September 11, 2008
Conscious (or moderate) sedation has become an increasingly important subject in recent years. We have seen a vast increase in the number of procedures moving from traditional OR settings to ambulatory surgery centers and office-based practices over the last decade. As this trend continues, physicians and staff who have not administered sedation previously are looking to become informed on safe and efficient use of sedation in their patients.
Based on a review of state guidelines from several states we have prepared the following:
Every patient needs a free flowing intravenous line and supplemental oxygen administered via nasal cannula or face mask.
A health care provider other than the person performing the procedure should monitor the patient at all times. This is non-negotiable. That person should record in the medical record at minimum every five (5) minutes:
Level of consciousness (0 = unconscious, 1 = sedate but responsive, 2 = alert)
Peripheral oxygenation via pulse oximeter and respiratory rate
Heart rate, Heart rhythm, Blood Pressure
Pain score (0= none, 1= tolerable, 2= not tolerated)
This level of monitoring meets JCAHO guidelines. The provider monitoring the patient should be aware of known allergies, medical history, NPO status, and whether the patient may be difficult to intubate. Large men with bull necks and small mouths can be very difficult to ventilate and intubate. Such a person, or those with morbid obesity or other significant airway issues should be evaluated by an anesthesia provider.
Important history includes personal or family history of malignant hyperthermia, cardiac arrest, congestive heart failure, recent MI, stroke or TIA, heart rhythm disturbance, smoking, diabetes, COPD, or recent change in respiratory status. Is there recent onset of URTI or flu? A listing of current medications is important. It is recommended that patients be NPO for eight (8) hours before drug administration.
There should be suction capability and resuscitation equipment immediately available. Do not start until it is available.
All providers should have ACLS certification.
For almost all patients, a combination of two drugs, midazolam (Versed: 1 mg/cc) and fentanyl (Sublimaze: 50 ug/cc) can accomplish the goal of safely getting the patient through the procedure. Patients should be tolerating the procedure, and responsive to a command to open their eyes at all times. This state is called conscious sedation. The risk of administering any intravenous sedative or narcotic drug is loss of consciousness, inability to maintain the
airway or apnea, desaturation and hypoxemia which if unrecognized and treated can proceed all the way to cardiac arrest. It can happen.
Midazolam treats anxiety. It has a specific anxiolytic action. The onset is 60-90 seconds. The duration of action for small doses is 10-15 minutes. Dose range for relatively healthy people is 1-5 mg total over 60 minutes. It is important to wait the 90 seconds to see what the effect of the first dose is before giving a second dose. Additional effects of midazolam are antegrade amnesia, and sedation. By itself, it rarely results in apnea when given in doses of 0.5 to 1 mg at a time. If the patient becomes disoriented- stop. Wait 15 minutes before resuming. Consider trying again later with an anesthesia provider.
Fentanyl treats pain. Onset of action is 90-120 seconds. Duration is also 10-1 minutes. Initial dose is 25-50 ug. Again it is important to wait to evaluate the effect of the first dose before administering a second dose. Dose range is 50-150 ug over 60 minutes. Effects of fentanyl are analgesia and respiratory depression. There may be a sedative effect, but there is rarely loss of consciousness. The patient may experience pruritus.
Each of these drugs by themselves are fairly predictable. However in combination, especially when administered simultaneously, there may be unpredictable loss of consciousness and or apnea. So do not administer both drugs simultaneously. Wait between doses. Patience is good.
For a non-invasive procedure give a milligram of midazolam after monitoring is established, and before positioning the patient. For relatively healthy and robust patients a second milligram can be given safely.
If the patient still seems to be especially anxious, continue with midazolam. Wait between doses. Look for spontaneous eye closure, but with retained responsiveness to verbal commands. The simple phrase “Open your eyes” said gently should be able to establish responsiveness. Avoid the question “Are you OK?” It requires the patient to make an abstract evaluation of the situation. They think you are in charge. Ask what they sense or feel, and whether it is painful, tolerable or any other specific question. Warn them before inserting the examining finger or beginning the procedure. They probably won’t remember anything, but they are supposed to be conscious and should be able to cooperate.
If the patient obviously experiences pain, then add fentanyl. Once you start using the fentanyl do not give any more midalozam unless you can really justify it to yourself. Start with half a cc (25 ug). Wait. Resume the procedure. If not tolerated repeat the dose. Wait. If you need more than 100-150 ug of fentanyl reexamine the situation. Fentanyl as the sole drug works nicely in patients who have previous experience with medical procedures, or otherwise seem to have good coping mechanisms. The dose range can be 150-300 ug over 60 minutes in divided doses. In the event the patient’s respiratory rate slow to 6 breaths per minute, they may still be able to maintain adequate oxygenation. Occasionally you may have to encourage them to breathe. At these doses apnea unresponsive to stimulation is unusual unless there has been prior administration of midazolam. Meperidine (Demerol) in doses of 25-50 mg to a maximum of 200 mg is another good agent used by itself. It increases recovery time.
Another technique involves the use of a constant infusion of propofol. Propofol is a very short acting anesthetic which has been used frequently for GI procedures. Repeated use of this drug has the potential to render the patient unconscious, and thus it has been employed primarily by specilized anesthesia providers. Emergency Department physicians and gastroenterologists with appropriate training have successfully administered propofol for procedures in those arenas. It is used as a constant infusion to avoid fluctuating levels of sedation and responsiveness associated with intermittent bolus administration. Usually a base pre-medication with 1-2 mg of midazolam given IV over 5 minutes is followed by 2-3 ccs of propofol as an IV bolus followed by an infusion of 25-75 ug/kg/min. This regimen rarely results in apnea, but upper airway obstruction is a real possibility if the patient becomes deeply sedated. A jaw thrust usually suffices to relieve the obstruction. Supplemental oxygen administration is obviously crucial, as is constant awareness of the status of the patient.
Regardless of the pharmaceutical regimen, if the patient loses consciousness, but continues to ventilate and maintain oxygenation, then nothing needs to be done other than continued evaluation. Avoid further drug administration. If heavy snoring or desaturation occurs, then a simple jaw thrust is usually adequate. Unresponsiveness with cessation of spontaneous ventilation should be treated with mask ventilation. Hopefully intubation will never be required, but the capacity to do so should always be available. This is why all providers should have ACLS Certification.
You can get a feel for how the patient will respond to the drugs by carefully watching the response to the first dose. Patients taking narcotics or benzodiazepines chronically may require doubling of the corresponding doses. The art of it all involves balancing the dose to the level of stimulation associated with the procedure, with a common sense evaluation of how the patient is responding to the situation. Remember that if higher doses have been necessary to get the patient through the procedure, he may become unconscious or apneic once the stimulation ceases.
It may take 20-50 patients to gain some confidence with the regimen.
Patients should not drive themselves home. If nausea occurs it can be treated with Zofran, 4 mg, though it usually resolves spontaneously within 2-3 hours.
For additional information or comments, call Conscious Sedation Consulting 888-581-4448
or visit us online at
John Hexem MD, PhD
Randy Pigg BSN
Our consulting firm and Web-site make every effort to provide accurate and up-to-date information, which is in accord with accepted standards and guidelines. Under no circumstances should any advice or information we may provide be considered the practice of medicine in Missouri or any other State. Diagnosis and treatment recommendations can only be made by a licensed independent practitioner in accordance with any laws or regulations in the state or states in which they may practice. The Partners of Conscious Sedation Consulting make no warranties that any information contained on their web site or which they may offer is totally free from error. This is the case especially because clinical standards are constantly changing through research and regulation. Conscious Sedation Consulting therefore disclaims all liability for direct or consequential damages resulting from the use of material presented on the web-site, in seminars or presentations, or in written or spoken responses to questions or requests. The proper dose for any medication cannot be predicted in advance. For sedative drugs, it is influenced by 1) the type, location, and duration of the procedure being performed in which sedation is being administered. 2) the age, sex, and family history of the person receiving the drug, 3) the acute or chronic administration of any other pharmaceuticals, herbal medicines, other treatment modalities, or other substances such as tobacco, alcohol, narcotics, and any and all other legal and illicit drugs 4) any concomitant medical, or psychological diseases for which the person may or may not be receiving treatment 5) the physiological state of the person including temperature, oxygenation, and function of all organ systems, and 6) the particular circumstances of any clinical or treatment situation. The administration of sedative medications is an art as in any form of healing art.