Managing Opioid-Induced Respiratory Depression

Chris Pasero, MS, RN-BC

Disclosures

November 07, 2012

Strategy Considerations

Reconsider Opioid-Only Treatment for Postoperative Pain

This patient scenario describes an event that occurs every day in hospitals nationwide. Patients undergo surgery and receive large doses of opioids for unrelieved postoperative pain and experience life-threatening opioid-induced respiratory depression. The Joint Commission revealed that on the basis of their 2004-2011 database of reported opioid-related sentinel events, 47% were the result of wrong dose, 29% from improper monitoring, and 11% due to other factors, such as excessive dosing, medication interactions, and adverse effects[3] The Joint Commission underscores the need for hospital staff to be vigilant in safe opioid prescribing and administration, as well as careful monitoring of the effects of opioids.

For many years, opioids were the only analgesic in postoperative pain treatment plans. Although opioids are considered first-line for moderate-to-severe postoperative pain, opioid-only treatment plans should raise a red flag in the mind of every member of the healthcare team.[1] The reliance on a single drug (eg, the opioid) to do all the work of relieving moderate-to-severe pain almost always results in the need for high doses, followed by a high incidence of adverse effects. In the case of opioids, the most feared adverse effect is respiratory depression.

Implement Multimodal Pain Treatment Plans

One way to reduce the risk for life-threatening opioid-induced respiratory depression is to routinely implement multimodal analgesia treatment plans.[1] Multimodal analgesia combines 2 or more analgesics with different underlying mechanisms of action to produce better pain relief at lower doses than would be possible with a single analgesic.[4] The underlying rationale for this approach is that lower doses result in fewer or less severe adverse effects.[1,4,5,6]

Unless contraindicated, acetaminophen and an NSAID should serve as the foundation of the pain treatment plan for every patient who undergoes surgery. Whenever possible, these should be initiated preoperatively, or at the latest, on admission to the PACU and continued throughout the postoperative course.[1,7,8]Local anesthetic approaches, such as continuous peripheral nerve blocks, should be considered whenever indicated by the type of surgical procedure.[9] The healthcare team may be surprised to find that many patients experience adequate pain relief with no opioid or a minimal amount of opioid postoperatively with these approaches.[1,7,8,9] Patients who have more severe pain and would benefit from ongoing opioid analgesia are likely to require much lower doses than they would without a nonopioid foundation.

By virtue of their assessment skills and 24-hour presence, nurses are their patients' primary pain managers.[10] They must be on the alert when opioid-only pain treatment plans are prescribed, and instead aggressively advocate for multimodal approaches. Early intervention is essential, which reinforces the important role that nurses play in the preoperative setting to ensure that a multimodal approach is initiated before surgery whenever possible.

Use Recommended Opioid Dosing Guidelines

Hydromorphone is more potent than morphine. This means that a single dose of 1.5 mg of IV hydromorphone produces approximately the same pain relief (equianalgesia) as 10 mg of IV morphine.[1,6] These equianalgesic doses are considered appropriate over a 4-hour period; guidelines recommend a starting IV hydromorphone dose of 0.4 mg-0.5 mg in an opioid-naive adult.[1,6] An order for 2 mg of IV hydromorphone every 2 hours is excessive for an opioid-naive patient and should be questioned. If given, the patient's sedation level and respiratory status must be monitored very closely.

Assess Sedation and Respiratory Status

Sedation precedes opioid-induced respiratory depression, and its systematic assessment is considered a critical nursing responsibility that can prevent this life-threatening opioid adverse effect.[1,11] Nursing assessment of opioid-induced sedation is convenient and inexpensive and takes minimal time to perform. A simple, easy-to-understand scale designed to assess for unwanted advancing sedation (as opposed to a scale for purposeful, goal-directed sedation) is recommended to ensure clear communication between members of the healthcare team and to evaluate trends in the patient's level of sedation.[1,3,11]

The sedation scale used most often during opioid administration for pain management is the Pasero Opioid-induced Sedation Scale (POSS)[1] (Table 2).Two studies have established the validity and reliability (0.903[12] and 0.909[13] by the Cronbach alpha) of the POSS for this purpose. A unique feature of the POSS is that it links interventions to each level of sedation in the scale. For example, the opioid dose should be reduced in patients who are so sedated that they fall asleep mid-sentence.

Table 2. Pasero Opioid-induced Sedation Scale (POSS), With Interventionsa

S = Sleep, easy to arouse
Acceptable; no action necessary; may increase opioid dose if needed
1 = Awake and alert
Acceptable; no action necessary; may increase opioid dose if needed
2 = Slightly drowsy, easily aroused
Acceptable; no action necessary; may increase opioid dose if needed
3 = Frequently drowsy, arousable, drifts off to sleep during conversation
Unacceptable; monitor respiratory status and sedation level closely until sedation level is stable at less than 3 and respiratory status is satisfactory; decrease opioid dose 25% to 50%b or notify primaryc or anesthesia provider for orders; consider administering a nonsedating, opioid-sparing nonopioid, such as acetaminophen or an NSAID, if not contraindicated; ask the patient to take deep breaths every 15-30 minutes.
4 = Somnolent, minimal or no response to verbal and physical stimulation
Unacceptable; stop opioid; consider administering naloxone,e; stay with patient, stimulate, and support respiration as indicated by patient status; call rapid response team (Code Blue) if indicated; notify primary>c or anesthesia provider; monitor respiratory status and sedation level closely until sedation level is stable at less than 3 and respiratory status is satisfactory.

NSAID = nonsteroidal anti-inflammatory drug
aAppropriate action is given in italics at each level of sedation.
bOpioid analgesic orders or a hospital protocol should include the expectation that a nurse will decrease the opioid dose if a patient is excessively sedated.
cFor example, the physician, nurse practitioner, advanced practice nurse, or physician assistant responsible for the pain management prescription.
dFor adults experiencing respiratory depression, mix 0.4 mg of naloxone and 10 mL of normal saline in syringe and administer this dilute solution very slowly (0.5 mL over 2 minutes) while observing the patient's response (titrate to effect). If sedation and respiratory depression occur during administration of transdermal fentanyl, remove the patch; if naloxone is necessary, treatment will be needed for a prolonged period, and the typical approach involves a naloxone infusion (see text). Patient must be monitored closely for at least 24 hours after discontinuation of the transdermal fentanyl.
eHospital protocols should include the expectation that a nurse will administer naloxone to any patient suspected of having life-threatening opioid-induced sedation and respiratory depression.
From Pasero C, McCaffery M, eds. Pain Assessment and Pharmacologic Management. St. Louis: Mosby Elsevier; 2011:510 © 1994, Chris Pasero. Used with permission.

An adequate assessment of respiratory status requires the nursing staff to observe the rise and fall of the patient's chest [14] and includes counting respiratory rate, ensuring adequate depth and regularity of breathing, and listening to the patient breathe.[11] The respiratory assessment should be done before arousing the sleeping patient.

Snoring indicates respiratory obstruction and should be attended to promptly by arousing and repositioning the patient. Even subtle snoring can progress to full obstruction, so it must be addressed.[11] Many times patients or family members report that snoring is "normal" because the patient snores at home. This thinking can lead to fatal consequences. In the home setting, patients are typically awakened by their own snoring and ineffectual respiration; however, in the context of opioid administration and other sedating medications, patients may be too sedated to self-arouse. Under these circumstances, snoring is an ominous sign and requires the nurse to further evaluate the patient to avert disaster.[11]

Consider Mechanical Monitoring

The American Society for Pain Management Nursing recommends that every patient's risk factors be considered when determining the need for mechanical monitoring during opioid administration.[15] High risk factors for opioid-induced respiratory depression that warrant consideration of continuous mechanical monitoring are many, and include preexisting pulmonary or cardiac dysfunction; morbid obesity; obstructive sleep apnea and other sleep-disordered breathing; concomitant administration of sedating medications, and high opioid dose requirements (eg, more than 10 mg IV morphine equivalent in a short period of time, such as while the patient is in the PACU).[1,15]

Although pulse oximetry is the most commonly used mode of mechanical monitoring during opioid administration, it has numerous pitfalls including the fact that it measures oxygenation but does not measure ventilation.[1,14,15] Low oxygen saturation levels as measured by pulse oximetry are considered a late indicator of respiratory depression.[1,15] Another recognized disadvantage of pulse oximetry is that it will yield high oxygen saturation readings in patients who are receiving supplemental oxygen. Dark skin pigmentation and poor perfusion may also affect accuracy.[1,15]

The practice of obtaining periodic "spot-check" pulse oximetry readings is misleading and not recommended because respirations are often adequate while awake but become rapidly insufficient during sleep.[1,3,11,15] The process of applying the pulse oximeter sensor to obtain a periodic reading is likely to stimulate the patient to take a deep breath, which can yield a higher oxygen saturation reading than when the patient has not been stimulated.[11] Such readings can lead to false assumptions and a failure to intervene to prevent an adverse outcome.

Capnography (end-tidal CO2) is considered an accurate tool for measurement of perfusion and ventilation and a sensitive and early predictor of impending respiratory depression.[1,11,15] Research shows that capnography can detect compromised respiratory status before oxygen desaturation or diminished chest excursion is observed.[16] Advances are under way to improve this technology so that it is more practical for routine application in the clinical setting.

The inadequacy of current technology underscores an urgent need for industry to develop monitoring systems that recognize patterns and evaluate trends in respiration. Nevertheless, it is crucial that nurses embrace their role as the patient's best monitor, be aware of risk factors for opioid-induced respiratory depression, and take prompt action when they see early signs of patient deterioration (eg, increasing sedation levels, shallow respirations).

Evaluate Need for Concomitant Administration of Sedating Medications

Many of the medications used to treat the adverse effects of opioids, such antihistamines for itching and some antiemetics for nausea, are sedating, and when combined with opioids can have an additive effect and increase the likelihood of respiratory depression.[2] The coadministration of benzodiazepines significantly diminishes respiratory drive. Careful evaluation of the need for concomitant administration of these drugs is recommended, and if given, careful monitoring of sedation and respiratory status is warranted.[15]

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