Diaphragmatic Thickening Fraction Research Articles

Abstract No.: ABS1330: A prospective observational study on ultra-sound of the diaphragm in weaning mechanically ventilated patients

Background and Aims:Weaning mechanically ventilated patients is a challenging task in the intensive care unit. Rapid shallow breathing index (RSBI) is a known weaning index to guide extubation. The aim of our study was to determine the use of diaphragm ultra-sound in weaning these patients.Methods:After obtaining ethics committee approval and Clinical Trials Registry India registration, this prospective study was performed on 200 patients on mechanical ventilation for more than 24 hours. After meeting clinical weaning criteria, spontaneous breathing trial (SBT) was performed for 1 hour to assess weaning and then trachea was extubated. Independent observers recorded RSBI and performed bedside ultra-sound of the diaphragm before extubation to measure diaphragm thickening fraction (DTF) and diaphragmatic excursion (DE). We assessed the predictability of weaning success with DTF and DE. Weaning failure was defined as the requirement of non-invasive ventilation or re-intubation within 48 h.Results:One hundred and seventy one patients out of 200 were successfully weaned. The area under the receiver operating characteristic curve (AUROC) values for RSBI, DTF, and DE for successful weaning prediction were 0.422, 0.654, and 0.809, respectively. The predictability using cut-off values were RSBI <82 (sensitivity 94%, specificity 31%, Youden’s index 0.25), DTF >37% (sensitivity 80%, specificity 52%, Youden’s index 0.31), and DE >1.21 cm (sensitivity 94%, specificity 71%, Youden’s index 0.65). The AUROC values for the combination of RSBI–DTF and RSBI–DE were 0.656 and 0.807, respectively.Conclusion:Diaphragm ultra-sound helps in determining weaning readiness in mechanically ventilated patients. Both DTF and DE showed a higher specificity than RSBI, and the combination of RSBI–DE and RSBI–DTF further increased the specificity in successful weaning.ParameterCut off rangeSensitivity %Specificity %PPV %NPV %Youden’s IndexAUROCRSBI<8294.031.089.045.00.250.422DTF (%)>37%79.551.790.730.00.310.654DE (cm)>1.2193.671.495.264.50.650.809RSBI-DTF> 0.85466.769.092.726.00.360.656RSBI-DE>0.73893.071.495.262.50.640.807

8: Ultrasonographic assessment of diaphragmatic parameters for predicting weaning outcome in patients on mechanical ventilation in the intensive care unit setting.

Background and Aims:The aim of this study was to ultrasonographically assess diaphragmatic parameters for predicting weaning outcome in patients on mechanical ventilation in the intensive care unit ( ICU ) setting. The primary objective was to assess the diagnostic accuracy of diaphragmatic excursion(DE) and diaphragmatic thickness fraction(DTF) by ultrasonography to predict weaning outcome in patients on mechanical ventilation. The secondary objectives were: To correlate diaphragmatic dysfunction with re-intubation within 48 hours of extubationTo assess which of the two - DE) or DTF is a better predictor of weaning.To compare diaphragmatic rapid shallow breathing index (RSBI) with clinical RSBI. Methods:This cohort study was conducted on 50 adult patients of either sex, admitted in the ICU and scheduled to undergo extubation. The patient’s readiness to wean was assessed by clinical judgment. When the patient was ready to be weaned, he/she was put on pressure support ventilation (PSV). The pressure support was gradually reduced to 6cm H2O. If the patient remained stable and extubation was planned, T-piece trial was given. Baseline parameters (Heart rate, non invasive blood pressure, respiratory rate, tidal volume, RSBI, SpO2, signs of respiratory distress- nasal flaring, sweating, agitation, use of accessory muscles,arterial blood gas analysis, Maximum Inspiratory Pressure (MIP), Maximum Expiratory Pressure(MEP) were recorded.Results:DE and DTF were assessed ultrasonographically and diaphragmatic RSBI was later calculated. DE andDTF were found to have similar sensitivity (94.12% and 97.06%), specificity (75%), positive predictive values(88.89 and 88.19% respectively) and negative predictive values (85.71% and 92.31% respectively). Overall DTF was comparable to DE in terms of diagnostic accuracy (88% and 90% respectively). (p value=1)Conclusion:DE and DTF are rapid and non invasive ultrasonographic indices with a high diagnostic accuracy for predicting weaning outcome. They provide objective and accurate results and are comparable to each other for predicting weaning outcome. Diaphragmatic RSBI is a good predictor of weaning outcome and is comparable to clinical RSBI.Weaning outcomeDiaphragmatic excursion (mm)Diaphragmatic thickness fraction (%)Sensitivity (95% CI)94.12% (80.32%-99.28%)97.06% (84.67%-99.93%)Specificity (95% CI)75% (47.62%-92.73%)75% (47.62%-92.73%)AUC (95% CI)0.85 (0.72-0.93)0.86 (0.73-0.94)Positive Predictive Value (95% CI)88.89% (73.94%-96.89%)89.19% (74.58%-96.97%)Negative Predictive Value (95% CI)85.71% (57.19%-98.22%)92.31% (63.97%-99.81%)Diagnostic accuracy88.00%90.00%P after Comparison of sensitivity1P after Comparison of specificity1

14: Ultrasonography of the diaphragm to predict successful extubation

Background and Aims:Successful weaning from mechanical ventilation and extubation is always a challenge to an intensivist because, both prolonged ventilation and premature extubation are associated with various complications. Prolonged mechanical ventilation is associated with complications such as ventilation associated pneumonia, barotrauma, and atrophy of respiratory muscles.Premature extubation can result in hypoxia, hypercarbia and increased respiratory and cardiac distress. For optimal functioning of the diaphragm, the primary muscle of inspiration, it is important to resume spontaneous ventilation after extubation irrespective of the cause for respiratory failure.Currently, ultrasonography measurement has been studied to predict the success of extubation along with other standard extubation protocols. The study objectives were :1. To measure the diaphragmatic thickening fraction (dTF) and diaphragmatic excursion (DE) before and after spontaneous breathing trial (SBT).2.To compare dTF and DE with standard extubation criteria in predicting extubation outcome.Methods:This was a prospective, double blind observational study. Number of patients was 41. Informed consent was taken from the patients’ attenders..Results:We observed that 68% of the patients with normal dTF and DE values were extubated successfully, 19% were still extubated successfully with slightly lower values of dTF and DE and 9% of patients were reintubated with normal dTF and DE values.Conclusion:We concluded that 68% of cases for dTF>35% and DE >1cm were successfully extubated along with standard parameters.ObservationPrior to PSPrior to extubationDifference t P 1st - DE1.68±0.411.81±0.27-0.127-2.4580.018*2nd - DE1.61±0.311.84±0.30-0.225-0.6630.5113rd - DE1.61±0.351.85±0.27-0.2354.575<0.001**Average - DE1.63±0.331.83±0.26-0.1971.6570.1051st - dTF57.30±26.0262.86±24.71-5.561-1.4080.1672nd - dTF57.00±19.8662.67±18.52-5.676-1.8500.072+3rd - dTF55.52±21.9666.22±17.14-10.700-3.7420.001**Average - dTF54.96±17.9463.87±17.70-8.908-3.7180.001**

Ultrasound-assessed diaphragmatic dysfunction as a predictor of weaning outcome in mechanically ventilated patients with sepsis in intensive care unit

BackgroundWeaning from mechanical ventilation is one of the most common challenges in the intensive care unit (ICU). Most of predictive indices of weaning from mechanical ventilation are often inaccurate. This study was performed to assess the accuracy of diaphragmatic ultrasonography for predicting weaning outcome in mechanically ventilated patients with sepsis in ICU.ResultsSixty patients with sepsis in medical ICU were prospectively enrolled. All patients were ventilated in pressure support. Patients underwent a spontaneous breathing trial (SBT) on T-piece when they met all the following criteria: FiO2 < 0.6, PEEP ≤5 cmH2O, PaO2/FiO2 > 200, respiratory rate <30 breaths per minute, absence of fever, alert and cooperative, hemodynamic stability without or with low-dose vasoactive therapy support, and rapid shallow breathing index (RSBI)<105. During the trial, the patient was instructed to perform deep breathing to total lung capacity (TLC) and then exhaling to residual volume (RV) and the diaphragm was visualized in the 8th or 9th intercostal space between anterior and mid-axillary lines using a 3–5-MHz curved ultrasound probe to measure diaphragmatic excursion (DE) and a 7–11-MHz linear ultrasound probe to measure diaphragmatic thickness (DT) at TLC and RV, and the diaphragmatic thickness fraction (DTF) was calculated as percentage from the following formula (thickness at end inspiration—thickness at end expiration)/thickness at end expiration. According to weaning outcome, patients were divided into 2 groups: successful weaning group and weaning failure group. Weaning failure was defined as the inability to maintain spontaneous breathing for at least 48 h, without any form of ventilatory support.In the present study, right DTF of more than 37% and DE during deep breathing of more than 6.1 and 5.4 cm on the Rt and Lt side, respectively, were associated with successful weaning from MV. In the study, the sensitivities for right and left DE and DTF were 58.33, 62.5, and 58.33%, respectively, and the pooled specificities were 83.33, 83.33, and 100%, respectively, with p value = 0.032, 0.028, and 0.001, respectively. The area under curve (AUC) for Rt, Lt DE, and DTF were 0.701, 0.712, and 0.840, respectively. The present data indicate a satisfactory diagnostic accuracy in predicting extubation outcome.ConclusionsUltrasonography-based determination of diaphragm function by assessing DTF and DE can be used as predictor of weaning outcome in mechanically ventilated patients with sepsis.

Randomized Clinical Study of Temporary Transvenous Phrenic Nerve Stimulation in Difficult-to-Wean Patients.

Rationale: Diaphragm dysfunction is frequently observed in critically ill patients with difficult weaning from mechanical ventilation. Objectives: To evaluate the effects of temporary transvenous diaphragm neurostimulation on weaning outcome and maximal inspiratory pressure. Methods: Multicenter, open-label, randomized, controlled study. Patients aged ⩾18 years on invasive mechanical ventilation for ⩾4 days and having failed at least two weaning attempts received temporary transvenous diaphragm neurostimulation using a multielectrode stimulating central venous catheter (bilateral phrenic stimulation) and standard of care (treatment) (n = 57) or standard of care (control) (n = 55). In seven patients, the catheter could not be inserted, and in seven others, pacing therapy could not be delivered; consequently, data were available for 43 patients. The primary outcome was the proportion of patients successfully weaned. Other endpoints were mechanical ventilation duration, 30-day survival, maximal inspiratory pressure, diaphragm-thickening fraction, adverse events, and stimulation-related pain. Measurements and Main Results: The incidences of successful weaning were 82% (treatment) and 74% (control) (absolute difference [95% confidence interval (CI)], 7% [-10 to 25]), P = 0.59. Mechanical ventilation duration (mean ± SD) was 12.7 ± 9.9 days and 14.1 ± 10.8 days, respectively, P = 0.50; maximal inspiratory pressure increased by 16.6 cm H2O and 4.8 cm H2O, respectively (difference [95% CI], 11.8 [5 to 19]), P = 0.001; and right hemidiaphragm thickening fraction during unassisted spontaneous breathing was +17% and -14%, respectively, P = 0.006, without correlation with changes in maximal inspiratory pressure. Serious adverse event frequency was similar in both groups. Median stimulation-related pain in the treatment group was 0 (no pain). Conclusions: Temporary transvenous diaphragm neurostimulation did not increase the proportion of successful weaning from mechanical ventilation. It was associated with a significant increase in maximal inspiratory pressure, suggesting reversal of the course of diaphragm dysfunction. Clinical trial registered with www.clinicaltrials.gov (NCT03096639) and the European Database on Medical Devices (CIV-17-06-020004).

Diaphragm ultrasound as a better predictor of successful extubation from mechanical ventilation than rapid shallow breathing index.

BackgroundIn 3%–19% of patients, reintubation is needed 48–72 hours following extubation, which increases intensive care unit (ICU) morbidity, mortality, and expenses. Extubation failure is frequently caused by diaphragm dysfunction. Ultrasonography can be used to determine the mobility and thickness of the diaphragm. This study looked at the role of diaphragm excursion (DE) and thickening fraction in predicting successful extubation from mechanical ventilation.MethodsThirty-one patients were extubated with the advice of an ICU consultant using the ICU weaning regimen and diaphragm ultrasonography was performed. Ultrasound DE and thickening fraction were measured three times: at the commencement of the T-piece experiment, at 10 minutes, and immediately before extubation. All patients' parameters were monitored for 48 hours after extubation. Rapid shallow breathing index (RSBI) was also measured at the same time.ResultsSuccessful extubation was significantly correlated with DE (P<0.001). Receiver curve analysis for DE to predict successful extubation revealed good properties (area under the curve [AUC], 0.83; P<0.001); sensitivity, 77.8%; specificity, 84.6%; positive predictive value (PPV), 84.6 %; negative predictive value (NPV), 73.3% while cut-off value, 11.43 mm. Diaphragm thickening fraction (DTF) also revealed moderate curve properties (AUC, 0.69; P=0.06); sensitivity, 61.1%; specificity, 84.6%; PPV, 87.5%; NPV, 61.1% with cut-off value 22.33% although former one was slightly better. RSBI could not reach good receiver operating characteristic value at cut-off points 100 breaths/min/L (AUC, 0.58; P=0.47); sensitivity, 66.7%; specificity, 53.8%; PPV, 66.7%; NPV, 53.8%).ConclusionsTo decrease the rate of reintubation, DE and DTF are better indicators of successful extubation. DE outperforms DTF.

Extubation Failure Prediction by Echography of the Diaphragm After Cardiothoracic Surgery: The EXPEDIA Study.

Successful extubation is difficult to predict. Ultrasound measurement of the diaphragm thickening fraction (DTF) might help predict weaning failure after cardiothoracic surgery. We assessed the predictive performance of diaphragm ultrasound in a derivation cohort of 50 prospectively included cardiothoracic surgery subjects ready for a weaning trial and in a validation cohort of 39 subjects ventilated for ≥ 48 h. DTF was assessed by ultrasound during pressure support ventilation (PSV) then during a T-piece spontaneous breathing trial (SBT). DTF was the percentage change in diaphragm thickness between expiration and inspiration and DTFmax, the higher DTF value of the 2 hemidiaphragms. DTFmax during SBT (static study) and the difference in DTFmax between PSV and SBT (dynamic study) were analyzed. In the derivation cohort, DTFmax during SBT was 25.6 ± 17.3% in subjects with successful extubation and 65.2 ± 17.3% in those with weaning failure (difference 39.7 [95% CI 27.4-51.9], P < .01). During SBT, DTFmax ≥ 50% was associated with weaning failure (area under the receiver operating characteristic curve [AUC] 0.94 ± 0.05). In the dynamic study, a ≥ 40% DTFmax increase was associated with weaning failure (AUC 0.91 ± 0.06). In the validation cohort, DTFmax during SBT was 20.3 ± 17.1% in subjects with successful extubation and 82.0 ± 51.6% in those with weaning failure (difference 61.8 [95% CI 41.6-82.0], P < .01). During SBT, DTFmax ≥ 50% predicted weaning failure (AUC 0.99 ± 0.02). In the dynamic study, a ≥ 40% increase in DTFmax predicted weaning failure (AUC 0.81 ± 0.09). Measuring DTFmax during SBT and the DTFmax change when switching from PSV to SBT may help predict weaning failure after cardiothoracic surgery. The study was registered on ANZCTR. U1111-1180-1999.

Comparison of Ultrasound-based Diaphragmatic Thickness Fraction (DTF) with Rapid Shallow Breathing Index and DTF alone for Predicting Successful Weaning from Mechanical Ventilation: A Randomised Control Trial

Introduction: The timing for weaning from mechanical ventilator support is crucial because both early discontinuation and delayed weaning may lead to increased morbidity and mortality as well as high medical cost. Diaphragmatic Thickness Fraction (DTF), among the various ultrasound-based diaphragmatic measurements, can not only assess the readiness to wean but also predict the simple weaning. The Rapid Shallow Breathing Index (RSBI) or Yang Tobin index is a tool that is used in the weaning of mechanical ventilation. RSBI is the ratio of respiratory rate to tidal volume in litre (RR/VT). Aim: To estimate success of weaning process by using the ultrasound-guided DTF% alone as a weaning predictor, and compare it with the index derived from the combination of both DTF% and RSBI. Materials and Methods: This randomised control study was conducted on 100 patients admitted to Intensive Care Unit (ICU) during one year, from October 2019 to September 2020. When the patients satisfied the weaning criteria, they were given Spontaneous Breathing Trial (SBT). After SBT the ultrasound was done and RSBI were calculated. Composite Index (CI) was derived by combining DTF% and RSBI. Patients were divided in two groups. In “group C” CI was used as weaning predictor, and in “group D” DTF% alone was taken as weaning predictor. Incidence of weaning failure was noted in each group. The statistical analysis was done using Statistical Package for the Social Sciences (SPSS) Version 19.0. Chi-square test, Student’s t-test, Receiver Operating Characteristic (ROC) curve, 2x2 tables were used. Results: The DTF% value &gt;44.0% was found to be 95.2% sensitive, and 96.2% specific based on the ROC curve. The proportion of cases requiring reintubation was significantly higher in group D (DTF%) compared to group C (CI) (30.0% vs. 12.0%). RSBI with DTF% had a better sensitivity and specificity than DTF% alone. Conclusion: DTF% with RSBI is a much better predictor than DTF% alone. Sonography is subjective and has a long learning curve DTF% can be combined with RSBI to improve patient outcome.

Diaphragm ultrasound evaluation during weaning from mechanical ventilation in COVID-19 patients: a pragmatic, cross-section, multicenter study

BackgroundDiaphragmatic dysfunction is a major factor responsible for weaning failure in patients that underwent prolonged invasive mechanical ventilation for acute severe respiratory failure from COVID-19. This study hypothesizes that ultrasound measured diaphragmatic thickening fraction (DTF) could provide corroborating information for weaning COVID-19 patients from mechanical ventilation.MethodsThis was an observational, pragmatic, cross-section, multicenter study in 6 Italian intensive care units. DTF was assessed in COVID-19 patients undergoing weaning from mechanical ventilation from 1st March 2020 to 30th June 2021. Primary aim was to evaluate whether DTF is a predictive factor for weaning failure.ResultsFifty-seven patients were enrolled, 25 patients failed spontaneous breathing trial (44%). Median length of invasive ventilation was 14 days (IQR 7–22). Median DTF within 24 h since the start of weaning was 28% (IQR 22–39%), RASS score (− 2 vs − 2; p = 0.031); Kelly-Matthay score (2 vs 1; p = 0.002); inspiratory oxygen fraction (0.45 vs 0.40; p = 0.033). PaO2/FiO2 ratio was lower (176 vs 241; p = 0.032) and length of intensive care stay was longer (27 vs 16.5 days; p = 0.025) in patients who failed weaning. The generalized linear regression model did not select any variables that could predict weaning failure. DTF was correlated with pH (RR 1.56 × 1027; p = 0.002); Kelly-Matthay score (RR 353; p < 0.001); RASS (RR 2.11; p = 0.003); PaO2/FiO2 ratio (RR 1.03; p = 0.05); SAPS2 (RR 0.71; p = 0.005); hospital and ICU length of stay (RR 1.22 and 0.79, respectively; p < 0.001 and p = 0.004).ConclusionsDTF in COVID-19 patients was not predictive of weaning failure from mechanical ventilation, and larger studies are needed to evaluate it in clinical practice further.Registered: ClinicalTrial.gov (NCT05019313, 24 August 2021).

Effects of Dexmedetomidine on Diaphragm Activity Measured by Ultrasonography in Spontaneously Breathing Patients.

Background: Diaphragm movement is well correlated with inspired volume of the lung. Dexmedetomidine (DEX) has less effect on respiratory functions than other sedatives. The objective of this study was to investigate diaphragmatic movement using ultrasound (US) during DEX infusion for sedation in spontaneously breathing patients undergoing unilateral upper limb surgery.Methods: A total of 33 consecutive patients were enrolled in this study. Patients were sedated using DEX with ipsilateral axillary brachial nerve plexus block. Diaphragmatic activity was evaluated using diaphragmatic thickening at end-inspiration (TEI), diaphragmatic thickening at end-expiration (TEE), and diaphragmatic thickening fraction (DTF) measured by diaphragmatic US at three time-points; T0, baseline; T1, after DEX sedation; and T2, after DEX recovery. Supplementary oxygen was applied with a simple mask at 5 L/min. Peripheral oxygen saturation (SpO2), end tidal CO2 (EtCO2), and respiratory rate (RR) were recorded.Results: TEI and TEE showed no significant changes during the study period (P = 0.394 and P = 0.205, respectively). DTF was maintained at both T0 and T1 (P = 1.000). At recovery after DEX infusion discontinued, DTF was increased by 3.85%, although such increase was not statistically significant (T0 vs. T2, P = 0.525). SpO2 remained above 99% and EtCO2 remained below 36 mmHg. Desaturation episodes were not observed during the study period.Conclusions: Results of this study showed that DEX sedation did not affect the diaphragmatic movement in situation of decreased RR induced by DEX. This finding implies that DEX-induced sedation does not result in clinically significant respiratory depression.

Integrated ultrasound protocol in predicting weaning success and extubation failure: aprospective observational study.

Difficulty in weaning from mechanical ventilation is encountered in appro-ximately 20% of patients in the intensive care unit. We assessed the utility of a combined lung, diaphragmatic, and cardiac ultrasound protocol to predict extubation failure. All patients extubated following a successful spontaneous breathing trial (SBT) were included in the study. Lung ultrasonography score (LUS), diaphragmatic thickness fraction (DTF), changes in velocity time integral (VTI) to passive leg raise at the beginning of SBT, and change in LUS following SBT were recorded. A total of 60 patients who underwent successful SBT were included in the study. Twenty-seven patients required either non-invasive or invasive mechanical ventilation during the next 48 hours and were classified as weaning failure (Group F). The remaining 33 patients were designated as weaning success (Group S). Compared to group S, patients in Group F had significantly longer ICU length of stay (6.96 ± 4.30 days vs. 11.66 ± 3.85 days, P < 0.001), higher LUS change during SBT (1 [0-2] vs. 2 [1-4], P < 0.001), lower DTF (30.87 ± 5.32 vs. 27.88 ± 6.24, P = 0.04), and showed lower VTI increment to PLR (13.63 ± 3.44 vs. 9.11 ± 4.59, P < 0.001). Using a binary logistic regression model, DTF < 26% (odds ratio 6.20, 95% CI: 1.06-36.04) and VTI change to PLR < 10.2% (odds ratio 6.16, 95% CI: 1.14-33.13) were found to be significant predictors of weaning failure (P < 0.05). The AUROC for VTI and DTF for predicting weaning failure were 0.79 and 0.64, respectively. An integrated ultrasound protocol using a combination of lung, diaphragm, and cardiac sonography was a reliable predictor of weaning failure.

Diaphragm ultrasound to predict weaning outcome: systematic review and meta-analysis.

Proper timing for discontinuation of mechanical ventilation is of great importance, especially in patients with previous weaning failures. Different indices obtained by ultra-sonographic evaluation of the diaphragm muscle have improved determination of weaning success. The aim of the present systematic review was to evaluate and compare the accuracy of the diagnostic indices obtained by ultrasonographic examination, including diaphragm thickening fraction (DTF), diaphragmatic excursion (DE) and the rapid shallow breathing index (RSBI). Asystematic literature search (Web of Science, MEDLINE, Embase and Google Scholar) was performed to identify original articles assessing diaphragm muscle features including excursion and thickening fraction. Atotal of 2738 citations were retrieved initially; available data of 19 cohort studies (1114 patients overall) were included in the meta-analysis, subdivided into groups based on the ultrasonographic examination type. Our results showed the superiority of the diagnostic accuracy of the DTF in comparison to the DE and the RSBI. Data on the combination of the different indices are limited. Diaphragmatic ultrasound is acheap and feasible tool for diaphragm function evaluation. Moreover, DTF in the assessment of weaning outcome provides more promising outcomes, which should be evaluated more meti-culously in future randomised trials.

Peri-operative diaphragm ultrasound as a new method of recognizing post-operative residual curarization

BackgroundThis study sought to evaluate the diagnostic accuracy of peri-operative diaphragm ultrasound in assessing post-operative residual curarization (PORC).MethodsPatients undergoing non-thoracic and non-abdominal surgery under general anaesthesia were enrolled from July 2019 to October 2019 at Peking Union Medical College Hospital. A train-of-four ratio (TOFr) lower than 0.9 was considered as the gold standard for PORC. Diaphragm ultrasound parameters included diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) during quiet breathing (QB) and deep breathing (DB). The diaphragm excursion fraction (DEF) was calculated as the DE-QB divided by the DE-DB. The diaphragm excursion difference (DED) was defined as DE-DB minus DE-QB. Receiver operating characteristic curve analysis was used to determine the cut-off values of ultrasound parameters for the prediction of PORC.ResultsIn total, 75 patients were included, with a PORC incidence of 54.6%. The DE-DB and DED were positively correlated with the TOFr, while the DEF was negatively correlated with the TOFr. The DE-DB cut-off value for predicting PORC was 3.88 cm, with a sensitivity of 85.4% (95% confidence interval [CI]: 70.1–93.9%), specificity of 64.7% (95% CI: 46.4–79.7%), positive likelihood ratio of 2.42 (95% CI 1.5–3.9), and negative likelihood ratio of 0.23 (95% CI: 0.1–0.5). The DED cut-off value was 1.5 cm, with a specificity of 94.2% (95% CI: 80.3–99.3%), sensitivity of 63.4% (95% CI: 46.9–77.9%), positive likelihood ratio of 10.78 (95% CI: 2.8–42.2), and negative likelihood ratio of 0.39 (95% CI: 0.3–0.6).ConclusionsPeri-operative diaphragm ultrasound may be an additional method aiding the recognition of PORC, with DED having high specificity.

Determinants of diaphragm inspiratory motion, diaphragm thickening, and its performance for predicting respiratory restrictive pattern in Duchenne muscular dystrophy.

Respiratory status is a key determinant of prognosis in patients with Duchenne muscular dystrophy (DMD). We aimed to evaluate the determinants of diaphragm ultrasound and its performance in predicting restrictive respiratory patterns in DMD. This was a retrospective study of DMD patients followed in our center and admitted for an annual checkup from 2015 to 2018. We included DMD patients who underwent diaphragm ultrasound and pulmonary functional tests. This study included 74 patients with DMD. The right diaphragm thickening fraction (TF) was significantly associated with age (P= .001), Walton score (P= .012), inspiratory capacity (IC) (P= .004), upright forced vital capacity (FVC) (P< .0001), supine FVC (P= .038), and maximal inspiratory pressure (MIP) (P= .002). Right diaphragm excursion was significantly associated with age (P< .0001), steroid use (P= .008), history of spinal fusion (P< .0001), body mass index (BMI) (P= .002), Walton score (P< .0001), IC (P< .0001), upright FVC (P< .0001), supine FVC (P< .0001), and MIP (P< .0001). A right diaphragm TF >28% and a right diaphragm excursion>25.4 mm were associated with an FVC >50% with, respectively, an area under the curve (AUC) of 0.95 (P= .001) and 0.93 (P< .001). A left diaphragm TF >26.8% and a left diaphragm excursion >21.5 mm were associated with an FVC >50% with, respectively, an AUC of 0.95 (P= .011) and 0.97 (P< .001). Diaphragm excursion and diaphragm TF can predict restrictive pulmonary insufficiency in DMD.

Influence of Dexmedetomidine on Diaphragm Function and Postoperative Outcomes in ICU Patients with Mechanical Ventilation.

Objective To probe into the influence of dexmedetomidine (DEX) on diaphragm function and postoperative outcomes of mechanically ventilated patients in the intensive care unit (ICU). Methods 84 patients with mechanical ventilation (MV) in the ICU of our hospital were selected as the research participants, including 38 patients in the control group (CG) sedated with midazolam (MZ) and 46 patients in the research group (RG) with DEX sedation. Ramsay sedation score, visual analogue scale (VAS), and restlessness score (RS) were used to evaluate their state before sedation (T0), as well as 2 h (T1), 6 h (T2), and 24 h (T3) after sedation, and the alterations of mean arterial pressure (MAP) and heart rate (HR) were recorded. Serum cortisol (Cor), adrenocorticotropic hormone (ACTH), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin- (IL-) 1β, IL-6, and tumor necrosis factor-α (TNF-α) were measured before and 24 h after sedation. The end-inspiratory diaphragm thickness (DTei) and end-expiratory diaphragm thickness (DTee) were measured within 2 h after the initiation of MV and 5 min after the spontaneous breathing test (SBT), and the diaphragm thickening fraction (DTF) was calculated. Finally, the ventilator weaning, MV time, and the incidence of adverse reactions (ADs) of the two groups were counted. Results T0 and T3 witnessed no distinct difference in Ramsay, VAS, and RS scores between the two arms (P > 0.05), but at T1 and T2, RG had better sedation state and lower VAS and RS scores than CG (P < 0.05), with more stable vital signs (P < 0.05). After sedation, the contents of oxidative stress and inflammatory factors in RG were lower, while DTee, DTei, and DTF were higher, versus CG (P < 0.05). Moreover, RG presented higher success rate of first ventilator weaning, less MV time, and lower incidence of ADs than CG (P < 0.05). Conclusions DEX is effective in mechanically ventilated patients in the ICU, which can protect patients against diaphragm function damage, improve the success rate of ventilator weaning, and benefit the postoperative outcome, with excellent and rapid sedation effect and less stress damage to patients.

VENTILATOR-INDUCED DIAPHRAGMATIC DYSFUNCTION: MODIFIABLE CAUSES OF INJURY AND CORRELATED OUTCOMES

TOPIC: Critical Care TYPE: Late Breaking PURPOSE: The purposes of this study are to correlate the incidence of ventilator-induced diaphragmatic injury in the MICU to patient outcomes, and to assess for associations between diaphragmatic dysfunction and modifiable variables in mechanical ventilator management or sedation strategy. METHODS: Adult critically-ill patients admitted to Yale New Haven Hospital MICU were enrolled if intubated, mechanically ventilated, and qualified for a breathing trial. Diaphragm thickness, thickening fraction, and excursion were measured by bedside ultrasound, alongside an airway occlusion maneuver and maximum inspiratory pressure. These measurements were correlated with patient outcome variables, including duration of mechanical ventilation, re-intubation within 7 days of extubation, NIV following extubation, tracheostomy, and death during hospitalization, as well as modifiable ventilator settings and level of sedation. RESULTS: In an analysis of our first 13 patients, we found that there was a non-statistical difference in length of hospital stay between those with a reduced diaphragm thickening fraction (TF) ≤ 20% vs those with a normal TF (49.75 vs 32.22 days, p=0.087), although there was no difference in days on mechanical ventilation or length of ICU stay. When dividing patient subsets into categories of reduced or excessive effort (TF ≤ 20% or TF > 30%) vs normal effort (20% < TF ≤ 30%), we found that only those with abnormal effort had re-intubation within 7 days of extubation (3 vs 0) or required tracheostomy (3 vs 0). Those with a diaphragm thickening fraction ≤ 20% had near-statistically significant differences in admission APACHE II score (20.5 in low TF vs 15 in normal TF, p=0.063), as well as lower ventilatory pressure support (inspiratory pressure 17.78 cmH2O in low TF vs 22.39 cmH2O in normal TF, p=0.099). CONCLUSIONS: Although underpowered given a small initial dataset, our study may indicate that a reduced thickening fraction at time of breathing trial may correlate with a prolonged hospital stay, although is not a marker for prolonged mechanical ventilation. Reduced or increased effort may also suggest increased risk of re-intubation or need for tracheostomy. It is also important to note that those who had a higher severity of critical illness at time of intubation, and those who received less inspiratory support while on mechanical ventilation, had a reduced thickening fraction relative to those less ill or receiving greater pressure support. CLINICAL IMPLICATIONS: Only recently has diaphragmatic myotrauma been characterized as a potential mediator for prolonged mechanical ventilation and poor patient outcomes. However, the assessment of its presence by simple, reproducible, and non-invasive means has remained elusive, and its clinical utility dubious at best. This study illustrates the potential use of ultrasound-based diaphragmatic thickening fraction at time of spontaneous breathing trial as a measure of normal, decreased, or increased respiratory muscle effort, and how this may correlate to length of hospital stay, risk of re-intubation, and need for tracheostomy. It also suggests that the level of critical illness may correspond with a higher incidence of diaphragmatic injury, and that increased mechanical support, while maintaining lung protective strategy, may help maintain normal respiratory muscle function. Further studies will be necessary in the future to corroborate these results. DISCLOSURES: No relevant relationships by Jan Fouad, source=Web Response No relevant relationships by Lauren Killingsworth, source=Web Response No relevant relationships by Margaret Pisani, source=Web Response

Effect of awake prone position on diaphragmatic thickening fraction in patients assisted by noninvasive ventilation for hypoxemic acute respiratory failure related to novel coronavirus disease

BackgroundAwake prone position is an emerging rescue therapy applied in patients undergoing noninvasive ventilation (NIV) for acute hypoxemic respiratory failure (ARF) related to novel coronavirus disease (COVID-19). Although applied to stabilize respiratory status, in awake patients, the application of prone position may reduce comfort with a consequent increase in the workload imposed on respiratory muscles. Thus, we primarily ascertained the effect of awake prone position on diaphragmatic thickening fraction, assessed through ultrasound, in COVID-19 patients undergoing NIV.MethodsWe enrolled all COVID-19 adult critically ill patients, admitted to intensive care unit (ICU) for hypoxemic ARF and undergoing NIV, deserving of awake prone positioning as a rescue therapy. Exclusion criteria were pregnancy and any contraindication to awake prone position and NIV. On ICU admission, after NIV onset, in supine position, and at 1 h following awake prone position application, diaphragmatic thickening fraction was obtained on the right side. Across all the study phases, NIV was maintained with the same setting present at study entry. Vital signs were monitored throughout the entire study period. Comfort was assessed through numerical rating scale (0 the worst comfort and 10 the highest comfort level). Data were presented in median and 25th–75th percentile range.ResultsFrom February to May 2021, 20 patients were enrolled and finally analyzed. Despite peripheral oxygen saturation improvement [96 (94–97)% supine vs 98 (96–99)% prone, p = 0.008], turning to prone position induced a worsening in comfort score from 7.0 (6.0–8.0) to 6.0 (5.0–7.0) (p = 0.012) and an increase in diaphragmatic thickening fraction from 33.3 (25.7–40.5)% to 41.5 (29.8–50.0)% (p = 0.025).ConclusionsIn our COVID-19 patients assisted by NIV in ICU, the application of awake prone position improved the oxygenation at the expense of a greater diaphragmatic thickening fraction compared to supine position.Trial registration ClinicalTrials.gov, number NCT04904731. Registered on 05/25/2021, retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT04904731.

Application of Ultrasound Evaluation of Diaphragm Function in Guiding Ventilator Evacuation

Objective. To investigate the clinical effect of the application of ultrasound evaluation of diaphragm function in guiding ventilator evacuation. Methods. 100 patients with ventilator evacuation who were admitted to our hospital from March 2019 to June 2020 were selected as the study objects, and divided into the observation group and the control group, according to whether they succeeded in weaning. Among them, 50 patients succeeding in weaning were from the observation group; while 50 patients failing in weaning were from the control group. The Diaphragm Movement Degree (DMD) and Diaphragmatic Thickness at the End of Expiration (DTee), Diaphragmatic Thickness at the End of Inspiration (DTei) and Diaphragm Thickening Fraction (DTF), the right diaphragm displacement, diaphragm contraction velocity at 0 min, 5 min and 30 min of two groups as well as the ROC curve were all analyzed to predict weaning results of the ultrasound diaphragm index. Results. (1) There were no significant differences in Sequential Organ Failure Assessment (SOFA) score. Acute Physiology and Chronic Health Evaluation II (APACHE II) score, ventilator ventilation time and oxygenation index before weaning between the two groups (T=0.14,0.03, 0.04, 0.59, P=0.89, 0.97, 0.56). (2) Left DMD (18.59±2.96) mm. Right DMD (19.86±2.94) mm. Left DTei (2.69±0.16) mm. Right DTei (2.81 ±0.31) mm. Left DTee (1.93±0.11) mm. Right DTee (1.92±0.16) mm. Left DTF (0.40±0.11) mm and Right DTF (0.47±0.09) mm in the observation group were significantly higher than Left DMD (13.05±3.16) mm. Right DMD (13.13±3.63) mm. Left DTei (2.16±0.34) mm. Right DTei (2.18±0.39) mm. Left DTee (1.92±0.16) mm. Right DTee (1.68±0.24) mm. Left DTF (0.25±0.06) mm and right DTF (0.27±0.07) mm in the control group, T = 9.05, 10.19, 9.97, 8.94, 6.93, 5.88, 8.46, 12.40, P=0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, with statistical significance. (3) The ROC curve showed that left and right DMD, left and right DTei, left and right DTee as well as left and right DTF can be used to predict the success of weaning. Conclusion. In the guidance of ventilator evacuation, the application of ultrasound evaluation of diaphragm function can effectively evaluate the timing of weaning, and played a positive role in improving the success rate of weaning.

Does diaphragm ultrasound improve the rapid shallow breathing index accuracy for predicting the success of weaning from mechanical ventilation?

BackgroundThis prospective study investigated whether taking into account diaphragmatic excursion (DE) measured by ultrasonography would improve the performance of the rapid shallow breathing index (RSBI) to predict extubation success or failure. ObjectivesThe aim of the study was to compare the new composite index named the rapid shallow diaphragmatic index (RSDI), and the RSBI measured during a spontaneous breathing trial regarding their ability to predict the need for re-intubation at 72 h. MethodsOne hundred mechanically ventilated patients underwent daily 30-min spontaneous breathing trials (SBTs) under pressure support ventilation of 6 cm H2O and end-expiratory pressure of 0 cm H2O until the SBT was considered successful and followed by extubation. The performances of RSBI (respiratory rate/tidal volume) and of the ratio RSBI/DE measured at 5 and 25 min of the successful SBT were compared in terms of area under the receiver operating characteristics curve (AUC), for predicting extubation success at 72 h. As secondary analysis, extubation and weaning success at 7 d were also considered. As exploratory analyses, predictive indices incorporating both clinical characteristics, the DE, and ultrasound diaphragm thickening fraction (DTF) were investigated. ResultsRSBI and RSBI/DE showed AUCs with 95% confidence intervals consistently extending below 0.50, either at the 5th (0.55 [0.36–0.74] and 0.55 [0.34–0.75], respectively) or at the 25th minute of SBT (0.49 [0.27–0.71] and 0.50 [0.29–0.68], respectively) for predicting weaning success at 72 h or at 7 d (5th min: 0.53 [0.37–0.70] and 0.54 [0.37–0.70], respectively; 25th min: 0.54 [0.37–0.71] and 0.55 [0.39–0.71], respectively). An exploratory index incorporating the accessory respiratory muscle activity, DE, DTF, and respiratory rate at 5th min of SBT showed AUCs for predicting extubation success at 7 d in the 78 patients with DTF measurement (0.77 [0.64–0.90]) that were significantly higher than that of the RSBI (P = 0.017) and RSBI/DE (P < 0.001) in the same respective populations. ConclusionsThe RSBI and the ratio RSBI/DE failed to predict weaning success when measured during an SBT performed under minimal pressure support. Predictive indices incorporating ultrasound DE and DTF may merit further investigation.

Application of bedside ultrasound in predicting the outcome of weaning from mechanical ventilation in elderly patients

BackgroundWith the increased ageing of society, more and more elderly people are admitted to the intensive care unit, How to accurately predict whether elderly patients can successfully wean from the ventilator is more complicated. Diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) were measured by bedside ultrasound to assess diaphragm function. The lung ultrasound score (LUS) and the rapid shallow breathing index (RBSI) were used as indices of diaphragm function to predict the outcome of weaning from mechanical ventilation. The aim of this study was to examine the clinical utility of these parameters in predicting extubation success.MethodsThis prospective study included 101 consecutive elderly patients undergoing a trial of extubation in the ICU of Haidian Hospital between June 2017 and July 2020. Patients were divided into the successful weaning group (n = 69) and the failed weaning group (n = 32). Baseline characteristics, including RSBI, were recorded. Measurements of DE, DTF and LUS were made using ultrasound within 24 h before extubation.ResultsMedian DE was greater in patients with extubation success than in those with extubation failure (1.64 cm vs. 0.78 cm, p = 0.001). Patients with extubation success had a greater DTF than those with extubation failure (49.48% vs. 27.85%, p = 0.001). The areas under the receiver operating curves for the RSBI, LUS, DE and DFT were 0.680, 0.764, 0.831 and 0.881, respectively. The best cut-off values for predicting successful weaning were DTF ≥ 30%, DE ≥ 1.3 cm, LUS ≤ 11, and RSBI ≤ 102. The specificity of DTF (84%) in predicting weaning outcome was higher than that of RBSI (53%), that of LUS (55%), and that of DE (62%). The sensitivity of DTF (94%) was greater than that of RBSI (85%), that of LUS (71%), and that of DE (65%). The combination of RSBI, LUS, DE, and DTF showed the highest AUC (AUC = 0.919), with a sensitivity of 96% and a specificity of 89%.ConclusionsDTF has higher sensitivity and specificity for the prediction of successful weaning in elderly patients than the other parameters examined. The combination of RSBI, LUS, DE and DFT performed well in predicting weaning outcome. This has potentially important clinical application and merits further evaluation.