Pediatric Temperature Variation in the MRI Scanner Under General Anesthesia
Summary
The number of children undergoing MRI imaging has increased significantly in the past years, because many young children cannot stay still for the duration of the scan, have difficulty tolerating the confined space and the noise produced by the Magnetic Resonance Imaging (MRI) machine, sedation or General Anesthesia is required in these cases. In the investigators institution, the investigators use General Anesthesia for children undergoing MRI.
Because children have a larger surface area to body weight ratio; hypothermia from passive heat loss is one of the anesthesiologists' concerns.
MRI requires a cool environment with low humidity; this specialized environment represents a significant thermal challenge to the anesthetized children. Since most temperature devices are not compatible with the MRI, the simple task to measure temperature change has never been investigated.
Description
It is known that following the induction of anesthesia, core hypothermia occurs in three stages;
1. Redistribution
2. Linear phase
3. Plateau phase Redistribution This accounts for the largest drop in core temperature of the three stages. Vasodilatation causes redistribution of heat from the core to the periphery.
Linear Phase This begins at the start of surgery as the patient is exposed to cold cleaning fluids and cool air flow in the theatre. Heat loss exceeds heat production, and most surgery does not extend past the linear phase.
- Radiation contributes the most (40%) and is proportional to environment/core, temperature difference to the power of four.
- Convection contributes up to 30% and is proportional to air velocity.
- Conduction contributes up to 5% and is proportional to the difference in surface temperatures.
- Evaporation contributes up to 15% and occurs from cleaning fluids, skin, respiratory and wound. A laparotomy can contribute up to 50% of the total.
- Respiratory contributes 10% (8% evaporation of water; 2% heating of air) and is enhanced by the cooling effect of cold anesthetic gases.
- Cold intravenous fluids. Plateau Phase Once core temperature falls below the thermoregulatory threshold, peripheral vasoconstriction increases and acts to limit the heat loss from the core department. When core heat production = heat loss to the peripheral compartment, core temperature reaches a plateau. Patients with an autonomic neuropathy (diabetics) have impaired sympathetic vasoconstriction and are unable to establish a core plateau in phase 3. Combined general and regional anesthesia will have a similar effect as the regional anesthetic (spinal/epidural) will prevent vasoconstriction in the legs; i.e. failure to establish a core plateau.
The ability to maintain body temperature is also compromised because anesthesia impairs intrinsic thermoregulatory response.
Heating devices including fluid warmers and bear huggers, commonly used in the Operating Room theaters, are incompatible with MRI.
On the other hand, MRI produces Radiofrequency Energy that transforms into heat within the patient's tissues. This may partially offset the heat loss.
The purpose of our study is to determine if children undergoing MRI under General Anesthesia become hypothermic and whether aggressive measures should be taken to prevent passive heat loss during MRI studies.
Study Design This is an observational, prospective non blinded study.
Study Design
Observational Model: Case-Only, Time Perspective: Prospective
Conditions
Children Requiring MRI
Location
University Hospital
Newark
New Jersey
United States
07101
Status
Recruiting
Source
University of Medicine and Dentistry New Jersey
Results (where available)
Links
- Source: http://clinicaltrials.gov/show/NCT01119248
- Information obtained from ClinicalTrials.gov on July 15, 2010
Published on BioPortfolio: 2014-07-23T21:09:17-0400
Clinical Trials
The objective of this study is to assess the safety and clinical utility of Duragesic® 12.5 micrograms/hour (a transdermal patch delivering the narcotic pain-reliever fentanyl) in the t...
Hand and feet lacerations are common in children with repair often requiring conscious sedation and needle sticks for repair. Growing evidence in adults reveal that many of these small lac...
The purpose of this study is to assess the effectiveness and safety of Durogesic® (a transdermal patch delivering the narcotic pain-reliever fentanyl) in the treatment of children with ...
Sodium nitroprusside (SNP) has been approved for control of blood pressure in adults, yet there are no controlled studies in children. The purpose of this study is to determine the effica...
Pediatric Appendicitis Risk Calculator (pARC) in Children With Appendix Ultrasounds
Acute appendicitis (AA) is the most common condition requiring emergency surgery in children. At a network of institutions nationwide, a tool called the pediatric appendicitis risk calcula...
PubMed Articles
Few studies of how exposure of children to anesthesia may affect neurodevelopment employ comprehensive neuropsychological assessments. This study tested the hypothesis that exposure to multiple, but n...
Therapeutic Plasma Exchange in Critically Ill Children Requiring Intensive Care.
To characterize the clinical indications, procedural safety, and outcome of critically ill children requiring therapeutic plasma exchange.
Impact of childhood type 1 diabetes on maternal work-family relations.
The aim of the study was to evaluate work-family conflict (WFC) and work-family facilitation (WFF) of working mothers of children with type 1 diabetes (T1D) compared with those of working mothers of c...
To identify associations between use of ipratropium and/or intravenous magnesium and outcomes of children hospitalized with acute asthma exacerbations and treated with continuous albuterol.
Pneumonia in HIV-Exposed and Infected Children and Association with Malnutrition.
We evaluated the association between HIV exposed-uninfected (HEU) status, malnutrition, and risk of death in Ugandan children hospitalized with pneumonia. Both HIV exposure and infection were associat...
Medical and Biotech [MESH] Definitions
Adult Children
Children who have reached maturity or the legal age of majority.
Disabled Children
Children with mental or physical disabilities that interfere with usual activities of daily living and that may require accommodation or intervention.
Aid To Families With Dependent Children
Financial assistance provided by the government to indigent families with dependent children who meet certain requirements as defined by the Social Security Act, Title IV, in the U.S.
Emergencies
Situations or conditions requiring immediate intervention to avoid serious adverse results.
Hymenolepis Nana
The smallest species of TAPEWORMS. It is the only cestode that parasitizes humans without requiring an intermediate host.
