Ingrid Steinvall

Acute kidney injury is common, parallels organ dysfunction or failure, and carries appreciable mortality in patients with major burns: a prospective exploratory cohort study

IntroductionThe purpose of this study was to determine the incidence, time course, and outcome of acute kidney injury after major burns and to evaluate the impact of possible predisposing factors (age, gender, and depth and extent of injury) and the relation to other dysfunctioning organs and sepsis.MethodWe performed an explorative cohort study on patients with a TBSA% (percentage burned of total body surface area) of 20% or more who were admitted to a national burn centre. Acute kidney injury was classified according to the international consensus classification of RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease). Prospectively collected clinical and laboratory data were used for assessing organ dysfunction, systemic inflammatory response, and sepsis.ResultsThe incidence of acute kidney injury among major burns was 0.11 per 100,000 people per year. Of 127 patients, 31 (24%) developed acute kidney injury (12% Risk, 8% Injury, and 5% Failure). Mean age was 40.6 years (95% confidence interval [CI] 36.7 to 44.5), TBSA% was 38.6% (95% CI 35.5% to 41.6%), and 25% were women. Mortality was 14% and increased with increasing RIFLE class (7% normal, 13% Risk, 40% Injury, and 83% Failure). Renal dysfunction occurred within 7 days in 55% of the patients and recovered among all survivors. Age, TBSA%, and extent of full thickness burns were higher among the patients who developed acute kidney injury. Pulmonary dysfunction and systemic inflammatory response syndrome were present in all of the patients with acute kidney injury and developed before the acute kidney injury. Sepsis was a possible aggravating factor in acute kidney injury in 48%. Extensive deep burns (25% or more full thickness burn) increased the risk for developing acute kidney injury early (risk ratio 2.25).ConclusionsAcute kidney injury is common, develops soon after the burn, and parallels other dysfunctioning organs. Although acute kidney injury recovered in all survivors, in higher acute kidney injury groups, together with cardiovascular dysfunction, it correlated with mortality.

Acute respiratory distress syndrome is as important as inhalation injury for the development of respiratory dysfunction in major burns

Respiratory dysfunction is common after major burns. The pathogenesis is, however, still under debate. The aim was to classify and examine underlying reasons for respiratory dysfunction after major burns. Consecutive adult patients (n=16) with a total burned body surface area of 20% or more who required mechanical ventilation were assessed for acute respiratory distress syndrome (ARDS), inhalation injury, sepsis, ventilator-associated pneumonia (VAP), ventilator-induced lung injury (VILI), using conventional criteria, together with measurements of cardiovascular variables and viscoelastic properties of the lung including extravascular lung water. Nine patients developed ARDS within 6 days of injury. ARDS was characterized by a large reduction in the PEEP-adjusted PaO(2):FiO(2) ratio, pulmonary compliance, and increased extra vascular lung water together with increased renal dysfunction rates. Seven patients fulfilled the criteria for inhalation injury. They also had decreased PaO(2):FiO(2) ratios. There was an increase in extra vascular lung water and a decrease in compliance measures though not to the same extent as in the ARDS group. White blood cell counts dropped from (mean) 21.4x10(9)l(-1) (95% CI 15.3-27.5) in day 1 to 4.3x10(9)l(-1) (2.2-6.5) on day 3, and lower values tended to correlate with the development of ARDS. Sepsis occurred before onset of ARDS in only three cases. One patient fulfilled the criteria for VAP, but none was thought to have VILI. We found that respiratory dysfunction after burns is multifactorial, and ARDS and inhalation injury are most important. The early onset of ARDS, together with the changes in white blood cell count and organ dysfunction, favours a syndrome in which respiratory distress is induced by an inflammatory process mediated by the effect of the burn rather than being secondary to sepsis. The power of these conclusions is, however, hampered by the small number of patients in this study.

Human cardiovascular dose-response to supplemental oxygen

Aim:  The aim of the study was to examine the central and peripheral cardiovascular adaptation and its coupling during increasing levels of hyperoxaemia. We hypothesized a dose‐related effect of hyperoxaemia on left ventricular performance and the vascular properties of the arterial tree.

Hemodynamic Changes During Resuscitation After Burns Using the Parkland Formula

BACKGROUND The Parkland formula (2-4 mL/kg/burned area of total body surface area %) with urine output and mean arterial pressure (MAP) as endpoints for the fluid resuscitation in burns is recommended all over the world. There has recently been a discussion on whether central circulatory endpoints should be used instead, and also whether volumes of fluid should be larger. Despite this, there are few central hemodynamic data available in the literature about the results when the formula is used correctly. METHODS Ten burned patients, admitted to our unit early, and with a burned area of >20% of total body surface area were investigated at 12, 24, and 36 hours after injury. Using transesophageal echocardiography, pulmonary artery catheterization, and transpulmonary thermodilution to monitor them, we evaluated the cardiovascular coupling when urinary output and MAP were used as endpoints. RESULTS Oxygen transport variables, heart rate, MAP, and left ventricular fractional area, did not change significantly during fluid resuscitation. Left ventricular end-systolic and end-diastolic area and global end-diastolic volume index increased from subnormal values at 12 hours to normal ranges at 24 hours after the burn. Extravascular lung water: intrathoracal blood volume ratio was increased 12 hours after the burn. CONCLUSIONS Preload variables, global systolic function, and oxygen transport recorded simultaneously by three separate methods showed no need to increase the total fluid volume within 36 hours of a major burn. Early (12 hours) signs of central circulatory hypovolemia, however, support more rapid infusion of fluid at the beginning of treatment.

Microdialysis shows metabolic effects in skin during fluid resuscitation in burn-injured patients

IntroductionEstablished fluid treatment formulas for burn injuries have been challenged as studies have shown the presence of tissue hypoxia during standard resuscitation. Such findings suggest monitoring at the tissue level. This study was performed in patients with major burn injuries to evaluate the microdialysis technique for the continuous assessment of skin metabolic changes during fluid resuscitation and up to four days postburn.MethodsWe conducted an experimental study in patients with a burn injury, as represented by percentage of total body surface area burned (TBSA), of more than 25% in a university eight-bed burns intensive care unit serving about 3.5 million inhabitants. Six patients with a median TBSA percentage of 59% (range 33.5% to 90%) and nine healthy controls were examined by intracutaneous MD, in which recordings of glucose, pyruvate, lactate, glycerol, and urea were performed.ResultsBlood glucose concentration peaked on day two at 9.8 mmol/l (6.8 to 14.0) (median and range) and gradually declined on days three and four, whereas skin glucose in MD continued to increase throughout the study period with maximum values on day four, 8.7 mmol/l (4.9 to 11.0). Controls had significantly lower skin glucose values compared with burn patients, 3.1 mmol/l (1.5 to 4.6) (p < 0.001). Lactate from burn patients was significantly higher than controls in both injured and uninjured skin (MD), 4.6 mmol/l (1.3 to 8.9) and 3.8 mmol/l (1.6 to 7.5), respectively (p < 0.01). The skin lactate/pyruvate ratio (MD) was significantly increased in burn patients on all days (p < 0.001). Skin glycerol (MD) was significantly increased at days three and four in burn patients compared with controls (p < 0.01).ConclusionDespite a strategy that fulfilled conventional goals for resuscitation, there were increased lactate/pyruvate ratios, indicative of local acidosis. A corresponding finding was not recorded systemically. We conclude that MD is a promising tool for depicting local metabolic processes that are not fully appreciated when examined systemically. Because the local response in glucose, lactate, and pyruvate metabolism seems to differ from that recorded systemically, this technique may offer a new method of monitoring organs.

Mortality After Thermal Injury: No Sex-Related Difference

BACKGROUND Young women have been reported to be more likely to survive than men after severe trauma. Girls also have less inflammation and hypermetabolism after major burns. Yet burned women have been found to have a twofold greater risk of death than men. Our aim was to find out if there is a sex-related difference in mortality after thermal injury, particularly in the age group between 16 years and 49 years, when hormonal differences would be most influential. METHODS All patients admitted to the Linköping University Hospital Burn Unit with thermal injuries during the years 1993-2008 were included and the variables percentage burned total body surface area (TBSA%), age, type of burn, mechanical ventilation, and year were included in a multiple regression (Poisson log) model. RESULTS Of 1,119 patients with thermal injury, 792 (71%) were men. Crude mortality was 5% among men, and 8% among women (p = 0.04). After adjustment for age and TBSA%, there was no correlation between mortality and sex, in any age group. Eight men and four women died in the group of young adults (16-49 years) in which TBSA% correlated with mortality (p < 0.01) but age did not. Mortality was 14% (32 of 221) among the men and 23% (23 of 102) of women in the group of older adults (50 years and older), and both age and TBSA% correlated with mortality (p < 0.001). CONCLUSIONS There is no relevant sex-related difference in survival after thermal injury. The conclusion is, however, tempered by the few deaths, particularly among younger adults.

Cardiac dysfunction after burns

OBJECTIVES Using transoesophageal echocardiography (TEE) we investigated the occurrence, and the association of possible abnormalities of motion of the regional wall of the heart (WMA) or diastolic dysfunction with raised troponin concentrations, or both during fluid resuscitation in patients with severe burns. PATIENTS AND METHODS Ten consecutive adults (aged 36-89 years, two women) with burns exceeding 20% total burned body surface area who needed mechanical ventilation were studied. Their mean Baux index was 92.7, and they were resuscitated according to the Parkland formula. Thirty series of TEE examinations and simultaneous laboratory tests for myocyte damage were done 12, 24, and 36h after the burn. RESULTS Half (n=5) the patients had varying grades of leakage of the marker that correlated with changeable WMA at 12, 24 and 36h after the burn (p< or =0.001, 0.044 and 0.02, respectively). No patient had WMA and normal concentrations of biomarkers or vice versa. The mitral deceleration time was short, but left ventricular filling velocity increased together with stroke volume. CONCLUSION Acute myocardial damage recorded by both echocardiography and leakage of troponin was common, and there was a close correlation between them. This is true also when global systolic function is not deteriorated. The mitral flow Doppler pattern suggested restrictive left ventricular diastolic function.

Standardised mortality ratio based on the sum of age and percentage total body surface area burned is an adequate quality indicator in burn care: An exploratory review

Standardised Mortality Ratio (SMR) based on generic mortality predicting models is an established quality indicator in critical care. Burn-specific mortality models are preferred for the comparison among patients with burns as their predictive value is better. The aim was to assess whether the sum of age (years) and percentage total body surface area burned (which constitutes the Baux score) is acceptable in comparison to other more complex models, and to find out if data collected from a separate burn centre are sufficient for SMR based quality assessment. The predictive value of nine burn-specific models was tested by comparing values from the area under the receiver-operating characteristic curve (AUC) and a non-inferiority analysis using 1% as the limit (delta). SMR was analysed by comparing data from seven reference sources, including the North American National Burn Repository (NBR), with the observed mortality (years 1993-2012, n=1613, 80 deaths). The AUC values ranged between 0.934 and 0.976. The AUC 0.970 (95% CI 0.96-0.98) for the Baux score was non-inferior to the other models. SMR was 0.52 (95% CI 0.28-0.88) for the most recent five-year period compared with NBR based data. The analysis suggests that SMR based on the Baux score is eligible as an indicator of quality for setting standards of mortality in burn care. More advanced modelling only marginally improves the predictive value. The SMR can detect mortality differences in data from a single centre.

Hand Function, Experienced Pain, and Disability After Distal Radius Fracture

OBJECTIVE We sought to explore differences in range of motion (ROM), grip strength, and self-reported pain and disability over time after plate-fixation surgery for distal radius fracture. METHOD We used a prospective repeated-measures research design with four measure points for a study sample of 101 patients. The Disabilities of the Arm, Shoulder and Hand (DASH) Questionnaire; the Global Assessment Scale; and the Canadian Occupational Performance Measure were used to assess ROM, grip strength, and pain level. RESULTS ROM and grip strength improved over time. Pain improved until 6 mo after surgery but greatly deteriorated from 6 to 24 mo. Concurrently, overall discomfort (global index) from the wrist extensively improved from 12 to 24 mo. DASH score decreased 20.1 points from 6 wk to 6 mo and remained stable until 24 mo. CONCLUSION Even when ROM and grip strength were almost fully regained at 12 mo, pain at rest and during activity was still an issue at 24 mo.

Inclusion of coexisting morbidity in a TBSA% and age based model for the prediction of mortality after burns does not increase its predictive power.

INTRODUCTION Several models for predicting mortality have been developed for patients with burns, and the most commonly used are based on age and total body surface area (TBSA%). They often show good predictive precision as depicted by high values for area under the receiver operating characteristic curves (AUC). However the effect of coexisting morbidity on such prediction models has not to our knowledge been thoroughly examined. We hypothesised that adding it to a previously published model (based on age, TBSA%, full thickness burns, gender, and need for mechanical ventilation) would further improve its predictive power. METHODS We studied 772 patients admitted during the period 1997-2008 to the Linköping University Hospital, National Burn Centre with any type of burns. We defined coexisting morbidity as any of the medical conditions listed in the Charlson list, as well as psychiatric disorders or drug or alcohol misuse. We added coexisting medical conditions to the model for predicting mortality (age, TBSA%, and need for mechanical ventilation) to determine whether it improved the model as assessed by changes in deviances between the models. RESULTS Mean (SD) age and TBSA% was 35 (26) years and 13 (17) %, respectively. Among 725 patients who survived, 105 (14%) had one or more coexisting condition, compared with 28 (60%) among those 47 who died. The presence of coexisting conditions increased with age (p<0.001) among patients with burns. The AUC of the mortality prediction model in this study, based on the variables age, TBSA%, and need for mechanical ventilation was 0.980 (n=772); after inclusion of coexisting morbidity in the model, the AUC improved only marginally, to 0.986. The model was not significantly better either. CONCLUSION Adding coexisting morbidity to a model for prediction of mortality after a burn based on age, TBSA%, and the need for mechanical ventilation did not significantly improve its predictive value. This is probably because coexisting morbidity is automatically adjusted for by age in the original model.