Effect of Resected Lung Volume on Pulmonary Function and Residual Lung Volume in Patients Undergoing Segmentectomy: A Retrospective Study.

PURPOSE: We elucidated the effects of planned resection volume on postoperative pulmonary function and changes in residual lung volume during segmentectomy. METHODS: This study included patients who underwent thoracoscopic segmentectomy between January 2017 and December 2022 and met eligibility criteria. Pre- and post-resection spirometry and computed tomography were performed. Three-dimensional reconstructions were performed by using computed tomography images to calculate the volumes of the resected, remaining, and nonoperative side regions. Based on the resected region volume, patients were divided into the higher and lower volume segmentectomy groups. Changes in lung volume and pulmonary function before and after the surgery were comparatively analyzed. RESULTS: The median percentage of resected lung volume was 10.9%, forming the basis for categorizing patients into the two groups. Postoperative forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) ratios to preoperative measurements in both groups did not differ significantly (FEV1, p = 0.254; FVC, p = 0.777). Postoperative FEV1 and FVC ratios to their predicted postoperative values were significantly higher in the higher volume segmentectomy group than in the lower volume segmentectomy group (FEV1, p = 0003; FVC, p < 0.001). The higher volume segmentectomy group showed significantly greater post-to-preoperative lung volume ratio in overall, contralateral, ipsilateral, residual lobe and residual segment than the lower volume segmentectomy group. CONCLUSIONS: Postoperative respiratory function did not differ significantly between the higher- and lower-volume segmentectomy groups, indicating improved respiratory function because of substantial postoperative residual lung expansion. Our findings would aid in determining the extent of resection during segmentectomy.

Lung Volumes in a Mouse Model of Pulmonary Allergic Inflammation.

PURPOSE: Air trapping, often attested in humans by elevated residual volume (RV) and ratio of RV on total lung capacity (RV/TLC), is frequently observed in asthma. Confirming these alterations in experimental asthma would be important for translational purposes. Herein, lung volumes were investigated in a mouse model of pulmonary allergic inflammation. METHODS: Eight- to 10-week-old male C57BL/6 and BALB/c mice were exposed once daily to intranasal house dust mite (HDM) for 10 consecutive days. All readouts were measured 24 h after the last exposure. Lung volumes were assessed with the flexiVent using a new automated method consisting of degassing the lungs followed by a full-range pressure-volume maneuver. The weight and the volume of the lungs were also measured ex vivo and a lobe was further processed for histological analyses. RESULTS: HDM exposure led to tissue infiltration with inflammatory cells, goblet cell hyperplasia, thickening of the airway epithelium, and elevated ex vivo lung weight and volume. It also decreased TLC and vital capacity but without affecting RV and RV/TLC. These observations were similar between the two mouse strains. CONCLUSION: Alterations of lung volumes in a murine model of pulmonary allergic inflammation are inconsistent with observations made in human asthma. These discrepancies reflect the different means whereby lung volumes are measured between species. The invasive method used herein enables RV to be measured more precisely and without the confounding effect of air trapping, suggesting that changes in RV and RV/TLC using this method in mice should be interpreted differently than in humans.

Differences in residual volume above different tracheostomy tube cuffs depending on tube structure, tube tilt angle, and liquid viscosity.

INTRODUCTION: Proper management of aspirated material above the tracheostomy tube cuff is crucial to prevent complications, such as aspiration pneumonia. This study aimed to thoroughly examine the effects of aspirated liquid viscosity, suction port positioning, and tube tilt angle on residual volume above the cuff (RVAC). METHODS: Five types of tracheostomy tubes (approximately 9 mm outer diameter) were placed through a transparent cylinder with an inner diameter of 18 mm. The cuff was inflated to completely seal the interior of the cylinder. Four liquids with different viscosities were poured onto the cuff, and the liquid above the cuff was suctioned from the side port. The cylinder was angled at 90° and 20°, and each test was performed thrice to determine the average RVAC. RESULTS: After side-port suctioning, some liquid residue was observed on the cuff of all tracheostomy tubes. The RVAC increased with higher liquid viscosity. The tubes with a longer distance from the suction port opening to the cuff top exhibited more RVAC. Moreover, the RVAC was almost the same regardless of the cylinder angle for tubes with a suction port on the lateral side. However, tubes with backside ports showed a decreased RVAC with cylinder tilt. CONCLUSIONS: This study underscores the persistence of residual material on cuffed tracheostomy tubes even with regular subglottic secretion drainage. This emphasizes the need for specialized tracheostomy tube development aimed at reducing post-suction RVAC. Improved designs can potentially minimize complications associated with residue accumulation.

Residual volume of extruded disc material and residual spinal cord compression measured on postoperative MRI do not predict neurological outcomes in dogs following decompressive surgery for thoracolumbar intervertebral disc extrusion.

Published studies on the validity of using quantitative MRI measures of pre- and postoperative spinal cord (SC) compression as prognostic indicators for dogs undergoing surgery for intervertebral disc extrusion (IVDE) are currently limited. The aim of this retrospective analytical study was to describe the volume of postoperative residual extradural material (VREM) and the ratio of the cross-sectional area (CSA) of maximum SC compression to the CSA of SC in a compression-free intervertebral space as MRI measures of preoperative and postoperative compression (residual spinal cord compression, RSCC), and to compare these measures between the neurological outcome in a group of dogs. Inclusion criteria were dogs that underwent surgery for thoracolumbar IVDE, were imaged pre- and immediately postoperatively by MRI, and had a neurological follow-up examination 2 to 5 weeks postoperatively. Two blinded observers independently performed measurements in pre- and postoperative MRI studies. Dogs were classified into positive outcome (PO) and negative outcome (NO) groups based on follow-up neurologic examination scores. Seventeen dogs were included (12 PO, 5 NO). Interobserver agreement for MRI measurements was good to excellent (ICCs: 0.76-0.97). The prevalence of residual extradural material in postoperative MRI studies was 100%. No significant differences in mean preoperative SC compression, mean RSCC, mean SC decompression, or VREM were found between outcome groups (P = .25; P = .28; P = .91, P = .98). In conclusion, neither postoperative VREM nor RSCC could predict successful neurological outcomes.

A threshold for mitotic activity and post-surgical residual volume defines distinct prognostic groups for astrocytoma IDH-mutant.

AIMS: The distinction between CNS WHO grade 2 and grade 3 is instrumental in choosing between observational follow-up and adjuvant treatment for resected astrocytomas IDH-mutant. However, the criteria of CNS WHO grade 2 vs 3 have not been updated since the pre-IDH era. METHODS: Maximal mitotic activity in consecutive high-power fields corresponding to 3 mm2 was examined for 118 lower-grade astrocytomas IDH-mutant. The prognostic value for time-to-treatment (TTT) and overall survival (OS) of mitotic activity and other putative prognostic factors (including age, performance status, pre-surgical tumour volume, multilobar involvement, post-surgical residual tumour volume and midline involvement) was assessed for tumours with ATRX loss and the absence of CDKN2A homozygous deletion or CDK4 amplification, contrast enhancement, histological necrosis and microvascular proliferation. RESULTS: Seventy-one per cent of the samples had <6 mitoses per 3 mm2 . Mitotic activity, residual volume and multilobar involvement were independent prognostic factors of TTT. The threshold of ≥6 mitoses per 3 mm2 identified patients with a shorter TTT (median 18.5 months). A residual volume ≥1 cm3 also identified patients with a shorter TTT (median 24.5 months). The group defined by <6 mitoses per 3 mm2 and a residual volume <1 cm3 had the longest TTT (median 73 months) and OS (100% survival at 7 years). These findings were confirmed in a validation cohort of 52 tumours. CONCLUSIONS: Mitotic activity and post-surgical residual volume can be combined to evaluate the prognosis for patients with resected astrocytomas IDH-mutant. Patients with <6 mitoses per 3 mm2 and a residual volume <1 cm3 were the best candidates for observational follow-up.

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.

Is monitoring of gastric residual volume for critically ill patients with enteral nutrition necessary? A meta-analysis and systematic review.

BACKGROUND: There are many controversies over the necessity of monitoring gastric residual volume in the nursing care of enteral nutrition. We aimed to conduct an updated meta-analysis to evaluate the effects of monitoring or not monitoring gastric residual volume on patients' outcomes and complications. METHODS: We searched the Cochrane Library database to 15 April 2021 for randomized controlled trials (RCTs) on the effects of gastric residual volume and no gastric residual volume monitoring. Review Manager software was used for data analysis. RESULTS: A total of seven RCTs involving 1240 enteral nutrition patients were included. Gastric residual volume monitoring was associated with reduced incidence of vomiting (OR2.33, 95% CI:1.68-3.24), whereas no gastric residual volume monitoring was associated with reduced incidence of unnecessary interruptions of enteral nutrition (OR0.38,95% CI:0.26-0.55). There were no significant differences on the incidence of abdominal distention (OR1.87, 95% CI:0.82-4.28), diarrhoea (OR1.03,95% CI:0.74-1.43), VAP (OR0.83, 95%CI:0.37-1.89), duration of mechanical ventilation (MD -0.06,95% CI:-1.22-1.10), length of ICU stay (MD -1.33, 95% CI:-3.58-0.91) and mortality (OR0.90,95% CI:0.61-1.34). CONCLUSIONS: Not monitoring gastric residual volume is associated with reduced unnecessary interruptions of enteral nutrition related to inadequate feeding and increased risk of vomiting.

Urine Residual Volume in Normal Dogs Determined by Direct Measurement and Comparison to Two-Dimensional Ultrasonographic Measurement.

Normal urine residual volume (URV) in dogs has not previously been established by direct measurement. Twenty-two client-owned normal healthy dogs (8 female spayed, 12 male castrated, 2 male intact) without history of urinary abnormalities were included. Dogs were walked outside for 5 min to allow for natural voiding, immediately followed by urinary bladder ultrasound and urinary catheterization. The URV was recorded, and the ultrasound images were used to estimate URV for each dog. There was no significant difference between male and female URV; therefore, all data were pooled. With a 90% confidence interval, URV was 0-0.47 mL/kg with a mean URV of 0.21 mL/kg and a median value of 0.175 mL/kg. There was no significant difference between the measured URV and the ultrasound-determined URV. This case series supports previously established normal URV in the dog; however, a reference interval based on a larger population of dogs with further evaluation of body size/weight, sex, and neuter status is recommended to be established for use in clinical setting to differentiate normal urination from urinary retention in patients.

The Effect of Residual Gastric Volume on Body Mass Index, Excess Weight Loss Rate and Metabolic Response after Sleeve Gastrectomy.

BACKGROUND/AIM: To investigate the metabolic response and body mass index reduction according to the remaining stomach volume between 6-12 months after the operation in patients who underwent sleeve gastrectomy surgery for obesity and to determine the relationship between the remaining stomach volume and metabolic improvement. Materials and Methods: Patients underwent sleeve gastrectomy in a single center by the same team and with the same standardized method. Residual gastric volumes were calculated from three-dimensional computed tomography images obtained 6-12 months postoperatively. BMI, excess weight loss (EWL), total cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), very low density lipoprotein (VLDL), triglyceride, hemoglobin A1c (HbA1c), total protein, albumin values were recorded preoperatively and at the time of residual volume measurement. Results: There were 49 subjects with a mean SD preoperative BMI of 47.26+-6.21 kg/m2 and mean age 37.51+-10.88 years. Mean residual volume was 155.36+-56.71 cc. Residual volume was associated with postoperative mean BMI (28.44+-3.23 kg/m2; p 0.001) and postperative mean EWL%(29.27+-7.66; p=0.001). Residual gastric volume was also negative correlated with postoperative mean HbA1c (p=0.004). HbA1c (p=0.828), LDL (p=0.661), HDL (p=0.848), triglycerides (p=0.641), VLDL (p=0.794), total protein relation (p=0.539) and albumin (p=0.824) were analyzed before and after surgery and were not correlated with residual gastric volume. CONCLUSION: The smaller the residual gastric volume after laparoscopic sleeve gastrectomy, the higher the %EWL and the greater the decrease in HbA1c. This study show that laparoscopic sleeve gastrectomy is an effective surgical procedure in patients with Type 2 diabetes mellitus.

Association of gastric residual volumes with necrotising enterocolitis in extremely preterm infants-a case-control study.

Necrotising enterocolitis (NEC) is a potentially serious illness with significant mortality and morbidity in preterm infants. Previous studies have reported association of volume and colour (bile and blood stained) of gastric residuals (GR) with NEC. We aimed to study this association in our cohort of extremely preterm (EP) infants. In a case-control study using retrospective data (January 2006-December 2011), EP (gestation < 28 weeks) infants with confirmed NEC ≥ stage II (cases) were compared with infants without NEC (controls) matched for birth weight (BW) and gestational age (GA). Forty cases of NEC ≥ stage II diagnosed at a median (IQR) age of 16.5 days (10.3-23) were compared with 40 controls matched for gestation (± 3 days) and birth weight (± 680 g). Median maximum GR volume (GRV) from birth to the day of occurrence of NEC was significantly higher in cases vs. controls (5.9 vs.3.7 ml; p < 0.001). Increased maximum GRV was associated with NEC ≥ Stage II in adjusted analysis (aOR 1.36, 95%CI 1.06-1.75, p = 0.017). There was no significant difference in GRV between cases and controls throughout the clinical course, including 72, 48 and 24 h before the onset of NEC. However, green (65.0% vs. 27.5%, p = 0.001) and haemorrhagic GRs (45.0% vs. 27.5%, p = 0.092) were higher 24 h before the diagnosis of NEC.Conclusion: GRV was not associated with NEC ≥ stage II. However, green and haemorrhagic GRs were significantly higher 24 h before the diagnosis of the illness. Adequately powered prospective studies are needed to confirm the significance of our findings. What is Known: •It is unclear whether large volume, dark-coloured and blood-stained GRs are associated with NEC. •The value of routine monitoring of gastric residuals in preterm infants is currently being questioned. What is New: •Volume of gastric residuals was not associated with significant NEC. •Green and haemorrhagic GRs were significantly higher 24 hours before diagnosis of NEC.

Effect of pre-operative oral paracetamol on gastric residual volume and pH in young children in the context of a 1-hour clear fluid fast: a randomised controlled trial.

High gastric residual volume and low pH are associated with increased mortality following pulmonary aspiration in animal studies. The use of pre-operative oral paracetamol has not been investigated in younger children and infants in the context of a prescriptive 1-h clear fluid fast aimed at reducing the risk of pulmonary aspiration while improving patient experience. Children aged 1 month up to a weight of 25 kg and scheduled for elective surgery were randomly allocated to receive a prescribed 3.6 ml.kg-1 drink of water alone (water group) or 3 ml.kg-1 water and oral Infant Calpol® syrup (24 mg.ml-1 concentration, equivalent volume 0.6 ml.kg-1 , paracetamol group) 1 h before the induction of anaesthesia. Following induction, a nasogastric tube was used to aspirate gastric contents and the volume and pH were recorded. Ninety-seven children, median (IQR [range]) age 24 (12-45 [1-96]) months and weight 12.4 (9.7-16.0 [2.9-27.0]) kg, were analysed. Median time from drink to induction was 54 (45-60 [21-113]) min. There was no significant difference in gastric residual volume (p = 1) or pH (p = 0.99) between the water and the paracetamol groups. Sub-group analysis revealed no significant difference in gastric residual volume or pH for 29 children who weighed < 10 kg compared with > 10 kg. Using a prescriptive fluid regime of 3 ml.kg-1 of water, the addition of oral paracetamol syrup did not significantly alter gastric residual volume or pH in the context of a 1-h fast in infants and young children.

Temporal changes in pulmonary gas exchange efficiency when breath-hold diving below residual volume.

NEW FINDINGS: What is the central question of this study? How does deep breath-hold diving impact cardiopulmonary function, both acutely and over the subsequent 2.5 hours post-dive? What is the main finding and its importance? Breath-hold diving, to depths below residual volume, is associated with acute impairments in pulmonary gas exchange, which typically resolve within 2.5 hours. These data provide new insight into the behaviour of the lungs and pulmonary vasculature following deep diving. ABSTRACT: Breath-hold diving involves highly integrative and extreme physiological responses to both exercise and asphyxia during progressive elevations in hydrostatic pressure. Over two diving training camps (Study 1 and 2), 25 breath-hold divers (recreational to world-champion) performed 66 dives to 57 ± 20 m (range: 18-117 m). Using the deepest dive from each diver, temporal changes in cardiopulmonary function were assessed using non-invasive pulmonary gas exchange (indexed via the O2 deficit), ultrasound B-line scores, lung compliance and pulmonary haemodynamics at baseline and following the dive. Hydrostatically induced lung compression was quantified in Study 2, using spirometry and lung volume measurement, enabling each dive to be categorized by its residual volume (RV)-equivalent depth. From both studies, pulmonary gas exchange inefficiency - defined as an increase in O2 deficit - was related to the depth of the dive (r2  = 0.345; P < 0.001), with dives associated with lung squeeze symptoms exhibiting the greatest deficits. In Study 1, although B-lines doubled from baseline (P = 0.027), cardiac output and pulmonary artery systolic pressure were unchanged post-dive. In Study 2, dives with lung compression to ≤RV had higher O2 deficits at 9 min, compared to dives that did not exceed RV (24 ± 25 vs. 5 ± 8 mmHg; P = 0.021). The physiological significance of a small increase in estimated lung compliance post-dive (via decreased and increased/unaltered airway resistance and reactance, respectively) remains equivocal. Following deep dives, the current study highlights an integrated link between hydrostatically induced lung compression and transient impairments in pulmonary gas exchange efficiency.

A guide to enteral nutrition in intensive care units: 10 expert tips for the daily practice.

The preferential use of the oral/enteral route in critically ill patients over gut rest is uniformly recommended and applied. This article provides practical guidance on enteral nutrition in compliance with recent American and European guidelines. Low-dose enteral nutrition can be safely started within 48 h after admission, even during treatment with small or moderate doses of vasopressor agents. A percutaneous access should be used when enteral nutrition is anticipated for ≥ 4 weeks. Energy delivery should not be calculated to match energy expenditure before day 4-7, and the use of energy-dense formulas can be restricted to cases of inability to tolerate full-volume isocaloric enteral nutrition or to patients who require fluid restriction. Low-dose protein (max 0.8 g/kg/day) can be provided during the early phase of critical illness, while a protein target of > 1.2 g/kg/day could be considered during the rehabilitation phase. The occurrence of refeeding syndrome should be assessed by daily measurement of plasma phosphate, and a phosphate drop of 30% should be managed by reduction of enteral feeding rate and high-dose thiamine. Vomiting and increased gastric residual volume may indicate gastric intolerance, while sudden abdominal pain, distension, gastrointestinal paralysis, or rising abdominal pressure may indicate lower gastrointestinal intolerance.

Interventional bronchoscopy for chronic obstructive pulmonary disease: more than a pipe dream.

Endoscopic lung volume reduction (ELVR) is recognised in both national and international expert guidelines as one of the few additive treatments to benefit patients with advanced chronic obstructive pulmonary disease (COPD) who are otherwise receiving optimal medical and supportive care. Despite these recommendations and a growing evidence base, these procedures are not widely offered across Australia and New Zealand, and general practitioner and physician awareness of this therapy can be improved. ELVR aims to mitigate the impact of hyperinflation and gas trapping on dyspnoea and exercise intolerance in COPD. Effective ELVR is of proven benefit in improving symptoms, quality of life, lung function and survival. Several endoscopic techniques to achieve ELVR have been developed, with endobronchial valve placement to collapse a single lobe being the most widely studied and commonly practised. This review describes the physiological rationale underpinning lung volume reduction, highlights the challenges of patient selection, and provides an overview of the evidence for current and investigational endoscopic interventions for COPD.

Monitoring of gastric residual volume during enteral nutrition.

BACKGROUND: The main goal of enteral nutrition (EN) is to manage malnutrition in order to improve clinical outcomes. However, EN may increase the risks of vomiting or aspiration pneumonia during gastrointestinal dysfunction. Consequently, monitoring of gastric residual volume (GRV), that is, to measure GRV periodically and modulate the speed of enteral feeding according to GRV, has been recommended as a management goal in many intensive care units. Yet, there is a lack of robust evidence that GRV monitoring reduces the level of complications during EN. The best protocol of GRV monitoring is currently unknown, and thus the precise efficacy and safety profiles of GRV monitoring remain to be ascertained. OBJECTIVES: To investigate the efficacy and safety of GRV monitoring during EN. SEARCH METHODS: We searched electronic databases including CENTRAL, MEDLINE, Embase, and CINAHL for relevant studies on 3 May 2021. We also checked reference lists of included studies for additional information and contacted experts in the field. SELECTION CRITERIA: We included randomized controlled trials (RCTs), randomized cross-over trials, and cluster-RCTs investigating the effects of GRV monitoring during EN. We imposed no restrictions on the language of publication. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the search results for eligible studies and extracted trial-level information from each included study, including methodology and design, characteristics of study participants, interventions, and outcome measures. We assessed risk of bias for each study using Cochrane's risk of bias tool. We followed guidance from the GRADE framework to assess the overall certainty of evidence across outcomes. We used a random-effects analytical model to perform quantitative synthesis of the evidence. We calculated risk ratios (RRs) with 95% confidence intervals (CIs) for dichotomous and mean difference (MD) with 95% CIs for continuous outcomes. MAIN RESULTS: We included eight studies involving 1585 participants. All studies were RCTs conducted in ICU settings. Two studies (417 participants) compared less-frequent (less than eight hours) monitoring of GRV against a regimen of more-frequent (eight hours or greater) monitoring. The evidence is very uncertain about the effect of frequent monitoring of GRV on mortality rate (RR 0.91, 95% CI 0.60 to 1.37; I² = 8%; very low-certainty evidence), incidence of pneumonia (RR 1.08, 95% CI 0.64 to 1.83; heterogeneity not applicable; very low-certainty evidence), length of hospital stay (MD 2.00 days, 95% CI -2.15 to 6.15; heterogeneity not applicable; very low-certainty evidence), and incidence of vomiting (RR 0.14, 95% CI 0.02 to 1.09; heterogeneity not applicable; very low-certainty evidence). Two studies (500 participants) compared no GRV monitoring with frequent (12 hours or less) monitoring. Similarly, the evidence is very uncertain about the effect of no monitoring of GRV on mortality rate (RR 0.87, 95% CI 0.62 to 1.23; I² = 51%; very low-certainty evidence), incidence of pneumonia (RR 0.70, 95% CI 0.43 to 1.13; heterogeneity not applicable; very low-certainty evidence), length of hospital stay (MD -1.53 days, 95% CI -4.47 to 1.40; I² = 0%; very low-certainty evidence), and incidence of vomiting (RR 1.47, 95% CI 1.13 to 1.93; I² = 0%; very low-certainty evidence). One study (322 participants) assessed the impact of GRV threshold (500 mL per six hours) on clinical outcomes. The evidence is very uncertain about the effect of the threshold for GRV at time of aspiration on mortality rate (RR 1.01, 95% CI 0.74 to 1.38; heterogeneity not applicable; very low-certainty evidence), incidence of pneumonia (RR 1.03, 95% CI 0.72 to 1.46; heterogeneity not applicable; very low-certainty evidence), and length of hospital stay (MD -0.90 days, 95% CI -2.60 to 4.40; heterogeneity not applicable; very low-certainty evidence). Two studies (140 participants) explored the effects of returning or discarding the aspirated/drained GRV. The evidence is uncertain about the effect of discarding or returning the aspirated/drained GRV on the incidence of vomiting (RR 1.00, 95% CI 0.06 to 15.63; heterogeneity not applicable; very low-certainty evidence) and volume aspirated from the stomach (MD -7.30 mL, 95% CI -26.67 to 12.06, I² = 0%; very low-certainty evidence) We found no studies comparing the effects of protocol-based EN strategies that included GRV-related criteria against strategies that did not include such criteria. AUTHORS' CONCLUSIONS: The evidence is very uncertain about the effect of GRV on clinical outcomes including mortality, pneumonia, vomiting, and length of hospital stay.

Identifying Responders and Exploring Mechanisms of Action of the Endobronchial Coil Treatment for Emphysema.

BACKGROUND: So far, 3 randomized controlled trials have shown that the endobronchial treatment using coils is safe and effective. However, the more exact underlying mechanism of the treatment and best predictors of response are unknown. OBJECTIVES: The aim of the study was to gain more knowledge about the underlying physiological mechanism of the lung volume reduction coil treatment and to identify potential predictors of response to this treatment. METHODS: This was a prospective nonrandomized single-center study which included patients who were bilaterally treated with coils. Patients underwent an extensive number of physical tests at baseline and 3 months after treatment. RESULTS: Twenty-four patients (29% male, mean age 62 years, forced expiratory volume in 1 s [FEV1] 26% pred, residual volume (RV) 231% pred) were included. Three months after treatment, significant improvements were found in spirometry, static hyperinflation, air trapping, airway resistance, treated lobe RV and treated lobes air trapping measured on CT scan, exercise capacity, and quality of life. The change in RV and airway resistance was significantly associated with a change in FEV1, forced vital capacity, air trapping, maximal expiratory pressure, dynamic compliance, and dynamic hyperinflation. Predictors of treatment response at baseline were a higher RV, larger air trapping, higher emphysema score in the treated lobes, and a lower physical activity level. CONCLUSIONS: Our results confirm that emphysema patients benefit from endobronchial coil treatment. The primary mechanism of action is decreasing static hyperinflation with improvement of airway resistance which consequently changes dynamic lung mechanics. However, the right patient population needs to be selected for the treatment to be beneficial which should include patients with severe lung hyperinflation, severe air trapping, and significant emphysema in target lobes.

Air Trapping Is Associated with Heterozygosity for Alpha-1 Antitrypsin Mutations in Patients with Asthma.

BACKGROUND: Alpha-1 antitrypsin deficiency (AATD) is a hereditary disorder involving lungs, characterized by low serum concentration of the protein alpha-1 antitrypsin (AAT) also called proteinase inhibitor (PI). Asthma is common in AATD patients, but there are only few data on respiratory function in asthmatic patients with AATD. OBJECTIVES: The aim of the study was to evaluate lung function in asthmatic outpatients with mutation in the SERPINA1 gene coding for AAT versus asthmatic subjects without mutation. METHODS: We performed the quantitative analysis of the serum concentration of AAT in 600 outpatients affected by mild to moderate asthma from the University Hospital of Parma, Italy. Fifty-seven of them underwent the genetic analysis subsequently; they were subdivided into mutated and non-mutated subjects. All the mutated patients had a heterozygous genotype, except 1 (PI*SS). We assessed the lung function through a flow-sensing spirometer and the small airway parameters through an impulse oscillometry system. RESULTS: The values of forced vital capacity (% predicted) and those of the residual volume to total lung capacity ratio (%) were, respectively, lower and higher in patients mutated versus patients without mutation, showing a significantly greater air trapping (p = 0.014 and p = 0.017, respectively). Moreover, patients with mutation in comparison to patients without mutation showed lower forced expiratory volume in 3 s (% predicted) and forced expiratory volume in 6 s (L) spirometric values, reflecting a smaller airways contribution. CONCLUSIONS: In asthmatic patients, heterozygosity for AAT with PI*MZ and PI*MS genotypes was associated with small airway dysfunction and with lung air trapping.

Pneumothorax in Patients with Idiopathic Pleuroparenchymal Fibroelastosis: Incidence, Clinical Features, and Risk Factors.

BACKGROUND: Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a rare form of idiopathic interstitial pneumonia that is characterized by predominantly upper lobe pleural and subpleural lung parenchymal fibrosis. Pneumothorax is one of the major respiratory complications in PPFE patients; however, its clinical features are poorly understood. OBJECTIVE: We aimed to investigate the complication of pneumothorax in patients with idiopathic PPFE. METHODS: A retrospective multicenter study involving 89 patients who had been diagnosed with idiopathic PPFE was conducted. We investigated the cumulative incidence, clinical features, and risk factors of pneumothorax after the diagnosis of idiopathic PPFE. RESULTS: Pneumothorax developed in 53 patients (59.6%) with 120 events during the observation period (41.8 ± 35.0 months). The cumulative incidence of pneumothorax was 24.8, 44.9, and 53.9% at 1, 2, and 3 years, respectively. Most events of pneumothorax were asymptomatic (n = 85; 70.8%) and small in size (n = 92; 76.7%); 30 patients (56.6%) had recurrent pneumothorax. Chest drainage was required in 23 pneumothorax events (19.2%), and a persistent air leak was observed in 13 (56.5%). Patients with pneumothorax were predominantly male and frequently had pathological diagnoses of PPFE and prior history of pneumothorax and corticosteroid use; they also had significantly poorer survival than those without pneumothorax (log-rank test; p = 0.001). Multivariate analysis revealed that a higher residual volume/total lung capacity ratio was significantly associated with the development of pneumothorax after the diagnosis. CONCLUSION: Pneumothorax is often asymptomatic and recurrent in patients with idiopathic PPFE, leading to poor outcomes in some cases.

Residual respiratory impairment after COVID-19 pneumonia.

INTRODUCTION: The novel coronavirus SARS-Cov-2 can infect the respiratory tract causing a spectrum of disease varying from mild to fatal pneumonia, and known as COVID-19. Ongoing clinical research is assessing the potential for long-term respiratory sequelae in these patients. We assessed the respiratory function in a cohort of patients after recovering from SARS-Cov-2 infection, stratified according to PaO2/FiO2 (p/F) values. METHOD: Approximately one month after hospital discharge, 86 COVID-19 patients underwent physical examination, arterial blood gas (ABG) analysis, pulmonary function tests (PFTs), and six-minute walk test (6MWT). Patients were also asked to quantify the severity of dyspnoea and cough before, during, and after hospitalization using a visual analogic scale (VAS). Seventy-six subjects with ABG during hospitalization were stratified in three groups according to their worst p/F values: above 300 (n = 38), between 200 and 300 (n = 30) and below 200 (n = 20). RESULTS: On PFTs, lung volumes were overall preserved yet, mean percent predicted residual volume was slightly reduced (74.8 ± 18.1%). Percent predicted diffusing capacity for carbon monoxide (DLCO) was also mildly reduced (77.2 ± 16.5%). Patients reported residual breathlessness at the time of the visit (VAS 19.8, p < 0.001). Patients with p/F below 200 during hospitalization had lower percent predicted forced vital capacity (p = 0.005), lower percent predicted total lung capacity (p = 0.012), lower DLCO (p < 0.001) and shorter 6MWT distance (p = 0.004) than patients with higher p/F. CONCLUSION: Approximately one month after hospital discharge, patients with COVID-19 can have residual respiratory impairment, including lower exercise tolerance. The extent of this impairment seems to correlate with the severity of respiratory failure during hospitalization.

The effects of residual parotid volume on symptom-specific quality of life and complications in patients undergoing parotid surgery.

PURPOSE: To measure postoperative residual parotid volumes in parotidectomy patients and to measure the effect of residual parotid volumes on the symptom-specific quality of life (SSQOL) and complications. METHODS: Between January 2010 and December 2016, 148 parotid gland surgeries were performed, and 74 patients were included in the study. Bilateral parotid gland volumes were measured by Magnetic Resonance Imaging (MRI). Parotidectomy Outcome Inventory-8 and aesthetic scale questionnaire were applied to the patients. The volumetric averages obtained were compared with the questions in the SSQOL scale, the aesthetic scale data, and complications. RESULTS: In the volumetric examination performed with MRI, the mean residual volumes of the operated parotid glands were 9.5 cm3, while the non-operated side was 28.8 cm3. The width of the surgery and the residual parotid tissue volume was inversely correlated. There was a statistically significant difference between the residual parotid gland volume and the pain related to the surgical area, depression in the surgical site, Frey's syndrome, incision scar, and numbness. As the residual parotid gland volumes decreased, the patients' cosmetic problems related to the surgical field increased significantly, and their SSQOL decreased. CONCLUSION: Postoperative residual parotid tissue volume could be an objective parameter to measure patients' SSQOL and complications. After parotidectomy, the maximum amount of disease-free tissue of the parotid gland should be left in place to increase patients' quality of life and minimize complications.