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Managing Post-op Pain in Pediatrics
For young patients, the pain is the same, but with more cautions.
Louis Stanfield
Publish Date: October 10, 2007   |  Tags:   Anesthesia

Children may not be able to articulate pain, but they know when they hurt. They don't have to suffer in silence if we do our part to prevent common, avoidable post-op discomforts that can complicate recovery and delay discharge.

First and foremost, it's essential to deliver adequate pain relief to every child. That's an obvious demand, of course, but carrying it out in practice isn't as automatic as it first seems, as pediatric patients are often undertreated. Many healthcare providers are understandably hesitant in prescribing pain drugs to children. They're afraid they'll give them too much. Smaller bodies, they reason, require smaller amounts of medication, so pediatric dosage recommendations are lesser concentrations in comparison to adult doses.

But that's backward from what's needed. On a milligram-per-kilogram basis, children have higher analgesic requirements than adults because they metabolize the drugs faster. The total dose will be small - peds don't have many kilograms - but should be higher per unit of mass. For instance, when dosing morphine, you'd start with one-tenth of a milligram per kilogram for adults, but children might require as much as two-tenths of a milligram per kilogram initially. Consult with your anesthesiologist, a pharmacologist or your pharmacist consultant on a case-by-case basis.

The power of pre-medication
In some respects, pain management begins as soon as a pediatric patient is prepared for surgery. Pre-op sedation can be a controversial topic, but in light of the anxieties that a child undergoing surgery faces, I can think of no reason why a child needs to remember being taken into the OR.

Consider pre-medicating pediatric patients with a sedative to minimize the trauma of separation. Children become calm and their parents can stay with them until induction; or, if you don't let parents remain with them to that point, most children don't seem to mind being separated from their parents and don't remember the separation later. Benzodiazepine or one of its derivatives work well. Sublingual Versed has the advantage of rapid onset as well as not being an injection.

For inhalational anesthesia, I favor sevoflurane for smooth inductions and emergences. It works rapidly, doesn't smell bad and, as opposed to desflurane, sidesteps the potential side effect of bronchial irritation in pediatric patients.

Intraoperative efforts
As with all patients, it's easier to manage pain by preventing it than by attempting to make it go away. If a child is undergoing surgery for the insertion of tympanostomy tubes, for example, the anesthesia is generally inhalational, not intravenous, in order to affect a speedy emergence after a short procedure. After the surgery, you can tame the discomfort of ruptured eardrums with acetaminophen, which is rarely a bad idea, but doesn't work particularly quickly. Pre-medicating while the patient is still anesthetized can stop post-op pain before it starts. A similar situation exists in the case of tonsillectomies or other surgeries using IV anesthesia, since morphine can take 20 minutes to take effect when administered by way of the patient's IV.

Regional anesthesia is a wonderful adjunct to other pain relief methods because you can employ a longer-lasting anesthetic. A local anesthetic block administered after induction but before incision can help to minimize site pain, reduce the amount of anesthesia needed and as a result speed recovery time. Your anesthesia providers will of course need to have extensive experience with the smaller pediatric anatomy to supply the correct volume and concentration of the dose, and providers who are reluctant to sedate children may be reluctant to use blocks, but I've found caudal epidural injections extremely effective. I've even performed an arm block on a 3-year-old.

7 Takeaway Points

  • Children feel pain in the same way that adults do.
  • Pediatric patients are often undertreated for pain.
  • Pre-medicate pediatric patients with an appropriate sedative to minimize the trauma of separation.
  • Parents have to be involved in the pain management process as advocates for their children.
  • On a milligram per kilogram basis, children have higher analgesic requirements than adults do.
  • In PACU, a larger, one-time dose may be a more effective option to control pain than a series of small doses.
  • Understand that PONV is a multifactorial condition with at least six discrete causes, no two of which answer to the same treatment.

PACU portions
If those methods of pre-emptive medication mean patients wake up free of pain and post-op discomfort, great. If not - if airway maintenance has left them with a sore throat, if they've got headaches or muscle or surgical site pain - you'll want to clear that up as soon as possible.

There is a tendency to think that the proper remedy would be administering a series of small doses to get the pain under control, but individual titrations of pain relief medications aren't terribly useful unless they're fast-acting. Little doses take more time and more attention and provide less overall effect. A larger, one-time dose may be a more effective option. The potential for overdose is a common fear, but if your anesthesia provider has a full understanding of what the dose requirements are for a child, it's difficult for them to make that mistake.

A non-narcotic analgesic such as acetaminophen is a long-lasting option for post-op pain, but as we said, it isn't fast-acting. Coupled with the fast-acting but short-lasting narcotic analgesic fentanyl, administered intranasally, the slower acetaminophen (or even morphine) can see the patient through to discharge. You can also use NSAIDs such as ketorolac for post-op pain, but they don't have acetaminophen's advantage of being able to be deployed before or during surgery due to concerns that they cause bleeding.

Communicating the need
The belief that the post-op pain children feel is qualitatively different from that which adults experience is flawed, but most children don't likely understand why they have to feel this pain and what can be done about it. Even some parents aren't well-informed on this issue.

For children, intellectualizing the pain and gritting their teeth to get through it isn't an option. That's why parents have to be involved in the pain management process. They have the right and the obligation to be an advocate and to seek appropriate medication for their children. Pre-op education for pediatric patients and their parents should explain what their options are. This seems elementary enough, but I still meet patients' parents who believe that "if the doctor wanted you to have more pain meds, he would give them to you." So I make sure to explain, to the children as well as the parents, "I'm going to give you pain medications before you wake up so you won't be uncomfortable. If you are uncomfortable, tell me, and I'll give you more medicine. I have lots of it." That usually elicits a grin, and is remembered.

Make sure, too, that you have an adequate number of nurses staffing your PACU to respond to patient and parent concerns. Nurses can't be overextended trying to handle multiple pediatric patients in recovery: Too much can go wrong too fast. PACU nurses appreciate receiving a child who's comfortable and preparing for the eventuality when one isn't.

The problem of PONV
If you intend to manage post-op discomfort among children, you're going to have to reckon with post-operative nausea and vomiting, a multifactorial condition with at least six discrete causes, no two of which answer to the same treatment, so a multi-modal approach is most effective.

Pain can cause PONV, so administer pre-emptive pain medication if possible. So can narcotics, so avoiding opioids may prove useful. Keep in mind that IV propofol has anti-emetic properties.

Some causes of PONV are the inescapable by-products of surgical procedures and not amenable to treatment with drugs or other methods. After a tonsillectomy, for instance, a trickle of blood in the throat may be swallowed, and the chemical irritation of blood in the stomach almost always causes nausea. Likewise, running the bowel during abdominal surgery is a mechanical cause of PONV.

Other causes are neurological. As you'll recall, the body's autonomic nervous system is divided into sympathetic and parasympathetic components. While pain relief drugs can suppress the sympathetic system, the parasympathetic system is the one implicated in vomiting and nausea responses, and the relative predominance of the parasympathetic tone in this situation can cause considerable post-op discomfort. Ondansetron (Zofran) is one option for suppressing this sort of response, as is glycopyrrolate (Robinul) in small doses.

Be sensitive to the fact that, by the time our patients emerge from surgery, we've kept them from eating and drinking for quite some time. If they're not properly hydrated during surgery, the fluids needed to sustain patients' metabolisms come out of their blood, possibly leading to hypovolemia. So be sure that they're delivered IV fluids before, during and perhaps even after surgery, as afterwards an IV of Lactated Ringer's solution or other fluid can hydrate without requiring oral intake. Also, try not to keep pediatric patients on NPO restrictions for overly long times. If they're undergoing surgery first thing in the morning, they should be off solid foods by midnight, but kids can take clear liquids up to four hours before surgery and infants up to two hours before.

Some patients just suffer from anxieties that lead to PONV. During the pre-op evaluation, they'll tell you, "I always vomit" or "I have a history of vomiting," and it's amazing what a mindset can do. You can't do anything about expectations except attempt to reassure them that you're making an effort to prevent such a result. I tell my patients, "We have several different anti-emetic methods that we'll be trying, and we'll do everything possible to decrease the likelihood that you'll vomit or feel nauseated, but of course there's no guarantee."

Philosophy of pain relief
In any analysis of pediatric procedures, it's clear that for the best results you need to manage post-op pain effectively. When I was trained in anesthesia some 30 years ago, the conventional wisdom was that children didn't feel pain in the same way that adults did. During the time that this idea held currency, it was abundantly clear to anyone who accidentally poked a child with a safety pin while changing a diaper that even infants could respond to stressful and uncomfortable stimuli.