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.

Estimation of urinary volume through ultrasonography in dog cadavers and experimental models.

The urinary volume and residual urine volume are pieces of information that can provide relevant clinical data for dogs and cats, especially those hospitalized. Thus, the present study aimed to evaluate mathematical formulas described in human and veterinary literature to estimate urinary volume in dogs and experimental models. For this purpose, nine male dog cadavers and twelve experimental models were used to evaluate residual volume, small, medium, and large, using three different formulas. Data were obtained by three different examiners: two ultrasonographers and one nonultrasonographer. Each examiner recorded three longitudinal and transverse images, obtaining measurements of width, length, and height at each proposed volume. The measurements were then averaged, and the result was added to the formulas, thus estimating urinary volume. All three formulas achieved higher accuracy in estimating smaller volumes, with a gradual decrease as urinary volume increased. The error of all formulas was less than 10%, even when compared with evaluations in experimental models and dogs. There was variation in estimation between ultrasonographers and nonultrasonographer examiners; however, this variation was low, allowing for the assertion that both can apply the technique. Thus, it is concluded that estimating urinary bladder volume using mathematical formulas and 2D ultrasound is accurate and, therefore, an alternative and viable option for evaluating the urinary tract.

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.

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.

Assessment of Gastric Residual Volume with Ultrasound in Children at Fasting and after Oral Intake of Carbohydrate-Rich Fluid in the Preoperative Period.

Purpose: Despite standard preoperative fasting guidelines, children are subjected to prolonged fasting due to various reasons. This does not reduce gastric residual volume (GRV) further, instead causes hypoglycemia, hypovolemia, and unnecessary discomfort. We calculated the cross-sectional area (CSA) of antrum and GRV in children in fasting state and 2 h after intake of oral carbohydrate-rich fluid, using gastric ultrasound. Methods: Anteroposterior and craniocaudal gastric antral diameters were measured by ultrasonography in the right lateral decubitus position, at fasting and at 2 h after 8 ml/kg of pulp-free fruit juice ingestion. CSA of antrum and GRV was calculated using validated mathematical models. Results: Data of 149 children of age >1-12 years were analyzed. Greater than ninety-nine percent of children emptied ≥95% of the ingested pulp-free fruit juice volume within 2 h. One hundred and seven (71.8%) children had reduced CSA and GRV at 2 h after fruit juice ingestion (2.01 ± 1.00 cm2 and 7.77 ± 6.81 ml) as compared to fasting state (3.18 ± 1.40 cm2 and 11.89 ± 7.80 ml). Fourty-nine (28.2%) children had slightly increased CSA and GRV at 2 h after fruit juice (2.46 ± 1.14 cm2 and 10.61 ± 7.26 ml) than at fasting (1.89 ± 0.92 cm2 and 8.61 ± 6.75 ml), but this increased GRV was grossly lower than limit of risk stomach (26.54 ± 8.95 ml). Conclusion: Carbohydrate-rich drink in the form of pulp-free fruit juice may be safely permitted up to 2 h before anesthetic induction, as it promoted gastric emptying in ≈ 72% of children and 28% of children, although GRV was slightly higher at 2 h after fruit juice ingestion than fasting but remained considerably lower than limit of risk stomach.

Serial Ultrasonographic-measurement of Gastric Residual Volume in Critically Ill Patients for Prediction of Gastric Tube Feed Intolerance: Views.

How to cite this article: Pratyusha K, Jindal A. Serial Ultrasonographic-measurement of Gastric Residual Volume in Critically Ill Patients for Prediction of Gastric Tube Feed Intolerance: Views. Indian J Crit Care Med 2023;27(1):79.

Air pollution enhance the progression of restrictive lung function impairment and diffusion capacity reduction: an elderly cohort study.

BACKGROUND: Some evidences have shown the association between air pollution exposure and the development of interstitial lung diseases. However, the effect of air pollution on the progression of restrictive ventilatory impairment and diffusion capacity reduction is unknown. This study aimed to evaluate the effects of long-term exposure to ambient air pollution on the change rates of total lung capacity, residual volume, and diffusion capacity among the elderly. METHODS: From 2016 to 2018, single-breath helium dilution with the diffusion capacity of carbon monoxide was performed once per year on 543 elderly individuals. Monthly concentrations of ambient fine particulate matters (PM2.5) and nitric dioxide (NO2) at the individual residential address were estimated using a hybrid Kriging/Land-use regression model. Linear mixed models were used to evaluate the association between long-term (12 months) exposure to air pollution and lung function with adjustment for potential covariates, including basic characteristics, indoor air pollution (second-hand smoke, cooking fume, and incense burning), physician diagnosed diseases (asthma and chronic airway diseases), dusty job history, and short-term (lag one month) air pollution exposure. RESULTS: An interquartile range (5.37 ppb) increase in long-term exposure to NO2 was associated with an additional rate of decline in total lung volume (- 1.8% per year, 95% CI: - 2.8 to - 0.9%), residual volume (- 3.3% per year, 95% CI: - 5.0 to - 1.6%), ratio of residual volume to total lung volume (- 1.6% per year, 95% CI: - 2.6 to - 0.5%), and diffusion capacity (- 1.1% per year, 95% CI: - 2.0 to - 0.2%). There is no effect on the transfer factor (ratio of diffusion capacity to alveolar volume). The effect of NO2 remained robust after adjustment for PM2.5 exposure. CONCLUSIONS: Long-term exposure to ambient NO2 is associated with an accelerated decline in static lung volume and diffusion capacity in the elderly. NO2 related air pollution may be a risk factor for restrictive lung disorders.

Large tumour volume reduction of IDH-mutated anaplastic glioma involving the insular region following radiotherapy.

BACKGROUND: The impact of near-total resection of IDH-mutated anaplastic glioma (IDHmutAG) is well-established but there remains uncertainty of benefit in tumours of the insular cortex where the extent of safe resection may be limited. This study aimed to assess tumour volume reduction in patients following IMRT and impact of residual post-surgical volume. METHODS AND MATERIALS: Patients with IDHmutAG involving insular cortex managed with IMRT from 2008 to 2019 had baseline patient, tumour and treatment factors recorded. Volumetric assessment of residual disease on MRI was performed at baseline, month+ 3 and month+ 12 post-IMRT. Potential prognostic factors were analysed for tumour reduction and relapse-free survival, and assessed by log-rank and Cox regression analyses. RESULTS: Thirty two patients with IDHmutAG of the insular cortex were managed with median follow-up post-IMRT of 67.2 months. Pathology was anaplastic astrocytoma (AAmut) in 20, and anaplastic oligodendroglioma (AOD) in 12 patients. Median pre-IMRT volume on T1 and T2Flair was 24.3cm3 and 52.2cm3. Twenty-seven patients were alive with 5-year relapse-free survival of 80%. There was a median 67 and 64% reduction from baseline occurring at 3 months post-IMRT for T1 and T2Flair respectively; and subsequent median 78 and 73% at 12 months. At 12 months AOD patients had median 83% T1 volume reduction compared to 63% in AAmut (p < 0.01). There was no difference on T2Flair volume (p = 0.64). No other pathological factors influenced volume reduction at 12 months. No factors were associated with relapse-free survival including baseline T1 (p = 0.52) and T2Flair (p = 0.93) volume. CONCLUSION: IMRT provides large tumour volume reduction in IDHmutAG of the insular cortex. While maximal safe debulking remains standard of care when feasible, this patient cohort reported no significant negative impact of residual disease volume on relapse-free survival.

Prevalence of urinary retention after vaginal delivery: a systematic review and meta- analysis.

INTRODUCTION AND HYPOTHESIS: Postpartum urinary retention requires timely detection and intervention as late detection can lead to long-term voiding dysfunction; however, trends in the prevalence of urinary retention during the postpartum period remain unclear. This systematic review and meta-analysis aimed to estimate the pooled overall prevalence of overt and covert urinary retention in women after vaginal delivery and the difference in prevalence within 4 days after delivery. METHODS: MEDLINE, CINAHL, Ichu-shi web, and J-stage databases were searched up until October 2020. Two researchers screened and included observational studies reporting the prevalence of urinary retention up to 4 days postpartum based on inclusion criteria. The overall prevalence of overt and covert urinary retention was calculated. RESULTS: From 24 studies, the overall overt and covert urinary retention prevalence rates were estimated to be 1% and 13%, respectively. The prevalence of overt urinary retention over time was 2% at 6 h postpartum, 1% at 6-12 h, and 3% from postpartum to 24 h postpartum. The prevalence of covert urinary retention over time was 19% (6 h postpartum), 15% (24 h postpartum), 11% (1 day postpartum), 7% (2 days postpartum), 8% (3 days postpartum), and 0.1% (4 days postpartum). CONCLUSIONS: By postpartum day 4 after vaginal delivery, 14% of women were found to have experienced urinary retention. The highest prevalence was observed at 6 h postpartum, suggesting that urinary retention could be identified at 6 h postpartum.

Postpartum urinary retention: what are the sequelae? A long-term study and review of the literature.

INTRODUCTION AND HYPOTHESIS: Postpartum urinary retention (PUR) may cause long-term urogenital tract morbidity. The incidence ranges from 0.18 to 14.6%, but the importance of prompt diagnosis and appropriate management is often underappreciated. The paucity of data on long-term outcome after PUR contributes to these drawbacks. The aim of this study was to assess long-term persistence of elevated PVR (post-void residual urine) volume after PUR. Pathophysiology, risk factors and management of PUR are reviewed. METHODS: In our tertiary referral urogynecology unit in the University Women's Hospital of Bern, Switzerland, all patients who were referred for PUR were asked to participate in this study. PVR was measured sonographically every 2 days until day 15, then after 6, 12, 24 and 36 months and, if increased, the patients were instructed to perform clean intermittent self-catheterization. If retention persisted longer than the lactation period, multichannel urodynamics was performed. RESULTS: Sixty-two patients were included. The median PVR normalized at day 7. Long-term voiding disorders were found in 8.2%, 6.7%, and 4.9% after 1, 2, and 3 years respectively. Multichannel urodynamics confirmed in all patients with persisting retention an acontractile detrusor and de novo stress urinary incontinence in 4 cases. Quantile regression did not reveal any factor contributing to earlier recovery. Eighty-nine percent of the patients with PUR had operative vaginal deliveries, emphasizing the importance of this risk factor for PUR. CONCLUSIONS: In most cases PUR resolves early, but voiding difficulties persist more often than previously thought, and for these patients the consequences are devastating. Obstetric awareness, early active management, and developing management strategies in the postpartum period might preclude lower urinary tract morbidity.

Small Airways: Not Just Air Ducts - Pathophysiological Aspects and Clinical Implications.

The airways smaller than 2 mm diameter are named small airways. They are essential for the transport and exchange of oxygen and carbon dioxide and at the same time play a relevant role in pulmonary mechanics, contributing to the subdivision of lung volumes. Measurement of small airway function is, therefore, crucial in patients with respiratory disease. This overview focuses on the physiological aspects of the small airways, considered as air ducts as well as determinants of pulmonary mechanics, the most common tools for evaluating their function and treatment implications.

Impact of sacrocolpopexy for the management of pelvic organ prolapse on voiding dysfunction and uroflowmetry parameters: a prospective cohort study.

PURPOSE: Voiding difficulties in the context of pelvic organ prolapse are often neglected or underestimated. To date, there are heterogeneous data available on the outcome of a surgical correction of pelvic organ prolapse and the impact on concomitant voiding dysfunction. The primary aim of this study was to evaluate whether laparoscopic sacrocolpopexy would resolve preoperative voiding dysfunction and the impact on objective uroflowmetry parameters. METHODS: Data from 103 women undergoing sacrocolpopexy for prolapse stage ≥ II with concurrent objective and/or subjective voiding dysfunction were prospectively evaluated. All women underwent full urogynecological examination, and completed a validated questionnaire pre- and postoperatively. Objective uroflowmetry parameters and subjective outcome data regarding voiding functions were compared pre- and postoperatively. RESULTS: All points of the POP-Q system improved significantly pre- to postoperatively (p < 0.001). Preoperatively, 42 of 103 women showed a postvoid residual ≥ 100 ml, whereas only six women had a relevant postvoid residual postoperatively. In total, the postoperative postvoid residual in all women decreased significantly (p < 0.001). Voiding time decreased significantly postoperatively (p < 0.001) with no significant change in the voided volume (p = 0.352). The maximum flow rate increased postoperatively, reaching no statistically significant change (p = 0.132). Subjective outcome measurements (weak or prolonged stream, incomplete bladder emptying, and straining to void) improved significantly (p < 0.001 for all the questions). CONCLUSION: Our prospective study demonstrates that sacrocolpopexy to correct pelvic organ prolapse can successfully resolve voiding dysfunction, as both objective and subjective parameters improved significantly after surgery.

Evaluation of gastric contents using ultrasound in full-term pregnant women fasted for 8 h: a prospective observational study.

BACKGROUND: We aimed to evaluate the gastric volume and contents after an 8-h fasting period in full-term, non-laboring, pregnant women following a standardized meal. METHODS: In this prospective observational study, we included full-term pregnant women scheduled for elective cesarean delivery. The participants were instructed to fast after a standardized meal (apple juice, bread, and cheese). Participants were scanned in the semi-recumbent and right-lateral positions 8 h after the standardized meal. The primary outcome was the proportion of patients with gastric volume > 1.5 mL kg-1 calculated by two equations. Secondary outcomes included the antral cross-sectional area and gastric volume. Data are expressed as frequency (%, 95% confidence interval [CI]), mean ± standard deviation (95% CI of the mean), or median (quartiles) as appropriate. RESULTS: Forty-one women were available for the final analysis. For the primary outcome, one participant (2.4%, 95% CI of 0.06 to 12.8%) had gastric volume > 1.5 mL kg-1, and none had solids in the antrum. For the secondary outcomes, the mean (95% CI of the mean) of the antral cross-sectional area was 2.11 ± 0.72 (1.88 to 2.34) cm2 and 4.08 ± 1.80 (3.51 to 4.65) cm2 during the semi-recumbent and right-lateral position, respectively. The median (quartiles) gastric volume was 0.53 (0.32, 0.66) mL kg-1 and 0.33 (0.13, 0.52) mL kg-1 as estimated by Perlas et al. and Roukhomovsky et al. equations, respectively. CONCLUSION: After 8-h fasting following a standardized meal, full-term pregnant non-laboring women are less likely to have a high residual gastric volume.

Postpartum voiding dysfunction following vaginal versus caesarean delivery.

In this prospective study, we evaluated postpartum voiding dysfunction stratified by mode of delivery - vaginal delivery versus elective caesarean delivery (CD). We recruited nulliparous women carrying singleton gestation at term admitted to delivery room or elective CD. Pre-labour voiding function was assessed by recording the post-voiding residual volume (PVRV) using a bladder scan. PVRV evaluation was repeated at least 12 hours following delivery and before discharge. PVRVs were considered abnormal if ≥150 mL. PVRVs were compared between vaginal and CD. Overall, 54 women were included. Of them, 34 (63%) delivered vaginally and 20 (37%) had an elective CD. Postpartum mean PVRVs were significantly higher compared to pre-labour PVRVs (215 vs. 133 mL, p<.001). Abnormal postpartum PVRV was significantly higher in vaginal delivery compared to CD (73.5% vs. 45%, p<.05). In conclusion, delivery adversely affects voiding function. Vaginal delivery is associated with more severe voiding dysfunction compared to elective CD.Impact StatementWhat is already known on this subject? Delivery is associated with voiding dysfunction. While most studies on postpartum voiding dysfunction were related to vaginal delivery, little is known on the effect of mode of delivery (vaginal versus caesarean delivery (CD)) on voiding dysfunction.What the results of this study add? In this study, we found that postpartum post-voiding residual volume is significantly higher than the pre-labour PVRV in women delivered vaginally. In addition, postpartum PVRV was significantly higher in women delivered vaginally compared to elective CD.What the implications are of these findings for clinical practice and/or further research? This study implicates that women with vaginal delivery are more prone to voiding dysfunction compared to elective CD. However, larger observational studies are warranted to confirm these results and evaluate whether this difference still exists beyond the post-partum period.

[Preventive Care for Aspiration Pneumonia in Patients With an Indwelling Nasogastric Tube].

More than 190,000 patients have been fitted with an indwelling nasogastric tube in Taiwan. Nasogastric tube feeding is a strategy for temporary or long-term feeding and for preventing aspiration pneumonia in patients with dysphagia. However, aspiration pneumonia is a common complication in patients fitted with a nasogastric tube. Displacement of the nasogastric tube, inappropriate length of the placed nasogastric tube resulting gastroesophageal reflux, inappropriate feeding posture and speed, and excessive gastric residual volume resulting in vomiting are important risk factors associated with aspiration pneumonia. In this article, the literature and clinical practice experiences were reviewed to identify methods used to confirm the length and positioning of nasogastric tubes. We further explored strategies for preventing oral-care and tube-feeding-induced aspiration pneumonia during the period of indwelling nasogastric tube. These strategies included adjusting the patient's positions for receiving tube feedings, feeding techniques, methods and frequency of gastric residual volume measurement, and conditions for stopping nasogastric feeding. This exploration was intended to provide nursing staff with relevant knowledge and skills for preventing aspiration pneumonia in patients with indwelling nasogastric tube to improve patient safety.

Serial Ultrasonographic-measurement of Gastric Residual Volume in Critically Ill Patients for Prediction of Gastric Tube Feed Intolerance.

Objective: To study the use of serial ultrasound gastric residual volume (GRV) measurements in predicting feed intolerance in critically ill patients. Patients and methods: This study was conducted in various intensive care units (ICUs) of All India Institute of Medical Sciences, New Delhi. Forty-three critically ill patients aged more than 18 years were studied for a total of 130 enteral feeding days. Gastric residual volume was obtained by calculating the antral cross-sectional area (CSA), which is the product of anteroposterior (AP) and craniocaudal (CC) diameters of gastric antrum obtained using ultrasound in the right lateral decubitus position. A baseline measurement was done before the initiation of the enteral feed and termed GRV0, the ultrasound scanning was repeated every 1 hour for the first 4 hours and termed GRV1, GRV2, GRV3, and GRV4, respectively, and the patients were watched for feed intolerance. The receiver operating characteristic (ROC) curves were constructed to correlate the GRV at each time with feed intolerance. Results: The data from 43 medical and surgical critically ill patients were analyzed. Out of 130 feeding days, 13 were noted to be feed intolerant. Gastric residual volume at the end of the fourth hour of feed, that is, GRV4 was the best predictor of feed intolerance with 99.3% area under the curve (AUROC), sensitivity of 99%, specificity of 99.3%, and 95% CI, 0.89-0.98 followed by GRV3, with AUROC of 96% and sensitivity and specificity of 92.3 and 96%, respectively, with 95% CI, 0.92-0.99. How to cite this article: Ankalagi B, Singh PM, Rewari V, Ramachandran R, Aggarwal R, Soni KD, et al. Serial Ultrasonographic-measurement of Gastric Residual Volume in Critically Ill Patients for Prediction of Gastric Tube Feed Intolerance. Indian J Crit Care Med 2022;26(9):987-992.

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.

The efficacy and safety of itopride in feeding intolerance of critically ill patients receiving enteral nutrition: a randomized, double-blind study.

BACKGROUND: Enteral feeding intolerance (EFI) is a frequent problem in the Intensive care unit (ICU) and is associated with poor clinical outcomes leading to worse prognosis in terms of mortality and ICU stay. Nowadays, prokinetic drugs are the mainstay of therapy in EFI. However, available prokinetics have uncertain efficacy and safety profiles. Itopride, is a prokinetic agent which is different and unique from the available prokinetics because of its dual mode of action as well as its tolerability and safety. The current study compared the efficacy and safety of Itopride against metoclopramide for EFI in critically ill patients. Moreover, it tested the utility and applicability of ultrasonography to measure gastric residual volume (GRV) in this population. METHODS: This randomized, double-blind study included 76 EFI patients who were randomly assigned to either Itopride or metoclopramide group. The primary outcome was to measure GRV by ultrasonography. Secondary outcomes included the percentage ratio of enteral feed volume, energy and protein received by patients over 7 days of treatment, ICU length of stay, safety parameters and occurrence of infectious complications or vomiting. RESULTS: Thirty-five patients of each group completed the study. At day 7, itopride significantly decreased GRV compared with metoclopramide group (p = 0.001). Moreover, there was a significant increase in the ratios of received enteral nutrition feed volume, calories, and protein after the one-week therapy in the itopride group more than the metoclopramide group (p = 0.001), (p = 0.002), (p = 0.01), respectively and there were no differences in any secondary outcomes or adverse events between the two groups. CONCLUSION: In critically ill patients with EFI, itopride was well tolerated with superior efficacy to metoclopramide. In addition, we demonstrated that ultrasonography is a simple, non-invasive, inexpensive, and undemanding method for GRV measurements and can offer reliable assessments in the gastric emptying modality. TRIAL REGISTRATION: The trial was registered in ClinicalTrials.gov (NCT03698292). Date: October 5, 2018.

Endobronchial Valve (Zephyr) Treatment in Homogeneous Emphysema: One-Year Results from the IMPACT Randomized Clinical Trial.

RATIONALE: The long-term safety and effectiveness of bronchoscopic lung volume reduction with Zephyr endobronchial valves in subjects with severe homogeneous emphysema with little to no collateral ventilation beyond 3 months have yet to be established. METHODS: Ninety-three subjects were randomized to either bronchoscopic lung volume reduction with Zephyr valves or standard of care (SoC) (1:1). Zephyr valve subjects were assessed at 3, 6, and 12 months. SoC subjects were assessed at 3 and 6 months; they were then offered crossover to Zephyr valve treatment. RESULTS: The mean group difference (Zephyr valve - SoC) for change in FEV1 from baseline to 6 months was 16.3 ± 22.1% (mean ± SD; p < 0.001). Secondary outcomes showed the mean between-group difference for the six-minute walk distance of +28.3 ± 55.3 m (p = 0.016); St. George's Respiratory Questionnaire, -7.51 ± 9.56 points (p < 0.001); modified Medical Research Council, -0.42 ± 0.81 points (p = 0.019); BODE index, -0.85 ± 1.39 points (p = 0.006); and residual volume of -430 ± 830 mL (p = 0.011) in favor of the Zephyr valve group. At 6 months, there were significantly more responders based on the minimal clinically important difference for these same measures in the Zephyr valve versus the SoC group. The clinical benefits were persistent at 12 months. The percentage of subjects with respiratory serious adverse events was higher in the Zephyr valve group compared to SoC during the first 30 days post-procedure but not statistically different for the Zephyr valve and SoC groups from 31 days to 6 months, and stable in the Zephyr valve group out to 12 months. There were 2 deaths in the SoC group in the 31-day to 6-month period and none in the Zephyr valve group out to 12 months. CONCLUSIONS: Bronchoscopic lung volume reduction with Zephyr valves in subjects with severe homogeneous emphysema and little to no collateral ventilation provides clinically meaningful change from baseline in lung function, quality of life, exercise capacity, dyspnea, and the BODE index at 6 months, with benefits maintained out to 12 months.