CHAPTER 5 TEACHING POINTS: MEDICATIONS AND PAIN MANAGEMENT

EXERCISE 5.1

Purpose: To review management of side effects and complications from medications used to control pain and anxiety. How would you manage the following case scenarios of patients undergoing uterine aspiration?

1. A patient states that last year they had an allergic reaction to the local anesthetic that the dentist used.
   • It is important to distinguish between allergic reaction, side effect, and toxicity.
   • There are two classes of anesthetics, esters (e.g. lidocaine) and amides (e.g. chloroprocaine). Allergy to one class does not infer an allergy to the other.
   • Allergic reactions to -caines are extremely rare, and mostly occur from the preservative or epinephrine. Allergic reactions include itching, hives, bronchospasm, and progression to anaphylaxis.
   • If the reaction appears to have been a true allergy, the safest alternative may be to avoid local anesthetic. If the type of anesthetic is known, the alternative class can be used. Or if unknown, may use saline (plain or bacteriostatic), which is less effective than lidocaine (Chanrachakul 2001).

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2. A patient chooses to have IV sedation for pain management. You administer midazolam 1 mg and fentanyl 100 mcg. As you dilate the cervix, the patient falls asleep and is not arousable to repeated stimulation. The oxygen saturation falls from 99% to 88%.

Both medications cause sedation and respiratory depression. Individuals react differently due to interaction with other agents (e.g. alcohol) or genetic differences in metabolism.

Prevention can be aided by using a stepwise approach to pain management.

• • Smaller doses for low weight patients.
  • Serial doses until adequate pain control is achieved.
  • Reversal using antagonists, in a stepwise and titrated fashion.

• • Hypoxic patients who have received both an opioid and a benzodiazepine should generally receive naloxone before flumazenil. Naloxone reverses both opioid sedation and respiratory depression. Flumazenil has not been shown to reliably reverse respiratory depression, and also carries seizure risk if the patient has benzodiazepine tolerance or a seizure disorder.
  • Monitoring is recommended for two hours after use of reversal agents, because the sedative may last longer than the antagonist (ASA 2002).

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3. A patient who is 5 weeks by LMP has a history of alcohol and heroin use, and states that they last used heroin yesterday. The patient requests IV sedation. Venous access is limited, but you are able to insert an IV and administer midazolam 1 mg and fentanyl 100 mcg. You insert the speculum, and the patient pulls away stating “I can feel everything.”
   1. How would you treat this pain?
      • Patients with regular opioid use have likely developed tolerance and often require higher doses of opioid medication to achieve pain control. A reasonable starting place for someone with significant tolerance would be to double the starting dose of fentanyl.
      • Rapid reversal of opiates or benzodiazepines in patients who chronically use these medications can also provoke withdrawal or seizures respectively.
      • Remember to utilize non-opioid forms of pain control and anxiolysis (as with all patients). Consider topical lidocaine (e.g. 4% lidocaine gel or cream in the lower ⅓ of the vagina for improved pain control with speculum placement.
   2. How would this change if the patient were on buprenorphine (Suboxone)?
      • Be aware that individuals on MAT or on chronic opioid pain medications often have higher tolerance of opioids.
      • Additionally, buprenorphine has a high affinity for the mu opioid receptor, thus higher doses of a similarly high affinity opioid (fentanyl or hydromorphone) are needed to overcome this effect.
      • Those who are prescribed MAT or chronic opioids should continue taking their medications as prescribed. MAT does not contribute to analgesia.
      • If possible, communicate with their prescriber to plan for the procedure and follow-up or provide a note for the patient regarding medications used.
      • Increase opioid dose as needed, guided by monitoring, reported pain, alertness, and vital signs.
      • Encourage the patient to have close follow-up with their prescribing physician.
   3. How would this change if the patient disclosed using heroin today?
      • Substance use (when chronic) on the day of the procedure should not impact decision making around pain management other than awareness of possible drug interactions.
      • Ability to complete a consent form is based on standard protocols for consent. Most individuals with active substance use are able to consent to a procedure regardless of prior use that day. Someone with withdrawal may in fact be less capable of providing consent depending on their symptoms.
      • Increase opioid dose as needed, guided by monitoring, reported pain, alertness and vital signs.

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4. Consider the consent process for each of the following people. What factors contribute to informed consent? What questions would you ask/what information would help you to make a decision in each case?

• • Consider the following key elements of medical decision making capacity:
    • Patients are able to demonstrate an understanding of the benefits and risks of a procedure/treatment as well as alternative options.
    • Patients are able to demonstrate an appreciation of those benefits and risks.
    • The patient shows reasoning in making a decision.
    • The patient can clearly communicate their choice.
      • a. An 18 year old patient at 5 weeks GA who appears nervous. When you enter the room you can smell marijuana.
        • Substance use including marijuana in most cases does not interfere with informed consent.
        • Techniques for evaluating if patients are able to consent include asking orientation questions and having patients repeat information back after reviewing it together.
        • If a patient is drowsy or not able to answer orienting questions, consider allowing the patient to rest awhile and then reevaluate for consent.

        b. A 35 year old patient at 12 weeks GA is on methadone for opioid use disorder. They have been on the same dose for 8 years, and last took their medication this morning.

        • Substance use disorder history, and use of MAT medications does not alter the informed consent process.
        • Using methadone on procedure day is recommended and in fact a state of withdrawal can more greatly interfere with informed consent.

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EXERCISE 5.2

Purpose: To become familiar with other medications used with uterine aspiration.

Please answer the following questions.

1. In which of the following situations is administration of Rh-D immunoglobulin (RhoGam) suggested in a patient over 12-weeks gestation?
   1. Patient has positive anti-D antibody titre.
      • The patient may already be sensitized (in which case RhoGam will not help).
      • Or the patient recently received RhoGam and still has those anti-D antibodies in their blood (t ½ is 24 days).
      • In either case, don’t give RhoGam unless there is a new indication and 3 weeks have elapsed since the last dose.
   2. Rh-negative patient received RhoGam 4 weeks ago during evaluation for threatened abortion.
      • RhoGam may be present for up to 9-12 weeks after full-dose administration (Bichler 2003), but the manufacturer advises that it be given if three or more weeks have elapsed since the initial injection in term pregnancies.
      • Until further data delineates therapeutic levels after mini-dose RhoGam, re-dosing after 3 elapsed weeks may be prudent.
   3. Rh-negative patient is 4 days post-abortion and did not receive RhoGam at the uterine aspiration visit.
      • RhoGam should ideally be administered within 72 hours.
      • Beyond 72 hours, some recommend anti-D still be given as soon as possible, for up to 28 days (Fung Kee Fung 2003).
      • For medication abortion, RhoGam is ideally given at the time of mifepristone, but many give it up to 72 hours afterwards.

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2. While completing an early uterine aspiration procedure using local cervical anesthesia and ibuprofen only, the patient complains of nausea and “feeling faint”. The patient is pale and sweating. The blood pressure is 90/50 with a pulse of 48.
   1. What is the differential diagnosis?
      • This appears to be a classic vasovagal reaction, with low pulse, hypotension, and sweating. Vasovagal reflex is caused by stimulation of the parasympathetic nervous system, and occurs often with cervical dilation, fear and other emotions. A patient who is overheated, dehydrated, hypoglycemic, or over-medicated may also be predisposed to syncope.
      • Differential Diagnosis: Vasovagal, hemorrhage, low blood sugar, or an inadvertent intravascular –caine injection.

      Vasovagal Reflex	Hemorrhage	Low Blood Sugar	Intravascular -caine
      Slow pulse (< 50) Low BP Pallor Cool clammy skin +/- N/V +/- Abdominal Cramps	Rapid Pulse Late low BP Pallor, Cool clammy skin +/- N/V +/- Uterine cramps	Normal / late rapid Late low BP Pallor, Cool clammy skin +/- N/V +/- Abdominal Cramps	Slow pulse (<50) Tinnitus Perioral tingling Metallic taste Irregular pulse
      Rare: Syncope, Seizure-like activity	Rare: Syncope	Rare: Syncope, Seizures	Rare: seizure, ventricular arrhythmias, cardiac arrest
      Not orthostatic	Becomes orthostatic	Not orthostatic	Not orthostatic

   2. How might you prevent this reaction?
      • To help prevent vasovagal reactions, emphasize hydration, keeping cool (i.e. be careful about being overheated from walking to the clinic in hot temperatures), and staying calm. Isometric extremity contractions may also help prevent vasovagal (see below).
   3. How would you manage this patient?
      • Vasovagal Management
        • Airway / Positioning: supine or Trendelenburg, head to side if vomiting
        • Cool cloth on head or neck
        • Sniffing ammonia capsule may help
        • Vasovagal reflex may be aborted prior to syncope by isometric contractions of the extremities (gripping the arm, hand, leg and foot muscles) (Cason 2014). These maneuvers activate the skeletal-muscle pump to augment venous return and abort the reflex.
        • Prolonged vasovagal, consider:
          • Atropine
          • IV Fluids, oxygen
          • Evaluation for other potential causes (hemorrhage, etc.)
          • Record events, and transfer as needed.