Acute changes in oxygen consumption and body temperature after burn injury

Critical Care of the Burn Patient

Care of the critically ill burned patient must integrate a multidisciplinary care team composed of burn care specialists. As resuscitative mortality decreases more patients are surviving to experience multisystem organ failure relating to complications of their injuries. Clinicians must be aware of physiologic changes following burn injury and the implicated impacts on management strategy. Promoting wound closure and rehabilitation should be the backdrop for which management decisions are made.

Multicentre observational study describing the systemic response to small-area burns in children

BACKGROUND AND OBJECTIVES

Burns of less than 10% total body surface area (TBSA) are common injuries in children under five years of age. The inflammatory response to burn injury is well recognised for burns greater than 20% TBSA but has not been described for smaller burns. The aim of this study was to describe the systemic response to burn injury in young children with small-area burns.

METHODS

The Morbidity In Small Thermal Injury in Children study (MISTIC) was a multicentre prospective observational cohort study that recruited 625 patients under five years of age with burns of less than 10% TBSA over eighteen months across three sites in England. Prospectively collected data included physical observations and laboratory blood tests taken in hospital as part of routine care. Additional information was sourced from temperature recordings taken at home following discharge.

RESULTS

Elevated temperatures were observed in children with scald or contact burns between 2-10% TBSA, with a peak on day one after burn followed by a fall over days four to seven after burn. No temperature rise was seen in children with burns of <2% TBSA. Higher temperature readings were associated with larger burn size, age under two years and male sex. Heart rate and C-Reactive Protein levels showed a peak on day three after burn.

CONCLUSIONS

An identifiable systemic inflammatory response to small-area burns in young children is reported. This knowledge can be used to aid in the diagnosis of children with a burn injury who re-present with a pyrexia, and no other symptoms to indicate clinical infection.

The management of small area burns and unexpected illness after burn in children under five years of age - A costing study in the English healthcare setting

The objective of this economic study was to evaluate the resource use and cost associated with the management of small area burns, including the additional costs associated with unexpected illness after burn in children of less than five years of age. This study was conducted as a secondary analysis of a multi-centre prospective observational cohort study investigating the physiological response to burns in children. 452 children were included in the economic analysis (median age=1.60years, 61.3% boys, median total burn surface area [TBSA]=1.00%) with a mean length of stay of 0.69 days. Of these children, 21.5% re-presented to medical care with an unexpected illness within fourteen days of injury. The cost of managing a burn of less than 10% TBSA in a child less than five years of age was £785. The additional cost associated with the management of illness after burn was £1381. A generalised linear regression model was used to determine the association between an unexpected illness after burn, presenting child characteristics and NHS cost. Our findings may be of value to those planning economic evaluations of novel technologies in burn care.

The acute febrile response to burn injury in children may be modified by the type of intravenous fluid used during resuscitation — observations using fresh frozen plasma (FFP) or Hartmann's solution

Fever is a common clinical problem in burned children. The purpose of this study was to compare rectal temperature (T(r)) in two groups of children with burns, > or =10% of the total body surface area (tbsa) who received fresh frozen plasma (FFP) or a crystalloid solution (Hartmann's) for restoration of blood volume. Twelve to 16 h after the burn T(r) reached a peak. The children who had received FFP for restoration of blood volume had significantly higher fever than those children who received crystalloid solutions only.

The effect of hypermetabolism induced by burn trauma on the ethanol-oxidizing capacity of the liver

OBJECTIVE

To study the rate of elimination of ethanol after a major burn trauma.

DESIGN

Prospective, controlled study.

SETTING

National burns unit in a Swedish university hospital.

PATIENTS AND SUBJECTS

Eight consecutive patients suffering from 18%-72% total burned surface area and nine healthy male control subjects.

INTERVENTIONS

The patients received ethanol, 0.35-0.60 g/kg body weight intravenously, during 1 hr. This was repeated daily during the first week postburn. The control subjects received the same amount of ethanol once.

MEASUREMENTS AND MAIN RESULTS

Blood samples were drawn at 20- to 30-min intervals during 5 hrs after the start of the infusion. Serum ethanol was determined by headspace gas chromatography. The rate of elimination of ethanol was calculated from the concentration time profile. In the control subjects, the median elimination rate was 0.074 g/kg/hr (range, 0.059-0.083 g/kg/hr). In the patients, it was already 0.138 g/kg/hr (range, 0.111-0.201 g/kg/hr) on the first day; this increased even further over the following 6 days, reaching 0.183 g/kg/hr (range, 0.150-0.218 g/kg/hr) on the seventh day.

CONCLUSIONS

Ethanol elimination is augmented postburn. A more effective reoxidation of reduced nicotinamide adenine dinucleotide seems the most likely explanation for the increased rate of ethanol elimination in these hypermetabolic trauma patients. This finding suggests that the oxidative capacity of the liver may be assessed by studying the rate of ethanol elimination in burn victims.

Tympanic membrane temperature as a measure of core temperature

BACKGROUND

Ear thermometers are becoming popular as a method for measuring deep body (core) temperature.

AIM

To determine the variability of a single user's tympanic membrane (ear) temperature measurements.

SUBJECTS

Forty-two, afebrile, healthy children, and 20 febrile children with acute burns.

RESULTS

In afebrile children measurements made in both ears (and within just a few minutes of each other) differed by as much as 0.6 degree C. Operator measurement error, sw of three consecutive measurements, in the same ear, was 0.13 degree C. In the group of febrile, burned children, core temperature was measured hourly at a number of sites (ear, rectum, axilla, bladder). A peak in core temperature occurred approximately 10-12 hours after the burn. Measurement error was calculated in 14 febrile, burned children with a peak temperature in excess of 38 degrees C. For the left ear, measurement error was 0.19 degree C and for the right ear, 0.11 degree C. In the febrile children agreement between the ears was poor. The limits of agreement were 0.4 degree C to -0.8 degree C. It was not possible to predict the occasions when the temperature differences between the ears would be large or small.

CONCLUSIONS

The measurement error of one recording from the next is probably acceptable at about 0.1 to 0.2 degree C. To limit the variations in temperature of one ear to the other, measurements should be restricted to one of the ears whenever possible and the same ear used throughout the temperature monitoring period. Nurses and parents should take more than one temperature reading from the same ear whenever possible.

Temperature response to severe head injury and the effect on body energy expenditure and cerebral oxygen consumption

This study examines the relationship between core temperature and whole body energy expenditure, cerebral oxygen consumption (CMRO2), cerebral blood flow (CBF), and intracranial pressure (ICP) in severely head injured children. A total of 107 serial measurements of temperature, energy expenditure, CMRO2, CBF, and ICP were made in 18 head injured children receiving neurointensive care. Energy expenditure was measured using indirect calorimetry, and CMRO2 and CBF using the Kety-Schmidt technique. The mean rectal temperature was 37.8 degrees C (34-39.1 degrees C) despite modification with paracetamol. Within each child there was a positive relationship between rectal temperature and energy expenditure, energy expenditure increasing by a mean of 7.4% per degree C. There was no evidence of significant relationships between rectal temperature and CMRO2, CBF, or ICP. Mild induced hypothermia in two children did not result in decreased CMRO2 or CBF measurements. The efficacy of interventions aiming to modify cerebral energy metabolism by changing core temperature cannot be readily assessed by the response of the whole body.