Sedation and Analgesia

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Chapter 72 Sedation and Analgesia

Richard J. Scarfone, MD, FAAP

1 Why is the term conscious sedation considered obsolete?

In the past, conscious sedation has been defined as a medically controlled state of depressed consciousness in which:

image Protective reflexes are maintained

image The airway remains patent

image The patient responds purposefully to physical or verbal stimuli

This term is now considered obsolete and has been replaced with the phrase moderate sedation and analgesia. For most clinical indications, emergency department (ED) physicians are attempting to achieve a deeper level of altered consciousness for their patients, referred to as deep sedation and analgesia. This state is characterized by:

image Partial or complete loss of protective reflexes

image An inability to independently maintain a patent airway

image No purposeful response to stimulation

American Society of Anesthesiologists: Continuum of depth of sedation: Definition of general anesthesia and levels of sedation/analgesia: www.asahq.org/publicationsAndServices/standards/20.pdf

EMSC Grant Panel on Pharmacologic Agents Used in Pediatric Sedation and Analgesia in the Emergency Department: Clinical policy: Evidence-based approach to pharmacologic agents used in pediatric sedation and analgesia in the emergency department. Ann Emerg Med 44:342–377, 2004.

2 What are some reasons for the mismanagement of pain in children?

image Lack of available data in children. The Food and Drug Administration studies and approves medications for use in adults. Physicians must extrapolate this information for pediatric patients. Until the past decade, few clinical trials assessed the safety and efficacy of sedatives or analgesics in children.

image Fear of addiction from opioids. In both adult and pediatric patients, physicians have been overly concerned about inducing addiction with the use of opioid analgesics. In fact, addiction is a rare consequence of the legitimate use of opioids for medical purposes in children.

image Belief that neonates and young children do not experience pain to the same degree as adults because of their immature nervous systems. Any physician who has attempted to intubate the trachea of an awake neonate or to perform a lumbar puncture in a struggling toddler can testify to the contrary. Young children cannot understand the purpose of a painful procedure or comprehend its time-limited nature. Therefore, they are likely to experience a greater degree of pain and anxiety compared to older children or adults and are more likely to benefit from the liberal use of procedural sedation and analgesia (PSA).

Berde CB, Sethna NF: Analgesics for the treatment of pain in children. N Engl J Med 347:1094–1101, 2004.

Lampell MS, Leder MS: Pediatric pain control. Pediatr Emerg Med Rep 4:73–84, 1999.

Zempsky WT, Cravero JP, Committee on Pediatric Emergency Medicine and Section on Anesthesiology and Pain Medicine: Relief of pain and anxiety in pediatric patients in emergency medical systems. Pediatrics 114:1348–1356, 2004.

3 What are tolerance, physical dependence, and addiction?

A child with sickle cell anemia who has been treated at home with acetaminophen and codeine for 2 weeks will probably require higher than usual doses of parenteral narcotics for management of a vaso-occlusive crisis. Such a child may have developed tolerance, diminished effectiveness of the drug with repeated administration. A child with leukemia and bony pain who abruptly discontinues daily oral morphine after 10 days may experience headaches, sweating, tachycardia, and tachypnea. Such a child may have developed physical dependence. In contrast, addiction is a psychological syndrome marked by compulsive drug-seeking behavior and associated with desire for euphoric effects.

4 Describe methods to reduce the pain of administration of local anesthetics

Local anesthetics administered through intact skin or into an open wound can cause considerable pain. Techniques that may be employed to reduce the pain of injection include using a needle of small caliber, buffering the lidocaine with bicarbonate, warming the drug, injecting slowly, and providing counterstimulation to the adjacent skin. Many physicians employ topical formulations, such as lidocaine, epinephrine, and tetracaine, either in a liquid or a gel form. This may be administered, without using a needle, to exposed mucosa. These drugs should not be used in any regions of the body in which epinephrine is contraindicated, such as fingertips or ears.

In addition, liposomal lidocaine (LMX) and a mixture of lidocaine and prilocaine (EMLA) may each be applied to intact skin to reduce the pain of venipuncture. Physicians have also found these topical mixtures to alleviate the pain associated with lumbar punctures incision of abscesses, and insertion of intravenous lines.

Berde CB, Sethna NF: Analgesics for the treatment of pain in children. N Engl J Med 347:1094–1101, 2002.

Eichenfield LF, Funk A, Fallon-Friedlander S, Cunningham BB: A clinical study to evaluate the efficacy of ELA-Max (4% liposomal lidocaine) as compared with eutectic mixture of local anesthetics cream for pain reduction of venipucture in children. Pediatrics 109:1093–1099, 2002.

Scarfone RJ, Jasani M, Gracey EJ: Pain of local anesthetics: Rate of administration and buffering. Ann Emerg Med 36:36–40, 1998.

Zempsky WT, Cravero JP, Committee on Pediatric Emergency Medicine and Section on Anesthesiology and Pain Medicine: Relief of pain and anxiety in pediatric patients in emergency medical systems. Pediatrics 114:1348–1356, 2004.

5 Describe the key elements of the medical history for a child about to receive PSA

Aspects of the history that should be known before drug administration include time since last meal, current medications, allergies, pregnancy status, significant medical history, history of complications with sedation or general anesthesia, and a complete review of systems. If the child was transported from another institution, the clinician must know whether he or she received sedation or analgesia at the referring hospital and, if so, what was given and when. In addition, physicians should ask questions pertinent to the specific medication that one is about to give. For example, active laryngotracheobronchitis should be considered a contraindication to the use of ketamine.

6 Describe the key elements of the physical examination for a child about to receive PSA

Clinicians must monitor the patient’s vital signs (especially blood pressure), cardiac and pulmonary examinations, and mental status. Many agents cause hypotension and should be used cautiously or not at all for children with impending shock. Similarly, agents that may cause hypoventilation and hypoxemia are poor choices for any child with respiratory distress.

7 How much time should elapse between the last oral intake of food or liquid and PSA?

This is perhaps the area of greatest controversy in the administration of PSA to children. These are the published fasting guidelines for elective procedures developed by the American Society of Anesthesiologists (ASA):

Ingested Material Minimum Fasting Period
Clear liquids 2 hr
Breast milk 4 hr
Infant formula, nonhuman milk, light meal 6 hr

8 What are the concerns about fasting guidelines for PSA?

Problems with these guidelines include:

image They are arbitrary: For example, what evidence exists to support a longer fasting time after formula intake compared to breast milk? How does the age of the patient or the volume ingested influence these recommendations? In fact, the ASA states that “the literature does not provide sufficient evidence to test the hypothesis that preprocedural fasting results in a decreased incidence of adverse outcomes.”

image They were written for fasting prior to general anesthesia.

image Physicians working in busy EDs with time and space constraints find these guidelines prohibitively conservative and difficult to adhere to.

image Aspiration following moderate or deep sedation is extremely rare.

Newer evidence suggests that prolonged fasting may not lead to fewer adverse events. In a recent report of over 1000 children receiving PSA, about half were not fasted as per the ASA guidelines. These children did not experience a greater incidence of aspiration or other adverse outcomes compared to the fasted group. A second study of over 2000 children and young adults found no correlation between preprocedural fasting time and adverse outcomes.

A recently published clinical practice advisory recommends weighing several factors when deciding what is the appropriate fasting for elective procedures. These factors include the overall health of the patient, the desired length and depth of sedation and analgesia, and the urgency of the procedure.

Agrawal D, Manzi SF, Gupta R, Krauss B: Preprocedural fasting state and adverse events in children undergoing procedural sedation and analgesia in a pediatric emergency department. Ann Emerg Med 42:636–646, 2003.

American Society of Anesthesiologists: Practice guidelines for sedation and analgesia by non-anesthesiologists. American Society of Anesthesiologists task force on sedation and analgesia by non-anesthesiologists. Anesthesiology 96:1004–1017, 2002.

Green SM.: Fasting is a consideration—not a necessity—for emergency department procedural sedation and analgesia. Ann Emerg Med 42:647–650, 2003.

Green SM, et al. Fasting and emergency department procedural sedation and analgesia: a consensus-based clinical practice advisory. Ann Emerg Med 49:454–461, 2007.

Roback, MG, Bajaj L, Wathen JE, Bothner J: Preprocedural fasting and adverse events in procedural sedation and analgesia in a pediatric emergency department: Are they related? Ann Emerg Med 44:454–459, 2004.

9 What is the ASA physical status classification?

This is a physical status classification based on the ASA recommendations. This status should be assigned before the initiation of sedation. There are five classes.

image Class I: Normally healthy patient

image Class II: Patient with mild systemic disease (e.g., mild asthma)

image Class III: Patient with severe systemic disease (e.g., poorly controlled diabetes mellitus)

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