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Special Circumstances

Special Circumstances

There are populations of patients with special conditions that may need additional assessment, monitoring and/or expertise to assure safe care. Special conditions that will be addressed are:

Pregnant Women



Difficult to Sedate Elderly   Sources  

Pregnant & Lactating Women

An estimated 20,000 pregnant women in the United States undergo a gastrointestinal endoscopic procedure each year. It is not definitively known whether exposure to anesthesia or sedation drugs during pregnancy places either the mother or fetus at additional risk for complications.

Indications for endoscopy in pregnancy

Endoscopy should be performed during pregnancy only when the indication for the procedure is clear and less invasive diagnostic or therapeutic modalities do not exist. In addition, whenever possible the procedure should be postponed until the second trimester. According to the American Society for Gastrointestinal Endoscopy (ASGE) Guidelines for Endoscopy in Pregnant and Lactating Women, the indications to perform gastroendoscopy during pregnancy include:

  • Significant or continued gastrointestinal bleeding
  • Severe or refractory nausea and vomiting or abdominal pain
  • Dysphagia or odynophagia
  • Severe diarrhea with unknown cause
  • Biliary pancreatitis, choledocholithiasis, or cholangitis
  • Biliary or pancreatic ductal injury
  • Strong suspicion of colon mass

Pre-procedure Evaluation

The following principles are taken from the 2012 American Society of Gastrointestinal Endoscopy (ASGE) publication:

  • Before 24 weeks of fetal gestation, simultaneous electronic fetal heart and uterine contraction monitoring should be performed before and after the procedure. Ideally, procedures should be done at an institution with neonatal and pediatric services. If possible, the fetal heart rate and uterine contractions should be monitored before, during and after the procedure by a qualified individual, with obstetric support readily available in case of fetal distress or a pregnancy related complication.

Endoscopy is contraindicated in placental abruption, imminent delivery, ruptured membranes, or uncontrolled eclampsia. (ASGE guideline 2012).

Maternal and Fetal Risks

Both mother and fetus face potential risks from endoscopic sedation. These risks vary depending on the trimester of pregnancy. Pregnancy causes a number of anatomic and physiologic changes which impact delivery of sedation during endoscopy.

Physiologic Changes in Pregnancy


  • Increased oxygen consumption
  • Decreased vascular resistance
  • Increased cardiac output
  • Increased blood volume
  • Edema of upper airway and mucous membranes
  • Increased risk of nosebleed from insertion of nasal airway
  • Reduced lung capacity as fetus enlarges increasing risk of maternal hypoxemia
  • Decreased gastrointestinal motility
  • Decreased food absorption
  • Increased gastric acidity
  • Decreased lower esophageal sphincter tone
In second and third trimesters:
  • Compression of vena cava and aorta by weight of uterus. This can lead to decreased venous pressure resulting in maternal tachycardia and fetal distress.

Monitoring Considerations

Standard procedures for physiologic monitoring during endoscopic sedation apply to procedures performed during pregnancy. Fetal monitoring should be considered on a case by case basis depending on the needs of the mother and fetus gestational age and available resources. Please see the Patient Care and Safety section for specific details.


The sensitivity and risks of sedation and analgesia in lactating women is similar to that of other adults. The primary concern related to sedation when a woman is breast feeding is the risk of transferring drugs to the infant through the breast milk. In cases where the medication may be harmful to the infant, the woman should be advised to pump her breast milk and discard it, with the timing dependent upon the agent of concern. Please see specific information in the Medication section.

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It is considered best practice that sedation for the pediatric population should be administered by an anesthesia provider.

Traditionally, pediatric populations span the first two decades of life and encompass both newborns and teenagers. Doses of sedatives in children should always be weight adjusted. It is also important to tailor sedative regimens to developmental stage. Generally speaking, the American Academy of Pediatrics has published a set of criteria that should be met to safeguard the needs of children undergoing sedation.

Summary of American Academy of Pediatrics
Guidelines for Sedation of Children

  • No administration of sedation medications without medical supervision
  • Careful pre-sedation evaluation for underlying medical or surgical conditions that could increase risk from sedation
  • Appropriate pre-procedure fasting for elective procedures; balance between sedation depth and risk of aspiration for urgent procedures in patients unable to fast
  • Careful airway examination to identify abnormalities that could increase the potential for airway obstruction
  • Thorough understanding of the pharmacokinetic and pharmacodynamic effects and drug interactions of medications used for sedation
  • Appropriate monitoring during and after the procedure
  • Properly equipped and staffed recovery area
  • Recovery to point of consciousness before discharge and appropriate discharge instructions

Physiological Differences

Anatomical and physiological differences between children and adults can make children more vulnerable to the adverse effects of sedatives. In addition, children's psychological needs and ability to cooperate will vary based on their developmental stage and need to be taken into consideration by the clinician performing the procedure.

Airway Anatomy

(see Airway Management)

Physiological differences

  • Larynx located higher in the neck
  • Narrow oropharyngeal passages
  • Large tongue

Sedation Considerations

  • Hyperextension of the neck may worsen airway obstruction
  • Large tongue can fall toward the roof of mouth in sedated child and obstruct airway
  • Critical to choose appropriately-sized oral airway if used; soft nasal airways more appropriate in mild and moderate sedation.
  • Airway obstruction is major cause of hypoxemia in children; airway should be reassessed frequently for signs of obstruction
  • Reduced ventilation caused by prone or supine positions, or by constraining garments or restraints, may result in hypoventilation.

Respiratory function

Physiological differences

  • Increased metabolic rate resulting in higher oxygen consumption
  • Less alveolar space
  • Sternum and ribs more pliable in children

Sedation considerations

  • Decrease in breathing rate due to sedation can cause significant respiratory insufficiency
  • Chest wall retractions and abdominal muscle use are used to identify respiratory distress

Cardiovascular system

Physiological differences

  • Normal parameters for heart rate, respiration, and blood pressure vary based on child’s age
  • Circulatory response to hypoxia in young children is bradycardia
  • Heart rate primary factor determining changes in pediatric cardiac output
  • Active parasympathetic nervous system
  • Drugs that slow heart rate will cause a drop in cardiac output and decrease circulation times

Sedation consideration

  • Knowledge of age-appropriate vital signs is critical 100% oxygen should be administered when heart rate decreases
  • Hypoxia, deep sedation, and painful events can produce bradycardia
  • Decrease in circulation times results in longer onset and prolonged length of action for sedation medications

Body composition

Physiological differences

  • Large body surface to body mass and thinner skin can result in dehydration and/or rapid loss of body heat
  • Higher total body water
  • Decreased tolerance for starvation and tendency to become hypoglycemic when fasting

Sedation considerations

  • Children should be well draped and room temperature adjusted to prevent hypothermia
  • May need maintenance fluids for circulatory support especially for children under age 8 and children who have been NPO fo signficant time
  • Replacement fluids should contain 2.5% dextrose and half normal saline

Hepatic & renal function

Physiological differences

  • Hepatic and renal function less developed

Sedation considerations

  • Length of action of drugs is longer dueto reduced hepatic function
  • Clearing times may be faster due to higher circulating volumes

Development characteristics

Physiological differences

  • Neurologic system not well developed in children younger than 8 to 10 years old
  • Significant psychological stress often associated with medical procedure especially at younger ages

Sedation considerations

  • Familiarity with normal age appropriate behaviors of child can help in identifying changes in child's level of functioning
  • Supplying age appropriate information before the procedure can reduce anxiety and allow for the use of less sedation

Pharmacologic considerations for pediatric patients

The American Academy of Pediatrics Guidelines for Monitoring and Management of Pediatric Patients During and After Sedation for Diagnostic and Therapeutic Procedures states the following goals for sedation in children:

  • Guard the patient's safety, privacy and welfare
  • Minimize physical discomfort and pain
  • Control anxiety
  • Minimize psychological trauma and maximize the potential for amnesia
  • Control behavior and movement to allow safe completion of the procedure
  • Return the patient to state in which safe discharge is possible

Patient Care, Assessment and Monitoring of Pediatric Patients

As a group, pediatric patients have needs that require particular attention in assessment, monitoring and care. See specific information in the Patient Care and Safety section.

Emergency Equipment

The resuscitative equipment available for pediatric procedures should reflect the equipment used for moderate sedation in adults with attention to the proper sizes and doses for the ages being treated. (For a complete list of specific equipment and medications for pediatric sedation, see the AAP guideline).

Postprocedure Monitoring and Discharge

In the Guidelines for Monitoring and Management of Pediatric Patients During and After Sedation for Diagnostic and Therapeutic Procedures, the American Academy of Pediatrics specifycriteria for post procedure monitoring and discharge of patients who have undergone moderate sedation. For specific post procedure information please refer to the Patient Care and Safety section.

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Physiological changes associated with aging

The aging process affects all major organ systems. Most data points to aging being caused by reactive oxygen species, byproducts of aerobic metabolism in mitochondria, which create oxidative stress and cell injury. Consequently, organ function declines at the rate of approximately 1% to 1.5% each year after the age of 30. These physiological changes can potentially impact sedation of elderly patients.

Cardiovascular system
Physiological differences

  • Reduced tissue elasticity in arteries and veins
  • Ventricular hypertrophy
  • Reduced cardiac output
  • Reduced arterial oxygenation
  • Deterioration of the cardiac conduction system

Sedation considerations

  • Increased oxygen consumption
  • Inability of the body to adjust to hemodynamic changes
  • Higher likelihood of arrhythmias
  • Slower cardiorespiratory response to hypercarbia and hypoxia


Body composition

Physiological differences

  • Higher proportion of body fat
  • Less intracellular fluid

Sedation considerations

  • Expanded distribution volume for pharmacologic agents
  • Higher risk of over sedation with water-soluble drugs
  • Slower recovery period for lipid-soluble drugs

Pulmonary system

Physiological differences

  • Decreased respiratory drive
  • Less lung capacity

Sedation considerations

  • Decreased ability for the body to compensate for respiratory depression caused by sedative agents
  • Higher incidence of transient apnea

Neurologic system

Physiological differences

  • Loss of neuronal density
  • Reduced levels of neurotransmitters

Sedation considerations

  • Increased sensitivity to CNS depressant drugs
  • Higher incidence of confusion

Renal system

Physiological differences

  • Reduced blood flow to the kidneys
  • Decreased glomerular filtration rate

Sedation considerations

  • Increased risk of renal insufficiency
  • Longer duration of action for some anesthetics and adjuvant drugs

Hepatic system

Physiological differences

  • Reduced blood flow to the liver
  • Less liver enzyme activity

Sedation considerations

  • Increased duration of action for lipid-soluble drugs
  • Altered metabolism of drugs


Physiological differences

  • Diminished gag reflex
  • Loss of teeth and use of dentures
  • Arthritis of the neck

Sedation considerations

  • Increased risk of aspiration
  • Difficulty in mask ventilation
  • Difficulty performing head-tilt, jaw-thrust maneuver of airway

Pharmacologic considerations

The general recommendations for the administration of sedation in geriatric patients are:

  • Use fewer agents at lower doses
  • Deliver agents at a slower rate to allow for assessment of effects at each dose level
  • Administer low initial and lower cumulative doses of sedative agents

For specific information related to medication use in the elderly please see the Medication section.

Patient care and assessment

A a vulnerable group, geriatric patients have needs that require particular attention in assessment, monitoring and care. Please see the Patient Care and Safety section for specific details.

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Difficult to Sedate

Moderate sedation can be achieved for most patients using a standard combination of opioids and benzodiazepines. Patients that may pose challenges for adequate sedation are listed below.


Risk factors for difficult sedation

  • A history of difficult sedation or failed sedation
  • A history of narcotic, anxiolytics and/or sedative use
  • Heavy alcohol and/or illicit drug use
  • Biliary dyskinesia
  • Morbid obesity
  • Preexisting behavioral health conditions
  • Pediatric patients and young adults
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Obstructive Sleep Apnea (OSA)

Most people with moderate to severe sleep apnea often are undiagnosed. This poses a challenge when administering sedation for endoscopic procedures.

Risk factors for OSA

  • Patients with OSA are at a greater risk of airway complications when they receive sedation
  • Diagnosis of OSA confirmed with a sleep study
    Sleep studies in patients with OSA measure the number of hypopneic episodes
  • Apnea-hypopneics index (AHI) is calculated by dividing the number of apneas and hypopneas by the number of hours of sleep
  • Mild OSA= when apnea-hypopnea index (AHI) is 5-15 per hour of sleep
  • Moderate is 15-30 AHI
  • Sever OSA is over 30 AHI

Mechanisms of obstructive sleep apnea

  • Muscles of the pharynx relax during stages of sleep
  • Airway size is reduced
  • People with OSA have airways that are narrower and more collapsible than normal, the airway obstructs when their pharyngeal muscles relax
  • Hypoxemia, hypercarbia and acidosis activates respiratory centers in the central nervous system
  • Ventilation ends the apneas
  • Normal sleep cycle is interrupted
  • Chronic condition
  • When episodes last longer than 10 seconds and occur more than 5-7 times an hour serious health problems can result
  • May eventually produce pulmonary hypertension and right ventricular heart failure

Medical conditions related to untreated sleep apnea

  • Daytime sleepiness
  • Impaired cognition
  • Anxiety
  • Depression
  • Increased risk of occupational and motor vehicle accidents
  • Hypertension
  • Heart failure
  • Cardiac arrhythmias
  • Angina
  • Heart attack

Assessment of sleep apnea

The majority of patients with sleep apnea who undergo sedation for endoscopy will not have received a formal diagnosis of the condition. Therefore, in the absence of a sleep study, the possibility of sleep apnea should be assessed based on the patient's physical characteristics (in particular upper body obesity), medical history, and interviews with family members regarding the patients snoring and sleep patterns. Many patients that don't look like they should have OSA because they are not overweight with a thick neck do in fact have OSA, sometimes due to enlarged tonsils for example. The converse can also occur. Not every large patient with a thick neck necessarily has OSA

Factors indicating possibility of obstructive sleep apnea

  • Physical characteristics
  • Obesity (BMI greater than 35)
  • Neck circumference greater than 17 inches for men or 16 inches for women
  • Craniofacial abnormalities
  • Anatomical nasal obstruction
  • Tonsillar hypertrophy
  • History of airway obstruction during sleep (two or more of the following; or one or more of the following if patient is not observed during sleep)
  • Snoring loud enough to be heard through a closed door
  • Frequent snoring
  • Observed pauses in breathing during sleep
  • Awakens from sleep with a choking sensation
  • Frequent arousals from sleep
  • In children:
  • Intermittent vocalization during sleep
  • Parental report of restless sleep or breathing difficulties during sleep
  • Somnolence (one or more of the following)
  • Frequent daytime sleepiness or fatigue despite adequate "sleep"
  • Falls asleep frequently in non-stimulating environment :
  • In children:
  • Parent or teacher comments that child appears sleepy; is easily distracted; is overly aggressive; or has trouble concentrating
  • Difficult to arouse at usual waking time

Another tool that has been effective to screen patients for obstructive sleep apnea is the STOP Questionnaire. This tool was developed by researchers from the University of Toronto, Ontario, Canada.

The STOP tool asks four basic questions:

  1. Snoring
    Do you snore loudly (louder than talking or loud enough to be heard though closed doors)?
  2. Tired
    Do you often feel tired, fatigued, or sleepy during daytime?
  3. Observed
    Has anyone observed you stop breathing during your sleep?
  4. Blood Pressure
    Do you have or are you being treated for high blood pressure?

The patient would be considered high risk if he/she would answer yes to two or more questions. (Chung, 2008)

Impact of sedation on patients with OSA

  • IV sedatives decrease the muscle tone of the upper airway
  • With loss of muscle tone airway resistance increases resulting in a reduction in the diameter of the upper airway
  • Can lead to airway collapse
  • Sedatives also interfere with the mechanism that normally arouses an individual from an apnea event
  • Individuals with OSA may be more sensitive to sedation
  • CPAP (Continuous Positive Airway Pressure) machine may be used to support breathing
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American Society of Anesthesiologists. (2003). Guidelines for ambulatory anesthesia and surgery (Approved by ASA House of Delegates on October 15, 2003, last affirmed on October 16, 2013). Retrieved from:

American Society for Gastrointestinal Endoscopy. (2012) Guidelines for Endoscopy in Pregnant and Lactating Women, Gastrointestinal Endoscopy. 76 (18-24). 

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Kahn, R.L., Stanton, M.A., Tong-Ngork, S., Liguori, G.A.,Edmonds, G.R. & Levine, D. S. (2008). One-Year Experience with Day-of-Surgery Pregnancy Testing Before Elective Orthopedic Procedures. Anesthesia & Analgesia.106: 1127-1131 Briggs, G.G., Greeman, R.K. & Yaffe, S.J. (2011). Drugs in pregnancy and lactation: a reference guide to fetal and neonatal risk. 9th ed. Philadelphia: Lippincott Williams & Wilkins. 

American Society for Gastrointestinal Endoscopy. (2008). Modifications in endoscopic practice for pediatric patients. Gastrointestinal Endoscopy.67:1-9. 

Cote, C.J. & Wilson, S. (2006). American Academy of Pediatrics: Guidelines for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures: an update. Pediatrics; 118:2587-2602. American Academy of Pediatrics. (2008). Guidelines for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures: an update. Pediatric Anesthesia. 18: 9-10. 

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Website resource 

American Society of Gastrointestinal Endoscopy. (2013). Guideline: modifications in endoscopic practice for the elderly. Gastrointestinal Endoscopy. 78(1):1-7. 

Kost M. (2004). Moderate Sedation/Analgesia: Core Competencies for Practice, 2nd Ed. St. Louis, MO: Saunders.202. 

American Society for Gastrointestinal Endoscopy. (2003). Guidelines for conscious sedation and monitoring during gastrointestinal endoscopy. Gastrointestinal Endoscopy.58(3): 317-322. 

Cohen, J., Haber, G.B., Dorais, J.A. et al. (2000). A randomized, double blind study of the use of droperidol for conscious sedation during therapeutic endoscopy in difficult to sedate patients. Gastrointest Endoscopy. 51(5):546-51. 

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Gazayerli, M. et al (2006). A correlation between the shape of the epiglottis and obstructive sleep apnea. Surgical Endoscopy. 20(5):836-7. 

Isono, S. (2009). Obstructive Sleep Apnea of Obese Adults. Anesthesiology, 110(4) 908-921. 

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Villegas T. (2004). Sleep apnea and moderate sedation. Gastroenterology Nursing.27(3):121-124.

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