Joachim Zdolsek

Utility of an intervention scoring system in documenting effects of changes in burn treatment

The consequences of the introduction of a program of consistent use of topical antimicrobials and early aggressive excision of deep burn wounds by utilizing a comprehensive, computerized patient registry/therapeutic intervention scoring system, were investigated. Prospectively, the clinical course, mortality, outcome and hospital costs were compared for the year preceding (89 patients) and the 4 years following (226 patients) the introduction of the new treatment program. It was found that mortality decreased from 10.1 to 4.6% after change in therapy (P<0.001), despite an increase in mean burn extent. The length of hospital stay per % burn surface area declined from 1.2 to 1.0 days (P<0.001). The number and complexity of therapeutic interventions and the associated costs, also declined. Patients in the new treatment program had a better level of physical and psychosocial function at follow up. In conclusion, the introduction of a program of consistent use of topical antimicrobials and early, aggressive surgical excision was associated with an improved outcome at lesser cost. The combined registry-intervention scoring system permits ready analysis of results using data entered on a daily, near-real time basis.

Non-invasive monitoring of blood haemoglobin for analysis of fluid volume kinetics.

Background: A commercially available pulse oximeter that reports blood haemoglobin (Hb) concentration is evaluated. This study considers whether this device can provide serial Hb data that would be sufficiently reliable for volume kinetic analysis of infusion fluids.

Interactions between the volume effects of hydroxyethyl starch 130/0.4 and Ringer´s acetate

IntroductionThe turnover of Ringer´s solutions is greatly dependent on the physiological situation, such as the presence of dehydration or anaesthesia. The present study evaluates whether the kinetics is affected by previous infusion of colloid fluid.MethodsTen male volunteers with a mean age of 22 years underwent three infusion experiments, on separate days and in random order. The experiments included 10 mL/kg of 6% hydroxyethyl starch 130/0.4 (Voluven™), 20 mL/kg of Ringers acetate, and a combination of both, where Ringer´s was administered 75 minutes after the starch infusion ended. The kinetics of the volume expansion was analysed by non-linear least- squares regression, based on urinary excretion and serial measurement of blood haemoglobin concentration for up to 420 minutes.ResultsThe mean volume of distribution of the starch was 3.12 L which agreed well with the plasma volume (3.14 L) estimated by anthropometry. The volume expansion following the infusion of starch showed monoexponential elimination kinetics with a half-life of two hours. Two interaction effects were found when Ringer´s acetate was infused after the starch. First, there was a higher tendency for Ringer´s acetate to distribute to a peripheral compartment at the expense of the plasma volume expansion. The translocated amount of Ringer´s was 70% higher when HES had been infused earlier. Second, the elimination half-life of Ringer´s acetate was five times longer when administered after the starch (88 versus 497 minutes, P <0.02).ConclusionsStarch promoted peripheral accumulation of the later infused Ringer´s acetate solution and markedly prolonged the elimination half-life.Trial registrationClinicalTrials.gov: NCT01195025

Preoperative urine-specific gravity and the incidence of complications after hip fracture surgery: A prospective, observational study.

BACKGROUND Mild to moderately severe dehydration is common in the elderly, but its relationship to surgical outcome is unclear. OBJECTIVES To study the incidence of dehydration prior to hip fracture surgery and its relationship to postoperative complications. DESIGN Prospective observational study. SETTING Operation department and orthopaedic ward at a regional hospital. PATIENTS Forty-five patients [median (interquartile range) age 78 (75 to 86) years] undergoing acute hip fracture surgery. INTERVENTIONS A urine sample was taken on admission to the operating theatre. Complications were assessed 2 days postoperatively using a check-list. MAIN OUTCOME MEASURES Dehydration was considered to be present if the urinary specific gravity was 1.020 or higher, indicating renal water conservation. The number and type of postoperative complications were recorded. RESULTS Dehydration was present in one third of the patients. Sixty percent of these patients had at least one postoperative complication, whereas the corresponding proportion was 30% in the euhydrated patients (P <0.01). Only one patient (3%) had more than one complication in the euhydrated group compared with six patients (40%) in the dehydrated group (P <0.01). Euhydrated patients had a mean of 0.3 postoperative complications per surgery, whereas dehydrated patients scored 1.1 complications (P <0.015). The higher incidence included confusion, arterial desaturation and cardiovascular events. CONCLUSION Dehydration before surgery nearly quadrupled the number of postoperative complications after hip fracture repair. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT 01294930.

Detection of dehydration by using volume kinetics.

BACKGROUND:Patients admitted to surgery may be dehydrated, which is difficult to diagnose except when it is severe (>5% Gl116 of the body weight). We hypothesized that modest dehydration can be detected by kinetic analysis of the blood hemoglobin concentration after a bolus infusion of crystalloid fluid. METHODS:Four series of experiments were performed on 10 conscious, healthy male volunteers. Separated by at least 2 days, they received 5 or 10 mL/kg acetated Ringers solution over 15 minutes. Before starting half of the IV infusions, volume depletion amounting to 1.5 to 2.0 L (approximately 2% of body weight) was induced with furosemide. The elimination clearance and the half-life of the infused fluid were calculated based on blood hemoglobin over 120 minutes. The perfusion index and the pleth variability index were monitored by pulse oximetry after a change of body position. RESULTS:Dehydration decreased the elimination clearance of acetated Ringers solution [median (25th–75th percentile)] from 1.84 (1.23–2.57) to 0.53 (0.41–0.79) mL/kg/min (Wilcoxon matched-pair test P < 0.001) and increased the half-life from 23 (12–37) to 76 (57–101) minutes (P < 0.001). The smaller infusion, 5 mL/kg, fully discriminated between experiments performed in the euhydrated and dehydrated states, whereas the urinary excretion provided a less-reliable indication of hydration status. Dehydration decreased the perfusion index but did not affect the pleth variability index. CONCLUSION:Dehydration amounting to 2% of the body weight could be detected from the elimination clearance and the half-life of an infusion of 5 mL/kg Ringers solution.

Measuring the Size of the Extracellular Fluid Space Using Bromide, Iohexol, and Sodium Dilution

There is a need to find methods to assess the size of the extracellular fluid (ECF) volume without involving radioactive tracers. For this purpose, we applied 3 methods for measuring the ECF volume in 10 male volunteers (mean age, 34 yr). Steady-state plasma bromide concentration (control) was compared to the results of kinetic analysis of plasma iohexol and to kinetic analysis of the dilution of serum sodium after IV infusion of 1 L of isotonic mannitol. The volume of distribution of these tracers was used to indicate the ECF volume. The results disclosed statistically significant correlations between the results of all 3 methods, although the average sodium dilution showed 0.7 L lower values than iohexol and 1.4 L lower than bromide. All three methods correlated significantly with body weight. The percentage of the body weight indicated by the methods was 18.3% (3.1%) for sodium, 19.6% (1.0%) for iohexol, and 20.5% (1.1%) for bromide. We conclude that sodium dilution may be performed at bedside but iohexol and bromide showed less intersubject variability. Iohexol simultaneously measures the glomerular filtration rate and should be a viable clinical option if the hospital performs routine assessments of kidney function using this tracer.

Distribution of crystalloid fluid changes with the rate of infusion: a population-based study.

Crystalloid fluid requires 30 min for complete distribution throughout the extracellular fluid space and tends to cause long‐standing peripheral edema. A kinetic analysis of the distribution of Ringer′s acetate with increasing infusion rates was performed to obtain a better understanding of these characteristics of crystalloids.

Accuracy of noninvasive haemoglobin measurement by pulse oximetry depends on the type of infusion fluid.

Context Measurement of blood haemoglobin concentration by pulse oximetry could be of value in determining when erythrocytes should be transfused during surgery, but the effect of infusion fluids on the results is unclear. Objective To study the effect of crystalloid and colloid fluid on the accuracy (bias) and precision of pulse oximetry haemoglobin estimation to indicate the venous haemoglobin concentration in volunteers. Design Open interventional crossover study. Setting Single university hospital. Participants Ten male volunteers aged 18–28 (mean 22) years. Interventions Each volunteer underwent three infusion experiments on separate days and in random order. The infusions were Ringers acetate (20 ml kg−1), hydroxyethyl starch 130/0.4 (10 ml kg−1) and a combination of both. Results At the end of the infusions of Ringers acetate, pulse oximetry haemoglobin concentration had decreased more than the true haemoglobin concentration (15 vs. 8%; P < 0.005; n = 10) whereas starch solution decreased pulse oximetry haemoglobin concentration less than true haemoglobin concentration (7 vs. 11%; P < 0.02; n = 20). The same differences were seen when the fluids were infused separately and when they were combined. The overall difference between all 956 pairs of pulse oximetry haemoglobin concentration and true haemoglobin concentrations (the bias) averaged only −0.7 g l−1 whereas the 95% prediction interval was wide, ranging from −24.9 to 23.7 g l−1. In addition to the choice of infusion fluid, the bias was strongly dependent on the volunteer (each factor, P < 0.001). Conclusion The bias of measuring haemoglobin concentration by pulse oximetry is dependent on whether a crystalloid or a colloid fluid is infused. Trial registration ClinicalTrials identifier: NCT01195025.CONTEXT Measurement of blood haemoglobin concentration by pulse oximetry could be of value in determining when erythrocytes should be transfused during surgery, but the effect of infusion fluids on the results is unclear. OBJECTIVE To study the effect of crystalloid and colloid fluid on the accuracy (bias) and precision of pulse oximetry haemoglobin estimation to indicate the venous haemoglobin concentration in volunteers. DESIGN Open interventional crossover study. SETTING Single university hospital. PARTICIPANTS Ten male volunteers aged 18-28 (mean 22) years. INTERVENTIONS Each volunteer underwent three infusion experiments on separate days and in random order. The infusions were Ringers acetate (20 ml kg), hydroxyethyl starch 130/0.4 (10 ml kg) and a combination of both. RESULTS At the end of the infusions of Ringers acetate, pulse oximetry haemoglobin concentration had decreased more than the true haemoglobin concentration (15 vs. 8%; P < 0.005; n = 10) whereas starch solution decreased pulse oximetry haemoglobin concentration less than true haemoglobin concentration (7 vs. 11%; P < 0.02; n = 20). The same differences were seen when the fluids were infused separately and when they were combined. The overall difference between all 956 pairs of pulse oximetry haemoglobin concentration and true haemoglobin concentrations (the bias) averaged only -0.7 g l whereas the 95% prediction interval was wide, ranging from -24.9 to 23.7 g l. In addition to the choice of infusion fluid, the bias was strongly dependent on the volunteer (each factor, P < 0.001). CONCLUSION The bias of measuring haemoglobin concentration by pulse oximetry is dependent on whether a crystalloid or a colloid fluid is infused. TRIAL REGISTRATION ClinicalTrials identifier: NCT01195025.

Human postburn oedema measured with the impression method

The course of tissue swelling in human non-injured skin after burn injury was investigated with a non-invasive impression method that measures force and tissue fluid translocation during mechanical compression of the skin. Time-dependent changes in the fluid translocation and the interstitial-pressure related to impression force were measured on 11 occasions, during 3 weeks, in seven patients postburn. A mathematical model was fitted to the impression force curves and the parameters of the model depicted the time-dependent compartmental fluid shift in the postburn generalized oedema. Tissue fluid translocation increased significantly (P < 0.05) up to a maximum value after 6 days postburn and declined thereafter. This indicated a continuous increase in the generalized postburn oedema for the first 6 days postburn. Impression force at 3 weeks postburn was significantly lower (P < 0.001) as compared with the half-day postburn value, indicating an increased tissue pressure during the first days postburn. Parameter analysis indicated a flux of water-like fluid from the vasculature to the interstitial space during the first 6 days postburn. The spread of the values registered between different measurement sites was, however, large.

Non-invasive blood haemoglobin and plethysmographic variability index during brachial plexus block

BACKGROUND Plethysmographic measurement of haemoglobin concentration ([Formula: see text]), pleth variability index (PVI), and perfusion index (PI) with the Radical-7 apparatus is growing in popularity. Previous studies have indicated that [Formula: see text] has poor precision, particularly when PI is low. We wanted to study the effects of a sympathetic block on these measurements. METHODS Twenty patients underwent hand surgery under brachial plexus block with one Radical-7 applied to each arm. Measurements were taken up to 20 min after the block had been initiated. Venous blood samples were also drawn from the non-blocked arm. RESULTS During the last 10 min of the study, [Formula: see text] had increased by 8.6%. The PVI decreased by 54%, and PI increased by 188% in the blocked arm (median values). All these changes were statistically significant. In the non-blocked arm, these parameters did not change significantly. CONCLUSIONS Brachial plexus block significantly altered [Formula: see text], PVI, and PI, which indicates that regional nervous control of the arm greatly affects plethysmographic measurements obtained by the Radical-7. After the brachial plexus block, [Formula: see text] increased and PVI decreased.