Biomedical subjects

D C Frankenfield

Publications and source records attributed to D C Frankenfield.

14 recordsLinked to original sources

PubMed2001

Limits of body mass index to detect obesity and predict body composition.

Body mass index (BMI) is commonly used to identify obesity. In this study, we determined how accurately BMI could determine body composition and identify obese from non-obese individuals. Fat-free mass and body fat were determined with bioelectrical impedance. Adiposity was calculated as body fat per body mass and as body fat divided by body height (m2). Obesity was defined as a BMI of at least 30 kg/m2 or an amount of body fat of at least 25% of total body mass for men and at least 30% for women. Obesity as defined by percentage of body fat was always present with a BMI of at least 30 kg/m2. However, 30% of men and 46% of women with a BMI below 30 kg/m2 had obesity levels of body fat. The greatest variability in the prediction of percentage of body fat and body fat divided by height (m2) from regression equations using BMI was at a BMI below 30 kg/m2. In conclusion, using impedance-derived body-fat mass as the criterion, people with BMI of at least 30 kg/m2 are obese. However, significant numbers of people with a BMI below 30 kg/m2 are also obese and thus misclassified by BMI. Percent of body fat and body fat divided by height (m2) are predictable from BMI, but the accuracy of the prediction is lowest when the BMI is below 30 kg/m2. Therefore, measurement of body fat is a more appropriate way to assess obesity in people with a BMI below 30 kg/m2.

Adipose Tissue↗

PubMed1999

Bioelectrical impedance plethysmographic analysis of body composition in critically injured and healthy subjects.

BACKGROUND: Determination of body composition during critical illness is complex because of various patient-related and technical factors. Bioelectrical impedance is a promising technique for the analysis of body composition; however, its clinical utility in critically injured patients is unknown. OBJECTIVE: The purpose of this study was to compare bioelectrical impedance with metabolic activity in healthy and critically injured patients. If bioelectrical impedance accurately determines body composition during critical illness, the slope between body-composition variables and oxygen consumption would be the same in critically injured and healthy subjects. DESIGN: There is a strong linear relation between body composition and metabolic activity. In the present study, body composition (fat-free mass and body cell mass) was determined by using bioelectrical impedance and resting metabolic activity (metabolic rate and oxygen consumption) by using gas exchange analysis in a group of healthy and critically injured subjects. The relation between these variables was compared by using linear regression to a similar relation established by hydrostatic weighing in a large historical control group. RESULTS: The slope of the line relating fat-free mass to resting metabolic rate was the same in the healthy and critically ill groups (P = 0.62) and each was similar to the slope of the line for the control group. However, in 37% of the critically injured group, overhydration contributed to an increase in fat-free mass, disturbing the relation with resting metabolic rate. The slope of the line relating body cell mass to oxygen consumption in our healthy and critically ill groups was almost identical. CONCLUSION: These results support the use of bioelectrical impedance to determine body cell mass in healthy and critically ill subjects.

Adult↗

PubMed1998

The Harris-Benedict studies of human basal metabolism: history and limitations.

In the early part of the 20th century, numerous studies of human basal metabolism were conducted at the Nutrition Laboratory of the Carnegie Institution of Washington in Boston, Mass, under the direction of Francis G. Benedict. Prediction equations for basal energy expenditure (BEE) were developed from these studies. The expressed purpose of these equations was to establish normal standards to serve as a benchmark for comparison with BEE of persons with various disease states such as diabetes, thyroid, and other febrile diseases. The Harris-Benedict equations remain the most common method for calculating BEE for clinical and research purposes. The widespread use of the equations and the relative inaccessibility of the original work highlights the importance of reviewing the data from which the standards were developed. A review of the data reveals that the methods and conclusions of Harris and Benedict appear valid and reasonable, albeit not error free. All of the variables used in the equations have sound physiologic basis for use in predicting BEE. Supplemental data from the Nutrition Laboratory indicates that the original equations can be applied over a wide range of age and body types. The commonly held assumption that the Harris-Benedict equations overestimate BEE in obese persons may not be true for persons who are moderately obese.

Basal Metabolism↗

PubMed1996

Validation of a 5-minute steady state indirect calorimetry protocol for resting energy expenditure in critically ill patients.

OBJECTIVE: Numerous protocols are used for indirect calorimetry in research and clinical settings. The objective of the current study was to validate in critically ill patients an abbreviated protocol that uses five consecutive stable 1-minute readings of oxygen consumption (VO2), carbon dioxide production (VCO2), and minute ventilation (VE) in a range of +/- 5%, versus a more standard protocol that uses 30 consecutive stable one minute readings of VO2, VCO2, and VE in a range of +/- 10%. METHODS: Indirect calorimetry was performed on resting, mechanically ventilated, critically ill patients. The first 5-minute period in which coefficients of variation for VO2, VCO2, and VE were < or = 5% was compared to the first 30-minute period in which coefficients of variation for these variables were < or = 10%. RESULTS: Thirty-four critically ill patients were studied. Twenty four patients (70%) successfully completed both protocols (Success Group). Eighteen percent of subjects completed neither the abbreviated nor the 30 minute protocol, and 12% completed only one protocol (Fail Group). The Success Group was marked by a higher incidence of sedation and/or medical paralysis. There were no significant differences in VE, VO2, VCO2, respiratory quotient, or energy expenditure between the protocols in the Success Group or the Fail Group. Coefficients of determination (R2) for VO2 and VCO2 between the two methods in the Success Group were 0.99. In the Fail Group, R2 values ranged from 0.75 for VCO2 to 0.91 for VO2. CONCLUSION: In sedated, mechanically ventilated patients, an indirect calorimetry test of five consecutive 1-minute periods with coefficient of variation < or = 5% is equivalent to a longer test consisting of 30 consecutive 1-minute periods with coefficient of variation < or = 10%.

Aged↗

PubMed1995

Glucose dynamics during continuous hemodiafiltration and total parenteral nutrition.

OBJECTIVE: To determine glucose balance during dextrose-free continuous hemodiafiltration with or without dextrose-containing ultrafiltrate replacement fluid and full nutritional support. DESIGN: Prospective, nonrandomized, observational study. SETTING: A 24-bed multiple trauma critical care unit in a level-I trauma center. PATIENTS: Seventeen multiple trauma patients with multiple organ dysfunction syndrome requiring hemodialysis for acute renal failure. INTERVENTIONS: Continuous hemodiafiltration effluent volume and glucose concentration were measured. Study days were classified according to whether dextrose was used in the ultrafiltrate replacement therapy. Use of dextrose in replacement therapy was determined clinically. Parenteral nutrition was not altered for potential glucose absorption from continuous hemodiafiltration. Ultrafiltrate replacement consisted of 5% dextrose in saline on 21 study days (D5YES) and dextrose-free solutions on 54 study days (D5NO). RESULTS: The D5YES group received 316 +/- 145 g glucose/day from the ultrafiltrate replacement fluid, in addition to glucose in total parenteral nutrition (total glucose intake = 942 +/- 229 g/day in D5YES, 682 +/- 154 g/day in D5NO) (p < 0.05). Glucose loss in continuous hemodiafiltration effluent was 82 +/- 61 g/day in D5YES and 57 +/- 22 g/day in D5NO (P < 0.05), for a net glucose uptake of 8.1 +/- 2.1 mg/kg per min in D5YES and 5.4 +/- 1.5 mg/kg per min in D5NO (p < 0.05). Glucose loss was predictable when dialysate and ultrafiltrate replacement fluids were dextrose-free (R2 = 0.77), but less so when dextrose was used as ultrafiltrate replacement (R2 = 0.47). CONCLUSION: Dextrose-free dialysate promotes glucose loss during continuous hemodiafiltration, but the loss is small and predictable. Use of a dextrose-containing ultrafiltrate replacement fluid results in a significant increase in glucose intake without a commensurate increase in glucose loss, and makes glucose loss in effluent less predictable.

Acute Kidney Injury↗

PubMed1994

Urea removal during continuous hemodiafiltration.

OBJECTIVE: To compare urea nitrogen removal by continuous hemodiafiltration vs. functional native kidneys in critically ill, septic patients receiving > 2 g of amino acids/kg body weight per day. DESIGN: Prospective, comparative, unblinded study. SETTING: Trauma critical care units of a Level I adult trauma hospital. PATIENTS: Fifteen septic patients with multiple organ failure including renal failure who were receiving continuous hemodiafiltration; 11 septic patients with multiple organ failure without renal failure (control group). Ages of patients ranged from 18 to 60 yrs. INTERVENTIONS: Collection of effluent (dialysate + ultrafiltrate) from hemodiafilters. Collection of urine from control patients. MEASUREMENTS: Urea nitrogen and creatinine concentrations in blood, urine, and the hemodiafiltration effluent, measured every 24 hrs for 6 days. Effluent and urine volumes were measured. MAIN RESULTS: Hemodiafilters were operational for 21.8 +/- 3.0 hrs/day. Mean urea nitrogen removal in the renal failure group was 28 +/- 10 g/day. Blood urea nitrogen was stable over the 6-day study period. In control subjects, urea nitrogen removal was 27 +/- 9 g/day, which was not significantly different from the continuous hemodiafiltration group. Blood urea nitrogen concentrations in control patients increased over the 6-day study period (p < .05). Urea nitrogen removal correlated moderately well with amino acid intake in the control group (r2 = .30), but not in the continuous hemodiafiltration group (r2 = .0004). In patients receiving continuous hemodiafiltration, effluent volume was most significantly correlated with urea nitrogen removal (r2 = .69). CONCLUSIONS: The technique of continuous hemodiafiltration can remove substantial amounts of urea nitrogen, similar to that of normal native kidneys. In addition, at amino acid intake rates of > 2 g/kg body weight/day, urea nitrogen removal during continuous hemodiafiltration remains a function of effluent volume, so there is no need to restrict amino acid intake in acute renal failure patients supported with continuous hemodiafiltration.

Acute Kidney Injury↗

PubMed1994

Relationships between resting and total energy expenditure in injured and septic patients.

OBJECTIVE: To quantify resting and total energy expenditure in patients who have suffered severe trauma and sepsis. DESIGN: Prospective, unblinded, observational, nonrandomized study. SETTING: Critical care unit of a Level I adult trauma center. PATIENTS: Immediate posttrauma patients or trauma patients exhibiting signs of sepsis with multiple organ dysfunction. INTERVENTIONS: An indirect calorimeter was used to measure energy expenditure at rest (resting energy expenditure) at 0700 and 1900 hrs. The energy expenditure measurement was then continued for up to 12 hrs (total energy expenditure). Clinical data were collected for computation of an illness severity score. RESULTS: Thirteen trauma and 20 septic patients were studied 240 times. All patients were mechanically ventilated. Morphine or fentanyl was infused during 99% of studies. Neuromuscular blocking agents were used in 42% of septic studies. Both the trauma and septic groups were hypermetabolic (mean trauma resting energy expenditure, 36 +/- 6 kcal/kg; mean septic resting energy expenditure, 44 +/- 8 kcal/kg; p < .05). Total energy expenditure was similar to resting energy expenditure (trauma total energy expenditure = resting energy expenditure x 1.035 +/- 0.078, septic total energy expenditure = resting energy expenditure x 1.039 +/- 0.071). Total energy expenditure and resting energy expenditure were linearly related (r2 = .89, p < .0001). CONCLUSIONS: Trauma and septic patients are hypermetabolic, even when heavily sedated or medically paralyzed. A measurement of resting energy expenditure is a close approximation of total energy expenditure in most patients.

Adult↗

PubMed1991

Dietary fiber and bowel function in tube-fed patients.

In tube-fed patients, dietary fiber is often used to manage constipation/diarrhea. Dietary fiber consists of water-soluble and insoluble plant compounds that are resistant to digestion by small-bowel enzymes but are fermented to varying degrees by colonic bacteria. Many physiologic effects of fiber may be related to the degree of fermentation. Few controlled studies of fiber-containing tube feedings have been performed. These studies have limitations and are nondefinitive as to whether fiber prevents or controls constipation/diarrhea. Constipation in tube-fed patients has not been shown to respond to mixed soluble/insoluble fiber in the few studies performed to date. Likewise, fiber may be of only limited benefit in controlling diarrhea in acute illness because of such factors as stress or medication. Fiber does play a role in maintaining gut integrity in all patients, whether they have diarrhea or not. Fiber may be recommended as part of a standard tube-feeding regimen to help assure gut mucosal integrity but not specifically to treat constipation/diarrhea. Further studies are necessary before the role of fiber in the management of constipation/diarrhea in tube-fed patients is determined.

Burns↗

PubMed1989

Soy-polysaccharide fiber: effect on diarrhea in tube-fed, head-injured patients.

In a randomized, double-blind, crossover study the effect of tube-feeding with soy-polysaccharide fiber (SPF) vs without SPF on stool weight (SW), stool consistency (SC), fecal nitrogen (FN), and incidence of diarrhea (ID) was compared in nine head-injured subjects; associations with feeding volume, albumin level, and medications were also examined. Subjects with and without SPF had (mean +/- SEM) SW of 245 +/- 47 and 277 +/- 49 g/d, SC of 2.17 +/- 0.01 and 2.52 +/- 0.13 (3 is watery) (p less than 0.01), FN of 1.35 +/- 0.45 and 1.36 +/- 0.33 g/d, and ID of 33% and 44%, respectively. Significant treatment X treatment-sequence interaction nullified results for SW and SC. Neither FN nor ID were affected by SPF. The condition of all variables tended to improve over time. Certain medications and SPF were predictive of SW and SC; albumin and tube-feeding volume were not. SPF-containing tube feedings did not seem to have an effect on bowel function in these well-nourished head-injured patients.

Craniocerebral Trauma↗

PubMedDate not supplied

Relative association of fever and injury with hypermetabolism in critically ill patients.

The purpose of this study was to determine the association of injury type (trauma, surgery, medical disease), systemic inflammatory response syndrome (SIRS) and fever with the degree of hypermetabolism in critically ill patients. Medical records of 204 critically ill, mechanically ventilated injured, surgical and medical patients were reviewed for indirect calorimetry and associated data. Analysis of variance and covariance was used to test the effects of injury, fever and SIRS on the degree of hypermetabolism. All injury types were found to be hypermetabolic. Analysis of variance of hypermetabolism with injury type and presence of fever as main effects revealed a significant increase in hypermetabolic response from fever, of similar magnitude across all injury types. Subjects with SIRS were significantly more hypermetabolic than subjects without SIRS. However, analysis of variance indicated no effect for SIRS but a significant effect for fever in increasing the hypermetabolic response. It is concluded that fever portends a magnification of the hypermetabolic response, being similar across injury types. SIRS does not identify hypermetabolic patients independent of fever. The host response to injury, not the injury itself, determines metabolic rate in critically ill patients. Neither SIRS nor injury type should be used to classify hypermetabolic states without stratifying for presence of fever.

Adult↗

PubMedDate not supplied

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.

Acute Kidney Injury↗

PubMedDate not supplied

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.

Adult↗

PubMedDate not supplied

Accelerated nitrogen loss after traumatic injury is not attenuated by achievement of energy balance.

BACKGROUND: We wanted to determine if achievement of energy balance decreases myofibrillar protein catabolism and nitrogen loss during posttraumatic catabolic illness. METHODS: Surgical intensive care unit of a level I trauma center in a university medical center. Trauma patients expected to be mechanically ventilated for at least 4 days were randomly assigned to one of three parenteral feeding groups: (1) nonprotein calorie group: dextrose and lipid intake equal to measured energy expenditure; (2) total calorie group: dextrose, lipid, and protein intake equal to measured energy expenditure; and (3) hypocaloric group: dextrose and lipid intake equal to 50% of measured energy expenditure. Target protein intake for all groups was 1.7 g/kg body wt. On day 4 of nutrition support, a 24-hour balance study was conducted. Urine urea and total nitrogen production, 3-methylhistidine excretion, energy expenditure, and substrate utilization were measured. RESULTS: Despite significant differences in nonprotein and total calorie balance among the groups, nitrogen loss, nitrogen balance, and catabolic rate were not significantly different. Nitrogen loss correlated with catabolic rate but not with energy expenditure or energy balance. Catabolic rate was associated with energy expenditure but not with energy balance. Nitrogen loss was positively correlated with the percentage of nonprotein energy expenditure met by nonprotein calorie intake. CONCLUSIONS: Achievement of energy balance (nonprotein or total energy) failed to decrease catabolic rate or nitrogen loss acutely in multiple trauma patients. Provision of caloric intake equal to energy expenditure does not seem necessary during the acute phase of posttraumatic catabolic illness.

Adult↗

PubMedDate not supplied

Nutritional effect of continuous hemodiafiltration.

Continuous arterial-venous and veno-venous hemodiafiltration are reliable methods of renal replacement therapy and are particularly suited to critically ill patients in acute renal failure. Fluid and uremic toxin removal from continuous hemodiafiltration is sufficient to allow unrestricted nutrition support. However, the hemodiafilter cannot discriminate between uremic toxins and nutrients. Therefore, the potential exists for significant nutrient loss during continuous hemodiafiltration. Amino acid loss during continuous hemodiafiltration is approximately 10-15 g/day, although in individual cases > or = 30 g/day can be lost. Neither lipids nor intact proteins are lost to any appreciable degree during continuous hemodiafiltration. Small amounts of glucose are lost if dextrose-free dialysate is used for dialysis. If dextrose-containing dialysate is used, significant amounts of glucose can be absorbed (35-45% of the infused glucose). Fluid replacement with dextrose-containing electrolyte solutions can also lead to significant infusion of glucose. Vitamin and mineral losses during continuous hemodiafiltration are not known; neither are the vitamin requirements for patients receiving continuous hemodiafiltration. Effects of continuous hemodiafiltration on vitamin and mineral loss and status remain an important research question.

Acute Kidney Injury↗