Acknowledgment
The authors would like to acknowledge and thank Dr. Eric C. McCarty and Dr. Gregory A. Mencio for their contributions to the previous version of this chapter.
Introduction
The goal of anesthesia in the management of fractures in children is to provide analgesia and relieve anxiety so that successful closed treatment of the skeletal injury is facilitated. Optimal pain management in the emergency department or other ambulatory setting is delivered by the combined efforts of the orthopaedic surgeon and anesthesiologist or emergency medicine specialist. Numerous techniques are available to control pain associated with fractures in children, including blocks (i.e., local, regional, and intravenous [IV]), sedation (i.e., moderate or deep), and general anesthesia. Important factors in choosing a particular technique include safety, efficacy, and ease of administration. Additional considerations include patient and parent acceptance and cost.
Local and regional techniques such as hematoma, brachial plexus, and IV regional blocks are particularly effective for upper extremity fractures. Sedation with inhalational agents such as nitrous oxide, parenteral narcotic and benzodiazepine combinations, ketamine, and propofol are not region-specific and are suitable for patients over a wide range of ages. With all of these techniques, protocol-based monitoring and adherence to hospital sedation safety guidelines are essential.
Fractures in children are common. The majority (approximately 65%) involves the upper extremity. Most are closed and best treated by closed reduction. Time, logistics, and cost favor treatment in the emergency department or other ambulatory setting, as opposed to the operating room, when possible. In a study of axillary block anesthesia for the treatment of pediatric forearm fractures in the emergency department, Cramer and colleagues estimated a cost reduction of almost 70% compared with similar treatment in the operating room.
Performance of satisfactory closed treatment of displaced musculoskeletal injuries in an ambulatory setting requires effective and safe levels of sedation and analgesia so that pain is minimized and the apprehensions of the child are allayed. A variety of anesthetic techniques are available to the orthopaedic surgeon faced with the challenge of treating a child with a closed fracture. The purpose of this chapter is to describe current methods of sedation and analgesia for fracture management in children.
Principles of Pain Management in Children
Children with fractures typically have significant pain and apprehension. Psychologically, their perceptions of the emergency department and the impending treatment of their injury often exacerbate their level of discomfort and anxiety. Children with painful injuries about to undergo an additionally painful procedure are entitled to adequate analgesia and sedation. Despite the rationale of this concept, the problem of undertreatment of pain in children in the emergency department has been documented and is still an all-too-common occurrence. ∗
∗
Ignorance of the problem of pain in children, lack of familiarity with the methods of anesthesia and sedation for children, and apprehension of complications such as respiratory depression and hypotension are reasons for the often inadequate management of pain in the pediatric population. ††
In recognition of the increase in the number of minor procedures performed on children in a variety of ambulatory settings, the American Academy of Pediatrics (AAP) and the American Society of Anesthesiologists (ASA) have both developed goals for sedation and analgesia in children. Their purpose is to ensure the child’s safety and welfare while minimizing the physical discomfort and negative psychological repercussions frequently associated with treatment of painful injuries, as well as returning the child to a state in which safe discharge is possible. From a practical perspective, the method of analgesia–sedation must also allow for the satisfactory treatment of the primary problem. Thus efficacy, safety, ease of administration, patient–parent acceptance, and cost are all-important factors to be considered in selecting a technique.
From an orthopaedic perspective, the ultimate goal of anesthesia for the child with a closed fracture requiring manipulation is to facilitate the satisfactory reduction of the injury and obviate the need for a trip to the operating room. The ideal method should efficaciously and safely eliminate pain, promote patient compliance, and produce amnesia of the procedure. It should be easy to administer, predictable in its action, and reliable for a wide range of ages. It should have a rapid onset and short duration of action, result in little or no complications or side effects, and be reversible. Finally, it should be relatively inexpensive to administer and completely satisfactory to the child and his or her parents. ∗
∗
Anesthetic Techniques
A variety of techniques short of general anesthesia have been used to achieve analgesia and sedation in children with closed fractures requiring treatment in the ambulatory setting. The techniques can be grouped into two broad categories: blocks (i.e., local, regional, and IV) and moderate (formerly referred to as conscious ) or deep sedation (i.e., anxiolytics, narcotic analgesics, or dissociative agents alone or in combination). Each technique incorporates various aspects of the “ideal” method described earlier. It is incumbent on the orthopaedic surgeon treating children’s fractures to be aware of the various techniques and the potential benefits, side effects, and complications of each to be able to make an educated decision about which to use in a particular situation.
Techniques to be Avoided
Vocal, or “O.K,” anesthesia is a technique that provides only the verbal assurance to the child that the manipulation of the fracture will be briefly painful. The concept that children are somehow more resilient to pain has been disproved as knowledge of the developmental and psychological makeup of children and their perception of pain has become better understood. The notion that it is acceptable for children to endure pain during the performance of therapeutic or diagnostic procedures has become dated with the evolution of techniques in pediatric pain management. Given the availability of many safe and effective options for pain management during the reduction of children’s fractures, the technique of “verbal reassurance” should be avoided if possible.
Chloral hydrate and the so-called lytic cocktail, a combination of meperidine (Demerol), promethazine (Phenergan), and chlorpromazine (Thorazine) (DPT), two techniques of sedation used frequently in the past, have fallen out of favor. Chloral hydrate was introduced in 1832 and was used commonly for children undergoing painless diagnostic procedures. Although it has been demonstrated to be effective for the sedation of young children (younger than 6 years) undergoing therapeutic procedures, it has several disadvantages for the management of fractures in children. The onset of sedation is slow (40 to 60 minutes), and recovery can be prolonged, taking up to several hours with residual effects lasting as long as 24 hours. Moreover, chloral hydrate has no analgesic properties, and children can become disinhibited and agitated in response to painful stimuli. For these reasons, chloral hydrate is not a preferred technique for sedation in the management of fractures in children. ∗
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The lytic cocktail (DPT) has been the second most commonly used method of sedation for children undergoing painless diagnostic tests and the one most widely used in children undergoing therapeutic procedures for the last 30 years. DPT is typically administered in a single intramuscular (IM) injection and provides sedation with some analgesia.
Despite widespread usage, the drugs in the lytic cocktail have many undesirable characteristics. The combination is poorly titrated and has a delayed onset of action (20 to 30 minutes). The duration of sedation can last 20 hours, but the duration of analgesia is only 1 to 3 hours. The mixture does not have any anxiolytic or amnestic properties. Recently, it was demonstrated that the DPT cocktail is a largely empiric mixture of three drugs, not based on sound pharmacologic data, with a relatively frequent occurrence of therapeutic failure (29%) and a relatively high rate (approximately 4%) of serious adverse effects such as seizures, respiratory depression, and death. For these reasons the use of DPT is discouraged by both the U.S. Agency for Health Care Policy and Research and the AAP.
Local and Regional Anesthesia
Local anesthetics work by blocking the conduction of nerve impulses. At the cellular level, they depress sodium ion flux across the nerve cell membrane and, in this way, inhibit the initiation and propagation of action potentials. After injection, local anesthetics diffuse toward their intended site of action and also toward nearby vasculature, where uptake is determined by the number of capillaries, the local blood flow, and the affinity of the drug for the tissues. Elimination occurs after vascular uptake by metabolism in the plasma or liver. Vasoconstrictors such as epinephrine are mixed with local anesthetics to decrease the vascular uptake and prolong the anesthetic effect.
Local anesthetics are classified chemically as either amines or esters ( Table 19-1 ). After absorption in the blood, esters are broken down by plasma cholinesterase, but amides are bound by plasma proteins and are then metabolized in the liver. Local adverse effects include erythema, swelling, and, rarely, ischemia when injected into tissues supplied by terminal arteries. Adverse systemic effects are caused by high blood levels of local anesthetics and include tinnitus, drowsiness, visual disturbances, muscle twitching, seizures, respiratory depression, and cardiac arrest. Bupivacaine is a long-acting amide that is particularly dangerous because it binds with high affinity to myocardial contractile proteins and can cause cardiac arrest. Ropivacaine, which is closely related to bupivacaine structurally, is a newer long-acting amide that, at clinically relevant doses, provides a greater sensorimotor differential block, has an increased cardiovascular safety profile, and a shorter elimination half-life with lower potential for accumulation than bupivacaine. The lower systemic toxicity and cardiotoxicity is desirable when the potential exists for high plasma concentrations of local anesthetics, such as in peripheral nerve blocks or after inadvertent intravascular injections.
| GENERIC NAME | BRAND NAME | ONSET | DURATION | MAXIMUM DOSE |
|---|---|---|---|---|
| Amines | ||||
| Lidocaine | Xylocaine | Fast | 1.0–2.0 hr | 5 mg/kg, 7 mg/kg (epinephrine) |
| Mepivacaine | Carbocaine | Fast (infiltration) | 1.5–3.0 hr | 5 mg/kg |
| Ropivacaine | Naropin | Slow (block) Fast (infiltration) | 2.0–8.0 hr | 3 mg/kg |
| Bupivacaine | Marcaine | Slow | 4.0–12.0 hr | 3 mg/kg |
| Esters | ||||
| Chloroprocaine | Nesacaine | Fast | 30–60 min | 15 mg/kg |
| Procaine | Novocain | Slow (block) Fast (infiltration) | 30–60 min | 7 mg/kg |
| Tetracaine | Pontocaine | Slow (topical) | 30–60 min | 2 mg/kg |
A number of local and regional techniques, including hematoma, IV regional, and regional nerve blocks, have been reported to be variably effective in providing anesthesia for fracture treatment in children. These methods require the surgeon to be familiar with regional anatomy, have working knowledge of the pharmocokinetics and dosing of local anesthetic drugs, and be proficient in the techniques of administering them. Compared with the performance of these techniques in adults, the performance of these techniques in children is often technically easier because anatomic landmarks are more readily identifiable. Physiologically, the relatively smaller calibers of the peripheral nerves in children are more susceptible to the pharmacologic actions of anesthetic agents.
Hematoma Block
The hematoma block has been a popular method of anesthesia for the reduction of fractures, particularly in the distal radius but also about the ankle. In this technique, a local anesthetic agent is injected directly into the hematoma surrounding the fracture. The anesthetic inhibits the generation and conduction of painful impulses primarily in small nonmyelinated nerve fibers in the periosteum and local tissues. This block is quick and relatively simple to administer. The skin is prepared with a bactericidal agent and draped at the site of infiltration. The fracture hematoma is aspirated with a 20- or 22-gauge needle and then injected with plain lidocaine. The typical dose of lidocaine is 3 to 5 mg/kg, which should be concentrated so as to limit the total amount of fluid injected to less than 10 mL; limiting the fluid will avoid elevating soft tissue compartment pressures and minimize the risk of creating a compartment syndrome or other neurovascular problem. Although direct injection of the hematoma theoretically converts a closed fracture into an open one, no infections have been reported with this technique.
Although children as young as 2 years have been included in reports of this method, studies of hematoma block anesthesia administered exclusively to a pediatric population have not been done. In three separate studies authored by Dinley and Michelinakis, Case, and Johnson and Noffsinger with a combined total of 491 adult and pediatric patients, hematoma block was shown to be effective for the reduction of a variety of fractures of the distal upper extremity in patients of all ages. Despite the generally favorable experience with hematoma block anesthesia, other methods of regional anesthesia have been shown to be more effective for the management of upper extremity fractures. A study by Abbaszadegan and Johnson found that analgesia during fracture reduction was superior with IV regional (Bier block) anesthesia compared with hematoma block and that fracture alignment after reduction was also better. The authors concluded that the more favorable outcomes achieved with the Bier block were related to better analgesia and muscle relaxation.
Intravenous Regional Anesthesia
IV regional anesthesia was originally described in 1908 by August Bier who used IV cocaine to obtain analgesia. Subsequently, a number of studies have described the effective use of this technique of anesthesia for the treatment of upper extremity fractures in children in an ambulatory setting. ∗
∗
The block has also been described for use in lower extremity fractures but is less common.
The technique for administering the Bier block in the upper extremity involves placement of a deflated pneumatic cuff above the elbow of the injured extremity. Holmes introduced the concept of two cuffs in an effort to minimize tourniquet discomfort with prolonged inflation, but the practice has not proven to be necessary for the limited amount of time it takes for fracture reduction in a child. The tourniquet should be secured with tape to prevent Velcro failure. IV access is established in a vein on the dorsum of the hand of the injured extremity with a 22- or 23-gauge butterfly needle. The arm is exsanguinated by elevating it for 1 to 2 minutes. Although exsanguination with a circumferential elastic bandage is described classically, this method can be more painful and difficult to perform in an injured extremity and is no more efficacious than the gravity method. The blood pressure cuff is then rapidly inflated to either 100 mm Hg above systolic blood pressure or between 200 and 250 mm Hg. ∗
∗
The arm is lowered after cuff inflation. Lidocaine is administered, the IV catheter is removed, and reduction of the fracture is performed. In the traditional technique, the lidocaine dose is 3 to 5 mg/kg and in the “minidose” technique, the dose is 1 to 1.5 mg/kg.The tourniquet is kept inflated until the fracture is immobilized and radiographs are obtained, in case repeated manipulation is necessary. In any event, the tourniquet should remain inflated for at least 20 minutes so that the lidocaine can diffuse and become adequately fixed to the tissues, thus minimizing the risk of systemic toxicity. The blood pressure cuff may be deflated in either a single stage or graduated fashion, although single-stage release has proven to be clinically safe and easier technically.
During the entire procedure, basic monitoring is required, and cardiac monitoring is suggested in case toxic effects occur. Routine IV access in the noninjured extremity may be beneficial but is not required. Patients should be observed for at least 30 minutes after cuff deflation for any adverse systemic reactions. Motor and sensory function typically returns during this period, allowing assessment of neurovascular status of the injured extremity before discharge.
The literature within the past decade certainly speaks to the effectiveness of the traditional Bier block, using a lidocaine dose of 3 to 5 mg/kg, in managing forearm fractures in children. Four large series with a total of 895 patients undergoing this technique demonstrated satisfactory anesthesia and successful fracture reduction in more than 90% of cases ( Table 19-2 ). The most common adverse effect of the procedure in these studies was tourniquet pain in about 6% of patients. One patient experienced transient dizziness and circumoral paresthesia. One patient developed persistent myoclonic twitching after tourniquet deflation and was admitted for observation.
| AUTHOR | LIDOCAINE DOSE | GOOD/EXCELLENT ANESTHESIA | SUCCESSFUL FRACTURE REDUCTION (%) | ADVERSE EFFECTS |
|---|---|---|---|---|
| Turner et al (1986) | 0.5%, 3 mg/kg | 177/205 (72%) | 98 | Tourniquet pain (12), dizziness (1), circumoral paresthesias (1) |
| Olney et al (1988) | 0.5%, 3 mg/kg | 361/401 (90%) | 98 | Myoclonus (1) |
| Barnes et al (1991) | 0.5%, 3–5 mg/kg | 100/100 (100%) | 100 | None |
| Colizza & Said (1993) | 0.5%, 3 mg/kg | 139/139 (100%) | 96 | Tourniquet pain (10) |
∗ Traditional technique uses 3 to 5 mg/kg of 0.5% lidocaine.
Despite the efficacy and relatively low number of complications with the “traditional” Bier block (lidocaine, 3 to 5 mg/kg), concerns and anecdotal reports of systemic lidocaine toxicity (i.e., seizures, hypotension, tachycardia, and arrhythmias) have prompted development of a minidose (lidocaine, 1 to 1.5 mg/kg) technique of IV regional anesthesia. Reports by Farrell and colleagues and Bolte and associates using a lidocaine dose of 1.5 mg/kg and by Juliano and colleagues using a dose of 1.0 mg/kg in a total of 218 patients have shown the minidose Bier block to be effective in achieving adequate anesthesia in 94% of children studied ( Table 19-3 ).
| AUTHOR | LIDOCAINE DOSE | GOOD/EXCELLENT ANESTHESIA | SUCCESSFUL FRACTURE REDUCTION | ADVERSE EFFECTS |
|---|---|---|---|---|
| Farell et al (1985) | 0.5%, 1.5 mg/kg | 29/29 (100%) | 100% | None |
| Juliano et al (1992) | 0.125%, 1.0 mg/kg | 43/44 (98%) | 100% | Tourniquet pain (1) |
| Bolte et al (1994) | 0.5%, 1.5 mg/kg | 61/66 (92%) | 100% | Tourniquet pain (2), local reaction (3) |
The primary site of action of the IV regional block is thought to be the small peripheral nerve branches. At this anatomic level, blockade is better achieved with a larger volume of anesthetic that can be distributed more completely to the peripheral nerve receptors. It appears to be the quantity (i.e., volume) and not the dose of anesthetic that predicates success of the block. For any given dose of lidocaine, diluting the concentration permits the administration of a larger volume of fluid ( Table 19-4 ). This mechanism explains the success of the minidose technique. In the series by Juliano and colleagues, forearm fracture reduction was pain-free in 43 of 44 patients (98%) after IV regional block achieved with a very dilute lidocaine solution (0.125%) and a relatively small total dose (1 mg/kg).
| Lidocaine dose (mg/mL) = lidocaine concentration (mg%) × 10 |
| Examples: 1.0% lidocaine = 10 mg/mL 0.125% lidocaine = 1.25 mg/mL |
| Calculations of infusion volumes for a 20-kg child with traditional∗ and minidose technique∗∗ |
| Dose (mg/kg) × Body weight (kg) ÷ lidocaine concentration (mg/mL) = IV infusion volume (mL) |
| 3 mg/kg∗ × 20 kg ÷ 5 mg/mL (0.5% lidocaine) = 12 mL of 0.5% lidocaine |
| 1 mg/kg∗∗ × 20 kg ÷ 1.25 mg/mL (0.125% lidocaine) = 16 mL of 0.125% lidocaine |
| Decreasing the concentration of lidocaine with the minidose technique permits the infusion of a large volume (mL) of anesthetic with lower risk of systemic toxicity because the total amount (mg) of lidocaine is much lower than with the traditional technique. |
IV regional anesthesia, with the use of either the traditional or minidose technique, has several advantages. The technique is fairly easy to administer. The onset of action of the block is relatively fast (<10 minutes) but also of relatively short duration, which allows for assessment of neurovascular function in the extremity after fracture reduction and immobilization. An empty stomach is not required. Tourniquet discomfort is the most common adverse side effect. Inadvertent cuff deflation with loss of analgesia or systemic toxicity is a potentially significant problem. Compartment syndrome has also been reported. Technically, placing the tourniquet and obtaining IV access in the injured extremity can be a challenge in the uncooperative child, and application of the splint or cast can be cumbersome with the tourniquet in place.
Axillary Block
The brachial plexus supplies all of the motor function to the upper extremity and sensation to the lower two thirds of the limb. It is formed from the fifth through eighth cervical and first thoracic nerve roots with occasional contributions from the fourth cervical and second thoracic nerves. A continuous fascial sheath that extends from the cervical transverse processes to the axilla encases it. Regional blockade of the brachial plexus within this sheath may be performed at the interscalene, supraclavicular, infraclavicular, or axillary level ( Fig. 19-1 ).
Axillary block provides excellent anesthesia for the forearm and hand. Initial use of the technique is attributed to Halsted and Hall, who first used axillary block for outpatient procedures in 1884. The technique has since proven to be a safe and reliable method of anesthesia for a variety of outpatient surgical procedures in the upper extremity in both adults and children. It is an excellent choice of anesthesia for treatment of fractures below the elbow because it provides muscle relaxation in addition to analgesia. Cramer and colleagues reported on the successful use of axillary anesthesia by orthopaedic surgeons in the emergency department for the reduction of forearm fractures in children. In this study, effective anesthesia was achieved in 105 of 111 children (95%) with no complications.
One administers axillary block anesthesia by placing the child in a supine position with the injured arm abducted and externally rotated 90°. IV access is usually established in the uninjured extremity. Mild sedation may be helpful before the procedure. The axilla is prepared with a bactericidal solution and draped with sterile towels. The block is performed with the use of a 1.0% lidocaine solution at a dose of 5 mg/kg. As with the Bier block, a larger volume of local anesthetic is preferable and can be achieved by use of a more dilute concentration of drug. The target for delivery of the anesthetic agent is the axillary sheath, which contains the axillary artery and vein surrounded by the radial nerve (behind), median nerve (above), and ulnar nerve (below). The musculocutaneous nerve courses outside this sheath through the coracobrachialis muscle and, for this reason, may escape blockade, which explains the unreliability of this technique for anesthesia above the elbow.
Several techniques have been described, including blind injection into the neurovascular sheath, patient-reported paresthesias, use of a nerve stimulator, and transarterial puncture, that ensure accurate delivery of the anesthetic into the axillary sheath. Elicitation of paresthesias provides reliable evidence of position within the neurovascular sheath but may be uncomfortable and requires a conscious and cooperative patient. For these reasons, it cannot be used in most children. The use of a nerve stimulator and insulated needle to elicit a motor response is another effective method for determination of accurate location within the sheath. However, this technique requires special equipment (nerve stimulator and insulated needles), which may not be readily available in an ambulatory setting; threshold stimulation of the nerves may also be distressful to the conscious patient.
The transarterial method is the most popular technique of axillary block and, as described in the study by Cramer and colleagues, has been shown to be an effective way to administer this block in children ( Fig. 19-2 ). With this method, the axillary artery is palpated, and a 23-gauge butterfly needle, connected via extension tubing to a syringe containing lidocaine, is inserted perpendicular to the artery. The needle is advanced while being continuously aspirated until a flash of arterial blood is seen and is then advanced through the artery. Approximately two thirds of the lidocaine is injected into the sheath deep to the artery; a check should be performed by aspiration after every 5 mL so that extravascular positioning is ensured. The needle is withdrawn to the superficial side of the artery, and the remaining lidocaine is injected. Pressure is held over the puncture site for 5 minutes, and fracture manipulation can usually begin shortly thereafter.
