Background: Pseudocholinesterase (PChE) polymorphism has been a subject of several pharmacogenetic studies worldwide. The patients with atypical homozygous genotype do not only have reduced serum cholinesterase activities but also their elimination rate for some pharmacologically potent drugs decrease drastically. This study was designed to evaluate the PChE polymorphism in Mazandaran province (northern Iran) for the first time.
Methods: About 5 ml plasma samples were collected from 200 healthy volunteers who visited "Iran Blood Transfusion Organization" centers all across Mazandaran province for blood donation. The PChE activity in presence or absence of dibucain was measured and based on obtained dibucain number (DN) volunteers were categorized to normal homozygous (Eu,u), atypical heterozygous (Eu,a), and atypical homozygous (Ea,a).
Results: The average (±SD) of the PChE activity among the blood donors was 9.14±1.93 IU (ranging from 4.1 to 16.6 IU). Only 2 persons (1%) had DN between 60 to 70 (Eu,a) and no one was categorized in 20
Conclusion: According to the findings, only 1% of the sample population had atypical heterozygous phenotype taking into account the experiment precision, the frequency of Ea,u is less than 4%. These findings suggest that the atypical allele frequency in northern Iran's population is probably less than the other regions of Iran and some other countries.
Pseudocholinesterase; Polymorphism; Succinylcholine; Mivacurium
PURPOSE: The present study was undertaken to evaluate onset, and early and late recovery of neuromuscular block after a combination of mivacurium (M) and rocuronium (R). METHODS: In this controlled, randomized study, 45 consenting ASA I-II patients were assigned to one of three treatment groups: 2.ED95 R alone (2R); 2.ED95 R plus 1.ED95 M (2R1M). or 2.ED95 R plus 2.ED95 M (2R2M). Neuromuscular monitoring of the ulnar nerve consisted of surface electrode stimulation and force transduction of the adductor pollicis muscle. Stable baseline stimulation (1 Hz, square-wave, supramaximal current) was established prior to relaxant administration and continued until 95 percent twitch height depression (onset). Thereafter, train-of-four stimulation every 10 seconds was used to record recovery data until 95 percent recovery (T(95%)). Data were analyzed using grouped t-tests, ANOVA, and Newman-Keuls multiple comparison tests. Significance was defined at the p < 0.05 level. RESULTS: The addition of mivacurium to rocuronium did not accelerate onset of block. The combination prolonged the clinical duration (time to 5 percent recovery, T(5%)), but did not affect subsequent recovery parameters: T(5%) in the 2R1M and 2R2M groups were 100 percent and 118 percent longer than in the 2R group, respectively (p < 0.05) the T(5-25%) (early recovery) and T(25-75%) (linear recovery) indexes were similar in all three groups. CONCLUSIONS: The present study did not note an acceleration of block onset when mivacurium was added to rocuronium. The findings suggest that the addition of mivacurium (1-2.ED95) to rocuronium (2.ED95) prolongs the clinical duration of the longer-acting agent, rocuronium, but has no effect on the early or linear recovery indexes of rocuronium. Thus, although clinical duration is prolonged, recovery from the combination regimens proceeds as if no mivacurium had been added to rocuronium.
The neuromuscular and hem+odynamic effects of mivacurium 0.15 mg/kg and succinylcholine 1 mg/kg were compared in 26 adult patients (ASA I and II) during nitrous oxide-oxygen-propofol-fentanyl anesthesia. Neuromuscular block was monitored by recording the compound electromyogram of the hypothenar muscle resulting from supramaximal train-of-four stimuli applied to the ulnar nerve. Time to onset of over 95% block and duration to 25% recovery of control twitch after injection of mivacurium were significantly longer than for succinylcholine (201 +/- 37.6 vs 54 +/- 5.2 sec and 13.0 +/- 2.2 vs 8.4 +/- 2.1 min; mean +/- SD). Onset of mivacurium with priming technique was shortened (125 +/- 20.7 sec), but was also slower than that of succinylcholine. Although the recovery index during spontaneous recovery was significantly longer for mivacurium than for succinylcholine (6.9 +/- 1.3 vs 5.1 +/- 0.9 min), antagonism with neostigmine at 25% recovery of twitch height sufficiently facilitated the recovery index of mivacurium (4.5 +/- 1.0 min) to a level similar to that of succinylcholine with no statistical difference. The hemodynamic effects of mivacurium were few as compared to those of succinylcholine. In conclusion, mivacurium is considered to have additional advantages for short procedures when succinylcholine is undesirable.
Arsenic is a potent pollutant that has caused an environmental catastrophe in certain parts of the world including Bangladesh where millions of people are presently at risk due to drinking water contaminated by arsenic. Chronic arsenic exposure has been scientifically shown as a cause for liver damage, cancers, neurological disorders and several other ailments. The relationship between plasma cholinesterase (PChE) activity and arsenic exposure has not yet been clearly documented. However, decreased PChE activity has been found in patients suffering liver dysfunction, heart attack, cancer metastasis and neurotoxicity. Therefore, in this study, we evaluated the PChE activity in individuals exposed to arsenic via drinking water in Bangladesh.
A total of 141 Bangladeshi residents living in arsenic endemic areas with the mean arsenic exposure of 14.10 ± 3.27 years were selected as study subjects and split into tertile groups based on three water arsenic concentrations: low (< 129 μg/L), medium (130-264 μg/L) and high (> 265 μg/L). Study subjects were further sub-divided into two groups (≤50 μg/L and > 50 μg/L) based on the recommended upper limit of water arsenic concentration (50 μg/L) in Bangladesh. Blood samples were collected from the study subjects by venipuncture and arsenic concentrations in drinking water, hair and nail samples were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). PChE activity was assayed by spectrophotometer.
Arsenic concentrations in hair and nails were positively correlated with the arsenic levels in drinking water. Significant decreases in PChE activity were observed with increasing concentrations of arsenic in water, hair and nails. The average levels of PChE activity in low, medium and high arsenic exposure groups were also significantly different between each group. Lower levels of PChE activity were also observed in the > 50 μg/L group compared to the ≤50 μg/L group. Moreover, PChE activity was significantly decreased in the skin (+) symptoms group compared to those without (-).
We found a significant inverse relationship between arsenic exposure and PChE activity in a human population in Bangladesh. This research demonstrates a novel exposure-response relationship between arsenic and PChE activity which may explain one of the biological mechanisms through which arsenic exerts its neuro-and hepatotoxicity in humans.
Pseudocholinesterase (butyrylcholinesterase) is a drug metabolizing enzyme responsible for hydrolysis of the muscle relaxant drugs succinylcholine and mivacurium. Deficiency from any cause can lead to prolonged apnoea and paralysis following administration of succinylcholine and mivacurium.
Within the last two years we have had four patients who have had prolonged apnea following the administration of mivacurium. It was understood that one was congenital and the other three due to various reasons had enzyme-deficiencies. In all four of the patients, the prolonged blocks deteriorated.
Prolonged blocks may be encountered due to mivacurium use. The diagnosis of pseudocholinesterase enzyme deficiency can be given after a careful clinic supervision and peripheral nerve stimulator monitoring. A decrease in the activity of pseudocholinesterase enzyme and improvement in neuromuscular function will help verifying our diagnosis. Instead of pharmacological applications that may further complicate the situation, what should be done in such patients is to wait until the block-effect goes down by the help of sedation and mechanical ventilation.
Infants usually respond differently to a neuromuscular relaxant compared to children or adults. Isoflurane is commonly used as an anesthetic gas in infants. In an RCT design, we investigated whether a dose of mivacurium 250 μg/kg results in faster onset of action than 200 μg/kg in infants under isoflurane anesthesia. Spontaneous recovery times and cardiovascular response were also evaluated.
Twenty-four low surgical risk children, aged 6–24 months, undergoing an elective surgery and requiring tracheal intubation were selected. After anesthetic induction, patients randomly received an iv bolus dose of mivacurium 200 or 250 μg/kg. After maximal relaxation, the patient was intubated. Isoflurane was administered to maintain anesthetic level during the surgical procedure. Neuromuscular function was monitored by accelerometry (TOF-Guard) at the adductor pollicies. The first twitch (T) of the TOF and the T4/T1 were measured. The time-course of heart rate and systolic and diastolic blood pressure were analysed by transforming them into their respective areas under the curve.
Mivacurium 250 μg/kg produced a maximal T block faster than 200 μg/kg, i.e. 2.4 ± 1.1 vs. 3.5 ± 1.4 min (p < 0.05). Spontaneous recovery times were similar in both groups. Heart rate was similar between doses while systolic and diastolic blood pressures were lower with the higher dose (p < 0.05). Flushing was observed in two cases, one in each group.
The maximal effect of mivacurium 250 μg/kg, in infants under isoflurane anesthesia, was present one minute faster than 200 μg/kg. However, it produced a significant cardiovascular response.
A 47-year-old Turkish male was scheduled for laparoscopic cholecystectomy under general anesthesia. The patient had 2 operations 28 and 19 years ago under general anesthesia. It was learned that the patient was administered succinylcholine during both of these previous operations and that he did not have a history of prolonged recovery or postoperative apnea. The patient had been using sertraline for 3 years before the operation. Pseudocholinesterase is a drug-metabolizing enzyme responsible for hydrolysis of the muscle-relaxant drugs mivacurium and succinylcholine. Deficiency of this enzyme from any cause can lead to prolonged apnea and paralysis following administration of mivacurium and succinylcholine. The diagnosis of pseudocholinesterase enzyme deficiency can be made after careful clinic supervision and peripheral nerve stimulator monitoring. A decrease in the activity of pseudocholinesterase enzyme and a decline in the block effect over time will help verify the diagnosis. Our patient’s plasma cholinesterase was found to have low activity. Instead of pharmacological interventions that may further complicate the situation in such cases, the preferred course of action should be to wait until the block effect declines with the help of sedation and mechanical ventilation. In our case, the prolonged block deteriorated in the course of time before any complications developed.
mivacurium; pseudocholinesterase deficiency; sertraline
The biosynthetic genes pchDCBA and pchEF, which are known to be required for the formation of the siderophore pyochelin and its precursors salicylate and dihydroaeruginoate (Dha), are clustered with the pchR regulatory gene on the chromosome of Pseudomonas aeruginosa. The 4.6-kb region located downstream of the pchEF genes was found to contain three additional, contiguous genes, pchG, pchH, and pchI, probably forming a pchEFGHI operon. The deduced amino acid sequences of PchH and PchI are similar to those of ATP binding cassette transport proteins with an export function. PchG is a homolog of the Yersinia pestis and Y. enterocolitica proteins YbtU and Irp3, which are involved in the biosynthesis of yersiniabactin. A null mutation in pchG abolished pyochelin formation, whereas mutations in pchH and pchI did not affect the amounts of salicylate, Dha, and pyochelin produced. The pyochelin biosynthetic genes were expressed from a vector promoter, uncoupling them from Fur-mediated repression by iron and PchR-dependent induction by pyochelin. In a P. aeruginosa mutant lacking the entire pyochelin biosynthetic gene cluster, the expressed pchDCBA and pchEFG genes were sufficient for salicylate, Dha, and pyochelin production. Pyochelin formation was also obtained in the heterologous host Escherichia coli expressing pchDCBA and pchEFG together with the E. coli entD gene, which provides a phosphopantetheinyl transferase necessary for PchE and PchF activation. The PchG protein was purified and used in combination with PchD and phosphopantetheinylated PchE and PchF in vitro to produce pyochelin from salicylate, l-cysteine, ATP, NADPH, and S-adenosylmethionine. Based on this assay, a reductase function was attributed to PchG. In summary, this study completes the identification of the biosynthetic genes required for pyochelin formation from chorismate in P. aeruginosa.
In Pseudomonas aeruginosa, the antibiotic dihydroaeruginoate (Dha) and the siderophore pyochelin are produced from salicylate and cysteine by a thiotemplate mechanism involving the peptide synthetases PchE and PchF. A thioesterase encoded by the pchC gene was found to be necessary for maximal production of both Dha and pyochelin, but it was not required for Dha release from PchE and could not replace the thioesterase function specified by the C-terminal domain of PchF. In vitro, 2-aminobutyrate, a cysteine analog, was adenylated by purified PchE and PchF proteins. In vivo, this analog strongly interfered with Dha and pyochelin formation in a pchC deletion mutant but affected production of these metabolites only slightly in the wild type. Exogenously supplied cysteine overcame the negative effect of a pchC mutation to a large extent, whereas addition of salicylate did not. These data are in agreement with a role for PchC as an editing enzyme that removes wrongly charged molecules from the peptidyl carrier protein domains of PchE and PchF.
Burn injury leads to resistance to the effects of non-depolarizing muscle relaxants. We tested the hypothesis that a larger bolus dose is as effective as priming for rapid onset of paralysis after burns.
Ninety adults, aged 18–59 yr with 40 (2)% [mean (se)] burn and 30 (2) days after injury, received rocuronium as a priming dose followed by bolus (0.06+0.94 mg kg−1), or single bolus of either 1.0 or 1.5 mg kg−1. Sixty-one non-burned, receiving 1.0 mg kg−1 as a primed (0.06+0.94 mg kg−1) or full bolus dose, served as controls. Acceleromyography measured the onset times.
Priming when compared with 1.0 mg kg−1 bolus in burned patients shortened the time to first appearance of twitch depression (30 vs 45 s, P<0.05) and time to maximum twitch inhibition (135 vs 210 s, P<0.05). The onset times between priming and higher bolus dose (1.5 mg kg−1) were not different (30 vs 30 s for first twitch depression and 135 vs 135 s for maximal depression, respectively). The onset times in controls, however, were significantly (P<0.05) faster than burns both for priming and for full bolus (15 and 15 s, respectively, for first twitch depression and 75 and 75 s for maximal depression). Priming caused respiratory distress in 10% of patients in both groups. Intubating conditions in burns were significantly better with 1.5 mg kg−1 than with priming or full 1.0 mg kg−1 bolus.
A dose of 1.5 mg kg−1 not only produces an initial onset of paralysis as early as 30 s, which we speculate could be a reasonable onset time for relief of laryngospasm, but also has an onset as fast as priming with superior intubating conditions and no respiratory side-effects.
burns; neuromuscular block, rocuronium
Pancuronium, vecuronium, rocuronium, and mivacurium are nondepolarizing neuromuscular blocking agents that affect the cardiovascular system with different potencies. Their cardiovascular effects are clinically significant in the anesthetic management of patients, particularly those undergoing cardiac surgery.
We aimed to compare the cardiac effects of these compounds, such as heart rate and developed force, in one species under identical experimental conditions in isolated rat atria.
The left or right atria of rats were removed and suspended in organ baths. Pancuronium, vecuronium, rocuronium, or mivacurium were added cumulatively (10–9–10–5 M) in the presence and absence of the nonselective β-blocker propranolol (10–8 M) and the noradrenaline reuptake inhibitor desipramine (10–7 M), and heart rate changes were recorded in spontaneously beating right atria. Left atrial preparations were stimulated by electrical field stimulation using a bipolar platinum electrode, and the effects of cumulative concentrations of these nondepolarizing neuromuscular blocking agents on the developed force in the presence and absence of propranolol (10–8 M) and desipramine (10–7 M) were recorded.
Pancuronium increased heart rate in a dose-dependent manner compared with the control group (P < 0.027). Vecuronium, rocuronium, and mivacurium also increased heart rate in a dose-dependent manner, but the changes were not statistically significant. Although propranolol decreased the pancuronium heart rate effect (P < 0.05), it did not change the heart rate effects with vecuronium, rocuronium, or mivacurium. Desipramine did not change the heart rate effects of vecuronium, rocuronium, mivacurium, or pancuronium. All 4 drugs increased developed force in a dose-dependent manner; the increases were significant at 10–5 M concentration for pancuronium and at 10–6 and 10–5 M concentrations for vecuronium, rocuronium, and mivacurium (P < 0.038). These increases in developed force were abolished with the addition of propranolol. Desipramine did not change the developed force effects of any of the 4 drugs.
The heart rate effect of pancuronium and developed force effects of pancuronium, vecuronium, rocuronium, and mivacurium may occur via direct stimulation of β receptors. Although our investigation was an in vitro study, the effects found may be important especially under pathologic conditions, such as hypertension, in which patients usually use β-blocking agents, which cause β receptor upregulation.
atrium; mivacurium; neuromuscular blockers; pancuronium; rat; rocuronium; vecuronium
Butyrylcholinesterase deficiency is characterized by prolonged apnea after the use of muscle relaxants (suxamethonium or mivacurium) in patients who have mutations in the BCHE gene. Here, we report a case of prolonged neuromuscular block after administration of suxamethonium leading to the discovery of a novel BCHE variant (c.695T>A, p.Val204Asp). Inhibition studies, kinetic analysis and molecular dynamics were undertaken to understand how this mutation disrupts the catalytic triad and determines a “silent” phenotype. Low activity of patient plasma butyrylcholinesterase with butyrylthiocholine (BTC) and benzoylcholine, and values of dibucaine and fluoride numbers fit with heterozygous atypical silent genotype. Electrophoretic analysis of plasma BChE of the proband and his mother showed that patient has a reduced amount of tetrameric enzyme in plasma and that minor fast-moving BChE components: monomer, dimer, and monomer-albumin conjugate are missing. Kinetic analysis showed that the p.Val204Asp/p.Asp70Gly-p.Ala539Thr BChE displays a pure Michaelian behavior with BTC as the substrate. Both catalytic parameters Km = 265 µM for BTC, two times higher than that of the atypical enzyme, and a low Vmax are consistent with the absence of activity against suxamethonium. Molecular dynamic (MD) simulations showed that the overall effect of the mutation p.Val204Asp is disruption of hydrogen bonding between Gln223 and Glu441, leading Ser198 and His438 to move away from each other with subsequent disruption of the catalytic triad functionality regardless of the type of substrate. MD also showed that the enzyme volume is increased, suggesting a pre-denaturation state. This fits with the reduced concentration of p.Ala204Asp/p.Asp70Gly-p.Ala539Thr tetrameric enzyme in the plasma and non-detectable fast moving-bands on electrophoresis gels.
One hundred and sixty burn patients suffering from septicaemia, hospitalized in the Al-Babtain Centre burns unit, Kuwait, between June 1992 and May 2001, were studied. Thirty-two patients (20%) had scalds and 128 (80%) flame burns, thus representing a ratio of 1:4 among septicaemic patients. There were 20 males (62.5%) in the scald group, compared to 73 (57%) with flame burns. Flame burns were significantly higher (p < 0.01) among non-Kuwaiti patients. The mean ages of the scald and flame burn patients were respectively 6.2 and 31.5 yr. The mean total body surface area burn in scalds was 20% and in flame burns 49%, which was significantly higher (p < 0.001). The 34 septicaemic episodes in 32 scald patients and 212 such episodes in 128 flame burn patients showed a significantly higher incidence in the latter group. The majority of septicaemic episodes, in scalds (82.4%) and flame burns (57.6%), were due to gram-positive organisms, mainly methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus epidermidis. A significantly increased number of episodes were due to S. aureus (p < 0.001) and Enterococcus (p < 0.05) in scald patients. More surgical operations were performed in flame burn patients and survival increased significantly with an increasing number of grafting sessions (p < 0.001). The mean hospital stay in flame burn patients (56 days) was significantly higher than in scald patients (23 days) (p < 0.001). It is significant to record that all the 38 deaths (29.7%) were in flame burn septicaemic patients (p < 0.001). The scald and flame burn patients were quite distinct in their demographic and clinical characteristics. The flame burn patients were more vulnerable to septicaemia, with a high risk of mortality.
SEPTICAEMIA; SCALD; FLAME; BURNS; SIGNIFICANT; DIFFERENCES
The rising number of obese patients poses new challenges for burn care. These may include adjustments in calculations of burn size, resuscitation, ventilator wean, nutritional goals as well as challenges in mobilization. We have focused this observational study on resuscitation in the obese patient population in the first 48 hours after burn injury. Prior trauma studies suggest a prolonged time to reach end points of resuscitation in the obese compared to non-obese injured patients. We hypothesize that obese patients have worse outcomes after thermal injury and that differences in the response to resuscitation contribute to this disparity.
We retrospectively analyzed data prospectively collected in a multi-center trial to compare resuscitation and outcomes in patients stratified by NIH/WHO BMI classification (BMI: normal weight 18.5-24.9, overweight 25-29.9, Obese 30-39.9, morbidly obese ≥40). Due to distribution of body habitus in the obese, total burn size was recalculated for all patients using the method proposed by Neaman and compared to Lund-Browder estimates. We analyzed patients by BMI class for fluids administered and end points of resuscitation at 24 and 48 hours. Multivariate analysis was used to compare morbidity and mortality across BMI groups.
We identified 296 adult patients with a mean TBSA of 41%. Patient and injury characteristics were similar across BMI categories. There were no significant differences in burn size calculations using Neaman vs. Lund-Browder formulas. Although resuscitation volumes exceeded the predicted formula in all BMI categories, higher BMI was associated with less fluid administered per actual body weight (p=0.001). Base deficit on admission was highest in the morbidly obese group at 24 and 48 hours. Furthermore, these patients did not correct their metabolic acidosis as well as lower BMI groups (p-values 0.04 and 0.03). Complications and morbidities across BMI groups were similar, although examination of organ failure scores indicated more severe organ dysfunction in the morbidly obese group. Compared to normal weight patients, being morbidly obese was an independent risk factor for death (OR = 10.1; CI 1.94-52.5, p= 0.006).
Morbidly obese patients with severe burns tend to receive closer to predicted fluid resuscitation volumes for their actual weight. However, this patient group has persistent metabolic acidosis during the resuscitation phase and is at-risk of developing more severe multiple organ failure. These factors may contribute to higher mortality risk in the morbidly obese burn patient.
burns; resuscitation; obesity
Despite several studies investigating the pathophysiologic effects of tourniquet usage in extremity surgeries, there are not enough data about these effects in adhesion release surgeries of burn patients. In the light of numerous metabolic changes of burn tissues, we tried to determine whether there are any significant differences in metabolic responses of burn tissues to tourniquet ischemia in comparison to the findings of other studies in non burn tissue responses during tourniquet usage in extremity surgeries.
From March 2009 to April 2011, eighteen patients who were candidates for performing upper extremity adhesion release surgeries were enrolled. Patients with renal, hepatic, metabolic and any other underlying diseases were excluded from the study. Blood samples for determination of pH, pCO2 and HCO3 were obtained from the occluded hand (as the local response indicator of the body to ischemia) and the other hand too (as the systemic response indicator). The time for blood sampling was just before tourniquet inflation, 30 seconds, one minute, three minutes and five minutes after cuff inflation.
Thirty seconds after tourniquet release, a rapid decrease was noticed in pH values (7.38±0.04-->7.21±0.08). This decrease was seen after 60s in the opposite hand (7.38±0.04-->7.27±0.01) and returned to the baseline values after 5 minutes in both hands. The blood PCO2 value in the occluded hand was found to be increased 30s after tourniquet release (34.93±3.96-->50.06±11.78), while this increase was seen after 180s in the opposite hand too (34.93±3.96-->38.98±9.21). HCO3 value increased after 30s (19.79±2.31-->20.62±2.37) in the occluded hand, but this increase was visible after 60s in the opposite hand. We found no significant difference in the response of burn patients to tourniquet ischemia in comparison to non-burn patients.
There was no extra risk in the application of tourniquet in extremity surgeries of burn patients in comparison to non-burn patients. So current protocols of tourniquet application in non-burn patients can be used for adhesion release surgeries in burn patients without any extra caution.
Burn; Metabolic effects; Tourniquet
1. The effect of body surface area (BSA) burn injury on neuromuscular pharmacodynamics of vecuronium was evaluated. 2. The neuromuscular responses of 15 burned children were compared with those in five controls. 3. The effective dose for 50% suppression of twitch tension (ED50) was 34 micrograms kg-1 for patients with less than 40% BSA burn, 55 micrograms kg-1 for 40-60% BSA burn, and 65 micrograms kg-1 for patients with greater than 60% BSA burn. These values were significantly higher than the value for control patients, which was 18 micrograms kg-1. 4. Burn injury induces a resistance to the neuromuscular effects of vecuronium, the magnitude of which is related to burn size.
An accurate knowledge of energy consumption in burn patients is a prerequisite for rational nutrition therapy. This study sought to create a formula that accounts for the metabolic characteristics of adult burn patients to accurately estimate energy consumption of patients with different areas and extents of burn and at different times after injury.
Resting energy expenditure (REE) data on 66 burn patients, with total body surface area (TBSA) of burns ranging from 4% to 96%, were evaluated at different times after injury. REE values were determined in patients using indirect calorimetry at days 1, 2, 3, 7, 14, 21, and 28 after injury. We then constructed a mathematical model of REE changes post-burn. Next, established two new formulas (one non-linear and the other linear) for energy consumption estimation using model-based analytical solution and regression analysis. The new formulas were compared with measured REE and commonly used formulas including those of Carlson, Xie, Curreri, and Milner to determine accuracy and reliability.
Comparative analysis showed that the new formulas offered significantly higher accuracy and reliability than the Milner formula, which is considered the most accurate of commonly used burn energy consumption estimate formulas. The accuracy of the new nonlinear formula (94.29%) and that of the linear formula (91.43%) were significantly higher than that of Milner formula (72.86%) when compared to measured REE (χ2 = 11.706, P = 0.001; χ2 = 8.230, P = 0.004, respectively). The reliabilities of the new estimation formulas were both 100% and that of Milner formula was 74.24% (χ2 = 19.513, P = 0.000).
The new formulas constructed in this study provide reliable simulation of the impact of the degree of burn and post-burn days on energy consumption and offer notably higher accuracy and reliability than other formulas. These formulas will help determine nutritional needs of burn patients.
The study was registered on Chinese Clinical Trial Registry as ChiCTR-TRC-13003806.
Main contributors to adverse outcomes in severely burned pediatric patients are profound and complex metabolic changes in response to the initial injury. It is currently unknown how long these conditions persist beyond the acute phase post-injury. The aim of the present study was to examine the persistence of abnormalities of various clinical parameters commonly utilized to assess the degree hypermetabolic and inflammatory alterations in severely burned children for up to three years post-burn to identify patient specific therapeutic needs and interventions.
Patients: Nine-hundred seventy-seven severely burned pediatric patients with burns over 30% of the total body surface admitted to our institution between 1998 and 2008 were enrolled in this study and compared to a cohort non-burned, non-injured children. Demographics and clinical outcomes, hypermetabolism, body composition, organ function, inflammatory and acute phase responses were determined at admission and subsequent regular intervals for up to 36 months post-burn. Statistical analysis was performed using One-way ANOVA, Student's t-test with Bonferroni correction where appropriate with significance accepted at p<0.05. Resting energy expenditure, body composition, metabolic markers, cardiac and organ function clearly demonstrated that burn caused profound alterations for up to three years post-burn demonstrating marked and prolonged hypermetabolism, p<0.05. Along with increased hypermetabolism, significant elevation of cortisol, catecholamines, cytokines, and acute phase proteins indicate that burn patients are in a hyperinflammatory state for up to three years post-burn p<0.05.
Severe burn injury leads to a much more profound and prolonged hypermetabolic and hyperinflammatory response than previously shown. Given the tremendous adverse events associated with the hypermetabolic and hyperinflamamtory responses, we now identified treatment needs for severely burned patients for a much more prolonged time.
Insulin resistance in the acute burn period has been well described, however, it is unknown if alterations in glucose metabolism persist beyond discharge from the acute injury. To measure the duration of insulin resistance following recovery from the acute burn injury, we performed a prospective cross-sectional study with a standard two hour oral glucose tolerance test in 46 severely burned children at 6, 9 or 12 months following initial injury. Glucose uptake and insulin secretion were assessed following the glucose load. Results were compared to those previously published in healthy children. At 6 months post-burn, the 2 hour glucose concentration was significantly (P<0.001) greater than controls, and the area under the curve (AUC) of glucose was significantly higher compared to 12 months and to healthy children (P=0.027 and P<0.001, respectively). The 9 month AUC glucose was higher than controls (P<0.01). The 6 month 2 hour insulin in was significantly higher than controls, as was the AUC of insulin in all time points post-burn. The AUC of C-peptide was significantly greater at 6 months post-injury compared to 9 and 12 months (P<0.01 for both). Increased 2 hour and AUC glucose and insulin indicate that glucose metabolism is still altered at 6 and 9 months post-injury, and coincides with previously documented defects in bone and muscle metabolism at these time points. Insulin breakdown is also still increased in this population. Further study of this population is warranted to determine if specific treatment is needed.
Burns; insulin resistance; OGTT; pediatrics
Pontocerebellar hypoplasia (PCH) represents a group of neurodegenerative disorders with prenatal onset. Eight subtypes have been described thus far (PCH1-8) based on clinical and genetic features. Common characteristics include hypoplasia and atrophy of the cerebellum, variable pontine atrophy, and severe mental and motor impairments. PCH1 is distinctly characterized by the combination with degeneration of spinal motor neurons. Recently, mutations in the exosome component 3 gene (EXOSC3) have been identified in approximately half of the patients with PCH subtype 1.
We selected a cohort of 99 PCH patients (90 families) tested negative for mutations in the TSEN genes, RARS2, VRK1 and CASK. Patients in this cohort were referred with a tentative diagnose PCH type 1, 2, 4, 7 or unclassified PCH. Genetic analysis of the EXOSC3 gene was performed using Sanger sequencing. Clinical data, MR images and autopsy reports of patients positive for EXOSC3 mutations were analyzed.
EXOSC3 mutations were found in twelve families with PCH subtype 1, and were not found in patients with other PCH subtypes. Identified mutations included a large deletion, nonsense and missense mutations. Examination of clinical data reveals a prolonged disease course in patients with a homozygous p.D132A mutation. MRI shows variable pontine hypoplasia in EXOSC3 mediated PCH, where the pons is largely preserved in patients with a homozygous p.D132A mutation, but attenuated in patients with other mutations. Additionally, bilateral cerebellar cysts were found in patients compound heterozygous for a p.D132A mutation and a nonsense allele.
EXOSC3 mediated PCH shows clear genotype-phenotype correlations. A homozygous p.D132A mutation leads to PCH with possible survival into early puberty, and preservation of the pons. Compound heterozygosity for a p.D132A mutation and a nonsense or p.Y109N allele, a homozygous p.G31A mutation or a p.G135E mutation causes a more rapidly progressive course leading to death in infancy and attenuation of the ventral pons.
Our findings imply a clear correlation between genetic mutation and clinical outcome in EXOSC3 mediated PCH, including variable involvement of the pons.
Pontocerebellar hypoplasia; Neurodegeneration; EXOSC3 gene; Genotype-phenotype correlations
Following reports of heparin use in burn treatment, an ethics-committee-approved prospective randomized study with controls compared results obtained using traditional usual burn treatment without heparin with results in similar patients similarly treated with heparin added topically. The subjects were 100 consecutive burn patients (age, 15-35 yr) with second-degree superficial and deep burns of 5-45% TBSA size. Two largely similar cohort groups, i.e. a control group (C) and a heparin group (H) with 50 subjects per group, were randomly treated, the main difference between the groups being that 13 C patients had burns of 35-45% extent vs. only one such patient in H (p < 0.01). The 50 C patients received traditional routine treatment, including topical antimicrobial cream, debridement, and, when needed, skin grafts in the early post-burn period. The 50 H patients, without topical cream, were additionally treated, starting on day 1 post-burn, with 200 IU/ml sodium aqueous heparin solution USP (heparin) dripped on the burn surfaces and inserted into the blisters 2-4 times a day for 1-2 days, and then only on burn surfaces for a total of 5-7 days, prior to skin grafting, when needed. Thereafter, C and H treatment was similar. It was found that the H patients complained of less pain and received less pain medicine than the C patients. H needed fewer dressings and oral antibiotics than C. Significantly less intravenous fluid was infused in H: 33.5 litres in 39 H patients vs. 65 litres in 41 C patients, i.e. nearly 50% less (p < 0.04). The 50 H patients had four skin graftings (8%), while the 50 C patients had 10 (20%). Five 5 C patients died (mortality, 10%). No H patients died. The number of days in hospital for H vs. C was significantly less (overall, p < 0.0001): 58% of H were discharged within 10 days vs. 6% of C; 82% of H were out in 20 days vs. 14% of C; 98% of H vs. 44% of C were out in 30 days; and while 100% of H were discharged by day 40, 56% of C required up to another 10 days. The burns in H patients healed on average in 15 days (maximum period 37 days) vs. an average of 25 days (maximum > 48 days) in C (p < 0.0006). Procedures and costs in H were much reduced compared with C. Photographs of the differences between H and C are presented for the sake of comparison. It is concluded that heparin applied topically for 5-7 days improved burn treatment: it reduced pain, pain medicine, dressings, and use of antibiotics; it significantly reduced IV fluids (p < 0.04), days in hospital (p < 0.0001), and healing time (p < 0.0006); and it reduced skin grafts, mortality, and costs.
COMPARATIVE; STUDY; BURNS; TREATED; TOPICAL; WITH; WITHOUT; HEPARIN
In this study, we retrospectively analysed healing times of ambulatory burn patients after silver-based dressings were introduced in late December 2005, and compared the results with those obtained before.
PATIENTS AND METHODS
Data were collected in November–December 2005 and in January–February 2006. We excluded from the study: (i) admitted patients; (ii) patients with mixed superficial partial thickness and deep partial thickness burns; (iii) patients with full-thickness burns; and (iv) operated patients that came for follow-up. We recorded the age, sex, cause (flame vs scald), burn depth, dressings used and healing times.
We selected 347 patients corresponding to 455 burned areas (64.4% superficial and 35.6% deep; 47.7% treated in 2005 and 52.3% in 2006). During the years 2005 and 2006, there was an increase in the use of silver-based dressings (2005, 9.7%; 2006, 38.7%; chi-squared test, P < 0.001) and a decrease in the use of paraffin gauzes (2005, 66.4%; 2006, 40.3%; chi-squared test, P < 0.001). The healing time of overall burns and of superficial burns showed no significant differences between 2005 and 2006. However, in deep partial thickness burns, a significant reduction was present (2006, 19; 2005, 29 days; Student's t-test, P < 0.01). Among all dressings, paraffin gauzes had the shortest healing times in superficial burns (5 days); with silver-based dressings in deep burns, the healing times were nanocrystalline silver (16 days) and silver carboxymethylcellulose (21 days).
Results of our retrospective study would suggest that paraffin gauzes are a valuable option in superficial burns, while silver-based dressings are preferable in deep burns.
Burn dressings; Ambulatory burns; Healing times
Radiation exposure and burn injury have both been shown to alter glucose utilization in vivo. The present study was designed to study the effect of burn injury combined with radiation exposure, on glucose metabolism in mice using [18F] Fluorodeoxyglucose (18FDG). Groups of male mice weighing approximately 30g were studied. Group 1 was irradiated with a 137Cs source (9 Gy). Group 2 received full thickness burn injury on 25% total body surface area followed by resuscitated with saline (2mL, IP). Group 3 received radiation followed 10 minutes later by burn injury. Group 4 were sham treated controls. After treatment, the mice were fasted for 23 hours and then injected (IV) with 50 µCi of 18FDG. One hour post injection, the mice were sacrificed and biodistribution was measured. Positive blood cultures were observed in all groups of animals compared to the shams. Increased mortality was observed after 6 days in the burn plus radiated group as compared to the other groups. Radiation and burn treatments separately or in combination produced major changes in 18FDG uptake by many tissues. In the heart, brown adipose tissue (BAT) and spleen, radiation plus burn produced a much greater increase (p<0.0001) in 18FDG accumulation than either treatment separately. All three treatments produced moderate decreases in 18FDG accumulation (p<0.01) in the brain and gonads. Burn injury, but not irradiation, increased 18FDG accumulation in skeletal muscle; however the combination of burn plus radiation decreased 18FDG accumulation in skeletal muscle. This model may be useful for understanding the effects of burns + irradiation injury on glucose metabolism and in developing treatments for victims of injuries produced by the combination of burn plus irradiation.
Burn induces a hypermetabolic state characterized by alterations in protein metabolism which is associated with increased morbidity and mortality. Eukaryotic elongation factor 2 (eEF2) plays a crucial role in regulating protein synthesis in many diseases, but whether it participates in burn-induced hypermetabolism is unclear. The aim of this study was to determine the expression of eEF2 and the upstream eEF2-inactivating kinase, eEF2K, in severely burned pediatric patients.
Eight pediatric patients (> 40% TBSA) and three non-burned pediatric volunteers were enrolled in this study. Muscle and skin biopsies were collected at early (0–10 days post burn [dpb]), middle (11–49dpb), and late (50–365dpb) time points. Resting energy expenditure (REE), body composition, and muscle protein synthesis rate (FSR) were measured. Proteins were extracted and analyzed by Western blotting. To further investigate the protein synthesis pathway, microarray data from muscle and skin were examined from 22 non-burned and 20 burned children.
Burn patients exhibited a profound hypermetabolic response, as seen by a significant increased in REE (p<0.05) and a loss of lean body mass (LBM) without altered muscle FSR, indicating a shift to catabolism after thermal injury. In muscle, the phosphorylation of eEF2K-dependent eEF2 was down-regulated early and middle post-burn. Similar changes in eEF2K and eEF2 levels occurred in skin at the early time point. Total amounts of eEF2 and eEF2K were not altered.
Burn induces prolonged activation of eEF2K and eEF2. Alterations in these mediators may contribute to profound hypermetabolism seen in severely burned patients.
burn; muscle; skin; protein synthesis; hypermetabolism