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At least 37 records · Page 2Linked to original sources
PubMed1988

Automated charting of physiological variables in anesthesia: a quantitative comparison of automated versus handwritten anesthesia records.

Eight physiological variables--tidal volume, breathing rate, end-tidal carbon dioxide fraction, oxygen fraction in the anesthetic circuit, oxygen saturation by pulse oximetry, systolic and diastolic blood pressure, and heart rate--recorded on-line by a commercially available automated system were compared with the same variables recorded on handwritten anesthesia records. We quantified the differences between the automated and handwritten records generated from the same 30 patients (2,412 minutes of general anesthesia for elective eye surgical procedures). Considering the design of the study, we claim that the differences between both records were caused by the incompleteness or inaccuracy of the handwritten records, except in two instances. The amounts of missing or erroneous data for these eight physiological variables were expressed as fraction ("error fractions") of the time being recorded, designated EFm and EFe, respectively. For the first five variables the EFm on the handwritten records ranged between 0.23 and 0.31, and the EFe ranged between 0.01 and 0.06. For the last three variables the EFm range was 0.08 to 0.13, and the EFe range was 0.05 to 0.11. Most of these missing or erroneous data occurred during the period of induction (first 15 minutes) and at the end of the case (last 10 minutes). The EFm and EFe during induction had increased to 0.62 and 0.26, respectively, and to 0.76 and 0.06, respectively, at the end of the case. Erroneous data were observed on the automated records for the tidal volume during induction (EFe = 0.0044) and for the oxygen fraction during maintenance (EFe = 0.0024). The effect of averaging by the recordkeeper is discussed. The results of this study indicate the clinical relevance of automated record keeping.

Anesthesia↗
PubMed1992

Seasonal deterioration of selected physiological variables in elite male skiers.

The purpose of this study was to determine whether seasonal deterioration in physiological variables could be observed in skiers. Eighteen international male British downhill, free-style, and speed skiers were subjected to a maximal treadmill running test, a 30-s Wingate test, and isokinetic dynamometry at the beginning, middle, and end of the 1989-90 competition season. Maximal oxygen intake (VO2max) and respiratory anaerobic threshold (T vent) were among the parameters measured on the treadmill test, while peak and mean power outputs were measured during the Wingate test. During dynamometry, knee flexors and extensors were bilaterally assessed at 1.04 and 3.14 rad.s-1. Mean VO2max (p < 0.01) and mean T vent (p < 0.05) were lower at the end compared to the beginning, but not compared to the middle of the competition season. The isokinetic test demonstrated lower mean peak torques at 1.04 rad.s-1, for the knee extensors measured at the end of the season, compared with both the start (p < 0.01) and the middle (p < 0.05). Also at 1.04 rad.s-1, knee flexors produced lower torques at the end than the start of the season (p < 0.05). No further statistical differences were found. It was concluded that seasonal deterioration in key physiological variables such as aerobic endurance and muscle strength, can be observed in elite alpine skiers, and that in-season fitness training programmes should take account of this.

Anaerobic Threshold↗
PubMed1999

Effects of age and physiologic variables on right ventricular filling dynamics in normal subjects.

The reference values for right ventricular (RV) filling of normal persons and the effects of physiologic variables in a large series have not been described. The objective of this study was to characterize superior vena cava, hepatic vein, and RV inflow Doppler measurements in a large normal reference group to reflect the aging process, gender, heart rate, and effects of respiration. We prospectively performed pulsed-wave Doppler echocardiography of the superior vena cava, hepatic vein, and RV inflow during inspiration, expiration, and apnea in 115 healthy volunteers (62 women and 53 men) ranging in age from 21 to 84 years (mean +/- SEM 48 +/- 17). For analysis, the study subjects were classified by age into 2 groups: those < 50 years of age (group 1; n = 60) and those > or = 50 years of age (group 2; n = 55). Multiregression models were used to assess the influence of age, gender, and heart rate on Doppler variables. There were important differences in superior vena cava and RV inflow between the 2 groups. Group 2 had a greater superior vena cava peak atrial flow velocity (16 +/- 3 vs 13 +/- 3 cm/s), flow integrals (1.5 +/- 0.4 vs 1.1 +/- 0.3 cm), and reverse flow as a percentage of forward flow (17 +/- 6% vs 14 +/- 6%) than group 1. In group 2, peak RV inflow early filling velocity (41 +/- 8 vs 51 +/- 7 cm/s) and ratio of early filling-to-atrial filling (1.3 +/- 0.4 vs 2 +/- 0.5) were lower than that of group 1. Likewise, peak atrial filling velocity was higher (33 +/- 8 vs 27 +/- 8 cm/s) and deceleration time was longer (198 +/- 23 vs 188 +/- 22 ms) in group 2. The superior vena cava and hepatic vein peak forward flow velocities were significantly higher during inspiration than during expiration and apnea. Similarly, RV inflow velocities were significantly higher during inspiration than in expiration and apnea. Multiregression analysis showed that age, gender, and heart rate had important effects on Doppler variables. Thus, this study demonstrates the effects of aging and normal physiologic variable flow velocities in the superior vena cava, hepatic veins, and RV inflow in a large series of normal subjects.

Adult↗
PubMed1982

Automated control of physiological variables and clinical therapy.

Improved transducers and low-cost computational power make the development of on-line systems to control physiological variables and clinical therapy feasible. This review deals only with systems that provide control by the infusion of chemical agents or by changing the concentration of respiratory gases; control provided by electrical stimulation or mechanical means (orthotic and prosthetic devices) are not considered. Applications reviewed include drug dosage planning by computer, insulin infusion, automated anesthesia, control of respiratory variables, and control of blood pressure by vasoactive agents. There is a general need for the development of new sensors for physiological variables, algorithms for adaptive control, and controllable miniature activators for delivering therapeutic agents. Proposed control systems should be thoroughly evaluated in a realistic environment, preferably by comparing them with systems that they were designed to replace.

Anesthesia↗
PubMed1997

Correlations between short-course triathlon performance and physiological variables determined in laboratory cycle and treadmill tests.

The aim of this study was to investigate the relationships between physiological variables measured in graded cycling (CM) and treadmill running (RM) maximal tests and the performance of a short-course triathlon (1 km swim, 30 km cycling and 8 km running) in recreational triathletes. Ten male athletes with mean (+/-SD) age of 27.4(+/-5.7) years and maximal oxygen consumption (VO2peak) of 63.3(+/-8.95) mL.kg-1.min-1 participated in the study. The results showed that the VO2peak and VO2 at ventilatory threshold (VO2VT) determined in CM were significantly correlated to the overall and running times of the triathlon (r = -0.64 - 0.77, p < or = 0.05). The VO2peak and VO2VT determined in RM were also correlated to the running time when expressed as mL.kg-1.min-1 (r = -0.73, p < or = 0.05). The VT expressed as %VO2peak in both tests showed no significant correlations to triathlon performance. It appears that it is the absolute aerobic capacity of these athletes being critical to maintain a high exercise intensity in the triathlon, especially during the running segment. The mean heart rate (HR) measured in four subjects during the cycling and running segments of the triathlon was similar to the HR at VT determined in CM, which indicated that these athletes could maintain an exercise intensity close to the VT level during the competition. There was no significant correlation found between the swimming time and physiological variables measured in the laboratory cycling and running tests, which could be explained by the specific skills and economy of movement required in these exercises.

Adult↗
PubMed2002

Physiological variables measured under field conditions according to age and state of training in French Trotters.

We hypothesised that the derived physiological variables V2 and V4 (velocity to achieve a blood lactate concentration of 2 and 4 mmol/l, respectively), HR2 and HR4 (the corresponding heart rate) and V200 (the velocity for a heart rate of 200 beats/min) would improve with training state and age, in French Trotters. A total of 194 French Trotters from one training establishment were followed for 6 years and 1105 standardised field exercise tests performed on a sand training track. The horses were divided into 6 age groups (from 1 to > or = 6 years) and 4 training groups (beginning, endurance training, sprint training, racing). A 2-way analysis of variance was performed to evaluate the effects of age, training and the interaction of age and training on these physiological variables with the level of statistical significance set at 5%. The results showed that there was a significant influence of age on HR4, V2, V4 and V200, with these variables increasing with age. Also, there was a significant influence of training and both age and training on V2, V4 and V200, with these variables increasing with training and age. These results, obtained in a longitudinal study in a reproducible field environment, are consistent with previous laboratory-based experimental studies. We conclude that objective indices of fitness obtained on the training track can be useful in the commercial training environment.

Age Factors↗
PubMed1991

Unpredictability of fighter pilot G tolerance using anthropometric and physiologic variables.

Correlation and regression analyses were used to study relationships between centrifuge G tolerances of 1,434 fighter pilots during High-G Training (HGT) and anthropometric and physiologic variables. Multiple regression analyses yielded a four-variable model in which gradual onset run (GOR) relaxed-G tolerance was inversely correlated with height and directly correlated with age, weight, and diastolic blood pressure. Although the four-variable model was able to predict more of the variation in G tolerance than any single variable, neither method showed a correlation (r) of greater than 0.35 with GOR relaxed or straining G tolerance. No subject variable was significantly different between the pilot groups that did and did not experience G-induced loss of consciousness. We conclude that prediction of G tolerance during centrifuge HGT is unreliable using anthropometric and physiologic variables. The anti-G straining maneuver remains the major determinant of an individual's G tolerance.

Adult↗
PubMed2006

Effects of extradural morphine on end-tidal isoflurane concentration and physiological variables in pigs undergoing abdominal surgery: a clinical study.

OBJECTIVE: To evaluate the effects of preoperative extradural morphine on the end-tidal isoflurane (Fe'ISO) concentration and on physiological variables in pigs undergoing abdominal surgery. STUDY DESIGN: Prospective, randomized, blinded study. ANIMALS: Fourteen healthy pigs (20 +/- 4 kg) undergoing intestinal cannulation. MATERIALS AND METHODS: Anaesthesia was induced with a combination of medetomidine (50 microg kg(-1)) and tiletamine-zolazepam (2.5 mg kg(-1)) injected intramuscularly, and was maintained with isoflurane in air and oxygen (FiO(2) = 50% O(2)). In the first group, morphine (0.1 mg kg(-1)) was administered extradurally before surgery. The second group received an equivalent volume of extradural saline as control. During the experiment, heart and respiratory rates, mean arterial blood pressure, tidal volume and minute ventilation were recorded every 10 minutes. The concentration of Fe'ISO was adjusted, according to the depth of anaesthesia, by an experienced animal nurse. Within treatment groups, time-related changes in Fe'ISO and physiological variables were analysed using a repeated measurement anova. Differences in data between treatment groups were analysed at specific time points using a Mann-Whitney U-test. Results are presented as mean +/- SD; p < 0.05 was considered as significant. RESULTS: After the onset of action of the morphine, the Fe'ISO required to maintain anaesthesia was significantly lower in the extradural morphine group compared with control. During the expected maximal effect of the drug, Fe'ISO was significantly lower in the morphine group (0.6 +/- 0.2%) than in the control group (0.9 +/- 0.2%). The decrease in Fe'ISO indicated that the onset of action of morphine was approximately 30 minutes after injection. No significant differences in other clinical variables were found between the groups. CONCLUSION: Pigs that received extradural morphine before abdominal surgery achieved surgical anaesthetic depth at a lower Fe'ISO concentration. CLINICAL RELEVANCE: Extradural morphine allows abdominal surgery to be performed at a lower Fe'ISO concentrations.

Abdomen↗
PubMed1999

Physiologic variability in the perinatal period. Origins, measurement, and applications.

Variability is inherent in all physiologic signals. This variability provides valuable clinical information or may confound physiologic measurements and the interpretation of results. Both physiologic and nonphysiologic factors may affect variability. Clinicians and researchers need to be aware of physiologic variability and its implications.

Circadian Rhythm↗
PubMed1988

Analytical and physiological variability of salivary microbial counts.

Quantitation of mutans streptococci (MS) and Lactobacillus has been proposed as a method for the identification of patients at high risk for dental caries. The purpose of the present study was to investigate the analytical and physiological variability of this procedure. Variability due to specimen collection and processing was investigated by repeated sampling studies. Sample stability was investigated over storage periods of up to 72 hr at 5 degrees C, room temperature, and 37 degrees C. Physiological variability was investigated by performance of serial analyses on ten individuals, who collected six samples at intervals on a single day, and rising and noon samples on ten subsequent days. Sample collection, rather than sample processing, was found to be the major factor determining the imprecision of salivary microbial analysis in the majority of cases. However, individual subjects varied considerably in the consistency with which they provided saliva samples. Imprecision due to sample processing was relatively small, with coefficients of variations of 2.3% for MS counts and 2.1% for Lactobacillus counts. Samples were generally stable over a wide temperature range for at least 72 hours, although there was some loss of viability of lactobacilli on prolonged storage at room temperature or 37 degrees C in one experiment. Rising samples yielded higher counts than samples collected after breakfast and toothbrushing. Day-to-day variability was considerable, with 95% confidence limits exceeding 1 log in 28% of data sets for MS count and 39% of data sets for Lactobacillus.

Circadian Rhythm↗
PubMed2006

Statistical evaluation of physiological variability of rifampicin in fixed dose combinations.

Tuberculosis is one of the microbial diseases having a long history of its occurrence and yet to be eradicated from the world. Due to the development of bacterial resistance, treatment has changed from monotherapy to combotherapy to fixed dose combinations (FDCs). Rifampicin has been found one of the most important anti-tubercular drugs, however variable bioavailability of rifampicin in some FDCs as well as separate formulations has been reported in the literature, and led to the development of WHO model protocol for evaluation of FDCs for bioequivalence trials. In present investigation, role of physiological variability in rifampicin bioequivalence was studied. Influence of subject's body weight, inter/intra-individual variability of elimination rate and impact of outliers on the decision of bioequivalence were investigated. Normalization of pharmacokinetic measures for bioequivalence (AUC and C(max)) were carried out as per body weights and elimination rate constants of subjects, then different statistical tests like two-way ANOVA, hauschke analysis, normal and log-transformed confidence interval were applied to check for the change in bioequivalence decision. It was found that normalization as per body weights did not play a significant role in the outcome of bioequivalence endpoint. Similarly, elimination rate variability and outliers have been found insignificant regarding final outcome of bioequivalence study. Hence, it has been concluded that physiological variability did not play a significant role in bioequivalence of rifampicin in FDCs.

Analysis of Variance↗
PubMed2007

Can physiological variables and early warning scoring systems allow early recognition of the deteriorating surgical patient?

OBJECTIVE: Early warning scoring systems are widely used in clinical practice to allow early recognition of the deteriorating patient, but they lack validation. We aimed to test the ability of physiologic variables, either alone or in existing early scoring systems, to predict major deterioration in a patient's condition and attempt to derive functions with superior accuracy. DESIGN: A comparative cohort study. SETTING: A teaching hospital in Scotland. PATIENTS: Two cohorts of general surgical high-dependency patients. The cohorts are a group of surgical high-dependency care patients who did not require intensive care admission and another group of patients who did require admission. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Prospective physiologic data on consecutive surgical high-dependency unit patients were collected and compared with physiologic data on patients admitted to the intensive care unit from the same surgical high-dependency units. Data were quality checked and summarized, and discriminant analysis and receiver operator curves were used to discriminate between the groups. There were significant physiologic differences between groups with regard to heart rate (p<.001, area under the receiver operating characteristic curve [AUC] 0.7), respiratory rate (p<.001, AUC 0.71), and oxygen saturation (p<.001, AUC 0.78) across time points. This was not present for systolic blood pressure or temperature. Existing early warning scoring systems had good discriminatory power (AUC 0.83-0.86). We derived discriminant functions, which have a high predictive ability to determine differences between groups (p<.0001, AUC 0.86-0.90). We found that heart rate and respiratory rate could detect differences between groups at 6 and 8 hrs before ICU admission, but oxygen saturation and the discriminant function 2 could detect differences 48 hrs before ICU admission. CONCLUSIONS: Some commonly used physiologic variables have reasonable power in determining the difference between patients requiring intensive care unit admission, but others are poor. Existing early warning scores have comparatively good discriminatory power. We have derived functions with excellent predictive power in this derivation cohort.

Adult↗
PubMed2005

Altitude decompression sickness susceptibility: influence of anthropometric and physiologic variables.

INTRODUCTION: There is considerable variability in individual susceptibility to altitude decompression sickness (DCS). The Air Force Research Laboratory Altitude DCS Research Database consists of extensive information on 2980 altitude exposures conducted with consistent procedures and endpoint criteria. We used this database to quantify the variation in susceptibility and determine if anthropometric and/or physiologic variables could be used to predict DCS risk. METHODS: There were 240 subjects who participated in at least 4 of 70 exposure profiles in which between 5 and 95% of all subjects tested developed DCS symptoms. A subject/study ratio (SSR) was calculated by dividing the DCS experienced by a subject during all their exposures by the DCS incidence for all subjects who participated in the identical exposures. The SSR was used to identify the relative susceptibility of subjects for use in analyzing possible relationships between DCS susceptibility and the variables of height, weight, body mass index, age, percent body fat, and aerobic capacity. RESULTS: The DCS incidence was 46.5% during 1879 subject-exposures by subjects exposed at least 4 times. A significant relationship existed between higher DCS susceptibility and the combination of lower aerobic capacity and greater weight (p < 0.05). DISCUSSION: Despite a correlation, less than 13% of the variation in DCS susceptibility was accounted for by the best combination of variables, weight and VO2max. CONCLUSION: Differences in DCS susceptibility cover a wide range and appear to be related to some anthropometric and physiologic variables. However, there was insufficient correlation to allow prediction of an individual's susceptibility.

Adaptation, Physiological↗
PubMed1995

Relationships between perceived exertion and physiological variables during swimming.

The relationships between perceived exertion and the physiological variables oxygen uptake (VO2), heart rate (HR) and blood lactate concentration (HLa) were studied in tethered swimming. Seven male and ten female subjects swam at five submaximal intensities. The degree of perceived exertion was measured both on the category scale (RPE) and on the category-ratio scale (CR-10). All five dependent variables (VO2, HR, HLa, RPE and CR-10) were described by the equation R = a+c (S-b)n with the drag (D) in tethered swimming as an independent variable. The relationships between D and VO2, HR and RPE were linear with a level of fitness correlation (r = 0.989-0.999) for both males and females. The HLa exponents were 3.2 for males (r = 1.000) and 3.6 for females (r = 0.991), and CR-10 were 1.5 for males (r = 0.998) and 1.9 for females (r = 1.000), respectively. The growth functions for males and females were very similar. The conclusion is that RPE is effective as a measure of exercise intensity and can be used for exercise prescription in practical swimming.

Adult↗
PubMedDate not supplied

[Physiological variables in calves and their significance for vitality and growth].

Calves from the dairy herd and from the mother cow herd and their dams were investigated just after parturition and the calves at the first two days of life and between fifteen and twenty days and than at ninety days of life as well using whole day heart rate and video recording, results of venous blood sample analysis and body growth and health criteria. The great variation of physiological variables in calves can partly be explained by maturity, degree of adaptation, gender, time of day and the birth course. Relationships between physiological variables and the adaptability, body growth performance and the degree of adaptation to specific rearing condition could be pointed out.

Adaptation, Physiological↗
PubMed2004

Physiologic variables that predict the outcome of treatment for fecal incontinence.

Identification of physiologic factors that predict response to fecal incontinence therapy would be helpful in choosing the optimal treatment and advising patients on the likelihood of a successful outcome. However, few physiologic parameters have been consistently identified as important in predicting response to either biofeedback or surgery. The process of isolating these factors has been hampered by heterogeneity in the definition of fecal incontinence, lack of consensus on what constitutes a successful outcome, lack of follow-up data, variations in the way "standard" treatments are implemented, and lack of properly powered randomized controlled trials. Among the physiologic variables that studies have generally found to be predictive of successful outcomes in biofeedback treatment are the threshold for external anal sphincter contraction after treatment, the inclusion of sensory training in treatment, and a reduction in volume for the first sensation after treatment. Factors that have not been found to be important in predicting outcome following biofeedback retraining include the duration of fecal incontinence, pudendal nerve damage, patient age, symptom severity, pretreatment anal canal pressures, and results of anal ultrasonography. The presence of some degree of anorectal sensation is the only preoperative assessment that has been found to be predictive of response to surgical therapy. It is recommended that outcome measures for fecal incontinence be more clearly defined, that future biofeedback studies elaborate the predictive value of pretreatment anorectal sensation and the response to sensory retraining, and that postsurgical measurements such as anal squeeze pressure and sphincter length be taken into account.

Fecal Incontinence↗
PubMed2000

Intraoperative physiologic variables and outcome in cardiac surgery: Part II. Neurologic outcome.

BACKGROUND: The impact of alterable physiologic variables on neurologic outcome after coronary artery bypass grafting procedures is unknown. The purpose of this study was to determine whether minimum intraoperative hematocrit, maximum glucose concentration, or mean arterial pressure during cardiopulmonary bypass influences risk-adjusted neurologic outcome after coronary artery bypass grafting. METHODS: Outcome data from 2,862 patients undergoing coronary artery bypass grafting were merged with intraoperative physiologic data. A preoperative stroke risk index was calculated for each patient. Variables found significant by univariate logistic regression were tested in a multivariable model to determine association with outcome. RESULTS: The incidence of stroke or coma in the study population was 1.3%. After controlling for stroke risk and bypass time, only an index of low mean arterial pressure during bypass retained a significant inverse association with outcome (p = 0.0304). CONCLUSIONS: This study found no evidence that glucose concentration or minimum hematocrit are associated with major adverse neurologic outcome. The association between lower pressure during bypass and decreased incidence of stroke or coma persisted in all risk groups. This points to mechanisms other than hypoperfusion as the primary cause of neurologic injury associated with cardiac surgery.

Aged↗