Spotlight Case March 2005

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Spotlight Case March 2005

• The Hidden Mystery

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Source and Credits

• This presentation is based on the March 2005
  AHRQ WebMM Spotlight Case in Hospital Medicine
• See the full article at http//webmm.ahrq.gov
• CME credit is available through the Web site
• Commentary by Douglas D. Brunette, MD, Hennepin
  County Medical Center
• Editor, AHRQ WebMM Robert Wachter, MD
• Spotlight Editor Tracy Minichiello, MD
• Managing Editor Erin Hartman, MS

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Objectives

• At the conclusion of this educational activity,
  participants should be able to
• Appreciate the challenges of caring for morbidly
  obese patients
• List specific interventions that can be
  implemented when caring for obese patients
• Develop a rational approach to medication dosing
  in obese patients

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Case The Hidden Mystery

• A 45-year-old morbidly obese woman with diabetes
  mellitus was transferred to a tertiary care
  center for management of abdominal pain,
  vomiting, and subjective fevers. Upon transfer,
  the patient complained of diffuse abdominal pain.
  She was febrile with stable vital signs. Exam
  revealed a diffusely tender abdomen with chronic
  erythematous changes extending over her pannus.

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Case (cont.) The Hidden Mystery

• Empiric broad-spectrum antibiotics were started.
  The consulting surgeon recommended abdominal
  imaging, but the patient was unable to fit in the
  CT scanner or MRI due to her obesity. She was
  observed, and her abdominal pain was treated with
  narcotics.

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Obesity in the United States

• Is defined as having a very high amount of body
  fat in relation to lean body mass
• Is a major health care problem in the U.S.
• Has increased dramatically in recent years
• Contributes to numerous negative health
  consequences

Source CDC web site. Flegal KM, et al. Int J
Obes Relat Metab Disord. 19982239-47. NIH. Obes
Res. 19986 Suppl 251S-209S
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Body Mass Index

• Body Mass Index (BMI) calculator
• A measure of an adults weight in relation to
  height specifically weight in kilograms divided
  by the square of height in meters
• Overweight BMI 25 kg/m2
• Obese BMI 30 kg/m2
• Morbidly obese BMI 40 kg/m2

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Obesity Trends Among U.S. Adults
(BMI ? 30)
Source Behavioral Risk Factor Surveillance
System, CDC.
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Leading Causes of Death the U.S. 2000
Source Mokdad AH, et al. JAMA. 20042911238-45.
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Challenges in Caring for Obese Patients

• Transportation
• Physical exam
• Diagnostic imaging
• Nursing care
• Airway management
• Venous access
• Medication dosing

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Transportation Challenges

• Need to recruit more personnel
• Need multiple slide boards
• Requires use of specially designed soft
  stretchers, operating room tables, hospital beds
• Must provide special commodes, mechanical lifts,
  and larger wheel chairs

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Physical Exam Challenges

• Pannus and increased thickness of subcutaneous
  fat interferes with auscultation, palpation, and
  inspection
• Positioning the patient is difficult due to
  decreased mobility
• Blood pressure readings may be inaccurate when
  wrong size cuff used
• Pain threshold in obese patients may be higher,
  further diminishing accuracy of exam

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Imaging Challenges

• Standard radiographsoften cannot fit entire
  field of image into single film
• CT and MRI hindered by weight and circumference
  restrictions of typically 300-350 lbs
• Ultrasound imaging technically difficult

Source Varon J, Marik P. Crit Care Clin.
200117187-200 Boulanger BR, et al. J
Trauma.19884552-56 Melanson SW, Heller M.
Emerg Med Clin North Am. 199816165-89 McKenney
KL. Radiologic Clin North Am. 199937879-93.
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Nursing Care Challenges

• Cardiac and pulse ox monitoring less reliable
• Wound care technically difficult
• Blood draws and IV access hard to establish
• Skin care and pressure sore prevention
  challenging due to need to move patient often

Source Hahler B. Medsurg Nurs. 20021185-90
Davidson JE, et al. Crit Care Nurs Q.
200326105-18.
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Airway Management Issues

• Bag-valve mask ventilation more difficult
• reduced pulmonary compliance
• increased chest wall resistance
• increased airway resistance
• abnormal diaphragmatic positioning
• Increased aspiration risk
• Larger volume of gastric fluid
• Increased intra-abdominal pressure
• Higher incidence of reflux

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Airway Management Issues

• Obesity limits physicians view of laryngeal
  structures during intubation
• Australian study of 85 difficult intubations
  obesity, limited neck mobility, or mouth opening
  accounted for two thirds
• Interventions to consider in morbidly obese
• Intubate in the semierect position
• Use the Intubating Laryngeal Mask Airway or
  Combitube

Williamson JA, et al. Anaesth Intensive Care.
199321602-7 Rocke DA, et al. Anesthesiology.
19927767-73.
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Intubation Laryngeal Mask Airway
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Venous Access Challenges

• Greater number of skin punctures during catheter
  placement
• Delayed catheter changes with increased infection
  and thrombosis
• Additional personnel needed for positioning and
  pannus retraction

Boulanger BR, et al. Crit Care Clin.
199410613-95.
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Medication Dosing Issues

• Marked alteration in pharmacokinetics due to
  altered volume of distribution
• Volume of distribution is correlated with drug
  lipophilicitydrugs with higher affinity for
  adipose have a larger volume of distribution
• Ideally base dosing on results of clinical
  research data

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Medication Dosing Issues

• When dosing guidelines not provided, base loading
  doses on drugs hydrophilic or lipophilic
  properties, and ideal body weight (IBW) or total
  body weight (TBW)
• Hydrophilic
• Dosing Weight IBW 0.3(TBW-IBW)
• Lipophilic use TBW
• Maintenance dose should be based on IBW if
  metabolic clearance is not known

Brunette DD. Am J Emerg Med. 20042240-7.
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Case (cont.) The Hidden Mystery

• Six days later, the patient developed fevers,
  hypotension, and leukocytosis. Exam showed newly
  identified gangrenous pannus in the deep skin
  folds. She was taken to the OR for presumed
  necrotizing fasciitis. Surgical exploration
  revealed a colocutaneous fistula arising from
  perforated sigmoid diverticula. The patient died
  of multiorgan failure after a complex
  several-month hospital course.

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Quality of Care for Obese Patients

• Documented delays in medical care
• Less likely to receive preventative care
• Negative physician attitudes and discrimination
• Reported feeling mistreated and misunderstood by
  medical personnel
• Surgeons possibly more reluctant to operate

Source Schwilk B. Anasthesiol Intensivmed
Norfallmed Schmerzther. 19953099-107
Heinzelmann M. Am J Surg. 2002183179-90.
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Obesity and Perioperative Mortality

• Longer operative times
• Increased surgical wound infection rate
• Higher risk of sepsis

Cruse PJ, Foord R. Surg Clin North Am.
19806027-40 Reference 29.
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Postoperative Complication Rates by Weight
Schwilk B. Anasthesiol Intensivmed Norfallmed
Schmerzther. 19953099-107
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Obesity and Medical Education

• Rotations on bariatric surgery service have
  improved students knowledge base
• Interventions in medical school using video audio
  and written components have lead to improved
  attitudes towards obese patients

Source Nanasiak M, Murr MM. Obes Surg.
200111677-9Wiese HJ, et al. Int J Obes Relat
Metab Disord. 199216859-68.
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Take-Home Points

• Obesity is an epidemic in the US and an
  increasing percentage of patients will be
  classified as obese
• Providing excellent care to this population is
  challenging and requires special attention and
  often the use of customized equipment
• Airway management is particularly risky and care
  givers should be prepared to use rescue techniques

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Take-Home Points

• Medication dosing must often be customized to
  this population
• Care givers must be mindful of potential biases
  that can influence interactions with patients and
  the quality of care
• Efforts should be made to increase curriculum at
  the medical school level focusing on the care of
  the obese patient