cardiovascular reserve amd CV complications in OBESES PATIENTS.
A
ORTHOPNEA
Paroxysmal nocturnal apnea.
11
Q
2 preop interventions for Obesity : HOB and consideration for OSA
A
Head up 30 degrees
CPAP prior to induction if OSA
12
Q
Airway that is very helpful to achieve if difficult ventilation of the obese
A
LMA
13
Q
3 Most important intraoperative consideration for obesity: comment on TV, PEEP and fiO2. Why do you want FiO2 that you mentioned?
A
TV 6-8 ml/kg of IBW (to avoid overdistention)
PEEP 10-12 cm H2O
FIO2 less than 0.8 because INCREASED FIO2, accelerates atelectasis.
14
Q
3 Most important POST-operative consideration for obesity:
A
CPAP or BIPAP
O2
Head up
15
Q
Intestinal mobility and regioonal
A
Early recovery of intestinal mobility
16
Q
This medication is not suitable for bariatric surgery and why?
A
ketorolac; increased chance of GI bleed.
17
Q
The most severe post op complications for bariatric surgery
A
Anastomotic leaks and strictures
PE
Sepsis
Gastric prolapse and bleeding
18
Q
Most common signs and symptoms of anastomotic leaks from most common to least
A
Tachycardia
Fever
Abdominal pain
19
Q
What is the most sensitive sign of an anastomotic leak?
A
Tachycardia (HR >120)
20
Q
Mortality of Roux en Y bypass
A
0.5-1%
21
Q
Most serious metabolic complication of bariatric surgery
A
Severe malnutrition ; red meat poorly tolerated
22
Q
Associated with biliopancreatic conversion?
A
Fat soluble vitamin malabsorption
23
Q
FAT soluble vitamins are
A
ADEK
24
Q
Ideal gas for obese patients
A
Low solubility
25
You can use all 3 MRs for obese patients but which one is preferred and why?
Vec, roc, cis
| cis preferred because organ-independent mechanism (HOFFMAN)
26
When blood loss is replaced , the ____ratio
3:1
| 3 mL of cristalloid for 1 ml blood loss.
27
Any advantage of Large TV for obese patients?
NO
28
Anatomical issues with the obese patients when in comes to regional anesthesia
Obscured bony landmarks
29
LA requirements in ______in the obese patients? why?
Decrease; because of the fatty infiltration and vascular engorgement caused by intra-abdominal pressure, which decreases the volume of the epidural space.
30
Extubation criteria for obese patients as far as RR and SPO2
RR >10 and < 30
| SPO2 > 95% on < 0.4 FiO2
31
Extubation criteria for obese patients as far as TV and VC
TV 5ml/kg IBW
| VC 10-15 ml/kg IBW
32
Supine position for obese: parameters affected
FRC and oxygenation are decreased
33
Position preferred and why?
Lateral decubitus positiion; better diaphragmatic excursion
34
What provides the safest safe apnea period during induction of anesthesia?
HEAD up position (Reverse trendelenburg)
35
CUFF with a bladder that encircles
75% of the UPPER ARM CIRCUMFERENCE
36
How is preoxygenation during induction in obese different from regular patients?
4 vital capacity breaths with 100% oxygen for 30 seconds, are superior to the 3 minutes of 100% preoxygenation.
37
The object of patient position for the intubation is to position the
chin at HIGHEST LEVEL than the chest.
38
Stacking for intubation is to
placing towels or folded blankets under the shoulder and head to compensate for the exaggerated flexed position of posterior cervical fat.
39
BEYOND STACKING step is the
HELP (Head elevated Laryngoscopy position)
40
HELP significantly
Elevates the patient's head, upper body and shoulder above the chest.
41
What is the most common mononeuropathy after bariatric surgery?
CARPAL TUNNEL SYNDROME
42
Regular OR tables have a MAX weight limit of approximately
200 kg
43
A difficult airway relation to BMI
NOT CLOSELY correlated with BMI/
44
What is the single major predictor of problematic intubation in morbidly obese patients?
Patient's neck circumference.
45
What is a normal neck circumference for a 70 kg male?
about 35 cm
46
Probability of difficult intubation for a male with a neck circumference of 40cm
5%
47
Probability of difficult intubation for a male with a neck circumference of 60cm
35%
48
my mnemonic AMTOMA difficult intubation
```
Age (increase age)
Male
TMJ pathology
OSA
Mallampati III or IV
Abnormal upper teeth
```
49
Anatomic changes associated with obesity that contribute to difficult airway: JOINTs
Limited movement Atlanto-axial joint and CERVICAL SPINE by upper and lower cervical fat pads
50
Anatomic changes associated with obesity that contribute to difficult airway: Mouth and pharynx changes
EXCESSIVE Tissue folds in mouth and pharynx
51
Anatomic changes associated with obesity that contribute to difficult airway: NeCk changes
Short THICK neck
| VERY thick submental fat (double chin)
52
Anatomic changes associated with obesity that contribute to difficult airway: Cervical
Suprasternal, presternal, posterior cervical fat.
53
Obesity and medication on DOS, except
Continue all except oral and oral hypoglycemics.
54
Medications. that must be discontinued?
Anorexiant drugs and herbal supplements for 14 days
55
Increased risk of infection in the obese necessitates
ABT prophylaxis
56
Medication to be considered for anxiolysis for the obese patients? why?
Dexmedetomidine ; low resp depressant effects
57
Effective at reversing low BP in the obese
Phenylephrine.
58
3 main system to assess during the preop of an obese patients/
CV
RESP
Hepatic function
59
ECG evidence of RV failure; 2
Right axis deviation
| TALL PRECORDIAL R WAVES
60
What is the most useful confirmation of pulmonary HTN?
TRICUSPID REGURGITATION on ECHO
61
Increase probability of OS is
NECK CIRCUMFERENCE > 40 cm
62
Common deficiencies in obese patients
```
CaFIB
Calcium
Folate
Iron
B12
```
63
What can lead to ACUTE POST-GASTRIC REDUCTION SURGERY NEUROPATHY?
Vitamin and nutritional deficiencies
64
Initial doses for obese patients are based on ____
LBW (Lean body weight)
65
Why are initial doses for obese patients based on Lean body weight (LBW) ?
Because LBW is HIGHLY CORRELATED with CO and drug clearance
66
Subsequent doses for obese patients based on
responses to initial dosing
67
Propofol dosing : Loading , Maintenance
Loading: TBW ; Maintenance: LBW
68
Midazolam dosing is based on
TBW
69
Thiopental dosing is based on
LBW
70
CIS- ATRACURIUM and ATRACURIUM dosing : Loading , Maintenance
Loading: TBW ; Maintenance: LBW
71
3 drugs with different dosing TBW then LBW
Propofol
Atracurium
Cis-atracurium
72
Succinylcholine dosing is based on
TBW
73
Fentanyl remifentanil, sufentanil dosing is based on
LBW
74
ROC and VEC dosing is based on
LBW
75
Pancuronium dosing is basd on
TBW
76
TBW dosing summary :
T- MI-SU-CI- A- PANDENE
77
What are the 2 pharmacokinetics principles to keep in mind when determining drug dosing for OBESE patients?
Vd and Clearance
78
What is the key to the administration of the loading dose:
Volume of distribution
79
A drugs that is WATER soluble should be based on
LEAN body weight (WATLe)
80
A drugs that is LIPID soluble should be based on
TBW (LiT)
81
How do you calculate Lean BODY weight?
IBW + (20-40%)
82
How do you calculate IBW?
Height in cm - 100 Male
| Height in cm -105 female.
83
What is crucial to the maintenance dose?
CLEARANCE
84
To remember: MAINTAIN CLEARANCE in CRNA school
maintenance - clearance.
85
Volume of the central compartment in the obese patients is
unchanged.
86
Absolute body water content for obesity?
DECREASED
87
Lean body and adipose tissue mass are _______ in the obesity which affect _____and_______
INCREASED; Lipophillic and polar drug
88
Show significant increases in VD
Highly Lipophillic drugs such as benzodiazepines.
89
Lipophillic and half life
Greater distribution to fat store leads to longer elimination of half life.
90
TBW in obese patients
Decreased
91
Total body fat in obese
INCREASE
92
Lean body mass in obese
Increase
93
Protein binding in obese
ALTERED protein binding
94
BV in obese
Increase
95
CO in obese
Increase
96
Serum free fatty acids in obese
INCREASE
97
Exception to these concepts are the highly lipophillic drugs are
digoxin
Procainamide
Remifentanil
98
This decreases the plasma concentration of rapidly injected IV drugs
Increased Blood volume, dilution
99
FAT has ____Blood flow and drugs dose based on _______ could lead to
Low: Excessive plasma concentrations use LBW insdead.
100
Blood triglycerides and obesity? Effect on drug
Increased; reduces free drug concentration
101
Serum cholesterol and obesity
Increased
102
Alpha-1 Glycoprotein and obesity
INcreased blood alpha 1 glycoprotein which lead to reduced free drug concentration
103
Frequent in patients having laparoscopic bariatric surgeries
RHABDOMYOLYSIS (1.4%)
104
What should alert the anesthetist of Rhabdomyolysis after surgery of bariatric patients?
Unexplained elevation in Creatinine and CK levels
| Complaints of buttocks, hips, and shoulder pain.
105
RHABDO: Stimulate diuresis with this medication
mannitol
106
May be necessary when rhabdomyolysis
Hemofiltration may be necessary for rapid clearance of myoglobin
107
URine in the tx of rhabdo
Alkalinization of urine to prevent myoglobin deposits in renal tubules.
108
Surgical goal of RESTRICTIVE oPerative bariatric procedures?
Reduce and limit the patient's capacity for intake of food.
109
Restrictive, most common is the creation of
Small pouch from the small intestine to the GE junction
110
LAP gastric band advantage
Avoidance of permanent alteration gastric anatomy by tissue stapling
111
LAP sleeve Gastrectomy
Narrow sleeve created by stapling the stomach vertically.
112
What is excised and removed from the abdomen LAP sleeve gastrectomy.
FUNDUS and greater curvature.
113
What is the most effective bariatric procedure to produce safe short and long term weight?
RYGB
| Roux-en-y Gastric bypass.
114
Weight loss with RYGB is
50-60% excess body weight.
115
Resolved in the majority of patients undergoing RYGB
DM type II
116
Restrictive surgeries for bariatric are
Lap Gastric band
| LAP sleeve gastrectomy
117
Largely restrictive surgeries and mildly malabsorptive
RYGB
118
Largely malabsorptive, min restrictive surgeries
BPD with DS
| Biliopancreatic diversion with duodenal switch
119
GFR and RBF with obesity are ____why?
INCREASED: because of increased CO and MAP
120
CO and MAP with obesity are
INCREASED
121
Renal tubular reabsorption are _______with obesity and why?
Increased because of the excessive weight gain.
122
Obesity on natriuresis
Impairs natriuresis through sympathetic activation of the RAAS
123
Prolonged obesity results in what with nephron?
Loss of nephron function further impairing natriuresis, thus increasing Arterial BP
124
Both obese males and females have increased risk of
Renal Cancers
125
Obese males are at increased risk of
Prostate CA
126
Obese female are at increased risk of
Endometrial and cervical CAs
127
Linear relationship between
arthritis and patient weight.
128
Bone with the obese patients?
Bone resorption occurs due to limited mobility lead to reduce bone density and contribute to stress fractures.
129
Renal tubular reabsorption are _______with obesity and why?
Increased because of the excessive weight gain.
130
Metabolic syndrome is a constellation of _____abnormalities including : DHOG
Obesity
Glucose intolerance
HTN
Dyslipidemia
131
Prolonged obesity results in what with nephron?
Loss of nephron function further impairing natriuresis, thus increasing Arterial BP
132
Both obese males and females have increased risk of
Renal Cancers
133
Endocrine CA : Obese females are at increased risk of
Breast CA
134
Obese female are at increased risk of
Endometrial and cervical CAs
135
Liver enzymes MOST FREQUENLY elevated in obese patients?
Increased ALT AKA
(SGPT, ALAT)
alanine aminotransferase (ALAT)
SGPT serum glutamic-pyruvic transaminase
136
Bone with the obese patients?
Bone resorption occurs due to limited mobility lead to reduce bone density and contribute to stress fractures.
137
Gallstones obese vs normal patients
30% more chance of occurring in the obese.
138
Metabolic syndrome is a constellation of _____abnormalities including
Obesity
Glucose intolerance
HTN
Dyslipidemia
139
Diagnosis of metabolic syndrome requires ____ of how many features?
3 out of 5
Central *(android) obesity: WAIST >102cm M; >88cm F
Triglycerides > 150 mg/dL
Reduce HDL < or equal 40 M; < or equal 50 F
HTN : >130/85 or taking antihypertensives
Fasting glucose: > or equal 100 mg/dL
140
Increase linear with BMI
Risk of Type II DM
141
Obese females are at increased risk of
Breast CA
142
Endocrine CA associated with obese men
Thyroid gland adenocarcinoma
143
GI cancer common in obese female patients
Gallbladder CA
144
Gastric volume and acidity in the obese patients
INCREASED
145
Fasting gastric volume and acid in the OBESE patients? What are they at risk for?
obese patients have a gastric volume of >0.35 ml/krg and pH < 2.5
Aspiration and regurgitation.
146
Gastric emptying in the obese
Delayed because of INCREASED ABDOMINAL MASS
147
BP and OBESITY
SYSTEMIC HTN causes CONCENTRIC (pressure ) HYPERTROPHY Of the LV in normal weight people but CAUSES ECCENTRIC HYPERTROPHY in OBESE PATIENTS
148
Hypertrophy seen with obese patients is
ECCENTRIC HYPERTROPHY of LV in OBESE PATIENTS (normal people is CONCENTRIC) 2 Es in eccentric 2 Es in obese
149
Adipose tissue in the OBESITY :
Adipose tissue releases a number of bioactive mediators (Cytokines, chemokines , hormones) THAT PROMOTE A CHRONIC SUBCLINICAL INFLAMMATORY STATE.
150
What contribue to the CV , insulin resistance and coagulopathies seen with obesity?
Bioactive mediators and inflammatory state
151
Risk of DVT in obese
2x greater risk
152
Factor elevated in obese
HIGH FACTOR VIII (hemophillia a) associated with increased mortality.
153
Hypertrophy seen with obese patients is
CAUSES ECCENTRIC HYPERTROPHY in OBESE PATIENTS
154
ECG changes associated with obesity ?
LOW QRS voltage
LV hypertrophy
LA Enlargement
Leftward shift of P wave , QRS complex, T wave axis.
155
ECG changes associated with obesity ? QT
Prolonged
156
ECG changes associated with obesity ? T wave
flat t waves
157
According to the LAW of laplace , LV hypertrophy
LV hypertrophy occurs in an attempt to reduce wall stress
158
Increased LV wall stress leads to :
| Compliance of LV, diastolic filling, Pressure, pulmonary system, dysfunction and failure.
```
Hypertrophy
reduced LV compliance
Impaired Diastolic filling
LV pressures
Pulmonary edema
systolic dysfunction
Biventricular failure.
```
159
ECG changes associated with obesity ? P wave
Leftward shift of P wave , QRS complex, T wave axis.
160
Obesity QRS Voltage
Low QRS voltage.
161
BMI normal
18.5 - 24.9
162
BMI Overweight
25 - 29.9
163
BMI Obesity Class I, II, III
```
30-34.9 Obesity Class I
35-39.9 Obesity Class II
40-49.99 Morbid Obesity Class III
> 50 Superobese
>60 Super superobese
```
164
What is the definite of android obesity?
Apple shape, also known as central obesity
165
Measurement use to diagnosed android obesity? How is android obesity defined for women and men?
Waist/hip ratio used. Women is WAIST/HIP ratio greater than 0.85 in men and greater than in women 0.92
166
Waist circumference greater than ____For men denotes an increase risk for Ischemic HD, DM, HTN, HLD, and death
40 inch
167
Waist circumference greater than ____For women denotes an increase risk for Ischemic HD, DM, HTN, HLD, and death
35 inch
168
What is gynecoid obesity?
Primarily found in women, act as energy depots for pregnancy and lactation .
169
Increased waist circumference > 35 inch for women and > 40 for men put them at risk for 5 major consequences
```
Ischemic HD
DM
HTN
HLD
Death
```
170
Gynecoid vs android which is LESS associated with cardiovascular diseases?
Gynecoid fat is less metabolically active
171
What pulmonary disease pattern exhibited by Morbidly obese patients?
Restrictive
172
Overtime, wHat happens to chest wall compliance and lung compliance and FRC for the obese patient
They develop THORACIC KYPHOSIS and LUMBAR LORDOSIS leading to impaired rib movement and fixation of thorax in an INSPIRATORY POSITION
173
Pulmonary compliance in the obese person is increase or reduced?
Reduced by 35% of predicted values.
174
Decreased pulmonary compliance seen with obesity leads to
Decline in FRC to less than CC
175
FRC and closing capacity in the obese patients?
FRC decrease to LESS than Closing capacity.
176
In the upright position, the obese patients FRC is _____and CC is ____
decreased, INCREASE
177
What is the definitive diagnosis of OSA
Polysomnography
178
How is the result of a polysomnography interpreted?
Apnea/hypopnea index
5-15 events/hr MILD
15-30 events/hr MODERATE
> 30 events/hr SEVERE
179
Physiologic abnormalities with OSA
Hypoxemia
Hypercapnia
Pulmonary vasoconstriction
Systemic vasoconstriction
180
Long term OSA lead to
Obesity hypoventilation syndrome
181
Obesity hypoventilation syndrome also known as
Pickwickian syndrome
182
Presence of both OBESITY and AWAKE arterial hypercapnia PaCo2> 45 in the absence of known causes of hypoventilation supports what diagnosis
Obesity hypoventilation syndrome
183
What causes the prolonged responses of some medications given to a patient with morbid obesity?
Increased volume o f distribution for lipid soluble drugs
184
Propofol dosing for obese patients (LITM)
Induction dose based on LBW
| Maintenance dose based on TBW
185
Succinylcholine dosing for obese patients : Intubating dose should be based on what weight and why? 2 reasons?
Total body weight:
Because they have increased fluid compartment and pseudocholinesterase levels require HIGHER doses to ensure adequate paralysis
186
All doses based on IBW for obese patients with those three drugs
Rocuronium
Vecuronium
Cisatracurium
187
Remifentanil infusion for obese patients are based on
Ideal body weight (IBW) because of increased volume of distribution and elimination rates NORMAL
188
Fentanyl and sufentanil loading and maintenance doses in obese patients
Loading dose on TBW
| Maintenance dose on LBW
189
Sugammadex reversal for obese patients, dosing based on LBW, TBW, IBW?
Total Body weight
190
Elimination of fentanyl and sufentanil in the obese patients? You should know that they hav
Increase volume of distribution and elimination time correlate with degree of obesity.
191
"Tumescent"
means distended, especially by fluids or gas, and comes from the same Latin root as "tumor:· During tumescent liposuction , a combi- nation of JV fluid, dilute lidocaine O.O5% to O. l %, and dilute epinephrine l:l,000,000 (collectively called the wetting solution) is used to emulsifyfat, provide anesthesia, and create hemostasis during liposuction
192
Pharmacokinetics change associated with obesity : CO, BV, LBW, plasma protein binding
Increase CO
Increase BV
Increase lean body weight
193
Pharmacokinetics change associated with obesity : Plasma protein binding
Changes
194
Total body water with obesity
Reduced
195
Pharmacokinetics change associated with obesity : Renal clearance
Increased
196
Pharmacokinetics change associated with obesity : Liver
Abnormal liver function
