A Bioreactor Technology for Modeling Fibrosis in Human and Rodent Precision-Cut Liver Slices.

Precision cut liver slices (PCLSs) retain the structure and cellular composition of the native liver and represent an improved system to study liver fibrosis compared to two-dimensional mono- or co-cultures. The aim of this study was to develop a bioreactor system to increase the healthy life span of PCLSs and model fibrogenesis. PCLSs were generated from normal rat or human liver, or fibrotic rat liver, and cultured in our bioreactor. PCLS function was quantified by albumin enzyme-linked immunosorbent assay (ELISA). Fibrosis was induced in PCLSs by transforming growth factor beta 1 (TGFß1) and platelet-derived growth factor (PDGFßß) stimulation ± therapy. Fibrosis was assessed by gene expression, picrosirius red, and α-smooth muscle actin staining, hydroxyproline assay, and soluble ELISAs. Bioreactor-cultured PCLSs are viable, maintaining tissue structure, metabolic activity, and stable albumin secretion for up to 6 days under normoxic culture conditions. Conversely, standard static transwell-cultured PCLSs rapidly deteriorate, and albumin secretion is significantly impaired by 48 hours. TGFß1/PDGFßß stimulation of rat or human PCLSs induced fibrogenic gene expression, release of extracellular matrix proteins, activation of hepatic myofibroblasts, and histological fibrosis. Fibrogenesis slowly progresses over 6 days in cultured fibrotic rat PCLSs without exogenous challenge. Activin receptor-like kinase 5 (Alk5) inhibitor (Alk5i), nintedanib, and obeticholic acid therapy limited fibrogenesis in TGFß1/PDGFßß-stimulated PCLSs, and Alk5i blunted progression of fibrosis in fibrotic PCLS. Conclusion: We describe a bioreactor technology that maintains functional PCLS cultures for 6 days. Bioreactor-cultured PCLSs can be successfully used to model fibrogenesis and demonstrate efficacy of antifibrotic therapies.

Haemodialysing babies weighing <8 kg with the Newcastle infant dialysis and ultrafiltration system (Nidus): comparison with peritoneal and conventional haemodialysis.

BACKGROUND: To compare the efficacy of the Newcastle infant dialysis and ultrafiltration system (Nidus) with peritoneal dialysis (PD) and conventional haemodialysis (HD) in infants weighing <8 kg. METHODS: We compared the urea, creatinine and phosphate clearances, the ultrafiltration precision, and the safety of the Nidus machine with PD in 7 piglets weighing 1-8 kg, in a planned randomised cross-over trial in babies, and in babies for whom no other therapy existed, some of whom later graduated to conventional HD. RESULTS: Two babies entered the randomised trial; 1 recovered rapidly on PD, the other remained on the Nidus as PD failed. Additionally, 9 babies were treated on the Nidus on humanitarian grounds: 3 because of failed PD, and 3 with permanent kidney failure later converted to conventional HD. We haemodialysed 10 babies weighing between 1.8 and 5.9 kg for 2,475 h during 354 Nidus sessions without any clinically important incidents, and without detectable haemolysis. Single-lumen vascular access was used with no blood priming of circuits. The urea, creatinine and phosphate clearances using the Nidus were around 1.5 to 2.0 ml/min in piglets and babies, and were consistently higher than PD clearances, which ranged from about 0.2 to 0.8 ml/min (p ≤ 0.0002 for each chemical). Ultrafiltration was achieved to microlitre precision by the Nidus, but varied widely with PD. Fluid removal using conventional HD was imprecise and resulted in some hypovolaemic episodes requiring correction. CONCLUSION: The Nidus can provide HD in the Pediatric Intensive Care Unit (PICU) and outpatient intermittent HD without blood priming for babies weighing <8 kg, It generates higher dialysis clearances than PD, and delivers more precise ultrafiltration control than either PD or conventional HD.

Differences in urodynamic voiding variables recorded by conventional cystometry and ambulatory monitoring in symptomatic women.

OBJECTIVES: To determine whether there are differences in pressure and flow measurements between conventional cystometry (CONV) and ambulatory urodynamic monitoring (AMB) in women with overactive bladder syndrome and urinary incontinence. MATERIALS AND METHODS: Retrospective study which included female subjects who underwent both CONV (with saline filling medium) and AMB, separated by less than 24 months, not using medication active on the lower urinary tract and without history of prior pelvic surgery. Both tests were carried out in compliance with the International Continence Society standards. The paired Student's t test was used to compare continuous variables. Bland-Altman statistics were used to assess the agreement of each variable between both studies. RESULTS: Thirty women with a median (range) age of 50 (14 - 73) years met the inclusion criteria. AMB was carried out at a mean (SD) of 11 (6) months after CONV. Measurements of pves and pabd at the end of filling, and Qmax were significantly higher from AMB recordings. There were no differences in pdet at the end of filling, pdetQmax or pdetmax during voiding, nor significant difference in Vvoid. CONCLUSIONS: We provide previously undocumented comparative voiding data between CONV and AMB for patients who most commonly require both investigations. Our findings show higher values of Qmax but similar values of pdetQmax measured by AMB which may partly reflect an overall lower catheter caliber, physiological filling but perhaps also more 'normal' voiding conditions.

Methods and value of home uroflowmetry in the assessment of men with lower urinary tract symptoms: a literature review.

AIMS: Uroflowmetry is a key clinical assessment for men with LUTS. Home uroflowmetry is a convenient way to obtain multiple flow readings and has the potential to combat problems inherent to clinic-based measurements. We reviewed current evidence regarding the technology and value of multiple and home uroflowmetry. METHODS: We searched PubMed and Embase from January 1988 to February 2011 using a predetermined strategy. Reference lists from retrieved articles were scanned and additional papers screened for relevance. Proceedings of the annual meetings of the International Continence Society since 2008 were also searched. Relevant guidelines were obtained from the UK NHS Evidence repository. RESULTS: Eight studies described five simple, low-cost instruments giving multiple representative estimates of Q(max) but not a complete flow curve. A further eight studies described home use of four sophisticated, electronic flowmeters similar to clinic-based equipment. The above methods were assessed against ICS recommendations for uroflowmetry and the results of several studies investigating variability of flow parameters such as Q(max) were presented. CONCLUSIONS: Our findings illustrate the gulf between low-cost methods of obtaining average or peak flow measurements and precise, expensive devices with the capabilities of clinic flowmeters. Further studies are required to confirm the statistical benefit of averaging multiple values of Q(max) and to investigate the diagnostic and predictive value of flow variables other than Q(max) that can be derived from multiple recordings.

Continuous non-invasive measurement of bladder voiding pressure using an experimental constant low-flow test.

PURPOSE: We developed a prototype device using an automatically controlled inflatable penile cuff to measure bladder voiding pressure continuously and non-invasively in men. The purpose of this study was to validate the pressure measurements made by this device by comparison to those during simultaneous invasive PFS. METHODS: A device was developed to automatically modulate flow rate by controlling pressure in a penile cuff. Men undergoing conventional urodynamics studies were recruited to have an additional fill-void cycle whilst using the new device. We report on 40 men using a standardized protocol. Pressure measured by this device was compared with simultaneous vesical pressure by evaluating maximum pressure during voiding, and calculating the root mean square (RMS) difference between p(cuff) and p(ves) . RESULTS: We recruited 80 men of whom 18 were excluded, 22 were involved in initial development phase and 40 in the standard protocol. Mean (SD) difference between maxima of p(cuff) and p(ves) (1.3 (15.6) cmH(2) O) was not significant. In 20 (50%) men, agreement between p(cuff) and p(ves) throughout the void was moderate or good (RMS difference <20 cmH(2) O). Causes of unsuccessful measurements were identified. CONCLUSIONS: Although a prototype device, this technique appears to be promising for continuous non-invasive bladder pressure measurement. From the results of this study a number of improvements have been recommended and implemented. The next generation of this technique will allow assessment of clinical application.

Interobserver agreement for noninvasive bladder pressure flow recording with penile cuff.

PURPOSE: We assessed variability in interpreting noninvasive measurements of bladder pressure and urine flow between experienced and novice users of the penile cuff. MATERIALS AND METHODS: Urodynamicists at 6 sites were asked to use the penile cuff test as part of clinical assessment in 30 men presenting with lower urinary tract symptoms. After a short training period they measured maximum flow rate and cuff interruption pressure from penile cuff test recordings to enable categorization of bladder outlet obstruction using a nomogram. Similar measurements were then made on the same traces by 2 expert observers from the originating center. Interobserver differences were assessed. RESULTS: Complete agreement on obstruction categorization was seen in 77% of subjects, which increased to 86% when plots positioned on category boundary lines were allocated to the favored category. The 95% confidence limits of interobserver variability in maximum flow rate and cuff interruption pressure measurements were +/- 1.7 ml per second and +/- 13 cm H(2)O, respectively, although a small number of studies yielded discrepancies between observers that were larger than expected. They arose from complex recordings but were equally likely between experts as between expert and novice. Investigation of the causes suggested in some cases how such discrepancies may be avoided in the future. CONCLUSIONS: The excellent level of agreement in measurement and categorization after a short training period suggests that introducing the penile cuff test as part of assessment in men with lower urinary tract symptoms would be straightforward.

Multisite evaluation of noninvasive bladder pressure flow recording using the penile cuff device: assessment of test-retest agreement.

PURPOSE: We performed a pragmatic study of the penile cuff test, a noninvasive method of categorizing bladder outlet obstruction, at a number of United Kingdom urology centers remote from the originating site. We report the agreement of the test and the subsequent retest using the cuff test in the short term. MATERIALS AND METHODS: Men requiring urodynamic investigation for lower urinary tract symptoms were recruited from 6 sites to perform a penile cuff test twice at an interval of approximately 4 weeks. Tests were analyzed by a single interpreter to assess differences in the flow rate, cuff interruption pressure and diagnostic categorization in an individual between the 2 tests due to measurement and physiological error. RESULTS: A total of 136 men (69%) performed 2 suitable cuff tests at a median of 20 days (IQR 8-31). The mean +/- SD difference between the 2 tests in the maximum flow rate was 0.2 +/- 3.7 ml per second and in cuff interruption pressure was 4.0 +/- 26 cm H(2)O. Of the men 33% changed diagnostic category on the Newcastle nomogram, while 47% maintained a consistent diagnosis of obstruction or no obstruction. CONCLUSIONS: Diagnostic category repeatability was similar to that of conventional urodynamics, although there was greater variability in pressure measurements. This supports widespread routine use of the penile cuff test.

Modeling the clinical assessment of men with suspected obstructed voiding using Bayes' Theorem.

AIMS: Pressure-flow studies (PFS) are the only reliable way to diagnose bladder outlet obstruction (BOO) in men with lower urinary tract symptoms (LUTS). However, in routine clinical practice, BOO is usually inferred by any of a number of tests (symptoms, flow rate, prostate size...). Bayes' Theorem provides a mathematical method, which may be similar to the process used by clinicians, for combining the results of multiple tests to reach a diagnosis. We have applied Bayes' Theorem to the results of several tests known weakly to predict BOO in men with LUTS to assess if they improve the diagnostic accuracy of a flow rate test which alone is known to predict obstruction moderately well. METHODS: We applied Bayes' Theorem to data from 50 patients using Q(max) alone and with the inclusion of additional variables (IPSS, PSA, and residual urine), to establish individual probabilities of BOO. The chi-squared statistic (with trend) was used to compare the relative diagnostic values, against the BOO index calculated from the results of subsequent PFS. RESULTS: The diagnostic value of Q(max) alone (chi-squared = 9.2, P = 0.002), was superior than that for the Bayesian model using the combination of tests available (chi-squared = 4.9, P = 0.026). CONCLUSIONS: Although in our sample relevant additional tests do not improve the diagnostic power of Q(max) as a predictor of BOO, we believe the Bayesian approach is conceptually suited to modeling clinical decision making but may be better tested for a more clinically relevant outcome such as treatment response.

Evaluation of potential predictors of outcome of laser-assisted uvulopalatoplasty for snoring.

OBJECTIVE: Laser-assisted uvulopalatoplasty (LAUP) is a common treatment for snoring, but up to 50% of patients obtain little or no sustained benefit. We investigated whether pre-operative measurements from lateral cephalometry, acoustic rhinometry, analysis of snoring sounds, and body mass index (BMI) could predict which snorers benefited from LAUP. STUDY DESIGN AND SETTING: Fifty-five snoring patients were assessed pre- and 6 months post-LAUP. Snoring severity was assessed by objective sound level recorded during polysomnography, and a Snoring Symptoms Inventory (SSI) questionnaire. RESULTS: The outcome of surgery was assessed by changes in objective sound measurements and in SSI, 6 months after LAUP. CONCLUSIONS: Relationships between the predictive measurements and outcome were at best only weak and none had sufficient predictive value to be useful in clinical practice.

Comparison of manual sleep staging with automated neural network-based analysis in clinical practice.

We have compared sleep staging by an automated neural network (ANN) system, BioSleep (Oxford BioSignals) and a human scorer using the Rechtschaffen and Kales scoring system. Sleep study recordings from 114 patients with suspected obstructed sleep apnoea syndrome (OSA) were analysed by ANN and by a blinded human scorer. We also examined human scorer reliability by calculating the agreement between the index scorer and a second independent blinded scorer for 28 of the 114 studies. For each study, we built contingency tables on an epoch-by-epoch (30 s epochs) comparison basis. From these, we derived kappa (kappa) coefficients for different combinations of sleep stages. The overall agreement of automatic and manual scoring for the 114 studies for the classification {wake / light-sleep / deep-sleep / REM} was poor (median kappa = 0.305) and only a little better (kappa = 0.449) for the crude {wake / sleep} distinction. For the subgroup of 28 randomly selected studies, the overall agreement of automatic and manual scoring was again relatively low (kappa = 0.331 for {wake light-sleep / deep-sleep REM} and kappa = 0.505 for {wake / sleep}), whereas inter-scorer reliability was higher (kappa = -0.641 for {wake / light-sleep / deep-sleep / REM} and kappa = 0.737 for {wake / sleep}). We conclude that such an ANN-based analysis system is not sufficiently accurate for sleep study analyses using the R&K classification system.

Comparison of stethoscope bell and diaphragm, and of stethoscope tube length, for clinical blood pressure measurement.

OBJECTIVE: This study investigated the effect of stethoscope side and tube length on auscultatory blood pressure (BP) measurement. METHODS: Thirty-two healthy participants were studied. For each participant, four measurements with different combinations of stethoscope characteristics (bell or diaphragm side, standard or short tube length) were each recorded at two repeat sessions, and eight Korotkoff sound recordings were played twice on separate days to one experienced listener to determine the systolic and diastolic BPs (SBP and DBP). Analysis of variance was carried out to study the measurement repeatability between the two repeat sessions and between the two BP determinations on separate days, as well as the effects of stethoscope side and tube length. RESULTS: There was no significant paired difference between the repeat sessions and between the repeat determinations for both SBP and DBP (all P-values>0.10, except the repeat session for SBP using short tube and diaphragm). The key result was that there was a small but significantly higher DBP on using the bell in comparison with the diaphragm (0.66 mmHg, P=0.007), and a significantly higher SBP on using the short tube in comparison with the standard length (0.77 mmHg, P=0.008). CONCLUSION: This study shows that stethoscope characteristics have only a small, although statistically significant, influence on clinical BP measurement. Although this helps understand the measurement technique and resolves questions in the published literature, the influence is not clinically significant.

Differences in urodynamic voiding variables recorded by conventional cystometry and ambulatory monitoring in symptomatic women

Objectives To determine whether there are differences in pressure and flow measurements between conventional cystometry (CONV) and ambulatory urodynamic monitoring (AMB) in women with overactive bladder syndrome and urinary incontinence. Materials and Methods Retrospective study which included female subjects who underwent both CONV (with saline filling medium) and AMB, separated by less than 24 months, not using medication active on the lower urinary tract and without history of prior pelvic surgery. Both tests were carried out in compliance with the International Continence Society standards. The paired Student’s t test was used to compare continuous variables. Bland-Altman statistics were used to assess the agreement of each variable between both studies. Results Thirty women with a median (range) age of 50 (14 - 73) years met the inclusion criteria. AMB was carried out at a mean (SD) of 11 (6) months after CONV. Measurements of pves and pabd at the end of filling, and Qmax were significantly higher from AMB recordings. There were no differences in pdet at the end of filling, pdetQmax or pdetmax during voiding, nor significant difference in Vvoid. Conclusions We provide previously undocumented comparative voiding data between CONV and AMB for patients who most commonly require both investigations. Our findings show higher values of Qmax but similar values of pdetQmax measured by AMB which may partly reflect an overall lower catheter caliber, physiological filling but perhaps also more ‘normal’ voiding conditions. .

Flow measurements: can several "wrongs" make a "right"?

AIMS: Although measurement of maximum flow rate (Qmax) is a standard and straightforward test, it is often difficult to obtain reliable readings. We obtained multiple measurements using a simple home uroflow device which categorizes Qmax into ranges. We hypothesize that the average of a series of relatively coarse measurements of Qmax would be more repeatable and therefore more representative of an individual's voiding function than a single, albeit more precise measurement. METHODS: We studied 22 male volunteers with a wide range of Qmax. They were asked to record flow category (<10 ml/sec; 10-15 ml/sec; 15-20 ml/sec; >20 ml/sec) and voided volume twice daily for 12 days using the home flow device. In addition, a clinic-based flow recording using a spinning-disc uroflowmeter was obtained at both the start and the end of the 12-day period. RESULTS: Good agreement between mean home flow and mean clinic flow was seen with mean (SD) difference of 1.3 (5) ml/sec. The mean for consecutive halves of an individual's home flow data showed excellent agreement (-0.2 (1.3) ml/sec). The two clinic readings showed poorer agreement (2.3 (6.8) ml/sec) than the home readings, and poorer agreement even than between clinic and home flows. CONCLUSIONS: Although simple in design, the home flowmeter actually shows greater accuracy than might be expected when used repeatedly to study the flow rates of men. Simple flow devices such as this could be used in conjunction with voiding diaries to give a more representative picture of patients' day-to-day voiding function.

Categorization of obstruction using noninvasive pressure flow measurements: sensitivity to change following prostatectomy.

PURPOSE: We determined whether categorizing men with lower urinary tract symptoms using a noninvasive pressure flow nomogram is sensitive to change following the removal of obstruction. MATERIALS AND METHODS: A prospective cohort of men undergoing transurethral prostate resection was recruited, of whom 143 (69%) underwent noninvasive pressure flow study using the penile cuff technique before and 4 months following surgery. Cuff pressure required to interrupt voiding, estimated isovolumetric bladder pressure and maximum flow rate were recorded during a single void. Values were plotted on a nomogram categorizing cases as obstructed (upper left quadrant), not obstructed (lower right quadrant) or diagnosis uncertain (upper right and lower left quadrants). Changes in maximum flow rate, cuff pressure required to interrupt voiding and nomogram position following transurethral prostate resection were then analyzed. RESULTS: Transurethral prostate resection resulted in an improved flow rate for all diagnostic groups, which was highest for obstructed cases with a mean +/- SD increase of 11 +/- 6 ml second(-1) (p <0.01). Men categorized with obstruction and those placed in the upper right quadrant showed significant decreases in cuff pressure required to interrupt voiding following transurethral prostate resection with a mean decrease of -45 +/- 35 and -48 +/- 32 cm H(2)O, respectively (p <0.01). The number of cases classified as not obstructed increased from 28 (19%) preoperatively to 114 (80%) after transurethral prostate resection. CONCLUSIONS: Sensitivity to change following the removal of obstruction further validates the usefulness of noninvasive measurement of bladder pressure by the penile cuff test and the categorization of obstruction by the noninvasive nomogram. Decreased isovolumetric bladder pressure following transurethral prostate resection may reflect a return to normal detrusor contraction strength.

Predicting the outcome of prostatectomy using noninvasive bladder pressure and urine flow measurements.

OBJECTIVES: To determine whether categorisation of bladder outlet obstruction (BOO) using measurements of bladder pressure and urine flow obtained by a novel noninvasive medical device (the penile cuff test) improves prediction of outcome from endoscopic prostatectomy (TURP). METHODS: A consecutive cohort of 208 men undergoing TURP following standard assessment in our institution was recruited, and 179 (86%) completed the protocol. Each subject underwent a penile cuff test prior to surgery; outcome was assessed by change in IPSS at 4 mo. The proportion of men with good outcome (>50% reduction in IPSS) was compared according to categorisation by noninvasive bladder pressure and urine flow measurements. RESULTS: The cuff test was completed by 93% of men with 2% experiencing an adverse event. Men categorised as having BOO by the test (37% of total) had an 87% chance of a good outcome from TURP (p<0.01), whilst of those deemed not obstructed (19% of total) 56% experienced good outcome (p<0.01). For the remaining men not categorised in these two groups, 77% had good outcome, which was identical to the result of the cohort as a whole (77%, p=NS). CONCLUSIONS: Urodynamic categorisation using measurements obtained by the noninvasive penile cuff test improves prediction of outcome for men with LUTS undergoing TURP. This finding together with the ease and acceptability of the test suggest its suitability for office-based clinical use to assist men and their physicians in the selection for surgical treatment for relief of LUTS.

Assessment of prostatic obstruction: A cuff may be enough.

AIMS: To investigate the use of an inflatable perile cuff to obstruct flow progressively during voiding in order to provide a noninvasive measure of bladder pressure. METHODS: In this study, we explain the observed relationship of flow rate with applied cuff pressure by analogy with a simple physical model. The model comprised a fixed-pressure reservoir (simulating the bladder), a collapsible tube around which a fixed pressure could be applied (simulating the prostatic urethra), connected by rigid conduit to a further collapsible tube around which pressure could be applied (simulating the penile urethra and cuff). Flow was progressively obstructed by incremental increase of pressure applied to the "penile urethra," with the experiment being repeated for a range of fixed pressures applied to the "prostatic urethra." RESULTS: The model reproduced the typical pressure/flow curves recorded during voiding by using penile cuff inflation in normal and obstructed men. CONCLUSIONS: Our data led us to hypothesise that the relationship between cuff pressure and flow rate can be used to deduce bladder pressure during voiding, prostatic opening pressure, and urethral diameter at the flow-controlling zone, three indicators of lower urinary tract function. These measurements may add to the accuracy of diagnosis and quality of care for a large number of men with lower urinary tract symptoms.

Relationship of abdominal pressure and body mass index in men with LUTS.

AIMS: In the development of a non-invasive method for estimating isovolumetric intravesical pressure (pves,isv) we looked for a relationship between intra-abdominal pressure (pabd) and general build, expressed as body mass index (BMI) in men with lower urinary tract symptoms (LUTS). MATERIALS AND METHODS: In 100 consecutive male patients undergoing an invasive pressure flow study (PFS) the pabd was recorded continuously during filling and voiding. The magnitude at four set points was measured: before filling, after filling, during voiding and at the end of voiding. Patients' weight (kg) and height (m) were also recorded and their BMI (weight/height(2)) was calculated. RESULTS: During the fill/void cycle pabd increased during bladder filling from 37 +/- 7 cm H2O (mean +/- SD) to 38 +/- 8 cm H2O, fell during voiding to 35 +/- 9 cm H2O before increasing to 36 +/- 8 cm H2O at the end of voiding. There was a clear relationship between the individual values of pabd and BMI (correlation co-efficient = 0.52) and to a lesser extent weight (correlation co-efficient = 0.42). The relationship with BMI was clarified by separating the subjects into groups of normal, overweight and obese. CONCLUSIONS: A clear relationship between BMI and pabd was demonstrated, but because of the difficulties in quantifying it for an individual, it is impractical to apply an adjustment to non-invasive estimates of pves,isv.

Inter-observer agreement in the estimation of bladder pressure using a penile cuff.

AIMS: Objective data are useful in quantifying a patient's lower urinary tract symptoms (LUTS). We are investigating the use of an inflatable penile cuff to obstruct flow progressively during voiding, and thereby determine the pressure p(cuff,int) at which flow is interrupted. The aim of this study was to determine the agreement between experienced observers in their estimates of p(cuff,int). METHODS: We recorded 486 cuff inflation cycles during 142 voids from 42 subjects recruited from urology out-patient's and prostate assessment clinics. Each inflation cycle was assessed independently by three experienced observers, a total of 1,458 ratings. According to our standard assessment procedure, the observers (i) indicated whether the inflation should be analyzed, (ii) estimated p(cuff,int) for those inflation cycles judged suitable for analysis, and (iii) discarded measurements that were clearly inconsistent with others from the same voiding cycle. RESULTS: Overall, 689 of the 1,458 ratings (45%) were excluded, with just 4% of all ratings discarded for inconsistency. For 385 of the 486 inflation cycles (79%) there was complete agreement that the cycle should or should not be analyzed. Thereafter, for the 262 inflation cycles analyzed by two or three observers, the overall SD error in measurements of p(cuff,int) was 4.6 cm H(2)O. CONCLUSIONS: We conclude that there is good agreement between experienced observers in their interpretation of data from the cuff test. For practical purposes, there is no need for multiple observers in the clinical application of the cuff method.