Quiet Expiration Research Articles

Do Respiratory Maneuvers Affect Rght Hepatic Vein Waveform and Maximum Velocity in Post LDLT Recipients?

AIM: Â To evaluate the effect of respiratory maneuvers on right hepatic vein (RHV) Doppler waveform and its maximum velocity in Living donor liver transplant (LDLT) recipients. METHODS: This was a prospective cross-sectional study performed at Pakistan Kidney and Liver Institute and Research Centre (PKLI& RC), Lahore Radiology department. The sample size of the study, calculated according to WHO sample size calculator, was 30 patients after applying the inclusion and exclusion criteria. Most of these patients were analyzed during their first post-operative week while staying in the surgical intensive care unit (SICU). The Doppler waveform and maximum velocity of RHV were recorded during normal gentle breathing, following breath-hold after deep inspiration and then after quiet expiration. The waveforms that were recorded were triphasic, biphasic, or monophasic in the pattern. To assess the RHV flow quantitatively, the Damping Index was also calculated during all these three respiratory maneuvers as follows (DI=Minimum velocity/maximum velocity) RESULTS: The maximum velocities during normal respiration, after quiet expiration and after breath-holding following deep inspiration were 125 cm/sec, 105 cm/sec and 94 cm/sec. The waveforms observed during gentle breathing were triphasic in 77%, biphasic in 10%, and monophasic in 13% of the patients. After quiet expiration, these were triphasic in 80%, biphasic in 6%, and monophasic in 13% of patients. However, after breath-hold following deep inspiration, the waveforms observed were triphasic in 42%, biphasic in 13%, and monophasic in 45% of the patients. (P <0.008) CONCLUSION: The study showed that not only did the RHV waveforms show significant change from triphasic pattern to monophasic pattern, but also the peak velocities were lower following expiration. Therefore, during the Doppler ultrasound assessment of post-LDLT recipient patients, respiratory variations must be taken into consideration.

Measuring Expiratory Diaphragm Activity: An Electrifying Tool to Guide Positive End-Expiratory Pressure Strategy in Critically Ill Children?

Measuring Expiratory Diaphragm Activity: An Electrifying Tool to Guide Positive End-Expiratory Pressure Strategy in Critically Ill Children?

Pectus excavatum in motion: dynamic evaluation using real-time MRI

ObjectivesThe breathing phase for the determination of thoracic indices in patients with pectus excavatum is not standardized. The aim of this study was to identify the best period for reliable assessments of morphologic indices by dynamic observations of the chest wall using real-time MRI.MethodsIn this prospective study, patients with pectus excavatum underwent morphologic evaluation by real-time MRI at 3 T between January 2020 and June 2021. The Haller index (HI), correction index (CI), modified asymmetry index (AI), and modified eccentricity index (EI) were determined during free, quiet, and forced breathing respectively. Breathing-related differences in the thoracic indices were analyzed with the Wilcoxon signed-rank test. Motion of the anterior chest wall was analyzed as well.ResultsA total of 56 patients (11 females and 45 males, median age 15.4 years, interquartile range 14.3–16.9) were included. In quiet expiration, the median HI in the cohort equaled 5.7 (4.5–7.2). The median absolute differences (Δ) in the thoracic indices between peak inspiration and peak expiration were ΔHI = 1.1 (0.7–1.6, p < .001), ΔCI = 4.8% (1.3–7.5%, p < .001), ΔAI = 3.0% (1.0–5.0%, p < .001), and ΔEI = 8.0% (3.0–14.0%, p < .05). The indices varied significantly during different inspiratory phases, but not during expiration (p > .05 each). Furthermore, the dynamic evaluation revealed three distinctive movement patterns of the funnel chest.ConclusionsReal-time MRI reveals patterns of chest wall motion and indicate that thoracic indices of pectus excavatum should be assessed in the end-expiratory phase of quiet expiration.Key Points• The thoracic indices in patients with pectus excavatum depend on the breathing phase.• Quiet expiration represents the best breathing phase for determining thoracic indices.• Real-time MRI can identify different chest wall motion patterns in pectus excavatum.

Dual bronchodilation for the treatment of COPD: From bench to bedside.

Because there is a solid pharmacological rationale based on positive interactions between long-acting muscarinic receptor antagonists (LAMAs) and long-acting β-agonists (LABAs) for their ability to relax human airway smooth muscle in vitro alongside several randomised controlled trials (RCTs) and real-world observational studies that support the use of LAMA/LABA fixed-dose combinations (FDCs) for the treatment of patients with chronic obstructive pulmonary disease (COPD), in this narrative review we discuss the preclinical and clinical proofs supporting the use of LAMA + LABA therapy in COPD and why this therapeutic approach optimises bronchodilation. Robust evidence indicates that all LAMA/LABA FDCs are consistently more effective than LAMA or LABA administered alone in improving lung function, dyspnoea, quality of life and exercise capacity in patients with COPD. However, the ability of dual bronchodilation with FDCs of LAMA/LABA to prevent or reduce the risk of COPD exacerbations remains unclear due to conflicting data from large RCTs, despite several mechanisms explaining why such combinations should be of value in decreasing the frequency of COPD exacerbations. Both LABAs and LAMAs mechanistically can affect the cardiovascular system, but from clinical studies to date, LAMA/LABA FDCs have an acceptable cardiovascular safety profile, at least in the COPD population enrolled in RCTs. Indirect evidence suggests that some FDCs may even exert a protective role against serious cardiovascular adverse events compared to monotherapies. Consequently, several LAMA/LABA FDCs have been developed and approved for clinical use as treatments for patients with COPD. However, to date, there are unfortunately very few head-to-head studies comparing the safety and efficacy of different LAMA/LABA FDCs, making it difficult to choose the most appropriate combination, although the use of meta-analyses has provided some information in this regard. Endurance time Exercise time until exhaustion measured by a standard endurance test. Inspiratory capacity The maximum volume of air that can be inspired after reaching the end of a normal, quiet expiration. It is the sum of the tidal volume and the inspiratory reserve volume. St George's Respiratory Questionnaire (SGRQ) A tool to measure health status in patients with respiratory disease. It has three domains: symptoms, activity and impacts. A total score is also calculated. A minimal important difference (range) of ∼4 (2.4-5.6) units in the SGRQ total score is supported by published studies. Surface under the cumulative ranking curve analysis (SUCRA) A numerical representation of the overall rating that displays a single value for each treatment. SUCRA levels vary from 0% to 100%. The higher the SUCRA value and the closer it is to 100%, the more likely therapy is in the top rank or one of the top rankings; the lower the SUCRA value and the closer it is to 0%, the more likely therapy is in the bottom rank or one of the bottom ranks. Transition dyspnoea index (TDI) Widely used in clinical studies of COPD to measure shortness of breath, indicating change in response to an intervention. The total score ranges from -9 to 9; the negative value indicates deterioration, whereas a positive value indicates improvement. There is sufficient evidence to suggest that the minimal important difference for the TDI score is 1 unit. Trough FEV1 The mean volume of air that can be forced out in 1 second approximately 12 (with a twice-daily agent) or 24 (with a once-daily agent) hours after the last administration of bronchodilator.

Do Respiratory Maneuvers Affect The Hepatic Vein Waveforms And Maximum Velocity?

Aim: To assess the effect of respiratory maneuvers on hepatic vein waveforms and flow velocity in patients without liver or cardiac disease. Methods: This prospective cross-sectional study was conducted in the Radiology Department of Pakistan Kidney and Liver Institute and Research Center, Lahore (PKLI &amp; RC) after approval from Institutional Review Board (IRB). The sample size of 70 patients was selected using the WHO sample size calculator, after applying the inclusion and exclusion criteria. Doppler waveforms and maximum velocities (Vmax) of the middle hepatic vein were recorded during normal respiration, after quiet expiration, and following breath-hold after deep inspiration. The waveforms were classified as triphasic, biphasic, or monophasic. Results: The maximum velocities (Vmax) during normal respiration, after quiet expiration, and following deep inspiration were 26.67±9.41, 24.08±6.77 and 19.31±.61 respectively. During normal breathing, the middle hepatic vein waveforms were triphasic, biphasic and monophasic in 80%, 6%, and 14% of the patients respectively. After quiet expiration, these percentages were 82%, 4% &amp; 14% respectively and following breath-hold after deep inspiration, these percentages were 41%, 14% and 45%, respectively (p&lt;0.05). Conclusion: The hepatic venous velocities were lower after deep inspiration. Their waveforms showed significant change from triphasic pattern to monophasic pattern following deep inspiration. Therefore, the respiratory variations must be considered during hepatic vein Doppler ultrasound assessment. Keywords MeSH: Hepatic veins, velocities, waveforms, inspiration, expiration.

Hypertrophic Cardiomyopathy as an Unexpected Mimic of Inducible Laryngeal Obstruction: The Case for Cardiopulmonary Exercise Testing in Otolaryngology

Inducible laryngeal obstruction is a common and challenging cause of exertional dyspnea. We report a case of an unanticipated cardiac condition that presented with symptoms suggestive of inducible laryngeal obstruction. A 55-year-old man was evaluated for progressive exertional dyspnea and throat tightness, unexplained after multiple medical evaluations. Resting laryngeal examination was suspicious for laryngopharyngeal reflux and mild vocal fold adduction during quiet expiration. Given progressive and refractory symptoms, maximal cardiopulmonary exercise testing with intermittent laryngeal examination was performed. This study excluded laryngeal causes of exercise limitation and led to an unexpected diagnosis of persistent atrial flutter and hypertrophic cardiomyopathy. Cardiopulmonary exercise testing with laryngeal examination can identify unexpected and life-threatening mimics of inducible laryngeal obstruction that may be missed by unmonitored exercise challenges. Suspicion for inducible laryngeal obstruction at rest may not predict the true nature of exercise limitation on cardiopulmonary exercise testing.

The evaluation of diaphragmatic morphology and function in septic patients by bedside ultrasound

Objective To evaluate the changes of the diaphragmatic morphology and function in septic patients by bedside ultrasound. Methods A cross-sectional study was conducted in the Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University over a 6-month period from September 2018 to February 2019. Thirty-one septic patients who were diagnosed within the past 7 days with Sequential Organ Failure Assessment (SOFA) scores less than or equal to 5 points were enrolled in the septic group. Thirty-eight healthy subjects who underwent regular physical examinations during the same period were enrolled randomly in the control group. All subjects′ clinical data, diaphragmatic morphology parameters (thickness at the end of quiet expiration, thickness at the end of deep inspiration) and function parameters (thickening fraction, quiet breath excursion and deep breath excursion) measured with bedside ultrasound were compared. The comparison of continuous variables was performed by using the Student t-test or Mann-Whitney U test. Chi-square test was performed for categorical variables. A value of P less than 0.05 was considered statistically significant. Results (1) There was no statistical difference in gender, age, body mass index, underlying diseases and mean arterial pressure between the septic group and the control group (all P>0.05). (2) Diaphragmatic morphology parameters: There was no statistical difference between the septic group and the control group in the thickness at the end of quiet expiration [septic group: 0.21 (0.18-0.23) cm; control group: 0.19(0.16-0.20) cm, Z=-1.739, P=0.082] or in the thickness at the end of deep inspiration [septic group: (0.27±0.84) cm; control group: (0.29±0.77) cm, t=1.344, P=0.183]. (3) Diaphragmatic function parameters: The thickening fraction in the septic group was significantly less than that in the control group [septic group: 24% (16%-56%); control group:61% (37%-82%), Z=-3.076, P=0.002]. The quiet breath excursion in the septic group was significantly less than that in the control group [septic group: (1.25±0.38) cm; control group: (1.65±0.82) cm, t=2.687, P=0.009]. The deep breath excursion in the septic group was also significantly less than that in the control group [septic group: 2.79 (1.80-4.16)cm; control group:3.77(2.92-5.05)cm, Z=-2.231, P=0.026]. Conclusion In septic (SOFA scores≤5 points) patients, diaphragmatic dysfunction occurred without significant morphology change in the first 7 days. Diaphragmatic dysfunction occurred before atrophy. Bedside ultrasound is a useful clinical tool in diaphragmatic morphology and function evaluation. Key words: Sepsis; Bedside ultrasound; Diaphragm

Correlation between thoracolumbar curvatures and respiratory function in older adults.

Aging is associated with alterations in thoracolumbar curvatures and respiratory function. Research information regarding the correlation between thoracolumbar curvatures and a comprehensive examination of respiratory function parameters in older adults is limited. The aim of the present study was to examine the correlation between thoracolumbar curvatures and respiratory function in community-dwelling older adults. Thoracolumbar curvatures (thoracic and lumbar) were measured using a motion tracker. Respiratory function parameters such as lung function, respiratory rate, respiratory muscle strength and respiratory muscle thickness (diaphragm and intercostal) were measured using a spirometer, triaxial accelerometer, respiratory pressure meter and ultrasound imaging, respectively. Sixty-eight community-dwelling older males and females from Kuala Lumpur, Malaysia, with mean (standard deviation) age of 66.63 (5.16) years participated in this cross-sectional study. The results showed that mean (standard deviation) thoracic curvature angle and lumbar curvature angles were −46.30° (14.66°) and 14.10° (10.58°), respectively. There was a significant negative correlation between thoracic curvature angle and lung function (forced expiratory volume in 1 second: r=−0.23, P<0.05; forced vital capacity: r=−0.32, P<0.05), quiet expiration intercostal thickness (r=−0.22, P<0.05) and deep expiration diaphragm muscle thickness (r=−0.21, P<0.05). The lumbar curvature angle had a significant negative correlation with respiratory muscle strength (r=−0.29, P<0.05) and diaphragm muscle thickness at deep inspiration (r=−0.22, P<0.05). However, respiratory rate was correlated neither with thoracic nor with lumbar curvatures. The findings of this study suggest that increase in both thoracic and lumbar curvatures is correlated with decrease in respiratory muscle strength, respiratory muscle thickness and some parameters of lung function. Clinically, both thoracic and lumbar curvatures, respiratory muscles and lung function should be taken into consideration in the holistic management of respiratory function among older adults.

Slow expiration reduces sternocleidomastoid activity and increases transversus abdominis and internal oblique muscle activity during abdominal curl-up

The aim of this study was to investigate the effects of quiet inspiration versus slow expiration on sternocleidomastoid (SCM) and abdominal muscle activity during abdominal curl-up in healthy subjects. Twelve healthy subjects participated in this study. Surface electromyography (EMG) was used to collect activity of bilateral SCM, rectus abdominis (RA), external oblique (EO), and transversus abdominis/internal oblique (TrA/IO) muscles. A paired t-test was used to determine significant differences in the bilateral SCM, RF, EO, and TrA/IO muscles between abdominal curl-up with quiet inspiration and slow expiration. There were significantly lower EMG activity of both SCMs and greater EMG activity of both IOs during abdominal curl-up with slow expiration, compared with the EMG activity of both SCMs and IOs during abdominal curl-up with quiet inspiration (p<.05). The results of this study suggest that slow expiration would be recommended during abdominal curl-up for reduced SCM activation and selective activation of TrA/IO in healthy subjects compared with those in abdominal curl up with quiet inspiration.

The quiet period has something to say

Recent studies suggest that analyst ratings have become less biased following the Global Settlement and National Association of Securities Dealers (NASD) and New York Stock Exchange (NYSE) Rules implemented in 2002. Assuming analyst ratings are more reliable due to the decline in positive bias, we investigate the existence of excess returns for various holding periods based on the strength of ratings issued around the expiration of the Initial Public Offering (IPO) quiet period. We also control for the impact of analyst affiliation and sanctions against investment banks on returns up to 1 year after quiet period expiration. Overall, we find that the strength of analyst coverage can indeed predict future returns, and several factors impact these returns. In addition, we find that only firms which receive positive coverage from a bank sanctioned in the Global Settlement earn positive risk-adjusted returns.

The Quiet Period Has Something to Say

Recent studies suggest that analyst ratings have become less biased following the Global Settlement and NASD and NYSE Rules implemented in 2002. Assuming analyst ratings are more reliable due to the decline in positive bias, we investigate the existence of excess returns for various holding periods based on the strength of ratings issued around the expiration of the IPO quiet period. We also control for the impact of analyst affiliation and sanctions against investment banks on returns up to one year after quiet period expiration. Overall, we find that the strength of analyst coverage can indeed predict future returns, and several factors impact these returns. In addition, we find that only firms which receive positive coverage from a bank sanctioned in the Global Settlement earn positive risk-adjusted returns.

Effects of respiratory manoeuvres on hepatic vein Doppler waveform and flow velocities in a healthy population

Objective This study was performed to determine the variations in Doppler waveforms and flow velocity during respiratory manoeuvres in healthy individuals with no liver disease. Materials and methods In total, 100 individuals (75 women and 25 men) without known cardiac or liver disease were examined prospectively with duplex Doppler ultrasonography (US). We recorded the Doppler waveforms and peak systolic velocities ( V max) of the middle hepatic vein during normal respiration, during breath-holding after quiet expiration and also during deep inspiration. Doppler waveforms are categorised as triphasic, biphasic or monophasic. Results During normal respiration, hepatic venous waveforms were triphasic in 93% of subjects, monophasic in 6% and biphasic in 1%. During breath-holding after quiet expiration, the percentages were 91%, 6% and 3%, respectively. During deep inspiration, they were 80%, 18% and 2%, respectively. Although significant differences were noted between rates during deep inspiration and normal respiration, they were quite similar during normal respiration and breath-holding after quiet expiration ( P < 0.05). The values of V max were significantly higher during normal respiration compared to quiet expiration and during quiet expiration compared to deep inspiration ( P < 0.05). Conclusion The velocities and waveforms of hepatic veins varied during respiratory manoeuvres. The status of respiration must be taken into consideration whilst examining the hepatic vein waveforms and velocities with duplex Doppler US.

Electrodiagnostic Evaluation of the Respiratory Muscles

Previously, the diaphragm was thought to be the only important contracting muscle during quiet breathing in humans. Now it is known that also the scalenes and the parasternal intercostals are primary inspiratory muscles, and that during expiration in most body positions except lying down the abdominal muscles and the transversus thoracis muscle (triangularis sterni or sternocostalis muscle) are regularly active, making quiet expiration an active process instead of a purely passive maneuver as was thought in the past. The external intercostal muscles, the levatores costarum longi and breves muscles, the sternocleidomastoid muscle, and the serratus posterior superior and inferior muscles can be regarded as accessory inspiratory muscles. The pyramidalis and internal intercostal muscles are accessory muscles of expiration. Several neuromuscular disorders can affect respiration. Nowadays, several electrodiagnostic techniques can be applied and can be of great value in more precisely determining the nervous system cause, if present, for respiratory failure or insufficiency. Nerve conduction studies of phrenic and intercostal nerves, and needle as well as surface electromyography of most respiratory muscles, can be performed. To measure central conduction to assess the integrity of the corticospinal tracts, magnetic transcortical and nerve root stimulation can be performed.

Evaluation of Markers to Estimate Volume Status in Hemodialysis Patients: Atrial Natriuretic Peptide, Inferior Vena Cava Diameter, Blood Volume Changes and Filtration Coefficients of Microvasculature

Relationships among five markers of volume status - cardio-thoracic ratio (CTR), atrial natriuretic peptide (ANP), inferior vena cava diameter at quiet expiration (IVCe), blood volume change (Delta BV/TUF) during ultrafiltration and filtration coefficients of microvasculature (Lpst) - were investigated. Fifty stable hemodialysis patients were enrolled. The CTR was measured before hemodialysis (HD), and ultrasonic measurement of IVCe and sample collection for ANP were performed shortly after HD. Lpst and Delta BV/TUF were calculated using a CRIT-LINE monitor. Overhydrated patients determined by each marker (OVERctr, OVERivc, OVERanp, OVERlp and OVERbv) were compared. The agreement of volume status determined by each marker was assessed by kappa value, and the sensitivity and specificity of each marker to distinguish overhydrated patients were analyzed by a receiver-operating characteristic (ROC) curve. IVCe, ANP, Delta BV/TUF and Lpst, significantly correlated with each other. The correlation coefficients of Lpst with IVCe, ANP and Delta BV/TUF were higher than the others. The kappa value between ANP and Lpst was the highest. OVERanp was the highest, then OVERlp, OVERivc and OVERbv, in this order. The OVERlp and OVERivc patients were completely included in OVERanp. All patients, except one OVERbv patient, were included in OVERlp. The relatively high distinguishing ability of Lpst was demonstrated by ROC analysis. These results suggest that the determination of overhydration solely by ANP was an overestimation and by Delta BV/TUF was an underestimation. The relatively high correlation coefficients of Lpst with other markers, as well as its distinguishing ability, suggest that Lpst fluctuates in close relation to other markers.

Relationship between Filtration Coefficients of Microvasculature and Levels of Atrial Natriuretic Peptide or Echocardiographic Measurements

Background/Aims: Assessing the volume status of hemodialysis (HD) patients and determining their adequate dry weight (DW) present great challenges for physicians involved in HD. In this study the relationship between standardized filtration coefficients of microvasculature (Lpst) and the plasma atrial natriuretic peptide (ANP) levels or echocardiographic measurements (UCGm) were clarified. The aim of this study was to evaluate the possibility of utilizing Lpst as one of the tools for assessing volume status of patients undergoing HD. Methods: 52 patients on maintenance HD were examined. Lpst was calculated by utilizing continuous measurements of blood volume during HD by means of monitoring changes of hematocrit with CRIT-LINE^TM. Plasma ANP levels were measured shortly after HD. Plasma ANP levels were elevated beyond the normal limit in 32 patients (Hi group) and were within the normal range in the remaining 20 patients (Lo group). UCGm were performed within 1 month prior to the study. Inferior vena cava diameters in quiet expiration (IVCe) were dilated in 21 patients (Hivc group) and were within the normal range in the remaining 31 patients (Livc group). Lpst was compared with plasma ANP level and UCGm. Results: Lpst in Lo group were significantly lower than those in the Hi group (0.83 ± 0.19 vs. 2.64 ± 2.73 ml/mm Hg/min; p < 0.001). Lpst correlated significantly with plasma ANP levels (r = 0.613; p < 0.001). Lpst in the Livc group were significantly lower than those in the Hivc group (1.33± 1.61 vs. 2.85 ± 2.88 ml/mm Hg/min; p < 0.001). Lpst also correlated with IVCe (r = 0.630; p < 0.001). The receiver operating characteristic (ROC) curves for high plasma ANP level and for dilated IVCe were significant for Lpst. Area under the ROC curve for elevated ANP was 0.909 (95% confidence interval (CI) 0.834–0.985) and for dilated IVCe was 0.833 (95% CI 0.724–0.941). Conclusion: We conclude that there exists a significant association between Lpst and plasma ANP levels at the end of a dialysis session. There is a possibility that high plasma ANP levels cause elevation of Lpst. Besides ANP, Lpst significantly correlated with IVCe. These results suggested that Lpst can be utilized as one of the tools for assessing volume status of patients undergoing HD.

Comparison of markers of circulating blood volume in hemodialysis patients

Pulse dye-densitometry (PDD) is a newly developed technique for monitoring the arterial concentration of indocyanine green (ICG). By using this method, the circulating blood volume (CBV) can be measured as accurately as by established dilution methods using (131)I-labeled human serum albumin in healthy subjects. In the present study, we estimated the CBV in hemodialysis (HD) patients, using PDD, and compared the utility of this method with that of other markers of the CBV. We measured the CBV in seven HD patients and eight healthy volunteers, using PDD, and evaluated the correlation between the CBV measured by PDD (CBV-PDD) and the calculated CBV (CBV-Cal), using a prediction formula (CBV (l) = 2.68 x BSA, where BSA is body surface area (m(2))). We also investigated the correlation between CBV-PDD and the maximal inferior vena cava diameters in quiet expiration (IVCe), and the plasma levels of atrial and brain natriuretic peptides (ANP and BNP, respectively) in the HD patients. CBV-Cal was closely correlated with CBV-PDD in the healthy volunteers, but there was no such correlation in the HD patients. On the other hand, IVCe was significantly correlated with the CBV-PDD in the healthy volunteers as well as in HD patients. ANP and BNP were not correlated with the CBV-PDD in the HD patients. We concluded that CBV-PDD and IVCe were useful parameters in evaluating the CBV in HD patients, while CBV-Cal was not a useful parameter. Also, as a marker of changes in the CBV in HD patients, IVCe was considered to be more sensitive than either ANP or BNP.

Improvement of cardiac function by dry weight optimization based on interdialysis inferior vena caval diameter.

In hemodialysis (HD) patients, the diameter of the inferior vena cava (IVC) serves for evaluation of the amount of body fluid. IVC measurement is usually performed immediately before and/or after an HD session. In the present study, we examined the validity of IVC diameter in the interdialysis period (interdialytic IVC) for dry weight (DW) optimization. In 100 HD patients, interdialytic IVC was measured ultrasonographically. The average maximum IVC diameter during quiet expiration (IVCe) was 14.2+/-3.8 mm. In 32 patients with volume dependent hypertension, the interdialytic IVCe was > 16 mm in 29 of 32. Thus, we defined an interdialytic IVCe > 16 mm as a hypervolemic state. Next, by screening 306 HD patients ultrasonographically, 31 patients with left ventricular volume overload were chosen based on criteria of an interdialytic IVCe > 16 mm, together with a left ventricular ejection fraction (EF) < 55%. After the DW was lowered to obtain an interdialytic IVCe < 16 mm, 25 of the 31 patients had a significant increase in EF, decrease in diastolic left ventricular dimension, and amelioration of hypertension. In conclusion, interdialytic IVCe is considered to be a useful parameter for DW optimization. In hypervolemic patients with IVCe > 16 mm, reduction in DW is expected to improve volume overload and cardiac function.

Utility of the inferior vena cava diameter as a marker of dry weight in nonoliguric hemodialyzed patients.

We have previously reported that the maximal inferior vena cava (IVC) diameter during quiet expiration (IVCe) measured by ultrasonography correlates well with the amount of body fluid, especially the circulating blood volume(2) and proposed using the criteria of IVC diameter to determine dry weight (DW) in anuric hemodialyzed (HD) patients: standard IVCe of pre- and post-HD are 14.9 +/- 0.4 and 8.2 +/- 0.3 mm, respectively (1). However, the same post-HD IVC criterion should not be applied to nonoliguric HD patients because it could result in rapid deterioration of residual renal function due to forced dehydration. Although the biochemical DW marker plasma atrial natriuretic peptide (ANP) is useful to evaluate hypervolemia but not hypovolemia, both hyper- and hypovolemia can be detected by IVC measurement. In the present study, we investigated whether the IVC diameter serves as an optimal evaluation of DW in nonoliguric HD (NO-HD) patients, avoiding not only overhydration but also dehydration. The IVCe and plasma ANP levels were measured in 14 euvolemic patients with chronic renal failure at conservative period (CP-CRF) and 11 NO-HD patients, in whom the average daily urine volume was more than 500 ml/day. In NO-HD patients, DW was adjusted to attain the euvolemic state with normotensive blood pressure, lack of edema, and lack of temporal oliguria after HD. The ANP in CP-CRF patients was 109.3 +/- 15.3 pg/ml, and pre- and post-HD ANP levels in NO-HD patients were 145.3 +/- 23.5 and 97.5 +/- 13.5 pg/ml, respectively. IVCe in CP-CRF was 13.4 +/- 0.9 mm, and pre- and post-HD IVCe in NO-HD patients were 14.2 +/- 1.0 mm and 11.9 +/- 0.9 mm, respectively. Although the post-HD IVCe was greater (i.e., less hypovolemic) than that in anuric HD patients, and close to the IVCe in CP-CRF, pre-HD IVCe was comparable with that in anuric HD patients. In addition, the pre-HD ANP level was no higher than that in CP-CRF. Thus, in NO-HD patients, the post-IVCe of 11.9 +/- 0.9 mm would be a marker for an appropriate DW setting avoiding severe post-HD dehydration as well as excessive hypervolemia during the interdialytic period.

Fluid balance in patients with chronic renal failure assessed with N‐terminal proatrial natriuretic peptide, atrial natriuretic peptide and ultrasonography

The N-terminal proatrial natriuretic peptide (proANP) has become an important parameter for assessing the prognosis of patients with cardiac disease. Its use for evaluating the hydration status in patients with chronic renal failure, however, is still under investigation. The present study comprised 12 haemodialysis (HD) and 17 pre-dialysis patients. In the HD patients, the inferior vena cava diameter during quiet expiration (IVCe) was estimated by ultrasonography and plasma concentrations of N-terminal proANP, atrial natriuretic peptide (ANP) and cyclic guanosine monophosphate (cGMP) were measured before and 4 h after termination of HD. In the pre-dialysis patients venous blood samples were taken during rest to measure plasma N-terminal proANP and ANP and serum creatinine. Normal values for N-terminal proANP and ANP were obtained from 18 healthy volunteers. The plasma concentrations of N-terminal proANP and ANP in healthy volunteers were 328 +/- 92 and 11.4.0 +/- 3.1 pM L-1, respectively. In pre-dialysis patients, serum creatinine ranged from 110 to 447 microM L-1 and was significantly correlated to plasma N-terminal proANP (r = 0.60, P < 0.05) but not to ANP. This may indicate that N-terminal proANP is more dependent on renal function for its clearance than ANP, which is probably cleared by extrarenal mechanisms as well. In HD patients, IVCe was significantly correlated to the three hormones before HD, most strongly to N-terminal proANP. After dialysis, IVCe was significantly correlated to ANP and cGMP but was not correlated to N-terminal proANP. This may suggest that proANP takes a longer time than other hormones to reflect changes in intravascular volume. In conclusion, N-terminal proANP is a hormone closely related to degree of renal function. Furthermore, it is a sensitive marker reflecting the interdialytic hydration status in HD patients, as indicated by its high correlation to IVCe, a standard method which is used frequently nowadays to assess the body hydration. However N-terminal proANP could not reflect the acute changes in fluid volume induced by HD, probably because it is slowly metabolized.

Lung density for assessment of hydration status in hemodialysis patients using the computed tomographic densitometry technique

The density of the lung reflects the total mass of fluid, air, and dry lung tissue per unit volume of the lung. Lung density can be measured by evaluation of attenuation of an electron beam with computed tomography (CT). This technique has been shown to be sufficiently reliable and sensitive to distinguish normal from abnormal lung water. The aim of this study was to find out whether lung density properly reflects the hydration status in hemodialysis patients in comparison with other standard methods. Fourteen hemodialysis patients, with an ultrafiltration ranging from 0.3 to 4.5 liters per session, underwent CT measurements of lung density, ultrasonographic measurements of the diameter of the inferior vena cava after quiet expiration (IVCe) and quiet inspiration (IVCi), and measurements of the hematocrit and plasma levels of the biochemical hydration markers cyclic guanosine monophosphate (cGMP) and atrial natriuretic peptide (ANP). These measurements were performed before and 3.5 to 4 hours after termination of dialysis. Quantitative estimates of lung density were obtained within pixels with CT numbers ranging between -1000 and -100 Hounsfield Units (HU), and compared with normal data from 18 normal controls. In normal controls, the lung density ranged from -800 to -730 HU. In hemodialysis patients, lung density was significantly higher than normal before dialysis (-678 +/- 96 HU, P < 0.01) and significantly decreased after dialysis (-706 +/- 92 HU, P < 0.05), indicating a decrease in fluid content of the lung. The density was normalized in 5 patients. A significant correlation was found between lung density and IVCe both before and after dialysis (r = 0.8, P < 0.01 for both). Change in density was significantly correlated to amount of ultrafiltration (r = 0.67, P < 0.01) and percent change in blood volume (r = 0.63, P < 0.05), indicating that lung density is greatly affected by changes in the extracellular fluid volume, mainly the intravascular volume. In conclusion, lung water reflects the hydration status in hemodialysis patients and can be monitored by measuring the lung density by CT. Accordingly, normalization of lung density can help to achieve a proper dry weight in these patients.