Methohexital

Hovering somewhere between alertness and deep sedation, your patient relies on you for a smooth return to full consciousness. Here's how to make sure he has a safe, comfortable journey.

IN RECENT YEARS, procedural sedation, previously known as conscious sedation, has moved outside of the controlled operating room (OR) setting into many other clinical areas. Now commonplace for an array of tests and treatments, it provides anxiolysis, amnesia, and analgesia while avoiding a depth of sedation that would require interventions to maintain airway patency. Less stressful for the patient, it can speed recovery times and reduce postoperative risks.

Like any form of sedation, however, procedural sedation has drawbacks and potentially serious risks. Because you're likely to care for patients undergoing procedural sedation, we'll discuss what you need to know to steer them clear of complications.

Depressed level of consciousness

Procedural sedation is a drug-induced, minimally depressed level of consciousness in which the patient can still maintain his airway and respond purposefully to verbal commands, with or without light tactile stimulation. Three organizations-the Joint Commission on Accreditation of Healthcare Organizations, American Association of Nurse Anesthetists, and American Society of Anesthesiologists (ASA)-have established guidelines for administering procedural sedation. (For more on levels of sedation, see How the JCAHO Defines Sedation Levels.)

Physician supervision is always required for procedural sedation, and you must be prepared to rescue patients who slip from procedural sedation into a deeper sedation level. Your facility should have a multidisciplinary protocol for treating sedated patients who lose their protective reflexes.

Because of the risk of airway compromise, facilities require practitioners who administer procedural sedation and deep sedation to be certified in basic life support; some require advanced cardiac life support certification as well. Pediatric practitioners typically must be educated in both basic and pediatric advanced life support.

In general, nurses who administer procedural sedation must have the appropriate institutional credentials and privileges. In addition, states, professional associations hospitals committees and reulatory bodies (such as state boards of nursing) may issue their own definitions and regulations regarding procedural sedation. If you're involved in administering or caring for patients undergoing procedural sedation, make sure you meet legal, professional, and institutional criteria relevant to your practice and be prepared to provide airway management interventions, such as a jaw lift, nasal or oral artificial airway insertion, and bag-valve-mask ventilation.

Many hospitals require health care providers who administer procedural sedation or who monitor patients during the procedure to complete institutionbased education and training in the pharmacology of drugs commonly used in sedation and analgesia, including reversal agents. Health care providers may also need to pass a procedural sedation competency exam. Some facilities require nurses who administer procedural sedation to gain experience in rescue techniques by partnering with an anesthesia care provider in the OR.

Who benefits from procedural sedation?

Indications for procedural sedation range from such procedures as repair of minor lacerations or bone fracture reductions in the emergency department to more extensive planned events, including central line placement, lumbar puncture, vasectomy, breast biopsy, endoscopy, and colonoscopy Some patients, such as children, confused adults, and mentally challenged patients, may benefit from procedural sedation to relieve anxiety associated with noninvasive physical exams and diagnostic testing.

The ASA has developed a simple classification system based on physical status that can help you and the physician you're working with decide if your patient is a candidate for procedural sedation. The ASA specifies these six physical status classes:

* P1-a normal, healthy patient

* P2-a patient with mild systemic disease that doesn't limit activities, such as controlled hypertension or controlled diabetes without target organ damage

* P3-a patient with severe systemic disease that does limit activities, such as stable angina or diabetes with target organ damage

* P4-a patient with severe systemic disease that's a constant threat to life, such as severe heart failure or end-stage renal disease

* P5-a moribund patient who's not expected to survive without the operation or other intervention

* P6-a patient declared braindead whose organs are being removed for donation.

If the procedure is an emergency, the physical status classification is followed by an E (for example, ASA Class P2E).

If your patient is an ASA Class P3 or higher, consult the anesthesia department. A patient with a complex multisystem problem requires care from someone specially educated and prepared to manage the effects of anesthesia on compromised patients.

Before the procedure

When taking the patient's history, focus on identifying conditions involving major organ systems; previous problems with sedation, analgesia, and regional or general anesthesia; current medications (including herbal preparations and over-the-counter products); allergies; and history of tobacco, alcohol, or drug use or abuse. Also check for a history of snoring or sleep apnea, which puts the patient at higher risk for respiratory complications. (For more on this topic, see "More Than a Snore: Recognizing the Danger of Sleep Apnea" in the August issue of Nursing2002.)

During the preprocedure interview, also ask the patient when he last took anything by mouth. For guidelines on preprocedural fasting, see Hold the Meal Tray.

At minimum, a focused physical exam should include taking vital signs, evaluating the patients airway, and assessing his lungs and heart. Airway evaluation, which is critical, should be performed by someone with expertise in endotracheal intubation if possible. These findings will be particularly important if a deep level of sedation is inadvertently reached and the patient's airway and breathing need support.

Obtain baseline vital signs before giving any sedative. Besides being a reference point for the sedation team, these measurements can affect the patients sedation plan. For instance, a patient previously categorized as an ASA Class P2 may be reclassified as ASA Class P3 if you discover extremely high blood pressure (BP) during your baseline vital sign check and, upon further questioning of the patient, learn that this has been an ongoing, untreated problem. (In this case, the procedure might be postponed until the patients BP is under control, or an anesthesia provider would take over if the procedure was an emergency)

Check that the patient has given informed consent for the procedure and for procedural sedation. Ensure that his intravenous line is patent and that ordered preprocedure medications, such as antibiotics, have been given. Check that the procedure-specific patient preparation was done and review the patients preprocedure test results.

Also make sure all equipment is assembled and working properly You'll need suction catheters and Yankauer-type suction catheters; oral and nasal oxygen delivery equipment, including nasal cannulas, face masks, and a self-inflating bag-valve-mask device; medications (including emergency medications and reversal agents) and the syringes to administer them; monitoring equipment; and emergency resuscitation equipment. Have extra bags of 0.9% sodium chloride solution available.

About the drug regimen

The pharmacology of sedation is complex, and medication choices have increased dramatically. Before selecting a drug regimen, the health care provider establishes the goals for procedural sedation-analgesia, sedation, amnesia, or a combination of these. Because no single drug can meet all the goals, he'll combine sedatives and analgesics to achieve the desired goal.

Besides achieving multiple goals (for example, sedation and analgesia), combining drugs takes advantage of synergistic sedative effects and reduces the total amount of each drug used.

However, synergism isn't completely predictable and can raise the risk of ventilatory depression, hypoxemia, and prolonged sedation. At the end of the procedure, identifying which drug is responsible for residual sedation may be impossible. If opioids or benzodiazepines are used for procedural sedation, antagonists such as naloxone (an opioid antagonist) and flumazenil (a benzodiazepine antagonist) should be readily available.

Ideally, the procedural sedation regimen has these qualities: rapid onset, short duration, rapid recovery, minimal adverse effects, rapid metabolism to inactive metabolites to prevent a cumulative effect, and residual amnesia. Learn about the drugs approved for use in your institution, including their onset of action and duration of effect. (For more details, see The Lowdown on Common Procedural Sedation Medications and Reversal Agents.)

In some facilities, drugs traditionally used to induce deep sedation and general anesthesia, such as propofol, ketamine, and methohexital, are used for procedural sedation. If that's the case in your facility, keep in mind that they carry a much higher risk of producing deep sedation or general anesthesia. The ASA practice guidelines state that health care providers administering these drugs must be prepared to rescue patients from any level of sedation, including general anesthesia. Facility policies and your state board of nursing regulations may prohibit nurses from administering these drugs outside very specific practice settings, if at all. Protect your patient and yourself by knowing and following your institutions and your state's guidelines.

How deep is enough?

Sedation is a continuum, and a drug regimen's effects depend on the patients condition and physical characteristics such as body mass index. An initial dose of midazolam or fentanyl may minimally sedate one patient but totally obtund another. So titrate drugs slowly to determine the appropriate dosage for each patient and procedure.

Never give a second dose of medication-even a small dose-until you assess the first dose's effect on the patient. What appears to be a weight-appropriate dose of an opioid could cause unconsciousness and respiratory arrest in certain patients. Also be aware that opioid-tolerant patients may need much higher doses of opioids or an alternative sedative medication for adequate effect. Consult with the physician when you encounter these patients during your preprocedure assessment.

Monitoring during the procedure

Monitoring requirements for a patient undergoing procedural sedation closely parallel the requirements for monitoring a patient receiving general anesthesia. Continuously assess oxygen saturation with pulse oximetry (Spot), cardiac rate and rhythm, and ventilation (auscultate breath sounds and observe chest movement). Monitor the patients vital signs and level of consciousness regularly (usually every 5 minutes).

The person performing the procedure shouldn't be responsible for delivering medication or monitoring the level of sedation, and the person who administers and monitors procedural sedation should have no other significant responsibilities.

Monitoring patient response to verbal commands should be routine, except in patients who can't respond meaningfully (for example, young children, mentally impaired patients, or uncooperative patients). During procedures in which verbal responses aren't possible, such as endoscopic retrograde cholangiopancreatography, agree on nonverbal communication signals before initiating sedation. For example, teach the patient to signal his status or level of comfort by giving a thumbs-up or thumbsdown sign or squeezing your hand. Children or confused adults who can't understand or follow directions usually receive general anesthesia instead.

Document the patients sedation level using one of several standardized scales, such as the Ramsay scale, the observer's assessment of alertness and sedation, the digit symbol substitution test, or a visual analog scale. Although most are easy to use, keep in mind that they may not detect subtle changes in sedation level.

Capnography: A sigh of relief

Some institutions have implemented bispectral index (BIS) monitoring and capnography in procedural sedation areas to enhance patient safety. The BIS monitor, introduced into the OR in the late 1990s, uses electrodes attached to the patients head to monitor cerebral electrical activity and provide a number that correlates to sedation depth.

Capnography monitors exhaled carbon dioxide (ETCO2) and creates a waveform that may let you identify ventilatory function problems 2 to 4 minutes before the pulse oximeter registers a drop in oxygen saturation. Newer capnography monitors with nasal-cannula-like sampling lines are making this technology easier to use, allowing simultaneous ETCO^sub 2^ monitoring and oxygen administration.

After the procedure

The patient should recover in an appropriately staffed area equipped to monitor his condition. He shouldn't be discharged from this area if he's nauseated, vomiting, or dizzy or if he has excessive bleeding or drainage. Use a guideline such as the modified Aldrete scoring system to compare the patients postprocedure level of consciousness with his preprocedural baseline. (See Using the Modified Aldrete System to Assess Recovery.)

If you note a significant variance in the patients status from baseline or a slower-than-expected recovery, he may need longer recovery time in a monitored room, admission for an inpatient overnight stay, or, in the unusual event of a life-threatening complication, admission to an intensive care unit.

Safe and sound

More and more nurses are learning how to administer procedural sedation. By knowing the laws and regulations, the drugs involved, and the latest technologies for monitoring your patient, you can minimize or avoid complications of procedural sedation and help your patient to a smooth recovery.

SELECTED REFERENCES

American Association of Nurse Anesthetists: Considerations for Policy Guidelines for Registered Nurses Engaged in the Administration of Conscious Sedation. Park Ridge, Ill., American Association of Nurse Anesthetists, June 1996, http//www.aana.com/practice/conscious.asp.

American Society of Anesthesiologists: "Practice Guidelines for Sedation and Analgesia by Non-Anesthesiologists: A Report by the American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-- Anesthesiologists," Anesthesiology. 84(2):459-471, February 1996.

Eichhorn, J.: "Protecting the Patient during Procedural Sedation: Meeting the Standard with Capnography," Anesthesiology News. June 2001.

Joint Commission on Accreditation of Healthcare Organizations: "Standards and Intents for Sedation and Anesthesia Care," in Revisions to Anesthesia Care Standards, Comprehensive Accreditation Manual for Hospitals. Oakbrook Terrace, Ill., Joint Commission on Accreditation of Healthcare Organizations, 2001.

Messinger, J., et at: "Getting Conscious Sedation Right," American Journal of Nursing. 99(12):44-49, December 1999.

Nursing2003 Drug Handbook, 23rd edition. Springhouse, Pa., Springhouse Corp., 2003.

BY JOHN M. O'DONNELL, RN, CRNA, MSN

KRISTA BRAGG, RN, CRNA, MSN

SANDRA SELL, RN, CRNA, MSN

John M. O'Donnell is director and instructor of the nurse-anesthesia program at the University of Pittsburgh (Pa.) School of Nursing. Krista Bragg is a staff nurse-- anesthetist at Children's Hospital of Pittsburgh. Sandra Sell is an instructor in the nurse-anesthesia program at the University of Pittsburgh School of Nursing.

Copyright Springhouse Corporation Apr 2003
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