Pain management:  Analgesia

Version 1.0 (7/1/2002 - 8/2/2005)

Nociception is intact at a very early gestational age, and appropriate pain management is an important part of neonatal intensive care. Analgesia has unequivocally been shown to improve post-surgical outcomes in neonates; and potential benefits for long-term neurodevelopmental maturation, although still under investigation, are quite plausible.
The pain control interventions provided depend upon the degree of pain and discomfort perceived by the patient. Although this can be challenging to determine in the neonatal population, NPASS, bedside nursing assessments, and common sense guide the provision of neonatal analgesia.

Non-pharmacologic interventions alone can be used to manage mild discomfort or distress in neonatal patients (NPASS scores ≤ 3.) Comfort measures include “nesting,” and swaddling. Term babies may respond to music, rocking, human speech, stroking, or pacifier use. Preterm babies < 30 weeks gestation may react negatively to increased stimulation; nesting and decreasing extraneous stimuli often benefit these patients more.
Patients experiencing mild or moderate pain (NPASS score 4-5) may also respond to non-pharmacologic measures. However, these patients may need pharmacologic assistance as well (Tylenol) depending on the etiology of the pain.

Local and/or systemic analgesia should be provided during invasive intensive care procedures. If an adult would experience pain and want pain medication for a procedure, assume the neonate would, too.
For fairly minor procedures, 24% sucrose in very small doses orally has been found to provide significant analgesia. 24% sucrose can be used to alleviate the pain associated with: heel-lancing, an iv start, a venous or arterial blood draw, an IM injection, suprapubic tap, and dressing changes or extensive tape removal. Suctioning, urinary catheterization, and ophthalmologic exams are also unpleasant. 24% sucrose administration should be treated as a pharmacologic intervention and recorded on the nursing flow sheet.
For more major procedures as lumbar puncture, the combination of 24% sucrose and a bolus dose of iv fentanyl provides adequate pain control. Bolus doses of iv fentanyl are typically provided with PICC line placement.
For surgical procedures, such as chest tube placement, local anesthesia as well as systemic analgesia should be provided, if possible. Xylocaine and lidocaine are both acceptable local anesthetics available in the NICU.
Local anesthesia in the form of a dorsal penile nerve block or subcutaneous ring block should ALWAYS be provided when performing a circumcision.
Tylenol should be provided to babies receiving multiple IM immunizations.

Dosages for Tylenol in neonates are as follows:

Tylenol PO:

Loading dose: 20mg/kg Once

<32 weeks gestational age: 15 mg/kg PO Q 8hrs

≥ 32 weeks gestational age: 15 mg/kg PO Q 6hrs

Tylenol PR:

Loading dose: 30 mg/kg Once

< 32 weeks GA: 20 mg/kg PR Q 12 hrs

≥ 32 weeks GA: 20 mg/kg PR Q 8hrs

Term: 20 mg/kg PR Q 6hrs

Premature infants < 32 weeks PCA and infants with hepatic dysfunction should have Tylenol dosed no more frequently than q8 hours.


For significant, post-operative pain (NPASS score 6-10), narcotics are the most effective and frequently used systemic analgesic. Vanderbilt’s neonatal opiate of choice is fentanyl, given its rapid action and decreased incidence of hemodynamic instability.  See POP Plan


Bolus doses of fentanyl

0.5 – 1 mcg/kg for the micropremie, and
1 - 2 mcg/kg for the term infant are effective for intermittent pain and for systemic analgesia during brief invasive procedures. For post-operative pain, a continuous infusion of fentanyl (0.5 – 2 mcg/kg/h) may be needed for adequate pain relief. The dosage must be titrated to the patient’s response. For rapid effect, boluses should be ordered when initiating an infusion or when increasing the infusion rate of a fentanyl drip.
An adverse effect peculiar to fentanyl is the phenomenon of chest wall rigidity upon rapid administration. This can cause potentially severe respiratory compromise; therefore, fentanyl should always be given very slowly iv, over 3-5 minutes. Fentanyl also causes rapid tachyphylaxis, and babies on prolonged infusions (over several days) will require escalating doses to achieve adequate effect.
 

For term infants and older infants without hemodynamic compromise, morphine, with its longer half-life can be substituted for fentanyl when tachyphylaxis to fentanyl leads to rapidly escalating doses with barely adequate analgesia. To convert to a morphine infusion, multiply the fentanyl dose in mcg/kg/h by 10 and administer morphine at that dose in mcg/kg/h. (For example: a baby receiving a fentanyl drip at 2 mcg/kg/h would need a morphine drip of 20 mcg/kg/h = 0.02 mg/kg/h.) After initiating morphine, you may increase the infusion rate 50 – 100% if the patient doesn’t show evidence of relief.

     Complications of all opiate analgesics include:

  • Respiratory depression – non-intubated patients receiving opiates should have Narcan readily available in the event of apnea
  • Hypotension (more likely with morphine, or when fentanyl is combined with sedatives such as Versed)
  • GI dysfunction/Ileus
  • Urinary retention-patients on high dose opiates may need an indwelling bladder catheter
  • Narcotic dependence


     Weaning from narcotics

Infants will show evidence of tolerance to narcotics after 24- 72 hours. Infants who have been on narcotics 5- 10 days or more may have symptoms of narcotic withdrawal if opiate administration is discontinued suddenly. The risk of narcotic withdrawal increases with the duration and dosage of the narcotic infusion. Symptoms of iatrogenic narcotic withdrawal can be quantitated using the Neonatal Withdrawal Scoring Sheet.
In an attempt to avoid symptoms of withdrawal, opiates should be weaned slowly.

Duration of infusion

< 3 days

3-7 days

> 7 days

 Recommended weaning rate

stop or reduce by 50% and stop within 24 hours

 reduce by 25-50% of maintenance dose per day

 reduce by 10% every 6-12 hours as tolerated


Even using this guideline, some infants will show signs of narcotic withdrawal. These infants, and infants who have received prolonged, high dose infusions, may require a methadone taper to diminish their symptomatology.

 

Tylenol as adjunctive therapy to opiates
Although acetaminophen alone has only mild analgesic properties, research has shown that appropriate Tylenol administration can significantly benefit post-operative patients. Tylenol administered routinely (NOT prn) is able to decrease the need for narcotics as much as 40%.
As most post-operative neonatal patients have had GI surgery and are NPO, routine Tylenol must be administered per rectum. This is an acceptable route of delivery in all surgical patients EXCEPT those who have undergone anoplasty for imperforate anus.


Sedatives
Sedatives and anxiolytics may also be given to neonates who require intensive care and are agitated by their abnormal environment, particularly if their agitation compromises their health. However, remember that sedatives do not provide analgesia, and one should first ensure that agitation does not arise from pain. Be aware that the use of sedatives may mask the behavioral expression of pain.
The most commonly used sedative in the NICU is midazolam (Versed.)
The dosage of Versed is 0.05 – 0.1 mg/kg/dose.
If sedatives are used in conjunction with narcotics, dosages of both drugs may need to be reduced to avoid hypotension.

References:
Anand, KJS and the International Evidence-Based Group for Neonatal Pain. Consensus Statement for the Prevention and Management of Pain in the Newborn. Archives of Pediatric and Adolescent Medicine 2001;155:173-180.

Anand, et al. “Systemic analgesic therapy.” In Pain in Neonates: 2nd Revised and Enlarged Edition. Eds.Anand KJS, Stevens BJ, McGrath PJ. Elsevier Science, 2000; p 180.

Yaster M, Krane EJ, Kaplan RF, et al. Pediatric Pain Management and Sedation Handbook. 1997. Mosby, St. Louis. p. 49

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