Download Special Considerations in the Critically Ill Morbidly Obese Child

Special Considerations
in the Critically Ill
Morbidly Obese Child
Karen Allison Bailey,
BSc, MD, FRCSC
KEYWORDS
Critical care Morbidly obese Child Pediatric
Special considerations
Obesity has been recognized as an increasing problem not only in North America but
globally. With a significant rise in the prevalence of obesity amongst children and
adolescents over the past 20 years, the comorbidities associated with obesity are
also now emerging at an earlier age. These comorbidities cause specific concern
and require special consideration when the morbidly obese child becomes critically ill.
In the United States the prevalence of obesity (body mass index [BMI] >95th percentile) was found to have increased among children aged 2 to 19 years with an agerelated prevalence of 12.4% (aged 2–5 years), 17% (aged 6–11 years), and17.6%
(aged 12–19 years).1 The prevalence of children who are overweight (BMI >85th
percentile) was found to be 33.3% to 34.1% based on the 2003 to 2006 National
Health and Nutrition Examination Survey data.1 The International Obesity Task Force
has estimated that among school-aged children worldwide, as many as 155 million
children are overweight or obese.2
As with adults, the causes of obesity in children are multiple. Although weight gain is
often viewed as simply being caused from taking in more calories than are expended
there are many other factors that influence obesity. These factors include heredity,
metabolic, behavior, environment, culture, and socioeconomic status. In children,
medical conditions and rare syndromes, such as hypothyroidism, Prader-Willi
syndrome, and Cushing syndrome, account for a small number of pediatric patients
who are morbidly obese but must be considered as potential causes.3,4
The rising prevalence of obesity will no doubt cause many pediatric critical care
units to face the challenges of managing children who are morbidly obese. Many units
are not physically designed to accommodate patients who are morbidly obese and
their staff has not been specially trained to care for these patients, which potentially
places patients and staff at risk. Weight-appropriate beds, chairs, scales, lifts, and
The author has nothing to disclose.
Pediatric General Surgery, Pediatric Trauma Program, McMaster Children’s Hospital, McMaster
University, 1200 Main Street West, Room 4E4, Hamilton, ON L8N 3Z5, Canada
E-mail address: [email protected]
Crit Care Clin 26 (2010) 699–702
doi:10.1016/j.ccc.2010.06.009
criticalcare.theclinics.com
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Bailey
blood pressure cuffs may not be present to facilitate treatment of morbidly obese
patients. Doorways and rooms may be too small to accommodate wider weightappropriate beds, chairs, lifts, and equipment.
Radiologic imaging can also be problematic in patients who are morbidly obese.
The patients’ size can limit visualization with all modalities. Increased radiation may
be required to adequately penetrate the tissues for plain films. Equipment specifications vary and typically have a maximum of 250 to 450 lb depending on the manufacturer’s specifications, which may preclude patients who are morbidly obese from
having a CT scan, MRI, or fluoroscopy depending on the equipment available. The
gantry size of the CT and MRI scanner, or the space between the table top to the fluoroscopy image intensifier, may also limit the ability to obtain adequate imaging.5
The comorbidities associated with morbid obesity have not been extensively
studied or reported on specifically in the pediatric critical care population but they
need to be carefully considered. Morbid obesity in childhood is clearly associated
with increased problems with asthma, obstructive sleep apnea, hypertension, dyslipidemia, impaired glucose tolerance, gastroesophageal reflux, cholelithiasis, osteoarthritis, and liver dysfunction. These complications were once considered to be only
long-term effects of obesity that appeared in adulthood, but pediatric studies have
shown that they are clearly appearing in childhood.6,7
The importance of addressing morbid obesity and the potential for reversing these
comorbidities after excess weight is lost has been most clearly demonstrated in the
literature in adolescents who have undergone bariatric surgery. Although diet, exercise, and behavioral therapy are essential components in preventing and addressing
obesity, sadly they are often inadequate alone. Bariatric surgery, although still considered controversial in children, has been effective in improving and resolving obesityrelated comorbidities.8–10
Many critically ill children will require ventilatory support so it important to understand that respiratory mechanics may be altered from both a restrictive and obstructive component in patients who are morbidly obese. Chest wall compliance and
diaphragmatic excursion may be decreased because of adiposity and its distribution.
Atelectasis is a greater problem in the obese population that requires increased diligence to ensure adequate ambulation, pulmonary toilet, and chest physiotherapy as
needed.3,6 Obese children are slower to recover after severe asthma exacerbations
and have been found to require longer intensive care unit (ICU) courses and more
supplemental oxygen, continuous albuterol, and intravenous steroids in comparison
to their lean peers.11
As with morbidly obese adults, the airway in morbidly obese pediatric patients may
be more difficult to visualize and maintain. Intubation can be more challenging in
young patients because of the more anterior position of the airway; this visualization
can be further impaired by adiposity. In patients who are morbidly obese, practitioners
should be prepared to have assistance readily called for and access to equipment for
difficult airway intubation. Training in advanced airway and bronchoscopy skills can be
life saving.
Obstructive sleep apnea may require patients to be given continuous positive
airway pressure when lethargic or at rest. Some of these morbidly obese children
may have had significant issues with night-time oxygen desaturations, which were
not detected before hospitalization.7,12
Obesity-related hypertension and insulin resistance may lead to significant renal
dysfunction, although this usually presents later in life. Morbid obesity may be associated with abnormal liver enzymes; if untreated, it has been associated with nonalcoholic steatohepatitis that can lead to frank liver failure if obesity is not addressed.13
Critically Ill Morbidly Obese Child
Drug doses are often based upon age or weight in children. Some pharmacokinetics
are well understood with doses adjusted for renal or hepatic dysfunction in children. In
the face of significant excess weight, the resulting changes in pharmacokinetics for
children with or without organ dysfunction are not as well defined. As described in
the anesthesia literature, when obese pediatric patients receive medications, such
as midazolam and fentanyl (which have an increased volume of distribution throughout
the body), they are often best administered based upon total body weight. Some
medications are distributed to lean tissues predominantly and are better administered
to patients according to their ideal body weight.3,14
If supplemental enteral or parenteral nutrition is required it is important to
consider that patients may require additional medications or liver-protecting strategies because of underlying insulin resistance and hyperlipidemia. Morbid obesity
does not equate to adequate nutrition and, if tested, many patients will be found
to be deficient in essential nutrients that are needed to promote healing and to fight
infection. Although patients are morbidly obese, adequate nutrition is essential to
prevent muscle loss. The morbidly obese child may already have difficulty with
ambulation and osteoarthritis. Rehabilitation and recovery will be impaired if there
is further loss of normal muscle mass caused by inadequate nutrition. Early involvement of physical and occupational therapy should be considered in this patient
population.10
In the pediatric trauma population, obese children and adolescents appear to have
higher complication rates, with longer time on ventilation and longer ICU stays than
lean pediatric trauma patients. Specific complications that have been identified as
being higher in association with obesity in the pediatric trauma population include
wound infection, sepsis, postoperative fistulas, decubitus ulcers, and deep venous
thrombosis.15,16
The morbidly obese child often appears to be much older than their actual age.
Although significantly larger in size than many of their peers, they are not more
emotionally mature or able to cope with a critical illness. These patients may be
less able to cope with the stresses of a critical illness because depression and psychiatric disease often present hand in hand with morbid obesity. It is important for the
critical care team to remember this, so as to compassionately care for their emotional
and psychological needs in an age-appropriate manner.17–19
A team approach is needed to address all of the special considerations in this
patient population. As the severity and prevalence of obesity continues to rise, we
must become aware and prepared to treat this patient population. The morbidly obese
child is not merely a large child, but a child with many potential complexities and
concerns that we must take into account within the critical care setting.
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