Humidification of Respired Gas by Nasal Mucosa

1973 ◽  
Vol 82 (3) ◽  
pp. 330-332 ◽  
Author(s):  
W. Liese ◽  
R. Joshi ◽  
G. Cumming
Keyword(s):  
Nasal Mucosa ◽  
Normal Subjects ◽  
Total Water ◽  
Tidal Water ◽  
Complete Saturation ◽  
Expired Gas ◽  
The Mean ◽  
The Difference ◽  
End Tidal ◽  
Average Contribution

End tidal water vapor tension of the expirate after nasal and then after oral inspiration was measured at the lips of seven normal subjects using a mass spectrometer. At a mean inspired air temperature of 23°C and Ph.o of 14.7 mmHg, the mean end tidal Ph.o was was 40.57 mmHg after nasal and 37.15 mmHg after oral inspiration. The difference was statistically significant. The evidence for complete saturation of expired gas is discussed. Assuming a 100% saturation of expired gas the average contribution of the nasal mucosa to the water content of the respired air in this experiment was 3 gm/m3 or approximately 10% of the total water contributed by the respiraory tract.

Sensation of dyspnea during hypercapnia, exercise, and voluntary hyperventilation

1990 ◽  
Vol 68 (5) ◽  
pp. 2100-2106 ◽  
Author(s):  
T. Chonan ◽  
M. B. Mulholland ◽  
J. Leitner ◽  
M. D. Altose ◽  
N. S. Cherniack
Keyword(s):  
Visual Analog Scale ◽  
Line Intensity ◽  
Time Course ◽  
Normal Subjects ◽  
Cycle Ergometer ◽  
Base Line ◽  
Analog Scale ◽  
Voluntary Hyperventilation ◽  
The Difference ◽  
End Tidal

To determine whether the intensity of dyspnea at a given level of respiratory motor output depends on the nature of the stimulus to ventilation, we compared the sensation of difficulty in breathing during progressive hypercapnia (HC) induced by rebreathing, during incremental exercise (E) on a cycle ergometer, and during isocapnic voluntary hyperventilation (IVH) in 16 normal subjects. The sensation of difficulty in breathing was rated at 30-s intervals by use of a visual analog scale. There were no differences in the level of ventilation or the base-line intensity of dyspnea before any of the interventions. The intensity of dyspnea grew linearly with increases in ventilation during HC [r = 0.98 +/- 0.02 (SD)], E (0.95 +/- 0.03), and IVH (0.95 +/- 0.06). The change in intensity of dyspnea produced by a given change in ventilation was significantly greater during HC [0.27 +/- 0.04 (SE)] than during E (0.12 +/- 0.02, P less than 0.01) and during HC (0.30 +/- 0.04) than during IVH (0.16 +/- 0.03, P less than 0.01). The difference in intensity of dyspnea between HC and E or HC and IVH increased as the difference in end-tidal PCO2 widened, even though the time course of the increase in ventilation was similar. No significant differences were measured in the intensity of dyspnea that occurred with changes in ventilation between E and IVH. These results indicate that under nearisocapnic conditions the sensation of dyspnea produced by a given level of ventilation seems not to depend on the method used to produce that level of ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Platelet Water Content is Decreased by Gel-Filtration

1977 ◽  
Author(s):  
J.S. Wiley ◽  
G. Wray ◽  
I.A. Cooper
Keyword(s):  
Water Content ◽  
Gel Filtration ◽  
Normal Subjects ◽  
Intracellular Water ◽  
Total Water ◽  
Initial Water ◽  
Mean Cell Volume ◽  
Cell Pellet ◽  
The Mean ◽  
Water Space

One approach to platelet sizing is to measure the intracellular water space of platelets with 3H-H2O since the % water content of platelets remains constant in states with different platelet sizes. Fresh citrated blood was centrifuged for 10 min at 150 'g' to obtain PRP. Aliquots of PRP were briefly incubated with either 3H-H2O or 14C-sucrose then layered over 0.3 ml dibutylphthalate and spun 4 min at 8000 'g'. The cell pellet was solubilized and counted to enable spaces to be calculated. The extracellular (sucrose) space was subtracted from the total water space of the pellet to give a mean intracellular water space of 0.56 ± 0.12 μ1/108 platelets (n =19). Assuming a water content of 7 5% and a density of 1.04, the mean platelet volume for normal subjects is 7.2 fl. Gel-filtration of platelets (GFP) on Sepharose-2B reduced their mean water space by 0.12 μl/108 platelets. However the amount of shrinkage on gel-filtration depended on the initial water space of the platelets in PRP and there was a linear relation between these two variables (r = 0.82). Shrinkage was 40% for an initial platelet water space of 0.70 μl/108 platelets but there was almost no shrinkage below a water space of 0.40 μl/108 platelets. Recovery of platelets from each column averaged 8 0% and showed no relation to the reduction in the mean cell water space. The lower water space of GFP may indicate a reduction in mean cell volume due to gel-filtration.

Analysis of reproducibility, evaluation, and preference of the new iC100 rebound tonometer versus iCare PRO and Perkins portable applanation tonometry

2019 ◽  
Vol 30 (6) ◽  
pp. 1349-1355 ◽  
Author(s):  
Mercedes Molero-Senosiaín ◽  
Laura Morales-Fernández ◽  
Federico Saenz-Francés ◽  
Julian García-Feijoo ◽  
Jose María Martínez-de-la-Casa
Keyword(s):  
Intraocular Pressure ◽  
Visual Analogue Scale ◽  
Analogue Scale ◽  
Normal Subjects ◽  
Applanation Tonometry ◽  
Rebound Tonometer ◽  
The Mean ◽  
The Difference ◽  
The Comparative Study ◽  
Mean Time

Objectives: To analyze the reproducibility of the new iC100 rebound tonometer, to compare its results with the applanation tonometry and iCare PRO and to evaluate the preference between them. Materials and methods: For the study of reproducibility, 15 eyes of 15 healthy Caucasian subjects were included. Three measurements were taken each day in three separate sessions. For the comparative study, 150 eyes of 150 Caucasian subjects were included (75 normal subjects and 75 patients with glaucoma). Three consecutive measurements were collected with each tonometer, randomizing the order of use. The discomfort caused by each tonometer was evaluated using the visual analogue scale. Results: No statistically significant differences were detected between sessions. In the comparison between tonometers, the measurements with iC100 were statistically lower than those of Perkins (−1.35 ± 0.417, p = 0.004) and that iCare PRO (−1.41 ± 0.417, p = 0.002). The difference between PRO and Perkins was not statistically significant ( p = 0.990). The mean time of measurement (in seconds) with iC100 was significantly lower than with Perkins (6.74 ± 1.46 vs 15.53 ± 2.01, p < 0.001) and that PRO (6.74 ± 1.46 vs 11.53 ± 1.85, p < 0.001). Visual analogue scale score with iC100 was lower than Perkins (1.33 ± 0.99 vs 1.73 ± 1.10, p < 0.05). In total, 61.7% preferred iC100 against Perkins. Conclusion: The reproducibility of this instrument has been proven good. iC100 underestimates intraocular pressure compared to applanation tonometry at normal values and tends to overestimate it in high intraocular pressure values. Most of the subjects preferred iC100 tonometer.

Effect of Erythropoietin on Platelet Function and Glycoprotein Expression in Patients with MDS.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3993-3993
Author(s):  
Fotis F.I. Girtovitis ◽  
Dimitrios D. Bougiouklis ◽  
Michel M.P. Makris ◽  
Elefteria E. Pithara ◽  
Pantelis P.E. Makris
Keyword(s):  
Flow Cytometry ◽  
Platelet Function ◽  
Normal Subjects ◽  
Mean Value ◽  
Special Treatment ◽  
Recombinant Erythropoietin ◽  
Mean Values ◽  
Human Recombinant Erythropoietin ◽  
The Mean ◽  
The Difference

Abstract Aim: We decide to study the effect of erythropoietin on the platelet function and glycoproteins expression in patients (pts) with myelodysplastic syndrome (MDS). All patients suffered from primary MDS but none of them received any special treatment. From our study pts that suffered from diseases or they were receiving medication that affect the function of platelets were excluded. Furthermore pts with platelet count&lt;50,000/μl were excluded also because we were unable to check the aggregation of platelets. Material: 41 subjects were studied, 15 normal subject (10 men and 5 women mean age 66,6±14 years old)and 26 pts (17 men and 9 women with mean age70,9±7,4 years old) suffered from all types of MDS according to FAB criteria (9 with RA, 3 with RARS, 7 RAEB, 4 with CMML and 3 with RAEB-t). We divided them in 2 groups: 1st - 7 Pts receiving human recombinant erythropoietin (rEPO) with mean dose 30.000 iu subcutaneous weekly and 2nd - 19 without rEPO. Methods. 1- The platelet function was studied in Platelet Ionized Calcium Aggregometer (PICA) using Ristocetin, ADP, Collagen and Adrenalin as stimulators. 2- The expression of platelet glycoproteins (GPIb, IX, IIb, IIIa and P-selectin) was studied using the flow cytometry and special monoclonal antibodies. This way the percentage of glycoprotein expressed in platelet membrane and MFI were estimated. We performed the statistical analysis of our results using the t-test with common standard deviation.. Results: our results concerning the aggregation test and flow cytometry are presented in tables 1,2 and 3. From the study of our results we can see that while the decrease of aggregation between the patients under EPO and normal subjects is statistically non significant (p&lt;0.1)the decrease of the corresponding values between the pts that did not received EPO and normal subjects was statistically very significant for all stimulators (p &lt;0,001). pts under EPO show an important increase of platelet expressing GPIIb percentage grater than the expressed percentage of patients without EPO (60% vs. 46,1% correspondingly, p&lt;0.001). The difference of expressed MFI was not statistically significant. Conclusion: The findings of our study show us that erythropoietin improves the function of platelets in patients with MDS, probably through the increase of platelet percentage which express glycoproteins. Table 1 Comparison of the mean value of aggregation between the groups Table 2 Comparison of the mean values of the platelets expressing corresponding glycoproteins percentage between the groups Table 3 Comparison of the mean value of MFI between the groups

Alveolar carbon monoxide: A comparison of methods of measurement and a study of the effect of change in body posture

1988 ◽  
Vol 74 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Andrew J. T. Kirkham ◽  
Andrew R. Guyatt ◽  
Gordon Cumming
Keyword(s):  
Carbon Monoxide ◽  
Linear Models ◽  
Body Posture ◽  
Breath Hold ◽  
Erect Posture ◽  
Indirect Measures ◽  
The Mean ◽  
The Difference ◽  
End Tidal ◽  
Inspired Oxygen

1. We have compared rebreathing, breath-hold and mean alveolar methods of measuring alveolar carbon monoxide (CO), at levels similar to those found in smokers, as a preliminary to using them as indirect measures of carboxyhaemoglobin levels. In the present study alveolar CO levels were raised by rebreathing a 2% CO mixture. 2. Breath-hold CO was measured after breath-hold times of 0–35 s in 5 s increments. Using generalized linear models, the maximum value for breath-hold CO was estimated to occur at 23 s. Breath-hold CO after a 20 and 25 s breath-hold were similar to and significantly greater than those of less than 20 s or greater than 25 s. 3. As expired CO increased, the difference between breath-hold and mean alveolar CO became proportionally larger. On average, breath-hold CO was 24% larger than mean alveolar CO. 4. Rebreathing, breath-hold and mean alveolar CO were compared at four different inspired oxygen concentrations. Expired CO increased significantly with increasing oxygen for all three methods. At end-tidal oxygen levels of less than 25%, breath-hold and rebreathing CO were similar, however, the overall mean difference between the three methods was significant. 5. While rebreathing CO was unaffected by changes in ventilation/perfusion of the lung, induced by change in body posture, both breath-hold and mean alveolar CO showed a significant fall with change from the supine to erect posture. 6. We conclude that under normoxic conditions, rebreathing and breath-hold CO (20 or 25 s breath-hold) were similar, whereas the mean alveolar method produced significantly lower values, presumably due to lack of equilibration. Altering ventilation/perfusion of the lung caused no mean change in the measurement of rebreathing CO but did affect the other methods.

THE EXCRETION OF C-16 OXYGENATED NEUTRAL STEROID SULPHATES AND DEHYDROEPIANDROSTERONE SULPHATE IN NORMAL PREGNANCY, AND A COMPARISON WITH THEIR EXCRETION BY ENDOCRINOLOGICALLY NORMAL SUBJECTS OF BOTH SEXES

1973 ◽  
Vol 72 (3) ◽  
pp. 587-603 ◽  
Author(s):  
J. Seth ◽  
G. W. Pennington
Keyword(s):  
Statistical Significance ◽  
Normal Subjects ◽  
Normal Pregnancy ◽  
Maternal Circulation ◽  
Pregnant Females ◽  
Neutral Steroid ◽  
Usual Criterion ◽  
The Mean ◽  
The Difference ◽  
Normal Males

ABSTRACT The respective mean 24 h urinary excretions of sulphoconjugated 16α-hydroxydehydroepiandrosterone, 16-oxo-androstenediol, and dehydroepiandrosterone were found to be 1040, 230, and 668 μg/24 h for normal males, and 621, 209, and 304 μg/24 h for normal non-pregnant females. None of the differences in mean steroid excretions between males and non-pregnant females was statistically significant according to the usual criterion for significance (P < 0.05). The mean excretions of sulphoconjugated 16α-hydroxydehydroepiandrosterone, 16-oxo-androstenediol and dehydroepiandrosterone between the 10th week of normal pregnancy and term were 1300, 505 and 226 μg/24 h respectively. No significant trend in the excretions of these neutral steroid sulphates between the 10th week of pregnancy and term could be detected. The increased excretion of both C-16 oxygenated steroid sulphates in pregnancy was highly significant (P < 0.001). In contrast, the statistical significance of the difference in excretion of dehydroepiandrosterone sulphate between pregnant and non-pregnant females could not be established. There did not appear to be any relationship between the excretion of 16α-hydroxydehydroepiandrosterone sulphate and oestriol in normal pregnancy. The results are considered to be consistent with a limited transplacental passage of neutral steroids from the foetoplacental to maternal circulation.

scholarly journals Time to adapt in the pandemic era: A prospective randomized non–inferiority  study comparing time to intubate  with and without  the barrier box

2020 ◽  
Author(s):  
Praneeth Madabhushi ◽  
Sudhakar Kinthala ◽  
Abistanand Ankam ◽  
Nitin Chopra ◽  
Burdett Porter
Keyword(s):  
Management Practices ◽  
Controlled Trial ◽  
Peripheral Nerve Stimulator ◽  
Secondary Endpoints ◽  
The Mean ◽  
The Difference ◽  
Clinically Significant ◽  
Induction Times ◽  
End Tidal ◽  
Bag Mask Ventilation

Abstract Background The challenges posed by the spread of COVID-19 disease through aerosols have compelled anesthesiologists to modify their airway management practices. Devices such as barrier boxes are being considered as potential adjuncts to full PPE's to limit the aerosol spread. Usage of the barrier box raises concerns of delay in time to intubate (TTI). We designed our study to determine if using a barrier box with glidescope delays TTI within acceptable parameters to make relevant clinical conclusions.Methods 78 patients were enrolled in this prospective non inferiority controlled trial and were randomly allocated to group C (without the barrier box) or the study group BB (using barrier box). The primary measured endpoint is time to intubate (TTI), which is defined as time taken from loss of twitches confirmed with a peripheral nerve stimulator to confirmation of end-tidal CO 2. 15 seconds was used as non-inferiority margin for the purpose of the study .We used an unpaired two-sample single-sided t-test to test our non- inferiority hypothesis (H 0 : Mean TTI diff ≥ 15 seconds, H A : Mean TTI diff < 15 seconds). Secondary endpoints include the number of attempts at intubation, lowest oxygen saturation during induction, and the need for bag-mask ventilation.Results Mean TTI in group C was 42 (CI 19.2 to 64.8) seconds vs. 52.1 (CI 26.1 to 78) seconds in group BB. The difference in mean TTI was 10.1 seconds (CI -∞ to 14.9). We rejected the null hypothesis and concluded with 95% confidence that the difference of the mean TTI between the groups is less than < 15 seconds (95% CI -∞ to 14.9,p = 0.0461). Our induction times were comparable (67.7 vs. 65.9 seconds).100% of our patients were intubated on the first attempt in both groups. None of our patients needed rescue breaths.Conclusions We conclude that in patients with normal airway exam, scheduled for elective surgeries, our barrier box did not cause any clinically significant delay in TTI when airway manipulation is performed by well-trained providers.The study was retrospectively registered at clinicaltrials.gov (NCT04411056) on May 27, 2020

Factors affecting expired waveform for carbon monoxide

1984 ◽  
Vol 56 (3) ◽  
pp. 708-715
Author(s):  
D. Z. Rubin ◽  
S. M. Lewis ◽  
C. Mittman
Keyword(s):  
Carbon Monoxide ◽  
Normal Subjects ◽  
Lung Model ◽  
Repeated Testing ◽  
Factors Affecting ◽  
Sensitivity Tests ◽  
Standard Parameter ◽  
Expired Gas ◽  
End Tidal ◽  
Computer Simulation Studies

We previously presented a method based on a computer lung model for determining the distribution of both specific ventilation and specific diffusing capacity. These argon and carbon monoxide (CO) washin and washout studies were obtained in 12 normal subjects and 24 patients with varying degrees of obstructive lung disease. In addition to end-tidal and mixed expired gas concentrations, the expired waveform for both gases was sampled. In patients we found that this method failed to adequately describe CO dynamics during the early part of expiration; predicted concentrations were higher than actual data. Modifications of the original model that satisfy all data are presented. This new model suggests that CO uptake occurs in spaces with ventilatory properties of dead space. The accuracy and reliability of these observations were established by computer simulation studies as well as by repeated testing in one subject. These proved to be highly reproducible over a period of 5 mo. Standard parameter sensitivity tests showed parameters to vary by less than 10% and to be stable even when realistic levels of noise were added to the data. We conclude that studies involving ventilation of insoluble gases are insufficient to describe gas exchange in the lung. The addition of an exchangeable gas adds significant understanding of lung function, particularly in disease.

A modified single breath method for estimation of cardiac output in humans at rest and during exercise

1987 ◽  
Vol 72 (4) ◽  
pp. 437-441 ◽  
Author(s):  
Y. M. H. Al-Shamma ◽  
R. Hainsworth ◽  
N. P. Silverton
Keyword(s):  
Cardiac Output ◽  
Normal Subjects ◽  
Random Errors ◽  
O2 Uptake ◽  
Mean Values ◽  
Single Breath ◽  
Expired Gas ◽  
The Mean ◽  
Rest And Exercise ◽  
Single Breath Method

1. This study was undertaken to determine the accuracy of a modification of a single breath method for estimation of cardiac output. The technique incorporated a single rebreathing stage followed by a prolonged expiration. Cardiac output was determined from the O2 uptake and the instantaneous changes in O2 and CO2 in the expired gas during the prolonged expiration. 2. The mean values and the random errors (determined from the differences between pairs of estimates) of cardiac outputs in normal subjects at rest and exercise were 5.42 and ± 0.60 litres/min (2 sd, 60 pairs) and 14.1 and ±1.8 litres/min (40 pairs). 3. Larger random errors were obtained in a group of cardiac patients but, except in hypoxic patients, the mean values obtained by the single breath and the direct (Fick) methods were almost identical. 4. We conclude that our modification of the single breath method is simple to use and sufficiently reliable for use in humans both at rest and during steady states of light exercise.

scholarly journals The Standardized Normal Ivy Bleeding Time and Its Prolongation by Aspirin

Blood ◽  
1969 ◽  
Vol 34 (2) ◽  
pp. 204-215 ◽  
Author(s):  
C. H. MIELKE ◽  
M. M. KANESHIRO ◽  
I. A. MAHER ◽  
J. M. WEINER ◽  
S. I. RAPAPORT
Keyword(s):  
Bleeding Time ◽  
Normal Subjects ◽  
Tolerance Test ◽  
Time Data ◽  
Double Blind ◽  
Large Size ◽  
Normal Individuals ◽  
The Mean ◽  
The Difference ◽  
Normal Males

Abstract A standardized, reproducible Ivy bleeding time technic has been described which permits one to obtain accurate bleeding time data in man. The technic was used to standardize an aspirin tolerance test in which 60 normal males had a control bleeding time; were given, on a double blind basis, either placebo or 1 Gm. of aspirin, and had a second bleeding time 2 hours later. The control values were: mean, 5 min.; mean ± 2 st. dev., 2 min., 30 sec. to 10 min. The values after placebo were: mean, 5 min., 30 sec.; mean ± 2 st. dev., 2 min., 30 sec. to 11 min. The values after aspirin were: mean, 9 min., 30 sec.; mean ± 2 st. dev., 4 min. to 21 min. The difference between the mean bleeding time after placebo and after aspirin was highly significant (p < 0.001). The distribution of the bleeding times after aspirin suggested that normal subjects do not respond to aspirin as a single population. The degree of prolongation of the bleeding time and the large size of the drops of blood observed in some subjects suggested to us that small amounts of aspirin may exert a significant effect upon hemostasis in normal individuals.

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