Alteration by burn injury of the pharmacokinetics and pharmacodynamics of cimetidine in children

Propofol clearance and volume of distribution are increased in patients with major burns

Propofol pharmacokinetics were examined in 17 adults with major burns during the hyperdynamic convalescent phase. Eighteen nonburned surgical patients served as controls. After a 2-mg/kg intravenous dose of propofol, blood samples were collected at multiple time points. Noncompartmental methods were used to calculate the pharmacokinetic parameters. The following indices were higher in burns than controls: propofol clearance (64+/-17 vs 29+/-4 mL/kg/min, P<.001) and volume of distribution (8+/-3 vs 4+/-1 L/kg, P<.001). The area under the curve was smaller in burns (556+/-152 vs 1193+/-183 microg/mL h, P<.001). The higher clearance of propofol in burned patients may imply that these patients require higher doses or infusion rates of propofol to attain a target plasma concentration or pharmacodynamic effect.

Burn injury pain: the continuing challenge

The development of more effective methods of relieving pain associated with burn injury is a major unmet medical need. Not only is acute burn injury pain a source of immense suffering, but it has been linked to debilitating chronic pain and stress-related disorders. Although pain management guidelines and protocols have been developed and implemented, unrelieved moderate-to-severe pain continues to be reported after burn injury. One reason for this is that the intensity of pain associated with wound care and rehabilitation therapy, the major source of severe pain in this patient population, varies widely over the 3 phases of burn recovery, making it difficult to estimate analgesic requirements. The effects of opioids, the most commonly administered analgesics for burn injury procedural pain, are difficult to gauge over the course of burn recovery because the need for an opioid may change rapidly, resulting in the overmedication or undermedication of burn-injured patients. Understanding the mechanisms that contribute to the intensity and variability of burn injury pain over time is crucial to its proper management. We provide an overview of the types of pain associated with a burn injury, describe how these different types of pain interfere with the phases of burn recovery, and summarize pharmacologic pain management strategies across the continuum of burn care. We conclude with a discussion and suggestions for improvement. Rational management, based on the underlying mechanisms that contribute to the intensity and variability of burn injury pain, is in its infancy. The paucity of information highlights the need for research that explores and advances the identification of mechanisms of acute and chronic burn injury pain.

PERSPECTIVE

Researchers continue to report that burn pain is undertreated. This review examines burn injury pain management across the phases of burn recovery, emphasizing 3 types of pain that require separate assessment and management. It provides insights and suggestions for future research directions to address this significant clinical problem.

Upper gastrointestinal tract bleeding in critically ill pediatric patients

Similar to adults, children under physiologic stress can develop an imbalance in defensive (mucosal layer, motility) and aggressive (gastric acid, bile salts, enzymes) factors responsible for maintaining a healthy gastrointestinal tract. Hypoxia in the gastrointestinal tract likely disrupts the defensive factors, thereby permitting damage by aggressive factors to upper gastrointestinal epithelium that may progress to stress ulceration and acute upper gastrointestinal tract bleeding (UGIB). The basic pathophysiology may be similar in children and adults; however, differences in the time to developing ulceration, ulcer location, and number of ulcers have been reported. Functional development of the gastrointestinal tract is influenced by disease, gestational and postnatal age, and exposure to and type of enteral feedings, thereby confounding the development and prophylaxis of UGIB in neonates and infants. In addition, pharmacotherapy decisions are often complicated by drug administration issues and adverse effects.