Ultrasound assessment of gastric residual volume in patients over 60 years of age undergoing gastroscopy under sedation: a prospective cohort study.

BACKGROUND: We aimed to assess the accuracy of ultrasonographic measurement of the antral cross-sectional area (CSA) in the preprocedural evaluation of gastric contents and volume in fasted patients > 60 yr of age scheduled for gastroscopy under sedation. METHODS: We included n = 81 patients > 60 yr of age and n = 79 younger controls scheduled to undergo elective gastroscopy in a prospective cohort study. A gastric ultrasound examination was performed to measure the antral CSA in both semisitting and right lateral decubitus (RLD) positions. Afterward, patients were graded using the Perlas qualitative grading scale. The actual gastric volume was endoscopically suctioned. Full stomach was defined as gastric volume > 1.5 mL·kg-1 and/or the presence of solid particles. We constructed receiver operating characteristic curves to determine the accuracy of ultrasonographic measurement of RLD CSA to detect a gastric volume > 1.5 mL·kg-1 and calculated the diagnostic test attributes of RLD CSA for the identification of a gastric volume > 1.5 mL·kg-1 RESULTS: The incidence of full stomach was 8/81 (9.8%) in patients > 60 yr of age and 1/79 (1.2%) in young patients (risk difference, 8.6%; 95% CI, 1.3 to 15.8; P = 0.03). The cut-off value of RLD CSA was 10.4 cm2 for the detection of gastric volume > 1.5 mL·kg-1 in patients > 60 yr of age, with a sensitivity of 75%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 98.6%. CONCLUSION: Patients > 60 yr of age scheduled for gastroscopy under sedation had a higher incidence of a full stomach detected with ultrasound compared with a younger cohort, which is potentially associated with a higher aspiration risk. We calculated a cut-off value of RLD CSA for detecting gastric volume in patients > 60 yr of age of approximately 10 cm2, which may help to quickly assess patients at risk of aspiration. TRIAL REGISTRATION: www.chictr.org.cn (ChiCTR2100048994); registered 19 July 2021.

RéSUMé: CONTEXTE: Notre objectif était d'évaluer la précision de la mesure échographique de la section transversale antrale (CSA) dans l'évaluation préprocédurale du contenu et du volume gastriques chez les patient·es à jeun > 60 ans devant bénéficier d'une gastroscopie sous sédation. MéTHODE: Nous avons inclus n = 81 patient·es > 60 ans et n = 79 patient·es témoins plus jeunes devant bénéficier d'une gastroscopie non urgente dans une étude de cohorte prospective. Une échographie gastrique a été réalisée pour mesurer la CSA antrale en position semi-assise et en décubitus latéral droit (DLD). Par la suite, la patientèle a été classée à l'aide de l'échelle de classement qualitatif de Perlas. Le volume gastrique réel était aspiré par endoscopie. Un estomac plein a été défini comme un volume gastrique > 1,5 mL·kg­1 et/ou la présence de particules solides. Nous avons construit des courbes de la fonction d'efficacité du récepteur (courbes ROC) afin de déterminer la précision de la mesure échographique de la CSA en DLD pour détecter un volume gastrique > 1,5 mL·kg­1 et calculé les attributs du test diagnostique de la CSA en DLD pour identifier un volume gastrique > 1,5 mL·kg­1. RéSULTATS: L'incidence d'estomac plein était de 8/81 (9,8 %) chez les patient·es > 60 ans et 1/79 (1,2 %) chez les patient·es jeunes (différence de risque, 8,6 %; IC 95 %, 1,3 à 15,8; P = 0,03). La valeur seuil de la CSA en DLD était de 10,4 cm2 pour la détection d'un volume gastrique > 1,5 mL·kg­1 chez la patientèle > 60 ans, avec une sensibilité de 75 %, une spécificité de 100 %, une valeur prédictive positive de 100 % et une valeur prédictive négative de 98,6 %. CONCLUSION: La patientèle > 60 ans devant bénéficier d'une gastroscopie sous sédation avait une incidence plus élevée d'estomac plein détecté par échographie par rapport à une cohorte plus jeune, ce qui est potentiellement associé à un risque d'aspiration plus élevé. Nous avons calculé une valeur seuil de la CSA en DLD pour détecter le volume gastrique chez les patient·es > 60 ans d'environ 10 cm2, ce qui peut aider à évaluer rapidement les personnes à risque d'aspiration. ENREGISTREMENT DE L'éTUDE: www.chictr.org.cn (ChiCTR2100048994); enregistrée le 19 juillet 2021.

Routine versus no assessment of gastric residual volumes in preterm infants receiving enteral feeding via intermittent feeding tubes: a randomized controlled trial.

OBJECTIVE: To evaluate whether eliminating routine gastric residual volume (GRV) assessments would lead to quicker attainment of full feeding volumes in preterm infants. STUDY DESIGN: This is a prospective randomized controlled trial of infants ≤32 weeks gestation and birthweight ≤1250 g admitted to a tertiary care NICU. Infants were randomized to assess or not assess GRV before enteral tube feedings. The primary outcome was time to attain full enteral feeding volume defined as 120 ml/kg/day. The Wilcoxon rank sum test was used to compare the days to reach full enteral feeds between the two groups. RESULTS: 80 infants were randomized, 39 to the GRV assessing and 41 to the No-GRV assessing group. A predetermined interim analysis at 50% enrollment showed no difference in primary outcome and the study was stopped as recommended by the Data Safety Monitoring Committee. There was no significant difference in median days to reach full enteral feeds between the two groups [GRV assessment: 12d (5) vs. No-GRV assessment:13d (9)]. There was no mortality in either group, one infant in each group developed necrotizing enterocolitis stage 2 or greater. CONCLUSION: Eliminating the practice of gastric residual volume assessment before feeding did not result in shorter time to attain full feeding.

Current practice of gastric residual volume measurements and related outcomes of critically ill patients: A secondary analysis of the intestinal-specific organ function assessment study.

BACKGROUND: Gastric residual volume (GRV) measurement to detect gastrointestinal (GI) dysfunction is a common diagnostic procedures in critical care, albeit still not well standardized being operator-, patient-, and tube-dependent. Our aim was to describe current practice of GRV measurements and its association with clinical outcomes in critically ill patients. METHODS: This was a secondary analysis of an international prospective observational cohort study (intestinal-specific organ function assessment). Eligibility criteria were defined as ≥1 GRV measurement during the 7-day study period. Data collection included GRV measurement practices, tube diameters and volumes, symptoms of GI dysfunction, and clinical outcomes. The primary aim was to describe current practices of GRV measurements, and the secondary aim was to test the association of high (>200 ml) vs. low GRV with symptoms of GI dysfunction and clinical outcomes using generalized linear regression and survival models. RESULTS: Two hundred fifty-eight patients with 2422 GRV measurements on 875 study days were analyzed. GRV was mainly measured via passive drainage twice daily using large diameter tubes. There was no significant association between tube size or measurement technique and high GRV. High GRV occurred in 34% of patients and was associated with other GI symptoms and with increased disease severity but not with 28-day or 90-day mortality, intensive care unit-free and ventilator-free days. CONCLUSION: There was substantial variability of GRV measurement techniques, but this had no impact on the amount of GRV. High GRV was not associated with mortality or ventilator-free days but may serve as a marker of GI dysfunction and disease severity.

Nurse-performed ultrasound assessment of gastric residual volume and enteral nasogastric tube placement in the general intensive care unit.

OBJECTIVE: Ultrasonography is an essential imaging modality in the critical care population and has been increasingly utilized to check gastric residual volume . Various studies have shown that intensive care unit nurses untrained in ultrasound can easily be trained in its accurate interpretation. We prospectively analyzed nurse-performed repeated measurements of gastric residual volume and nasogastric tube positioning via an ultrasound technique in the intensive care unit. DESIGN: This was a single-center, cross-sectional prospective study. Four intensive care unit nurses, evenly divided into two groups (teams A and B), underwent four hours of formal ultrasound training by three critical care staff physicians. The trained nurses provided bedside ultrasound assessments of gastric residual volume and nasogastric tube positioning which were compared to a standard protocol of syringe aspiration. RESULTS: Ninety patients were recruited to the study. Four measurements per patient were performed, for a total of 360 assessments. The ultrasound gastric residual volume assessments were correlated with the syringe aspiration protocol and demonstrated high Intraclass Correlation Coefficient rates of 0.814 (0.61-0.92) for team A and 0.85 (0.58-0.91) for team B. Nasogastric tube placement was successfully and independently verified by ultrasound in most of the critically ill patients (78% of team A and 70% of team B). The comparative ultrasound assessments of tube positioning demonstrated good correlation of 0.733 (0.51-0.88) between each team's two independent observers. CONCLUSION: Our study demonstrated a strong correlation between US utilization for assessment of gastric residual volume and nasogastric tube positioning and standard protocol methods, suggesting it is a safe, simple and effective practice for intensive care unit nurses.

Does ultrasonographic assessment of gastric antrum correlate with gastric residual volume in critically ill patients? A prospective observational study.

This study aimed to evaluate the relationship between ultrasonographic gastric antral measurements and aspirated gastric residual volume (GRV) in mechanically ventilated critically ill patients receiving enteral nutrition (EN). This prospective observational study included 56 enterally-fed critically ill patients in one-year period. All imaging procedures were done at 30-degree head-of-bed elevation and supine position on epigastric region of abdomen with 2.5-6 MHz convex-array probe just before routine GRV aspiration. The antral cross-sectional area (CSA) was calculated by measuring the anteroposterior (dAP) and craniocaudal diameters (dCC) of the gastric antrum. Total 283 ultrasonographic gastric antrum imaging procedures were done. In only eight (2.82%) attempts, the antrum could not be visualized due to inhibition from intra-gastric air or gas in the surrounding intestinal lumen. The calculated mean antral CSA was 568.15 ± 348.37 mm2 (103.43-2,846.30). The antral CSA correlated significantly with aspirated GRV, and the antral CSA increased linearly with increasing aspirated GRV (R2 = 0.73, p < 0.0001). In Receiver operating characteristic (ROC) analysis of antral CSA ≥ 920 mm2 (mean + 1*SD) for estimating aspirated GRV, the area under the curve (AUC) was 0.848 (95% CI, 0.76 ~ 0.93) (p < 0.0001), and ROC analysis of antral CSA to discriminate aspirated GRV ≥ 250 mL showed a significant relation (AUC = 0.969, 95% CI 0.94 ~ 0.99, p < 0.0001). Ultrasonographic measurement of gastric antral CSA is an easy and reliable bedside procedure to estimate GRV in critically ill patients receiving EN in 30-degree head-of-bed elevation and supine position. Trial registration number: NCT04413474, date of registration: June 17, 2020, retrospectively registered.

Routine gastric residual volume measurement to guide enteral feeding in mechanically ventilated infants and children: the GASTRIC feasibility study.

BACKGROUND: The routine measurement of gastric residual volume to guide the initiation and delivery of enteral feeding is widespread in paediatric intensive care and neonatal units, but has little underlying evidence to support it. OBJECTIVE: To answer the question: is a trial of no gastric residual volume measurement feasible in UK paediatric intensive care units and neonatal units? DESIGN: A mixed-methods study involving five linked work packages in two parallel arms: neonatal units and paediatric intensive care units. Work package 1: a survey of units to establish current UK practice. Work package 2: qualitative interviews with health-care professionals and caregivers of children admitted to either setting. Work package 3: a modified two-round e-Delphi survey to investigate health-care professionals' opinions on trial design issues and to obtain consensus on outcomes. Work package 4: examination of national databases to determine the potential eligible populations. Work package 5: two consensus meetings of health-care professionals and parents to review the data and agree consensus on outcomes that had not reached consensus in the e-Delphi study. PARTICIPANTS AND SETTING: Parents of children with experience of ventilation and tube feeding in both neonatal units and paediatric intensive care units, and health-care professionals working in neonatal units and paediatric intensive care units. RESULTS: Baseline surveys showed that the practice of gastric residual volume measurement was very common (96% in paediatric intensive care units and 65% in neonatal units). Ninety per cent of parents from both neonatal units and paediatric intensive care units supported a future trial, while highlighting concerns around possible delays in detecting complications. Health-care professionals also indicated that a trial was feasible, with 84% of staff willing to participate in a trial. Concerns expressed by junior nurses about the intervention arm of not measuring gastric residual volumes were addressed by developing a simple flow chart and education package. The trial design survey and e-Delphi study gained consensus on 12 paediatric intensive care unit and nine neonatal unit outcome measures, and identified acceptable inclusion and exclusion criteria. Given the differences in physiology, disease processes, environments, staffing and outcomes of interest, two different trials are required in the two settings. Database analyses subsequently showed that trials were feasible in both settings in terms of patient numbers. Of 16,222 children who met the inclusion criteria in paediatric intensive care units, 12,629 stayed for > 3 days. In neonatal units, 15,375 neonates < 32 weeks of age met the inclusion criteria. Finally, the two consensus meetings demonstrated 'buy-in' from the wider UK neonatal communities and paediatric intensive care units, and enabled us to discuss and vote on the outcomes that did not achieve consensus in the e-Delphi study. CONCLUSIONS AND FUTURE WORK: Two separate UK trials (one in neonatal units and one in paediatric intensive care units) are feasible to conduct, but they cannot be combined as a result of differences in outcome measures and treatment protocols, reflecting the distinctness of the two specialties. TRIAL REGISTRATION: Current Controlled Trials ISRCTN42110505. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 23. See the NIHR Journals Library website for further project information.

Nurses looking after babies and children on intensive care units in the UK usually pass a tube and aspirate whatever food or fluid is in the baby's stomach before they give a feed. The idea is to ensure that the stomach is not overdistended with food and prevent the baby vomiting or, worse, aspirating food into the lungs. However, there is little justification for this practice. It is rarely done in many other countries. It may not be pleasant for the child and perhaps is unnecessary. Some experts have suggested that the policy should be evaluated in a randomised controlled trial. This would mean allocating a large number of children at random to either have the stomach aspirated before feeds, or not. Such a trial would be a major undertaking and we are unsure if parents or staff would be willing to allow children to participate. The aim of this study was to see if it is possible to conduct such a large trial in the UK. Two surveys (of 119 units) showed us that regularly measuring the stomach contents when starting and increasing feeds is common practice for both newborn and older children in UK intensive care units. However, in some countries, such as France, this practice is rarely done. We asked 31 parents and 51 health-care professionals about a future study. Overall, parents were supportive of a trial if it was explained to them well by a knowledgeable and caring professional, and if they were approached at the right time. Some concerns were expressed about not picking up complications early if gastric residual volume was not measured. Health-care professionals were also mainly positive about a future trial, but mentioned similar concerns about not picking up complications early and the difficulty of changing a long-standing routine practice. Parents suggested study outcomes that were important to them. These, along with other outcomes, were voted on in a further survey of 106 professionals and at face-to-face meetings involving 41 participants. Overall, our findings suggest that a trial is feasible to perform and acceptable to parents. However, because of differences in both treatments and important outcomes between children's intensive care units and newborn baby intensive care units, two trials would be needed, one in each type of intensive care unit. These two trials will test whether or not the benefits of not measuring gastric residual volume (e.g. improved calorie intake) outweigh the potential harms (e.g. delayed diagnosis of complications).

Residual volume/total lung capacity ratio confers limited additive significance to lung clearance index for assessment of adults with bronchiectasis.

BACKGROUND: Mosaicism and hyperinflation are common pathophysiologic features of bronchiectasis. The magnitude of ventilation heterogeneity might have been affected by the degree of hyperinflation. Some studies have evaluated the discriminative performance of lung clearance index (LCI) in bronchiectasis patients, but the additive diagnostic value of hyperinflation metrics to LCI is unknown. OBJECTIVE: To compare LCI and the ratio of residual volume to total lung capacity (RV/TLC), along with the LCI normalized with RV/TLC, in terms of discriminative performance, correlation and concordance with clinical variables in adults with bronchiectasis. METHODS: Measurement items included chest high-resolution computed tomography, multiple-breath nitrogen washout test, spirometry, and sputum culture. We analyzed bronchodilator responses by stratifying LCI and RV/TLC according to their median levels (LCIHigh/RV/TLCHigh, LCILow/RV/TLCHigh, LCIHigh/RV/TLCLow, and LCILow/RV/TLCLow). RESULTS: Data from 127 adults with clinically stable bronchiectasis were analyzed. LCI had greater diagnostic value than RV/TLC in discriminating moderate-to-severe from mild bronchiectasis, had greater concordance in reflecting clinical characteristics (including the number of bronchiectatic lobes, radiological severity score, and the presence of cystic bronchiectasis). Normalization of LCI with RV/TLC did not contribute to greater discriminative performance or concordance with clinical variables. The LCI, before and after normalization with RV/TLC, correlated statistically with age, sex, HRCT score, Pseudomonas aeruginosa colonization, cystic bronchiectasis, and ventilation heterogeneity (all P<0.05). Different bronchodilator responses were not significant among the four subgroups of bronchiectasis patients, including those with discordant LCI and RV/TLC levels. CONCLUSION: LCI is superior to RV/TLC for bronchiectasis assessment. Normalization with RV/TLC is not required. Stratification of LCI and RV/TLC is not associated with significantly different bronchodilator responses.

Quantitative Assessment of Airway Pathology in Subjects With COPD Using Low-Dose High-Resolution Computed Tomography.

BACKGROUND: The purpose of this study was to correlate airway parameters of COPD determined by low-dose high-resolution computed tomography (HRCT) with pulmonary function testing (PFT) results. METHODS: PFT data were collected for subjects with COPD and healthy controls. All subjects received inspiratory and expiratory phase low-dose HRCT. Bronchi in the apical segment of the right upper lobe (RB1), posterior segment of the right lower lobe (RB6), and lower lingual segment of the left upper lobe (LB5) were the target bronchi. Software automatically calculated airway wall area, inner area, and airway wall area percentage (percentage wall area for bronchial external area). RESULTS: A total of 75 COPD and 20 control subjects were included. The subjects with COPD were classified according to COPD stage, with 20 grade I, II, and III subjects, respectively, and 15 grade IV subjects. In COPD grade II, residual volume/total lung capacity was negatively correlated with airway wall area in LB5 (r = -0.51). In COPD grade III, FVC was negatively correlated with airway wall area percentage in LB5 (r = -0.49) but positively correlated with airway wall area in RB6 (r = 0.52); percent-of-predicted FEV1 was negatively correlated with airway wall area percentage in RB1 (r = -0.49); residual volume was negatively correlated with airway wall area (r = -0.47), and total lung capacity was negatively correlated with airway wall area in RB1 (r = -0.52) (all, P < .001). CONCLUSIONS: The results of this study suggest that airway parameters in different COPD grades have no uniform tendency of correlation with PFT, but some HRCT parameters are correlated to some PFT parameters.

Quantitative assessment of lung stiffness in patients with interstitial lung disease using MR elastography.

PURPOSE: To investigate the use of magnetic resonance elastography (MRE) in the quantitative assessment of pulmonary fibrosis by comparing quantitative shear stiffness measurements of lung parenchyma in patients diagnosed with fibrotic interstitial lung disease (ILD) and healthy controls. MATERIALS AND METHODS: A 1.5T spin-echo, echo planar imaging MRE (SE-EPI MRE) pulse sequence was utilized to assess absolute lung shear stiffness in 15 patients with diagnosed ILD and in 11 healthy controls. Data were collected at residual volume (RV) and total lung capacity (TLC). Spirometry data were obtained immediately prior to scanning. To test for statistical significance between RV and TLC shear stiffness estimates a two-sample t-test was performed. To assess variability within individual subject shear stiffness estimates, the intraclass correlation coefficient (ICC) and Krippendorff's alpha were calculated. RESULTS: Patients with ILD exhibited an average (±1 standard deviation) shear stiffness of 2.74 (±0.896) kPa at TLC and 1.32 (±0.300) kPa at RV. The corresponding values for healthy individuals were 1.33 (±0.195) kPa and 0.849 (±0.250) kPa, respectively. The difference in shear stiffness between RV and TLC was statistically significant (P < 0.001). At TLC, the ICC and alpha values were 0.909 and 0.887, respectively. At RV, the ICC and alpha values were 0.852 and 0.862, respectively. CONCLUSION: In subjects with known fibrotic interstitial lung disease, parenchymal shear stiffness is increased when compared to normal controls at both RV and TLC, with TLC demonstrating the most significant difference. MRE-derived parenchymal shear stiffness is a promising new noninvasive imaging-based biomarker of interstitial lung disease. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:365-374.

Examination of accuracy in the assessment of gastric residual volume: a simulated, controlled study.

BACKGROUND: Increased gastric content from enteral nutrition intolerance is thought to place patients at risk for pulmonary aspiration. Although considered a questionable practice, blind gastric tube aspiration is the most common approach to measure gastric content. This simulated study evaluated the accuracy of residual volume (RV) assessment via tube aspirations made from known volumes by controlling the syringe pull technique, feeding tube properties, fluid viscosity, and placement of tubes in the fluid. MATERIALS AND METHODS: This study was conducted in a metrology laboratory. Aspirates were obtained using a force measurement test system to control force of the syringe pull technique using 3 different procedures (slow 10 inches per minute [ipm], intermittent 10 ipm, and fast 40 ipm). Four different feeding tubes, 10 Fr and 18 Fr, each made of polyurethane and polyvinyl chloride, were placed in varying depths of 100 mL of either water or formula. The effect of fluid viscosity was also examined. RESULTS: Overall, 108 RVs were analyzed using a force measurement test system. Actual content of RV was underestimated 19% on average and varied across tube size and viscosity. Intermittent and slow syringe pull techniques yielded greater aspirate quantities, although neither technique aspirated the full amount of volume available. The 10 Fr feeding tubes yielded larger RVs in more viscous fluid, yet the 18 Fr tubes performed better with fluids of lower viscosity. CONCLUSIONS: Based on this simulation, RV assessment does not accurately reflect the total volume of the contents available and, therefore, the clinical utility of this assessment should be further investigated.

[Assessment of lung functional residual capacity and oxygen consumption during PEEP trial procedure].

UNLABELLED: Purpose of the study was to compare the functional residual capacity and oxygen consumption with compliance and partial pressure of oxygen during automatic PEEP trial procedure--"PEEP INview". MATERIAL AND METHODS: Dynamics of functional residual capacity, oxygen consumption, compliance and partial pressure of oxygen were studied in 14 patients at cardiac surgical unit during automatic PEEP trial procedure--"PEEPINview". RESULTS: Significant dynamics of compliance and carbon dioxide production was not found. Partial pressure of oxygen cannot be used as the guideline in this study. Functional residual capacity increased in each incremental level of PEEP. Oxygen consumption increased during the PEEP changing from 6 to 8 cmH2O. CONCLUSION: It is defined that oxygen consumption is sensitive to PEEP level. Therefore the maximum diagnostics value of functional residual capacity measuring is expected in patients with restrictive lung disease.

Assessment of the alveolar volume when sampling exhaled gas at different expired volumes in the single breath diffusion test.

BACKGROUND: Alveolar volume measured according to the American Thoracic Society-European Respiratory Society (ATS-ERS) guidelines during the single breath diffusion test can be underestimated when there is maldistribution of ventilation. Therefore, the alveolar volume calculated by taking into account the ATS-ERS guidelines was compared to the alveolar volume measured from sequentiallly collected samples of the expired volume in two groups of individuals: COPD patients and healthy individuals. The aim of this study was to investigate the effects of the maldistribution of ventilation on the real estimate of alveolar volume and to evaluate some indicators suggestive of the presence of maldistribution of ventilation. METHODS: Thirty healthy individuals and fifty patients with moderate-severe COPD were studied. The alveolar volume was measured either according to the ATS-ERS guidelines or considering the whole expired volume subdivided into five quintiles. An index reflecting the non-uniformity of the distribution of ventilation was then derived (DeltaVA/VE). RESULTS: Significant differences were found when comparing the two measurements and the alveolar volume by quintiles appeared to have increased progressively towards residual volume in healthy individuals and much more in COPD patients. Therefore, DeltaVA/VE resulted in an abnormal increase in COPD. CONCLUSION: The results of our study suggest that the alveolar volume during the single breath diffusion test should be measured through the collection of a sample of expired volume which could be more representative of the overall gas composition, especially in the presence of uneven distribution of ventilation. Further studies aimed at clarifying the final effects of this way of calculating the alveolar volume on the measure of DLCO are needed. DeltaVA/VE is an index that can help assess the severity of inhomogeneity in COPD patients.

Two-year improvement in multidimensional body mass index, airflow obstruction, dyspnea, and exercise capacity index after nonresectional lung volume reduction surgery in awake patients.

BACKGROUND: This study analyzed the comprehensive 2-year outcome of nonresectional lung volume reduction surgery (LVRS) in awake patients, including calculation of the multidimensional BODE index (body mass index, degree of airflow obstruction assessed by spirometry, modified Medical Research Council dyspnea grade, and 6-minute walking distance), which has proved a useful predictor of survival in patients with chronic obstructive pulmonary disease. METHODS: The study cohort included 42 patients undergoing LVRS while awake within a staged bilateral program entailing unilateral LVRS, followed by contralateral treatment performed at the reappearance of disabling symptoms. Outcome measures included hospital stay, procedure-related costs, calculation of the multidimensional BODE index, actuarial survival, and freedom from contralateral LVRS. Results were compared with those of a control group undergoing resectional LVRS under general anesthesia. RESULTS: The groups were well matched in demographics and baseline measures. There was no operative mortality. Median hospital stay was significantly shorter in the awake group (6 days versus 9 days, p < 0.0001); median procedure-related costs were significantly lower in the awake group (euro5220 versus euro8580; p < 0.0001). At intergroup comparisons of awake versus control group of clinical results, the BODE index improved postoperatively in both groups (-2.24 +/- 1.0 versus -1.95 +/- 1.0, intergroup p = 0.35) and remained improved for up to 2 years (-1.95 +/- 1.3 versus -1.37 +/- 1.4, intergroup p = 0.1); 2-year survival and freedom from contralateral LVRS rates were 87% versus 91% (p = 0.52) and 74% versus 73% (p = 0.71), respectively. CONCLUSIONS: A significant improvement in the BODE index, satisfactory survival, and high rate of freedom from contralateral LVRS occurred both in the awake and control group, although the awake procedure proved more cost-effective.

Plethysmography and impulse oscillometry assessment of tiotropium and ipratropium bromide; a randomized, double-blind, placebo-controlled, cross-over study in healthy subjects.

AIMS: Spirometry, plethysmography and impulse oscillometry (IOS) measure different aspects of lung function. These methods have not been compared for their ability to assess long- and short-acting anticholinergic agents. We therefore performed a double-blind, placebo-controlled, four-way cross-over study in 30 healthy subjects. METHODS: Single doses of tiotropium bromide (Tio) 54 and 18 mcg, ipratropium bromide (IB) 40 mcg and placebo were administered. Specific conductance (sGaw), total lung capacity (TLC), inspiratory capacity (IC) and residual volume (RV) were measured using plethysmography, while IOS measured resistance (R5-25) and reactance (RF and X5). Pulmonary function was measured for 26 h post dose. RESULTS: Tio caused significant improvements in sGaw, forced expiratory voume in 1 s (FEV(1)), maximum mid-expiratory flow (MMEF) and R5-R25 at time points up to 26 h, with no clear differences between doses. IB improved the same parameters, but only up to 8 h. The weighted mean change (0-24 h) caused by Tio 54 mcg compared with placebo for FEV(1) was 240 ml (95% confidence interval 180, 300), while for sGaw the ratio of geometric means (Tio compared with placebo) was 1.35 (1.28, 1.41). Neither drug caused consistent statistically significant changes in RF, forced vital capacity, TLC or IC over 26 h. RV was significantly improved from 8 to 24 h by Tio 54 mcg only. CONCLUSIONS: In addition to spirometry, IOS resistance measurements and sGaw can distinguish between the effects of long- and shortacting anticholinergic effects in healthy subjects.

Pharmacological approaches to stable chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) causes disabling, slowly progressive breathlessness on exertion, chronic cough and sputum production. Its natural history is punctuated by increasingly frequent exacerbations which in turn accelerate disease progression and reduce a patient's quality of life. COPD has previously been ignored in the mistaken belief that nothing could be done. There are now a number of therapies that can be used to reduce symptoms and prevent exacerbations. In turn this reduces disability, improves the patient's health-related quality of life and has the potential to reduce costs to the health service and to society.

Diaphragm and chest wall: assessment of the inspiratory pump with MR imaging-preliminary observations.

Magnetic resonance (MR) imaging of the thorax with three-dimensional (3D) reconstruction and functional quantification was evaluated as a tool for structure-function evaluation of chest-wall mechanics. Good agreement was found between the corresponding spirometric and MR imaging values of lung volumes. Fast MR imaging of the thorax with 3D reconstruction should improve the ability to evaluate the inspiratory pump in clinical and research investigations.

Airway hyperreactivity: assessment with helical thin-section CT.

PURPOSE: To determine the accuracy of helical computed tomography (CT) for assessing reversible changes in bronchial size and air trapping due to airway hyperreactivity. MATERIALS AND METHODS: Spirometry and helical CT were performed in 15 patients with mild asthma and six healthy control subjects before and after bronchial provocation with methacholine chloride and after reversal of provocation with albuterol. CT was performed at suspended functional residual capacity and at residual volume in two lung regions (above and below the carina). Bronchial area and lung attenuation measurements were compared. RESULTS: At baseline, lung attenuation frequency distribution curves were similar between the control and asthma groups. After methacholine, control subjects showed a decrease of less than 10% in the forced expiratory volume at 1 second (FEV1) and no significant differences in lung attenuation curves. Patients with asthma showed a 20%-36% decrease in FEV1, with significant decreases in the median and lowest 10th percentile regions of the attenuation curves and in the cross-sectional area of small (< 5-mm2) airways (P < .001 for all comparisons). After albuterol, control subjects showed no change in spirometric measurements, lung attenuation, or bronchial size, whereas all such parameters returned to baseline levels in patients with asthma. CONCLUSION: Functional helical CT can accurately demonstrate reversible airflow obstruction resulting from airway hyperreactivity.

Three-dimensional volumetric assessment of abnormally low attenuation of the lung from routine helical CT: inspiratory and expiratory quantification.

OBJECTIVE: The purpose of this investigation was to quantitatively assess abnormally low attenuation of the lung by use of three-dimensional volumetric reconstructions from routine helical CT and to assess their correlation with pulmonary function tests. MATERIALS AND METHODS: Helical CT was performed in 100 patients in full inspiration. Examination was also performed in full expiration in 53 of these patients. Three-dimensional volumetric reconstructions were performed for total lung volumes at inspiration and at expiration, with a threshold of -896 H on inspiratory CT and -790 H on expiratory CT, to quantify emphysematous change. Correlation was made with pulmonary function tests in 79 patients. RESULTS: CT volumetric assessments of abnormally low attenuation of the lung at inspiration and expiration had a high correlation (r2 = .84, p < or = .0001). In comparison with pulmonary function tests, both inspiratory low attenuation of the lung and expiratory low attenuation of the lung correlated well with the logarithm of the ratio of the forced expiratory volume in 1 sec (FEV1) to the forced vital capacity (r2 = .74, p < or = .0001 and r2 = .74, p < or = .0001, respectively) and with the percentage of predicted ratio of the FEV1 to the forced vital capacity (r2 = .69, p < or = .0001 and r2 = .69, p < or = .0001, respectively). Linear correlations were also seen with FEV1, residual volume, and forced residual capacity. CONCLUSION: Three-dimensional volumetric reconstructions of hypoattenuating lung correlate well with pulmonary function tests. In addition, inspiratory and expiratory data are also correlative, suggesting that a dedicated expiratory examination is not needed. This easily obtainable information will prove useful for patients with obstructive lung disease from emphysema, providing a measure of pulmonary function status in this population.