Test 2: Obesity (pt 3/3) Flashcards
What are the S/sx of Cardiac Dz in obese patients?
-Dyspnea
-Pedal Edema
-JVD
-Hepatomegaly
-Exercise intolerance
-Body habitus complicates assessment
Why are dysrhythmias common in the obese population?
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
True/False: A LBBB is common in obesity.
False: A LBB Is unusual in obesity and raises suspicion of occult CAD.
-Warrants a Transthoracic Echo (TTE)
Patients with a BMI > ____ need increased doses of anticoagulants for their VTE prophylaxis.
> 50 kg/m2
Increased BMI = ______ comorbidities = _______ risk!!
Bottom line: increased BMI = increased comorbidities = increased risk!!!
What are some planning considerations to consider for the location and equipment needed in surgery for the obese patient?
-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
What are factors that potentiate injury complications related to positioning in obese patients?
-Hypothermia
-Hypotension
-Table positioning
-Pressure from adipose tissue on orthopedic and cardiopulmonary structures
How do you prevent or mitigate risk of positioning injury in obese patients?
-Frequent palpation of pulses
-Generous padding
-Correct alignment
-Repeated inspection of extremities for color & temperature
-Treatment of the Panniculus
True/False: You don’t have to worry about weight limits with OR tables.
False: Ensure the OR table can support the weight of the patient - high risk for falls and table failure!!!
What are the pharmacokinetic changes associated with obesity?
-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
Give water-soluble drugs according to _____.
IBW
Give lipid-soluble drugs according to ______.
TBW
Can you give inhalational agents to obese patients?
Yes; newer inhalational agents (Des/Sevo) have excellent recovery profiles
-Des is less soluble than sevo; clinical differences are minimal
True/False: You can never give Nitrous Oxide to an obese patient.
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
What are some benefits to using Nitrous Oxide in obese patients?
-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.
Appropriate antiemetic prophylaxis should be administered whenever _______, especially _____ are used.
Anesthetic gases; Nitrous Oxide
What is the induction dose and maintenance dose based on for propofol?
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
What is your intubating dose of succinylcholine based on?
TBW
Why is succinylcholine dosing based on TBW?
Increased fluid compartment and pseudocholinesterase levels require higher doses to ensure adequate paralysis
Dosing for Rocuronium/Vecuronium/Cisatracurium is based on:
IBW
Why are NDMR given based on IBW?
Hydrophilic drugs given according to IBW will ensure shorter duration and a more predictable recovery in this respiratory-challenged population
What are the Loading Dose and Maintenance Doses based on for Fentanyl/Sufentanil?
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
What is the infusion rate of Remifantanil based on?
IBW
Distribution volumes and elimination rates are similar to normal-sized individuals; fast offset requires planning for postoperative analgesia
What is the infusion rate of dexmedetomidine?
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
What is Sugammadex reversal dosing based on?
TBW; no change from normal dosing
What are the objectives for the maintenance of anesthesia in the obese patient?
-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
Despite the augmentation of circulatory fluid that accompanies extreme obesity, the estimated blood volume is actually __________.
diminished.
What should you do differently with volume replacement in obese patients to reduce the risk of cardiopulmonary compromise?
Use of reduced parameters for volume replacement and avoidance of rapid dehydration.
How do you guide fluid management in the obese patient?
BP, HR, and UOP
Fluid requirements for bariatric procedures may be ________ than anticipated to maintain renal perfusion.
greater
True/False: No difference in the criteria between the administration of blood products in normal-weight patients versus severely obese patients has been identified.
True
What are the things to know regarding mechanical ventilation in the obese population?
-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
What is the only mechanical ventilation parameter shown to improve respiratory function?
PEEP
What do you need to ensure before considering the use of regional anesthetic techniques?
That the patient can tolerate surgical positioning
What are some difficulties associated with the use of regional anesthesia in obese patients?
Anatomic landmarks are difficult to find or palpate
-Need US guidance
What are the positioning recommendations for neuraxial anesthesia in the obese patient?
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.
In general, patients with a BMI > ____ are not appropriate for Ambulatory Surgery Centers.
> /= 50
