Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “predictability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,495 records · Page 83Linked to original sources
PubMed2002

Predicting the resting metabolic rate of 30-60-year-old Australian males.

OBJECTIVES: This study: (a) generated regression equations for predicting the resting metabolic rate (RMR) of 30-60-y-old Australian males from age, height, mass and fat-free mass (FFM); and (b) cross-validated RMR prediction equations which are currently used in Australia against our measured and predicted values. DESIGN: A power analysis demonstrated that 41 subjects would enable the detection of (alpha=0.05, power=0.80) statistically and physiologically significant differences of 8% between predicted/measured RMRs in this study and those predicted from the equations of other investigators. SUBJECTS: Forty-one males ([X]+/-s.d.:, 44.8+/-8.6 y; 83.50+/-11.32 kg; 179.1+/-5.0 cm) were recruited for this study. INTERVENTIONS: The following variables were measured: skinfold thicknesses; RMR using open circuit indirect calorimetry; and FFM via a four-compartment (fat mass, total body water, bone mineral mass and residual) body composition model. RESULTS: A multiple regression equation using mass, height and age as predictors correlated 0.745 with RMR and the s.e.e. was 509 kJ/day. Inclusion of FFM as a predictor increased both the correlation and the precision of prediction, but there was no difference between FFM via the four-compartment model (r=0.816, s.e.e.=429 kJ/day) and that predicted from skinfold thicknesses (r=0.805, s.e.e.=441 kJ/day). CONCLUSIONS: Cross-validation analyses emphasised that equations need to be generated from a large database for the prediction of the RMR of 30-60-y-old Australian males.

Absorptiometry, Photon↗
PubMed2003

Delayed predictive accuracy of narrative recall after traumatic brain injury: salience and explicitness.

Fifteen adults with traumatic brain injury (TBI) and 15 adults without brain injury listened to narratives, made delayed predictions of recall, and took a delayed recall test. Narrative questions differed by salience (main ideas, details) and explicitness (implied, stated) (R. H. Brookshire & L. E. Nicholas, 1993). TBI survivors recalled less than control participants regardless of question type. All participants recalled main ideas and implied information with greater accuracy than details and stated information. Predictive accuracy for recalling stated information was strong regardless of group. Participants were unable to predict recall for implied information. The materials-appropriate-processing (MAP) hypothesis proposes that predictive accuracy is biased by text type (i.e., predictive accuracy for recalling main ideas should be higher than for details when learning narratives). However, there were no differences in predictive accuracy for recalling main ideas and details, with both groups predicting recall modestly well. Controlling for explicitness appears to be an important variable for future metamemory text studies.

Adult↗
PubMed1998

Prediction of resectability of pancreatic malignancy by computed tomography.

BACKGROUND: The accuracy of computed tomography (CT) in predicting resectability of pancreatic malignancy has been questioned recently and alternative methods have been recommended. METHODS: To determine the accuracy of CT for predicting resectability and its influence on survival, a standard protocol for performing CT and reporting the results was developed and then compared retrospectively with the ability of one surgeon to perform a resection during 1989-1994. Postoperative survival was determined. RESULTS: Of 88 consecutive patients 35 (40 per cent) had CT-resectable disease and 53 (60 per cent) had CT-irresectable disease. Twenty-one patients were excluded because of advanced disease or poor performance status. Of the remaining 67 patients, 47 (70 per cent) had pancreatic ductal adenocarcinoma and 20 (30 per cent) had ampullary adenocarcinoma, of whom 32 had a resection, 32 had a palliative bypass and three had only a staging laparoscopy. The sensitivity and specificity for computed tomographic prediction of resectability were 72 and 80 per cent respectively. The positive predictive value was 77 per cent and the negative predictive value 76 per cent. There were seven false-positive and nine false-negative findings. Survival was more dependent on whether or not resection was performed than on computed tomographic predictability of resection. CONCLUSION: CT was reasonably accurate in predicting resectability but cannot be relied on entirely, requiring an improvement in staging methods for pancreatic malignancy.

Adenocarcinoma↗
PubMed2000

Early postoperative growth hormone levels: high predictive value for long-term outcome after surgery for acromegaly.

OBJECTIVES: To explore the prognostic value of early - within 1 week - postoperative growth hormone (GH) measurements with regard to outcome after surgery for acromegaly in a short- and a long-term perspective. DESIGN: Retrospective study of patients operated on between 1987 and 1998, including follow-up for up to 60 months. SETTING: University hospital. SUBJECTS: Sixty-eight patients with acromegaly. INTERVENTION: Pituitary surgery aiming at adenomectomy with preservation of pituitary function. MAIN OUTCOME MEASURES: The effect of the operation was evaluated after 3 months, mostly by means of an oral glucose load or by insulin-like growth factor 1 (IGF-1). The specificity, sensitivity and the predictive values of an early postoperative mean GH concentration </= 4.8 mU L-1, as well as of the GH response to thyrotropin-releasing hormone (TRH) 3 months after surgery, were calculated with regard to outcome of the operation in both 3-month and long-term perspectives. RESULTS: Fifty patients (73.5%) showed a satisfactory effect at the evaluation 3 months postoperatively; 45 of these were followed between 12 and 60 months. Relapse was registered in five cases: 12, 12, 24, 24 and 48 months after surgery. In the long-term perspective, the predictive value of an early mean GH </= 4.8 mU L-1 was 93.6% with regard to a satisfactory effect of surgery, compared with 90.2% for a normalized somatomedin C (SmC)/IGF-1 and 90.0% for an absent GH response after TRH. An early mean GH > 4.8 mU L-1 had a 77.8% predictive value for persistent or recurrent disease, compared with 85.7% for persistently increased SmC/IGF-1 and 68.8% for an abnormal GH release after TRH 3 months after surgery. In the short-term perspective, the specificity and the predictive value of an early GH </= 4.8 mU L-1 were 77.3 and 97.1%, respectively. Early GH > 4.8 mU L-1 had a 94.4% sensitivity but a predicative value of only 63.0% for an unsatisfactory effect. CONCLUSION: Measurement of GH within 1 week after surgery is highly predictive for outcome of surgery for acromegaly. Specifically, an early mean GH </= 4.8 mU L-1 is as predictive for a satisfactory effect of treatment as a normalized IGF-1 3 months after surgery. Early postoperative GH values > 4.8 mU L-1 have a high sensitivity for persistent or recurrent disease in both the short- and long-term perspectives, but lower predictive value. The usefulness of the TRH test can be questioned.

Acromegaly↗
PubMed2001

An in vitro skin explant assay as a predictive assay for graft-versus-host disease in a cohort of pediatric transplants.

Severe acute graft-versus-host disease (GvHD) remains a serious complication of allogeneic stem cell transplantation. An in vitro skin explant assay was used to predict the occurrence and severity of acute GvHD in a cohort of 30 pediatric patients undergoing human leucocyte antigen (HLA)-matched sibling transplants (20 patients) and matched or one antigen mismatched unrelated donor transplants (10 patients). In the cohort of HLA-matched sibling transplants, the result appeared to reflect the degree of GvHD prophylaxis. The skin explant assay correlated with GvHD outcome in 12 of 20 children, but this did not reach statistical significance (chi-square 0.95, d.f.=1, p=0.32). These results support previous observations. In this present cohort, patients were treated either with cyclosporin A (CsA) monotherapy (n=7) or with CsA plus additional methotrexate (MTX) (n=13). We have previously demonstrated that the skin explant assay was not as predictive in patients receiving CsA plus additional MTX compared to cohorts treated with CsA alone. In the group of patients treated with CsA alone, four of five patients (80%) predicted to develop GvHD developed acute GvHD of grade II or above; of two patients predicted to develop only grade 0-I GvHD, one patient developed no GvHD and the other grade II GvHD. In the CsA plus MTX group, nine patients were predicted to develop GvHD. Five of nine (55%) developed acute GvHD of grade II or above, while three of four with grade 0 or I skin explant assay results developed only grade 0-I GvHD. In a cohort of 10 patients who received unrelated donor transplants, the skin explant assay correlated with GvHD outcome in all 10 patients (Fisher's exact test p=0.008). Hence, the skin explant assay is a pretransplant in vitro GvHD predictive test that predicts the occurrence and severity of acute GvHD in pediatric unrelated donor transplants and to varying degrees, depending on the GvHD prophylaxis protocols, in HLA-matched sibling cohorts.

Acute Disease↗
PubMed2003

Filtered QRS duration on signal-averaged electrocardiography predicts inducibility of ventricular tachycardia in arrhythmogenic right ventricle dysplasia.

Treatment of arrhythmogenic right ventricular dysplasia (ARVD) is mostly based on the prevention of sudden cardiac death that results from arrhythmias. A clinical history suggestive of ARVD requires careful evaluation including electrophysiological study. The potential ability to identify those patients who will have inducible VT with electrophysiological study will enable better risk stratification and selection of vulnerable patients for electrophysiologically guided therapy. The purpose of the study was to evaluate the predictive ability of signal-averaged electrocardiography (SAECG) to predict inducibility of VT in patients with ARVD. The patient population consisted of 31 ARVD patients diagnosed with McKenna's criteria who underwent electrophysiological study. Electrophysiological study was considered positive if sustained monomorphic VT was induced. The sensitivity, specificity, and predictive accuracy of various SAECG criteria for inducibility of sustained monomorphic VT were also calculated. Twenty-one patients had inducible VT. The filtered QRS duration (fQRS), duration of signal <40 uV (LAS40), and root mean square voltage in the last 40 ms of QRS duration (RMS40) in ARVD patients induced versus noninduced were 122 +/- 21 and 103 +/- 8 ms (P=0.007), 45 +/- 20 and 28 +/- 14 ms (P=0.02), 19 +/- 19 and 32 +/- 22 uV (0.03), respectively. The ejection fractions were comparable in both groups. fQRS duration > or =110 ms had sensitivity of 91%, specificity of 90%, and a total predictive accuracy of 90% in predicting inducibility of VT in these patients. Filtered QRS duration on SAECG is predictive of electrophysiological study outcome in ARVD. Further studies will be needed to determine if SAECG results can predict the development of ventricular arrhythmias during follow-up.

Adult↗
PubMed2000

Predicting patient outcome from acute renal failure comparing three general severity of illness scoring systems.

BACKGROUND: A major problem of studies on acute renal failure (ARF) arises from a lack of prognostic tools able to express the medical complexity of the syndrome adequately and to predict patient outcome accurately. Our study was thus aimed at evaluating the predictive ability of three general prognostic models [version II of the Acute Physiology and Chronic Health Evaluation (APACHE II), version II of the Simplified Acute Physiology Score (SAPS II), and version II of the Mortality Probability Model at 24 hours (MPM24 II)] in a prospective, single-center cohort of patients with ARF in an intermediate nephrology care unit. METHODS: Four hundred twenty-five patients consecutively admitted for ARF to the Nephrology and Internal Medicine Department over a five-year period were studied (272 males and 153 females, median age 71 years, interquartile range 61 to 78, median APACHE II score 23, interquartile range 18 to 28). Acute tubular necrosis (ATN) accounted for 68.7% (292 out of 425) of patients. Renal replacement therapies (hemodialysis or continuous hemofiltration) were used in 64% (272 out of 425) of ARF patients. RESULTS: Observed mortality was 39.1% (166 out of 425). The mean predicted mortality was 36.2% with APACHE II (P = 0.571 vs. observed mortality), 39.3% with SAPS II (P = 0.232), and 45.1% with MPM24 II (P < 0.0001). Lemeshow-Hosmer goodness-of-fit C and H statistics were 15.67 (P = 0.047) and 12.05 (P = 0.15) with APACHE II, 32.53 (P = 0.0001), 39.8 (P = 0.0001) with SAPS II, 21.86 (P = 0.005), and 20. 24 (P = 0.009) with MPM24 II, respectively. Areas under the receiver operating characteristic (ROC) curve were 0.75, 0.77, and 0.85, respectively. CONCLUSIONS: The APACHE II model was a slightly better calibrated predictor of group outcome in ARF patients, as compared with the SAPS II and MPM24 II outcome prediction models. The MPM24 II model showed the best discrimination capacity, in comparison with both APACHE II and SAPS II models, but it constantly and significantly overestimated mean predicted mortality in ARF patients. None of the models provided sufficient confidence for the prediction of outcome in individual patients. A high degree of caution must be exerted in the application of existing general prognostic models for outcome prediction in ARF patients.

APACHE↗
PubMed2001

Total body water reference values and prediction equations for adults.

BACKGROUND: The clinical interpretation of total body water (TBW) necessitates the availability of timely comparative reference data. The prediction of TBW volume in renal disease is critical in order to prescribe and monitor the dose of dialysis in the determination of Kt/V. In clinical practice, urea distribution (V) is commonly predicted from anthropometric equations that are several decades old and for white patients only. This article presents new reference values and prediction equations for TBW from anthropometry for white and black adults. METHODS: The study sample included four data sets, two from Ohio and one each from New Mexico and New York, for a total of 604 white men, 128 black men, 772 white women, and 191 black women who were 18 to 90 years of age. The TBW concentration was measured by the deuterium or tritium oxide dilution method, and body composition was measured with a Lunar DXA machine. An all-possible-subsets of regression was used to predict TBW. The accuracy of the selected equations was confirmed by cross-validation. RESULTS: Blacks had larger TBW means than whites at all age groups. The 75th TBW percentile for whites approximated the TBW median for blacks at most ages. The white men and black men and women had the largest TBW means ever reported for healthy individuals. The race- and sex-specific TBW prediction equations included age, weight, and stature, with body mass index (BMI) substituted for weight in the white men. The root mean square errors (RMSEs) and standard errors for the individual (SEIs) ranged from approximately 3.8 to 5.0 L for the men and from 3.3 to 3.6 L for the women. In both men and women, high values of TBW were associated with high levels of total body fat (TBF) and fat-free mass (FFM). CONCLUSION: : TBW in these healthy adults is relatively stable through a large portion of adulthood. There are significant race and sex differences in TBW. These accurate and precise equations for TBW provide a useful tool for the clinical prediction of TBW in renal disease for white and black adults. These are the first TBW prediction equations that are specific for blacks.

Adult↗
PubMedDate not supplied

The predictive value of transcutaneous oxygen tension measurement in diabetic lower extremity ulcers treated with hyperbaric oxygen therapy: a retrospective analysis of 1,144 patients.

The objective of this retrospective analysis was to determine the reliability of transcutaneous oxygen tension measurement (TcPO2) in predicting outcomes of diabetics who underwent hyperbaric oxygen therapy for lower extremity wounds. Six hyperbaric facilities provided TcPO2 data under several possible conditions: breathing air, breathing oxygen at sea level, and breathing oxygen in the chamber. Overall, 75.6% of the patients improved after hyperbaric oxygen therapy. Baseline sea-level air TcPO2 identified the degree of tissue hypoxia but had little statistical relationship with outcome prediction because some patients healed after hyperbaric oxygen therapy despite very low prehyperbaric TcPO2 values. Breathing oxygen at sea level was unreliable for predicting failure, but 68% reliable for predicting success after hyperbaric oxygen therapy. TcPO2 measured in chamber provides the best single discriminator between success and failure of hyperbaric oxygen therapy using a cutoff score of 200 mmHg. The reliability of in-chamber TcPO2 as an isolated measure was 74% with a positive predictive value of 58%. Better results can be obtained by combining information about sea-level air and in-chamber oxygen. A sea-level air TcPO2 < 15 mmHg combined with an in-chamber TcPO2 < 400 mmHg predicts failure of hyperbaric oxygen therapy with a reliability of 75.8% and a positive predictive value of 73.3%.

Blood Gas Monitoring, Transcutaneous↗
PubMed2001

A self-paced step test to predict aerobic fitness in older adults in the primary care clinic.

OBJECTIVES: To study the potential usefulness of a submaximal self-paced step test as a prediction of maximal aerobic capacity (VO2max) in older adults in the primary care setting. DESIGN: Data were collected during a prospective randomized study of an exercise program. SETTING: Four university family medical clinics in London, Ontario, Canada. PARTICIPANTS: A random sample of 240 healthy older (> or =65) men (n = 118) and women (n = 122) from four family medical clinics underwent self-paced step testing in the clinic with a family physician (n = 16), and step testing and a maximal exercise treadmill test with measurement of respired gases in an exercise laboratory. Testing was done in random order (clinic/laboratory) separated by 2 weeks and then repeated at 52 weeks, following introduction of an exercise program. Relationships between outcome variables were examined by Pearson correlation coefficients while prediction of VO2max was examined using multivariate regression analysis. Cross-validation with 30 age-matched hypertensive and 40 age-matched post-hip arthroplasty patients was used to test the accuracy of the predictive models. MEASUREMENTS: Measured VO2max, predicted VO2max, step test time, step test heart rate, body mass index (BMI), and O2 pulse. RESULTS: Two hundred women (n = 108) and men (n = 92) completed both the initial and 52-week assessments. Stepping time, heart rate, age, BMI, and O2 pulse were strongly associated with VO2max for both a normal and a fast step pace and were chosen to develop the predictive model. Normal step-pace correlation with VO2max (ml/kg/min) was no different (female 0.93: male 0.91) from fast pace (0.95:0.90) with no difference between clinic and laboratory measurement at baseline or 52 weeks. Cross-validation showed no significant difference from the main group using the predictive model. CONCLUSIONS: The self-paced step test is a safe and simple clinical instrument that strongly and reliably predicts VO2max, is sensitive to change, and is generalizable in the family practice setting among community-dwelling older adults differing in fitness and health status.

Aged↗
PubMed2003

Predictive value of nonspecific symptoms for acute illness in nursing home residents.

OBJECTIVES: To examine the predictive value of nonspecific symptoms for acute illness in nursing home residents. DESIGN: Prospective, observational study. SETTING: Academic nursing home located in an urban setting. PARTICIPANTS: Two hundred two newly admitted residents. MEASUREMENTS: Eleven nonspecific symptoms were ascertained by review of observations documented by nursing home staff in the medical record. Research staff independently identified acute illness according to previously established criteria from nurse report and medical record review. Follow-up was divided into 10-day intervals, and concordance between nonspecific symptoms and acute illness within these intervals was determined. Predictive values were calculated according to standard formulae. RESULTS: Nonspecific symptoms and acute illnesses occurred in 21.7% and 12.5% of 10-day intervals, respectively. Positive predictive values (PPVs) were highest for lethargy, weakness, and decreased appetite, each of which correctly predicted the presence of an acute illness one out of two times the symptoms were reported. Agitation and disorientation predicted an acute illness one out of three times, and falls predicted an acute illness one out of four times. Overall, the PPV of the occurrence of any nonspecific symptom was 0.24, and the negative predictive value of the absence of nonspecific symptoms was 0.91. CONCLUSION: Hypoactive nonspecific symptoms are more likely than other nonspecific symptoms to be signs of incipient acute illness. Studies are needed to determine whether an intervention in residents with these nonspecific symptoms can enable earlier detection and treatment of acute illness.

Acute Disease↗
PubMed2003

An evaluation of predictive factors for CD34+ cell harvest yields from patients mobilized with chemotherapy and growth factors.

BACKGROUND: Accurately predicting the outcomes of peripheral blood stem cell harvests is important because unproductive collections are expensive and subject the donor to unnecessary toxicity. STUDY DESIGN AND METHODS: Predictive factors for stem cell mobilization and collection by a retrospective review of 104 consecutive donors were evaluated. RESULTS: Of several previously suggested measures, the peripheral CD34+ cell concentration on the day of harvest (pCD34DH) correlated best with total numbers of CD34+ collected (r = 0.88). This was followed by the pCD34 on the day before harvest (pCD34Day -1) (r = 0.74). The peripheral WBC count on the day of harvest (pWBC) was inferior (r = 0.39). When ratios of potential predictive factors divided by the previous day's value were examined, pWBC ratio was found to be a significant independent predictive factor for cells collected (r = 0.45). Furthermore, the predictive value of both the pCD34Day -1 and the pWBC can be improved by combining with the pWBC ratio. To examine whether the chosen collection starting days were optimal, serial pCD34 obtained daily during the harvest procedures was examined. Poorly mobilizing donors, who required several days of collection, did not reach maximal harvest yields until the fourth collection day. CONCLUSIONS: pCD34DH is the optimal predictive factor for harvest yields. If pCD34DH is not available, pCD34Day -1 or pWBC combined with the pWBC ratio may offer the best prediction of harvest outcomes. The best harvest yields on poorly mobilizing donors occur 3 to 4 days after the usual collection starting times.

Adult↗
PubMed2003

A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C.

Information on the stage of liver fibrosis is essential in managing chronic hepatitis C (CHC) patients. However, most models for predicting liver fibrosis are complicated and separate formulas are needed to predict significant fibrosis and cirrhosis. The aim of our study was to construct one simple model consisting of routine laboratory data to predict both significant fibrosis and cirrhosis among patients with CHC. Consecutive treatment-naive CHC patients who underwent liver biopsy over a 25-month period were divided into 2 sequential cohorts: training set (n = 192) and validation set (n = 78). The best model for predicting both significant fibrosis (Ishak score > or = 3) and cirrhosis in the training set included platelets, aspartate aminotransferase (AST), and alkaline phosphatase with an area under ROC curves (AUC) of 0.82 and 0.92, respectively. A novel index, AST to platelet ratio index (APRI), was developed to amplify the opposing effects of liver fibrosis on AST and platelet count. The AUC of APRI for predicting significant fibrosis and cirrhosis were 0.80 and 0.89, respectively, in the training set. Using optimized cut-off values, significant fibrosis could be predicted accurately in 51% and cirrhosis in 81% of patients. The AUC of APRI for predicting significant fibrosis and cirrhosis in the validation set were 0.88 and 0.94, respectively. In conclusion, our study showed that a simple index using readily available laboratory results can identify CHC patients with significant fibrosis and cirrhosis with a high degree of accuracy. Application of this index may decrease the need for staging liver biopsy specimens among CHC patients.

Adult↗
PubMedDate not supplied

Validity of a V.O2 max prediction equation of the 2-km walk test in female seniors.

Walking is a useful exercise mode for most adults due to its general ease, acceptability, and safety. Therefore, many field tests based on performance in walking have been developed to predict V.O (2 max). Even if these tests are much easier to perform than laboratory tests, field tests have to be valid. The objective of the paper was to explore the accuracy and bias of a V.O (2 max) prediction equation of the 2-km Walk Test, in an active female senior group (n=18, mean age: 66.1+/-4.4). V.O (2 max) (l . min (-1)) was measured during cycle ergometry by direct gas analysis from a maximal test (step: 30 W, time: 2 min 30). V.O (2 max) related to body mass was then calculated (ml . min (-1) . kg (-1)). Subjects completed also the 2-km Walk Test (UKK Institute). V.O (2 max) (ml . min (-1) . kg (-1)) was then predicted from age, sex, body mass index, heart rate, and walking time measured during the 2-km Walk Test. Predicted V.O (2 max) and measured V.O (2 max) were highly correlated (r=0.63, p<0.01). Predicted V.O (2 max) (20.5+/-6.1 ml . min (-1) . kg (-1)) was not significantly different from measured V.O (2 max) (18.7+/-3.4 ml . min (-1) . kg (-1)). Prediction equation bias with its 95 % limits of agreement was - 1.8+/-4.8 ml . min (-1) . kg (-1) with a coefficient of variation of 24.2 %. In an active female senior population, the 2-km Walk Test offers a fairly accurate V.O (2 max) prediction. The training and learning effects can be neglected because when the test was repeated no significant bias was observed between the two trials.

Aged↗
PubMed1998

Gestational age can predict the need for prophylaxis with surfactant therapy.

Controversy exists as to whether prophylactic or rescue therapy with surfactant should be used in infants born at less than 30 weeks gestation. We developed the hypothesis that gestational age can be used to predict a need for prophylactic surfactant therapy. We designed this retrospective study to determine whether there was a gestational age below which one could accurately predict the need for prophylactic surfactant therapy in almost all infants and limit unnecessary treatment of infants. We conducted a retrospective study of infants born at 23-34 weeks' gestation to determine the frequency with which surfactant therapy was used in a rescue strategy at each gestational age, and to ascertain the sensitivity, specificity, and predictive values of gestational age as a predictor of the use of surfactant therapy. There was a significant inverse correlation between gestational age and the proportion of infants treated with surfactant (r = -0.923, p < 0.001). A gestational age cut-off of 26 completed weeks' had a positive predictive value of 85% and a specificity of 96% for the need for surfactant therapy. We conclude that gestational age can be used to predict a need for surfactant therapy in premature infants. At our institution, the failure to attain 26 completed weeks' gestation will accurately predict the need for surfactant therapy and will result in unnecessary treatment of very few infants. We suggest that each institution caring for very low birth weight infants should examine its population to determine the gestational age at which they can accurately predict the need for prophylaxis with surfactant therapy.

Gestational Age↗
PubMed2002

The prediction and prevention of intrapartum fetal asphyxia in preterm pregnancies.

OBJECTIVE: This study was undertaken to examine the contribution of electronic fetal heart rate monitoring in the prediction and prevention of intrapartum fetal asphyxia in the preterm pregnancy. STUDY DESIGN: The outcome of 40 pregnancies with biochemically confirmed intrapartum fetal asphyxia (ie, an umbilical artery base deficit >12 mmol/L) was examined. This included 20 pregnancies that were delivered abdominally matched with 20 pregnancies that were delivered vaginally. Antepartum and intrapartum clinical risk factors and newborn complications were documented. The interpretation of the fetal heart rate record as determined by the responsible clinicians was recorded. Fetal asphyxia was classified as mild, moderate, or severe on the basis of an umbilical artery base deficit of >12 mmol/L and newborn encephalopathy and other organ system complications. RESULTS: Fetal asphyxia was classified as mild in 21 pregnancies and as moderate or severe in 19 pregnancies. The fetal heart rate record was predictive of fetal asphyxia in 27 pregnancies and nonpredictive in 11 pregnancies. The predictive fetal heart rate record was the primary indication for intervention in 21 of the 24 pregnancies that were delivered by cesarean delivery in the first stage or operative vaginal delivery in the second stage of labor. Newborn outcome may have been influenced by intervention and delivery because of a predictive fetal heart rate record in 10 pregnancies with mild fetal asphyxia and in 9 pregnancies with moderate or severe fetal asphyxia. CONCLUSION: Electronic fetal monitoring is a useful screening test for the prediction of intrapartum fetal asphyxia in the preterm pregnancy. A predictive fetal heart rate record was the principle indication that led to intervention and delivery. A prediction of fetal asphyxia that leads to intervention and delivery may prevent or modify moderate or severe newborn morbidity as the result of fetal asphyxia.

Cesarean Section↗
PubMed2002

Prediction of early graft failure with intraoperative completion duplex ultrasound scan.

PURPOSE: The purpose of this study was to determine intraoperative hemodynamic parameters that predict early failure of infragenicular vein grafts with intraoperative completion duplex ultrasound scan. METHODS: We reviewed the results of intraoperative duplex scans that were selectively performed after completion of 45 tibial/pedal vein bypass grafts at high risk for failure. Bypass was performed for rest pain (39%) or tissue loss (61%), and 60% of the cases were disadvantaged because of compromised vein quality or poor arterial outflow. A 10-MHz low-profile transducer was used to scan the entire graft at bypass completion. All grafts were determined to be technically adequate (absence of retained valves, arteriovenous fistulas, or localized velocity increases and the presence of bypass-dependent distal pulses). Peak systolic velocity (PSV) and end diastolic velocity (EDV) were also measured at each anastomosis, in the outflow artery and in the proximal and distal portions of each graft. Resistive indices (RI) were calculated at each measurement point (PSV-EDV/PSV). Statistical analysis was performed with unpaired t test, chi(2) test, and multivariate analyses. RESULTS: Twenty infragenicular vein bypass grafts (44%) thrombosed within 12 months. Intraoperative hemodynamic parameters were significantly different between grafts that remained patent or thrombosed. EDV was lower (5 +/- 1 cm/s versus 13 +/- 3 cm/s; P =.02) and RI was higher (0.90 versus 0.81; P <.01) in the proximal portions of grafts that thrombosed within 12 months. Distal EDV was also lower (6 +/- 1 cm/s versus 15 +/- 2 cm/s; P <.01) and distal RI was higher (0.89 versus 0.78; P <.01) in grafts that thrombosed. With multivariate analysis, only low distal EDV was predictive of early graft failure (P <.05). Distal bypass EDV of less than 8 cm/s predicated early graft thrombosis with 76% sensitivity and 75% specificity (positive predictive value, 71%; negative predictive value, 78%). Absence of diastolic flow (EDV of 0 cm/s) predicted early graft failure with 100% specificity and 100% positive predictive value. CONCLUSION: In this initial experience, low EDV measured with intraoperative duplex scan was associated with early thrombosis of tibial level vein grafts. When such values are observed, measures should be taken to improve graft hemodynamic parameters. Prospective study of infragenicular vein bypass grafts may better define hemodynamic parameters predictive of early graft thrombosis.

Aged↗
PubMed2006

Thousands of samples are needed to generate a robust gene list for predicting outcome in cancer.

Predicting at the time of discovery the prognosis and metastatic potential of cancer is a major challenge in current clinical research. Numerous recent studies searched for gene expression signatures that outperform traditionally used clinical parameters in outcome prediction. Finding such a signature will free many patients of the suffering and toxicity associated with adjuvant chemotherapy given to them under current protocols, even though they do not need such treatment. A reliable set of predictive genes also will contribute to a better understanding of the biological mechanism of metastasis. Several groups have published lists of predictive genes and reported good predictive performance based on them. However, the gene lists obtained for the same clinical types of patients by different groups differed widely and had only very few genes in common. This lack of agreement raised doubts about the reliability and robustness of the reported predictive gene lists, and the main source of the problem was shown to be the small number of samples that were used to generate the gene lists. Here, we introduce a previously undescribed mathematical method, probably approximately correct (PAC) sorting, for evaluating the robustness of such lists. We calculate for several published data sets the number of samples that are needed to achieve any desired level of reproducibility. For example, to achieve a typical overlap of 50% between two predictive lists of genes, breast cancer studies would need the expression profiles of several thousand early discovery patients.

Breast Neoplasms↗