Toxic and essential trace metals in first baby haircuts and mother hair from Imam Hossein Hospital Tehran, Iran.

Hair metal level in newborn and mother pairs from Iran is reported. Toxic metals including cadmium (157 vs. 87.5 µg/kg), mercury (246 vs. 198 µg/kg), copper (14,313 vs. 11,776 µg/kg) and aluminum (52,022 vs. 408,207 µg/kg) were higher in newborn hair when compared to their mothers; suggesting that metals maybe discarded in the fetus as a detoxification method. Comparison with available data from Germany and Poland, and Iraq suggests overall similarities and significant differences in the case of the Iraqi subjects. Public protection from mixture toxicity of metals will be facilitated by studies such as ours.

A quantitative method for cost reimbursement and length of stay quality assurance in multiple trauma patients.

OBJECTIVE: To develop a statistically valid method for trauma reimbursement and quality assurance (QA) length-of-stay filters. This is needed because diagnosis related group (DRG)-based trauma payment systems assume a random sampling of injury severities from a normally distributed population and thus result in economic disincentives to level I trauma centers. METHODS: 142 trauma patients with MVC blunt multisystem injuries (MSI) (ISS > or = 16) were studied concurrently during their hospital course. SETTING: Level I regional trauma center. OUTCOME MEASURES: Outcome measures were (dependent variables) length of stay (LOS) and state-approved hospital charges (COST). RESULTS: Mean acute care COST was $74,310, but the distribution of COST was log normal, rather than Gaussian normal as assumed by DRGs. The LOS for MSI was more than twice the average for all trauma (22 vs. 9 days), reflecting skewed severities of level I patients and was related to COST (r2 = 0.802; p < 0.0001). The ISS alone was a weak determinant of COST or LOS (r2 = 0.05; p < 0.0001). The best single determinant of COST and LOS was survival (r2 = 0.15; p < 0.0001): as it increased, it increased LOS. The most costly injuries (all p < 0.0001) involved the lower extremity (LE) or hip joint (HIP), whereas sepsis and pulmonary and surgical complications constituted the most costly complications (all p < 0.0001). Regression models that accounted for the log-normal distribution of the dependent variable and based on binary variables for survival, LE and HIP injuries, and the complications of sepsis, ARDS, pulmonary failure, MOFS, plus ISS, explained nearly two thirds of the variability in COST (r2 = 0.621; p < 0.0001) or LOS (r2 = 0.687; p < 0.0001) and the residuals were normally distributed. CONCLUSIONS: These models provide a valid method of reimbursement for MSI trauma for level I trauma centers, since the data imply that good care associated with survival from specific complications of MSI are the major determinants of COST, rather than the specific type of injury or the resultant ISS. Moreover, using survival and ISS plus the disease-related complications as determinants of LOS, this method can be applied to any U.S. region since local factors can be used to adjust hospital COST as a highly correlated function of LOS. This method also permits identification of LOS outliers for QA, taking into account the influence of injury complications.

Correlation between measured energy expenditure and clinically obtained variables in trauma and sepsis patients.

BACKGROUND: Indirect calorimetry is the preferred method for determining caloric requirements of patients, but availability of the device is limited by high cost. A study was therefore conducted to determine whether clinically obtainable variables could be used to predict metabolic rate. METHODS: Patients with severe trauma or sepsis who required mechanical ventilation were measured by an open-circuit indirect calorimeter. Several clinical variables were obtained simultaneously. Measurements were repeated every 12 hours for up to 10 days. RESULTS: Twenty-six trauma and 30 sepsis patients were measured 423 times. Mean resting energy expenditure was 36 +/- 7 kcal/kg (trauma) vs 45 +/- 8 kcal/kg (sepsis) (p < .0001). The single strongest correlate with resting energy expenditure was minute ventilation (R2 = 0.61, p < .0001). Doses of dopamine, dobutamine, morphine, fentanyl, and neuromuscular blocking agents each correlated positively with resting energy expenditure. In the case of the inotropics and neuromuscular blockers, there was a probable covariance with severity of illness. A multiple regression equation was developed using minute ventilation, predicted basal energy expenditure, and the presence or absence of sepsis: resting energy expenditure = -11000 + minute ventilation (100) + basal energy expenditure (1.5) + dobutamine dose (40) + body temperature (250) + diagnosis of sepsis (300) (R2 = 0.77, p < .0001). CONCLUSION: Severe trauma and sepsis patients are hypermetabolic, but energy expenditure is predictable from clinical data. The regression equations probably apply only to severe trauma and sepsis. Other studies should be conducted to predict energy expenditure in other patient types.

Causes and costs of injuries in multiple trauma patients requiring extrication from motor vehicle crashes.

Prospective and contemporaneous medical and economic cost studies of 144 victims of motor vehicle crashes admitted to a regional level I trauma center with multiple injuries (ISS > or = 16) revealed 122 non-ejected patients, of whom 102 required extrication (EXTRIC) from the vehicle for physical or medical reasons and 20 who did not (N group). There were no differences in age (EXTRIC, 34 +/- 17 years; N, 41 +/- 24 years), type of crash (Frontal: 57% EXTRIC, 60% N; Lateral: 32% EXTRIC, 35% N) restraint use (35% EXTRIC, 35% N), or mortality (29% EXTRIC, 30% N). However, the estimated maximum speed before the crash was higher in EXTRIC patients (50 +/- 16 mph vs. 46 +/- 18 mph N, p < 0.04), as was the change in velocity (delta V) on impact (EXTRIC 30 +/- 15 mph; N, 24 +/- 8 mph, p < 0.01). Brain injuries (51% EXTRIC vs. 35% N) and lower extremity injuries were more numerous in EXTRIC patients (59% vs. 20% N, p < 0.003) and the number of splenic, lower extremity, and pelvic injuries associated with shock was greater in EXTRIC patients, p < 0.02; as were postinjury complications. As a result, operating room costs from orthopedic and plastic surgery increased professional charges in the EXTRIC group versus the N group ($20,000, EXTRIC; $17,000, N) and critical care costs ($13,000, EXTRIC; $4,000, N) with total costs of $72,000 and $77,000, respectively. The lower extremity injuries in EXTRIC patients were primarily a result of body part contacts with intrusions (CIs) of the car occupant compartment structures [73% with vs. 24% without (p < 0.0001)]. In lateral MVCs, brain injuries were also more commonly associated with CIs of the side window frame or A pillar (72% CI vs. 25% no CI; p < 0.035); but as a whole in MVCs in which extrication was necessary, lower extremity injuries from instrument panel or toepan CIs appeared more frequent than those resulting from contacts only (p < 0.0001). In EXTRIC patients, 69% of those in shock had CI injuries, and 80% of the deaths in the EXTRIC group were associated with CI injury. These data suggest that measures designed to prevent CIs by strengthening car passenger compartment structures may reduce the incidence of severe brain and lower extremity injuries and may reduce the need for extrication after MVCs.

Amino acid loss and plasma concentration during continuous hemodiafiltration.

Amino acid loss, plasma concentration, and the relationship between amino acid intake and balance during continuous hemodiafiltration (CHD) were investigated in a prospective, nonrandomized study of trauma patients exhibiting the systemic inflammatory response with acute renal failure. Data were compared with those from a group of similar patients who had maintained renal function (control). Both groups received similar amounts of nonprotein calories (3015 +/- 753 nonprotein calories per day in the control group vs 3077 +/- 1018 nonprotein calories per day in the CHD group) and amino acids (2.24 +/- 0.36 g/kg per day in the control group vs 2.19 +/- 0.48 g/kg per day in the CHD group) via the parenteral route. Amino acid solutions were either 19% or 45% branched-chain amino acid enriched. Studies were performed every 12 hours for a maximum of 6 days. Amino acid loss was 2.5 +/- 2.3 g/12 h in the control group vs 6.6 +/- 2.4 g/12 h in the CHD group (p < .0001). Increasing the dialysate rate from 15 to 30 mL/min increased amino acid loss from 5.7 +/- 1.7 to 7.9 +/- 2.6 g/12 h (p < .0001). Amino acid loss was unrelated to amino acid intake but was directly related to plasma amino acid concentration, CHD effluent volume, and the efficiency of filtration as measured by the ratio of filtered urea nitrogen to blood urea nitrogen (R2 = .69). A linear relationship was found between amino acid intake and balance (R2 = .991). The patterns of plasma amino acid concentrations were consistent with metabolic changes wrought by a combination of sepsis and multiple organ dysfunction and type of amino acid intake but seemed unaffected by increased amino acid loss in CHD effluent. Amino acid losses were 2 to 3 times greater from CHD than from normal kidney. However, CHD amino acid losses may not be clinically significant unless amino acid intake is restricted to levels used typically in traditional hemodialysis.

Effect of associated injuries and blood volume replacement on death, rehabilitation needs, and disability in blunt traumatic brain injury.

OBJECTIVE: To examine the effects of associated injuries on death, disability, rehabilitation needs, and cost in patients with blunt traumatic brain injury. DESIGN: A retrospective case series analysis of 1,709 patients with blunt traumatic brain injury, or 37.2% of 4,590 consecutive blunt trauma patients, was combined with a prospective study of a subset of 202 of the 1,709 brain-injured patients obtained during the same time period with regard to need for rehabilitation services, residual disability, and costs at 1 yr after discharge from the acute trauma center. SETTING: A level I regional trauma center that is also the statewide neurotrauma and multiple trauma unit serving a population of more than 3 million persons. RESULTS: Contingency table analysis showed the Glasgow Coma Scale to be highly predictive (p less than .0001) of likelihood of mortality, need for postacute inpatient rehabilitation, or discharge home. Of the blunt traumatic brain injury patients, 40.4% (691) had an isolated brain injury and 59.6% (1,018) had brain plus at least one other systemic injury. The mortality rate of the isolated brain injury group was 11.1% compared with 21.8% in all brain plus systemic injury groups (p less than .0001). Spine, lung, visceral, pelvis, or extremity injuries in blunt traumatic brain injury all increased mortality rate to greater than 25% (all simultaneously significant, p less than .0001). Analysis of the interaction of brain injury (quantified by Glasgow Coma Scale) with blood replacement in the initial 24 hrs showed that at any Glasgow Coma Scale range, percent mortality increased as the volume of blood increased. Hypovolemic shock increased the mortality rate from 12.8% to 62.1% (p less than .0001). The need for postacute inpatient rehabilitation in survivors also increased as blood replacement increased, and shock increased the percent of patients requiring post-acute inpatient rehabilitation from 39.7% to 60.3%. In 202 consecutive surviving brain trauma patients followed for 1 yr, isolated brain-injured patients with moderate brain injuries had a 4% need for posttrauma, postacute inpatient rehabilitation with a total cost per case of $12,489 compared with the brain plus extremity injury group, who had a 23% postacute inpatient rehabilitation rate and a total cost per case of $36,177 at 1 yr. With severe brain injury, isolated brain injury increased postacute inpatient rehabilitation to 29% and 1-yr cost to $59,274, but with the brain plus extremity injury group, postacute inpatient rehabilitation increased to 49% and cost to $84,950. CONCLUSIONS: In blunt traumatic brain injury, the addition of major visceral or extremity injuries, with need for blood replacement or shock, increases the risk of death, the need for rehabilitation, and the costs of disability.

Leucine dose response in the reduction of urea production from septic proteolysis and in the stimulation of acute-phase proteins.

The administration of branched-chain amino acids (BCAAs) has been proved useful in reducing both urea nitrogen production and muscle proteolysis in trauma patients with sepsis, but the optimum infusion rate to achieve these effects is still in question. In this prospective randomized study, a group of 16 posttrauma patients with sepsis received a branched chain-enriched (BCAA = 49.4%) amino acid mixture (8 patients; 120 observations) or a standard amino acid infusion (BCAAs = 15.5%; 8 patients; 227 observations). Total calories, percent lipid calories, and amino acid nitrogen administration were not different in the two groups. Each patient was studied at 8-hour intervals for the plasma levels of amino acids, six hepatic acute-phase proteins, albumin, and other metabolic parameters, including urinary urea nitrogen and 3-methylhistidine excretion. The total intake of each amino acid and its clearance were calculated and the dose of leucine during each 8-hour period was related to the leucine clearance, plasma acute-phase protein levels, and the urinary production of urea and 3-methylhistidine, as an indicator of proteolysis. The results show a significant (r2 = 0.691; p less than 0.0001) reduction of urea nitrogen production and proteolysis as a function of the increase in leucine dose. The identification of a critical mean rate of leucine infusion has been derived from the analysis of the significant linear correlation between leucine intake and leucine clearance (r2 = 0.594; p less than 0.0001). Significant positive correlations between the leucine intake dose and the platelet count (r2 = 0.402; p less than 0.0001), the plasma fibrinogen level (r2 = 0.218; p less than 0.0001), and the regression-derived sum of six acute-phase proteins plus albumin (r2 = 0.696; p less than 0.0001) were found. The increase in leucine clearance was progressively less marked above a mean daily leucine intake rate of 1.4 mumol/kg/min, which also appeared to be the dose level that maximized the acute-phase protein and coagulation effects and reduced proteolysis and urea nitrogen production, suggesting that this is a critical BCAA infusion rate at which an optimum leucine effect occurs. From these data a BCAA (leucine) dose nomogram has been derived.

Oxygen debt and metabolic acidemia as quantitative predictors of mortality and the severity of the ischemic insult in hemorrhagic shock.

BACKGROUND AND METHODS: An experimental canine model of hemorrhagic, hypovolemic shock is described that uses oxygen debt and its metabolic consequences of lactic acidemia and metabolic base deficit as independent variables for the prediction of probability of death. RESULTS: Lactic acidemia and metabolic base deficit are compared with the conventional hemodynamic variables of BP and cardiac output (Qt) as predictors of outcome and are shown to be superior using a modified Kaplan-Meier probability statistic. The LD50 for oxygen debt is shown to be 113.5 mL/kg, 12.9 mmol/L for lactate, and -18.8 mmol/L for base excess (BE). Comparison is made between the ability of Qt, BP, shed blood, BE, and lactate to predict oxygen debt. CONCLUSIONS: Of the single-variable predictors, BE shows the highest explained variability. However, a combined prediction from both lactate and BE appears superior to the use of either alone. Using this regression to compute the oxygen debt, it is possible to estimate accurately the actual level of oxygen debt from the BE and lactate values obtained during hemorrhagic hypovolemia. From serial determinations over time of the increase in these biochemical variables above the oxygen debt baseline, it is possible to estimate the rate of oxygen debt accumulation and the time remaining until the LD50 will be reached as indicators of the severity of the total body ischemia resulting from hemorrhagic shock.

Early physiologic predictors of injury severity and death in blunt multiple trauma.

The importance of admission physiological and biochemical variables was modeled on data from 185 patients with blunt liver trauma with regard to their significance in prediction of mortality. The variables used were admission Glasgow Coma Score, base excess (or deficit), arterial lactate, Injury Severity Score, and initial 24-hour volume of blood required for replacement. Each variable was modeled as a predictor of survival alone and in combination, using a linear logistic model. In any two-variable combination, Glasgow Coma Score had a high likelihood ratio for prediction representing the influence of brain injury. But as a single variable reflecting the probability of death, both base excess (LD50 = -11.8 mmol/L) and initial 24-hour volume of blood (LD50 = 5.4 L) were highly significant. A combined logistic model of admission Glasgow Coma Score and base excess had the greatest likelihood of accurate prediction of outcome: P death = e lambda/l + e lambda; where lambda = -0.21(Glasgow Coma Score) -0.147(base excess) + 0.285. Testing of this predictive model on data from 323 additional patients with multiple trauma who had pelvic fracture as their index injury also showed it to be a highly significant early predictor of outcome.

Probability and the patient state space.

This paper describes work to develop a model-based system to support clinical decision-making. In previous articles, we have developed (from 695 measurement sets obtained from 148 patients) a physiologic state classification based on a set of 11 cardiovascular and metabolic measurements. There is an R or reference state, for stable ICU patients. Patients under (operative, traumatic, or compensated septic) stress, or with (septic or hepatic) metabolic, respiratory, or cardiac insufficiency are in the A, B, C, or D states, respectively. We wished to make the state easier to measure and eventually available continuously, automatically, and noninvasively, as well as reflecting a wider group of bodily systems. The 5 centers define a 4 dimensional affine subspace, designated the cardiovascular state space. Using eigenvector analysis, we have found four new derived physiologic variables CV1, CV2, CV3, and CV4 that span the state space. We have fit sets of linear regression equations that allow the patient's position in the state space, and therefore his state, to be determined from more easily obtainable sets of measurements. Further, we selected 1966 measurement sets from 512 patients at two hospitals. We used the data from 250 of these patients to define 13 prototypical types, namely survivors and deaths from various combinations of sepsis, cardiogenic decompensation, cirrhosis, and pneumonitis, following trauma or general surgery. For any future patient, the statistical theory of Bayesian inference allows one to infer back from the measurements observed to the probability of his being of any of these types and of surviving or dying. We used this method to predict the outcome of the other 262 patients, prospectively. Statistically, the predictions of survival or death were not significantly different from the actual. For individual patients, the method predicts a clinical course that closely follows the actual episodes in their history. These results confirm and explain the validity of the concept of the patient state and make the state easier to compute. The patient state and the probability plot together help to stage, select, and evaluate therapy. They do not replace the clinician's judgement, but rather are tools that help the clinician to exercise judgement.

Prediction of arterial blood gases by transcutaneous O2 and CO2 in critically ill hyperdynamic trauma patients.

The management of severe adult respiratory distress syndrome in critically injured patients requires the frequent measurement of arterial blood gases for adjustment of cardiovascular and ventilatory support. Since these require blood withdrawal and laboratory determinations, a noninvasive method of assessment of arterial gas tensions would permit more frequent assessment of the patient as well as permitting rapid changes in the patient's ventilatory status to be detected earlier in the clinical course. The role of transcutaneous O2 and CO2 tension in providing these measurements was evaluated in 92 studies in 38 critically ill patients with ARDS due to trauma and/or sepsis. All patients were normodynamic or hyperdynamic at the time of study (cardiac index 2.5 to 7.6 L/min/m2) and were intubated and on increased inspired oxygen fractions (FIO2 = 30 to 100%) delivered by mechanical ventilation, had a range of body temperature from 35.0 to 39.5 degrees C and pH from 7.29 to 7.57 The data from a transcutaneous O2 and CO2 sensor applied to the skin of the anterior thorax were analyzed by multiple regression analysis of variances. Prediction of the arterial oxygen tension (PaO2) from 52 to 253 torr was possible from regression-corrected measurements of the transcutaneous O2 (TcO2): [PaO2 = 1.1 (TcO2) - 0.28 (FIO2) + 45.5]. The arterial carbon dioxide tension (PaCO2) from 26 to 57 torr was predicted from the transcutaneous CO2 (TcCO2):[PaCO2 = 0.76 (TcCO2) + 0.06 (FIO2) + 0.035 (TcO2) + 4.1]. With these corrections, a noninvasive Respiratory Index was computed for assessing ARDS severity, and dynamic changes in arterial gases could be followed in response to postural changes, ventilatory alterations, or cardiovascular perturbations. These data suggest that a reasonable estimate of the arterial blood gases can be obtained from a regression-corrected measurement of the transcutaneous O2 and CO2 tensions in critically injured normodynamic or hyperdynamic ARDS patients.

Advanced signal-processing method for the detection, localization, and quantification of acute myocardial ischemia.

In this study of a canine heart model of localized reversible ischemia, a computer-based single-processing method is developed to detect and localize the epicardial projections of ischemic myocardial electrocardiograms (ECGs) during the cardiac activation, rather than the repolarization, phase. This is done by transforming ECG signals from an epicardial sensor array into the multichannel spectral domain and identifying three decision variables: (1) the frequency in hertz of the spectral peak (f0), its frequency band width 50% below the peak value (w0), and the maximum eigenvalue difference of the ECG signal's autocorrelation matrix (e0). With use of the histograms of the f0, w0, and e0 parameters of 3256 ECGs from normal and 957 from ischemic areas of myocardium obtained from 12 dogs, it was possible to predict ischemia in a new test group of nine animals from a Neyman-Pearson (NP) test in which the threshold probabilities of detecting ischemia for each decision variable are compared with those of detecting normality. Quantification of each sensor area by the NP tests revealed that, compared with the control, ECG spectra with decreased F0 and w0 and increased e0 relative to their respective thresholds had increased myocardial lactate (p less than 0.01), decreased adenosine triphosphate (ATP) (p less than 0.05), and reduced creatine phosphate (p less than 0.01). Prediction of f0 (p less than 0.0006) as a continuous variable could be obtained from the regression of the myocardial levels of ATP plus creatine phosphate, which demonstrated that this decision variable appears to directly reflect myocardial energetics. It appears that an advanced signal-processing method for ECG array data can be used to detect, localize, and quantify reversible myocardial ischemia.

Time series modeling of neuromuscular system.

The dynamic response of the human ankle joint to a bandlimited random torque perturbation superimposed on a constant bias torque is observed in normal human subjects. The applied torque input, the joint angular rotation output, and the electromyographic activity using surface electrodes from the extensor and the flexor muscles of the ankle joint were recorded. Transfer function models using time series techniques were developed for the torque - angular rotation input-output pair and for the angular rotation - electromyographic activity input-output pair. A parameter constraining technique was applied to develop more reliable models. It is shown that the asymptotic behavior of the system must be taken into account during parameter optimization to develop better predictive models.