Guidelines for Obese patients Flashcards
Midazolam dose for obese patients
0.6mg/kg
What dose of hydroxyzine to be used with N2O on obese patients?
up to 2mg/kg
What can be given to obese patients prior to sedation to prevent aspiration that have a history of vomiting during sedation?
H2 blockers (best to refer to hospital for treatment)
Should post-op opioids be used for obese patients that have been sedated?
Should be avoided due to potential for respiratory depression and arrest. Obese pt take longer to recover from sedative drugs due the the lipophilic sequestering of the sedative drugs
Percentage of children in US that are obese?
17% and rising
What ratio of overweight preschool age children and school-age children remain obese into adulthood?
1/3 of preschool age children
1/2 of school age children
How does obesity impose a restrictive ventilation defect?
Excess weight added to the thoracic cage and abdomen impedes motion of the diaphragm, especially in the supine position
What decreases in lung capacity are seen with obese patients?
Functional reserve capacity, expiratory reserve volume. Also a reduction in chest wall compliance and increase respiratory airway resistance. (more tissue to imped airflow)
Morbidly obese-vital capacity and total lung volume
How much reduction in functional residual capacity occurs in obese patients when in supine position?
There is a 50% reduction in functional residual capacity (FRC) in obese. Even with pre-oxygenation, cessation of breathing can quickly lead to arterial hypoxemia.
Non obese have a 20% reduction.
What occurs to the myocardium when obese patients are placed in the supine position?
Tend to have an increase cardiac output. Leads to potential myocardial hypoxia due to decreased respiratory function and cardiac workload, especially in sedated patients.
What increases the chances of aspiration during sedation of obese patients?
Increased gastric volumes, increased intra-abdominal pressure.
What pharmacokinetics deviations occur in the obese patients?
Drug absorption, distribution, metabolism, and excretion are all affected by increase BMI
What classification are most sedation drugs considered to be?
Lipophilic
Why do obese patients take longer for complete recovery from sedation drugs?
Sequestering of drugs into fat and away from brain. Takes more drugs to induce due to fat but then quicker to recover. Fat tissues then release sedative and complete recovery is longer after drug delivery has stopped.
Most complications seen in which type of patient during sedation?
ASA III
Those with cerebral palsy, followed by those with autism.
Airway obstruction seen in those with cerebral palsy.
Vomiting with those that had learning disability
What was the concluding results of the study of sedation on patients with special needs?
Dental sedation on special needs patients is safe and complications are only mild. Mild airway obstruction.
Goals of sedation in dentistry
1) Guard the patient’s safety and welfare
2) minimized physical discomfort and pain
3) control anxiety and maximize the potential for amnesia
4) control behavior in order for safe completion of treatment
5) return patient to a state in which safe discharge from medical supervision is possible
Why is meperidine a desirable agent for OCS
sedative and analgesic properties.
It has a metabolite (normeperidine) that is CNS stimulant that can cause agitation, tremors and seizures.
Some clinics have banned meperidine and use morphine now, but little research into its use. Morphine shown to cause post-discharge excessive somnolence, nausea, and emesis.
Benefits of combining sedative drugs
Synergistic sedative effect that allows for reduce dosing of the single agents but giving desired sedative effect.
sedative effects of benzos
sedative and anxiolytic, amnesia
Hydroxyzine sedative effects
anti-histamine producing antiemetic, anxiolytic, sedative,
AAPD indications for OCS
- fearful patient whom basic behavioral techniques have not been successful
- patient unable to cooperate due to lack of psychological or emotional maturity
- desire to protect the patient’s developing psyche or desire to reduce medical risk
What outcome on sedation does the patient’s willingness to drink the medication and the effectiveness of sedation?
Likelihood of successful sedation appt
What success rate was seen in the triple combination of midazolam, hydroxyzine and oral morphine on sedation appts according to the study?
80% success rate with the triple combination use.
For what medical history is it contraindicated to administer opioids (meperidine, morphine) for OCS?
history of asthma, wheezing
If occurs during sedation, treat with albuterol
The use of hydroxyzine can help prevent the histamine release caused by Opioids
What age and weight should you reconsider OCS?
Under 15kg and age 3 or under
Ideal tidal volume?
6-8ml/kg
average 500ml
An SpO2 of 95% indicates a partial pressure PaO2 of what?
80mmHg PaO2
A SpO2 of 90% indicates partial arterial pressure ( PaO2) of what?
60mmHg
How to calculate sedation drugs when no preweight is known
use 50th percentile range for pt age and sex
Should you use a consistent dose of sedative drugs for all patients?
No, dosage should be individually dose
Also based on temperament, age, weight, and amount of dentistry needed to be complete.
What affect do benzodiazepines have on on local anesthetic toxicity effects?
They reduce the clinical signs of LA toxicity making it more difficult to diagnosis
What age group are at the greatest risk for adverse events during sedation appointments?
Age 3 and younger
Prilocaine MRD
6mg/kg
Max dose 400mg
Role of red blood cells
1) transport oxygen
2) transport carbon dioxide
3) buffer for acid/base system
Normal oxidized state of RBD porphyrin rings
2+ ferrous state
has 4 porphyrin rings
What happens to RBC in methemoglobin state?
It is oxidized further to ferric state (3+).
Higher affinity for already bound oxygen but doesn’t bind additional oxygen.
Doesn’t release oxygen to tissues or transport carbon dioxide to lungs.
Normal levels of methemoglobin in blood?
0-2%
Signs of methemoglobin
cyanosis, chocolate brown blood,
Mental status change- headache, dizziness, syncope, confusion
Tachycardia, tachypnea, acidosis,
Local anesthetic that has shown to cause methemoglobinemia
Benzocaine and prilocaine
Factors that increase chance of methemoglobin?
Female gender
young age
higher concentration of prilocaine
higher dose
Should prilocaine be used with caution when a patient is receiving other oxidizing agents?
Yes,
General anesthesia, oxygen
care must be taken in patients with hemoglobinopathies
When was peak methemoglobin development for prilocaine and lidocaine
Both peak at 60 minutes after administration.
Can occur at home!!!
