Diaphragmatic Index Research Articles

Sonographic assessment of diaphragmatic thickening and excursion as predictors of weaning success in the intensive care unit: A prospective observational study.

Ultrasonographic assessment of diaphragmatic function can be a useful bedside tool in the weaning and extubation of mechanically ventilated patients, especially in patients with difficult weaning, in whom diaphragmatic weakness is suspected. Thus, this study was planned to assess the role of bedside sonographic assessment of diaphragmatic indices such as diaphragmatic thickening fraction (DTf) and diaphragmatic excursion (DE) in predicting successful extubation or extubation failure in weaning eligible patients by comparing the measurements with outcome. This prospective observational study was conducted on 50 mechanically ventilated, weaning-ready patients during the spontaneous breathing trial (SBT). The DE and DTf of patients were noted along with conventional parameters of weaning. Probability value <0.05 was considered statistically significant. Receiver operating characteristic (ROC) curves were used for analysis. Area under the curve (AUC) was measured, and sensitivity and specificity for different cut-off values were estimated. Out of 50 patients, 15 (30%) had SBT failure and 4 had extubation failure. The group with SBT failure had significantly higher rapid shallow breathing index (RSBI) and airway occlusion pressure (P0.1s), whereas DE and DTf were lower compared to the SBT successful group. Strong correlation existed between RSBI, DTf, DE and P0.1s. DTf of nearly 24% (sensitivity 93.5%, specificity 94.7%) and DE of 1.10 cm (84% sensitivity, 89.5% specificity) were associated with best outcome. Along with conventional parameters of weaning, sonographic assessment of diaphragmatic parameters can be useful in predicting the success of SBT and in avoiding unnecessary extubation failures and thereby help in achieving a successful weaning outcome.

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.

Are diaphragmatic indices assessed by ultrasound good predictors of weaning outcome in mechanically ventilated respiratory patients?

Background Prediction of weaning outcome is still challenging. Among the reported causes of weaning failure is the diaphragmatic dysfunction. Diaphragmatic ultrasound indices were endorsed for predicting weaning outcome but with conflicting results. Therefore, this study aimed to evaluate ultrasonographic diaphragmatic indices for predicting weaning outcome in respiratory intensive care unit (RICU) patients. Patients and methods The study enrolled 40 RICU patients who were considered eligible for spontaneous breathing trial (SBT). Ultrasound of the right hemidiaphragm was performed immediately after the start of SBT. Assessment of the diaphragmatic excursion using M-mode in semisitting position was done. Moreover, the diaphragmatic thickness at the end of inspiration (Tdi) and expiration (Tdex), with the patient in supine position, was assessed. Diaphragmatic thickness fraction was then calculated. During SBT, patients’ respiratory rate, heart rate, rapid shallow breathing index (RSBI), and minute ventilation were recorded. Tracheal airway occlusion pressure (P0.1) and negative inspiratory force were measured using the ventilator software. Results The diaphragmatic indices did not appear to have a significant role in predicting successful weaning with area under the curve less than 0.56 for all of them. Moreover, no statistically significant difference in Tdi, Tdexe, thickness fraction, and diaphragmatic excursion was observed between the success and failure weaning groups. However, the RSBI performed as the best parameter in predicting weaning success, with area under the curve of 0.831. A cutoff value of 78 had 91% sensitivity and 84% specificity. Conclusion Ultrasonographic diaphragmatic indices are not satisfactory tools to predict weaning outcome in RICU compared with RSBI and other reported traditional indices.

Assessment of diaphragmatic mobility by chest ultrasound in relation to BMI and spirometric parameters

ContextUltrasound of the diaphragm is an evolving diagnostic modality with several techniques and measurements that can be used for structural and functional assessment of the diaphragm. Weight may have effects on pulmonary function tests including its impairment. Assessment of the diaphragm is one of these important measures of function by measuring the diaphragmatic thickness, excursion, and diaphragmatic thickness fraction (DTF).AimAssessing the relation between these sonographic diaphragmatic indices with spirometry and BMI.Settings and designThis was a prospective clinical study in which 107 normal healthy volunteers with different age, height, and weight were enrolled; most of them were coming for routine preoperative assessment at the Ain Shams University Chest Department Pulmonary Function Unit.Patients and methodsIt included 107 healthy persons who came for routine preoperative lung function assessment or normal volunteers. Full medical and smoking history, BMI, chest radiography spirometry, and diaphragmatic assessment by ultrasound for excursion, thickness, and DTF were done. All persons were divided into obese individuals of BMI more than or equal to 25 and nonobese individuals of BMI less than 25.Statistical analysisStatistical package for the social sciences program (SPSS) software version 18.0.ResultsIn obese individuals, forced expiratory volume in the first second (FEV1%) and right diaphragmatic excursion show a significant decrease when BMI increases. There was a statistically significant increase in right and left diaphragmatic excursion and DTF in men rather than women. There was a highly significant increase in both right and left diaphragmatic thickness and excursion when forced vital capacity increases. There was a highly significant increase in right diaphragmatic excursion and both right and left diaphragmatic thickness when FEV1 increases. A significant increase in left excursion and DTF was also noticed with increased FEV1. However, there was a significant decrease in DTF with increased percent of forced vital capacity.ConclusionSpirometric parameters and right diaphragmatic excursion show a significant decrease when BMI increases. Different relations were found between spirometric parameters and ultrasonographic measurements regardless of the BMI.

Assessment of Diaphragmatic Index in Hospitalized Patients with Lung Disease and Obesity

Assessment of Diaphragmatic Index in Hospitalized Patients with Lung Disease and Obesity

Supine volume drop and diaphragmatic function in adults with Pompe disease: Table 1–

To the Editors: The onset of the adult form of Pompe disease, also known as acid maltase deficiency or glycogen storage disease type II, is a slow progressive muscular disorder in which little correlation exists between respiratory function and locomotor function [1]. The greater degree of respiratory dysfunction, compared with mobility loss, is mainly ascribable to the predominant and progressive involvement of the diaphragm [1]. The prominent diaphragmatic dysfunction in Pompe disease, together with the recent introduction of enzyme replacement therapy in adults, indicate a need for clarifying respiratory outcomes in adult-onset Pompe disease [2]. An international database of medical information on patients with Pompe disease has been set up by Genzyme Corporation (Cambridge, MA, USA), a manufacturer of replacement enzymes (www.pomperegistry.com). The only parameter recommended in the Genzyme Pompe registry for assessing diaphragmatic function is vital capacity (VC) in the upright position. However, it has been demonstrated in a population of patients with suspected diaphragmatic weakness that the supine VC drop provided a good estimate of diaphragmatic dysfunction [3–5]. The aim of the current study was to determine the relationship between invasive diaphragmatic indices and noninvasive respiratory function variables in patients with adult-onset Pompe disease. We retrospectively retrieved data from the clinical files of patients with adult-onset Pompe disease at the respiratory laboratory of the Raymond Poincare Teaching Hospital (Garches, France) between 2002 and 2010 for diaphragmatic muscle evaluation. Our study was approved by the French Commission Nationale de l’Informatique et des Libertes in accordance with current French legislation. …

Pulmonary Function and Thoraco-abdominal Configuration After Elective Craniotomy

Background and Purpose The development of pathophysiologic pulmonary alterations are observed after thoracic and abdominal surgeries. The purpose of this article is to report the alterations in the thoracoabdominal configuration and ventilometric parameters that occur during the postoperative period after elective craniotomy. Subjects Forty-seven patients submitted to craniotomy owing to the presence of an aneurysm or tumor, under general anesthesia were analyzed. Methods Tidal volume (TV), respiratory rate, and diaphragmatic index were measured from the preoperative period to the fourth postoperative day and pH, PaCO2, PaO2, and SaO2 to the second postoperative day. Results We observed a decrease in TV, an increase in respiratory rate, increased alveolar ventilation, and a change in the respiratory pattern from predominantly abdominal to predominantly thoracic respiration. Conclusions A decrease in the diaphragmatic index, and a reduction in abdominal motion, associated to a lower TV, is suggestive that the lower parts of the lungs were less ventilated than the higher ones.

Alterações funcionais respiratórias na colecistectomia por via laparoscópica

Objetivo: Estudar as alterações da ventilação e volumes pulmonares e da força muscular respiratória no pós-operatório de colecistectomia por via laparoscópica. Tipo de estudo: Estudo prospectivo. Material e métodos: Foram avaliados 20 pacientes provenientes da enfermaria de gastrocirurgia da Unifesp, com média de idade 42,7 anos, sendo 7 (35%) homens e 13 (65%) mulheres. No período pré-operatório todos foram submetidos a um questionário clínico, exame físico, radiografia de tórax, espirometria. No pré e no pós-operatório foram obtidas as medidas da força muscular respiratória (pressões inspiratória e expiratória máximas), da ventilação pulmonar (volume corrente e volume minuto), da capacidade vital, a oximetria de pulso e o índice diafragmático (ID). Este índice é capaz de refletir o movimento toracoabdominal, determinado pelas mudanças nas dimensões ântero-posteriores da caixa torácica (CT) e do abdome (AB) e foi calculado utilizando-se a seguinte fórmula: ID = D AB/D AB + D CT. Resultados: Observou-se que os pacientes evoluíram no primeiro dia de pós-operatório com diminuição média significante de 26% do volume corrente, de 645ml ± 220ml para 475ml ± 135ml; 20% do volume minuto, de 15,0L ± 4,5L para 11,9L ± 3,6L; 36% da capacidade vital, de 2,7L ± 0,6L para 1,74L ± 0,7L; 47% da pressão inspiratória máxima, de -75 ± -22cm/H2O para -40 ± 17cm/H2O; 39% da pressão expiratória máxima, de +90 ± 28cm/H2O para +55 ± 28cm/H2O e 36% do índice diafragmático, de 0,60 ± 0,10 para 0,39 ± 0,14 (p &lt; 0,05). O volume corrente, o volume minuto e a pressão expiratória máxima retornaram aos seus valores basais no 3º dia de pós-operatório; a capacidade vital, pressão inspiratória máxima e o índice diafragmático retornaram aos seus valores basais entre o 4º e o 6º dia de pós-operatório. Dos vinte pacientes, somente um apresentou atelectasia como complicação pulmonar, tendo evoluído bem com as medidas habituais de fisioterapia respiratória. Conclusão: Concluímos que os pacientes submetidos à colecistectomia por via laparoscópica apresentam no 1º dia de pós-operatório diminuição significante dos volumes pulmonares e da força muscular respiratória. Porém, quando comparados com dados de literatura, o retorno aos valores pré-operatórios é mais rápido na cirurgia por via laparoscópica (3º e 4º dias de pós-operatório) do que na cirurgia abdominal convencional.

Effects of nitric oxide on diaphragmatic muscle endurance and strength in pigs.

The aim of the study was to evaluate the effects of nitric oxide (NO) on diaphragmatic fatigue in fifteen anaesthetized, mechanically ventilated pigs, divided into three groups. The animals were pre-treated with indomethacin (3 mg kg-1, i.v.) to block the cyclo-oxygenase pathway. To group 1 pigs (n = 6) NG-nitro-L-arginine methyl ester (L-NAME, 5 mg kg-1 i.v.) was administered as a bolus to block endogenous NO production, while group 2 pigs (n = 6) were infused with sodium nitroprusside (SNP, 0.023 mg kg-1, i.v.), a donor of NO. Group 3 pigs (n = 3) were used as the controls. We evaluated diaphragmatic strength by measuring the transdiaphragmatic pressure (P di) generated during bilateral phrenic nerve stimulation at 10, 20, 30 and 50 Hz, 15 V, while the diaphragmatic endurance was assessed by a 30s stimulation at 10 Hz, 15 V. Diaphragmatic index was assessed as the ratio of peak force between single twitches performed before and after the 30 s stimulation west. We also evaluated mean systemic (MAP) and pulmonary (MPAP) arterial pressures, pulmonary wedge pressure (PW), systemic (SVR) and pulmonary vascular resistance (PVR) and cardiac output (CO). L-NAME increased MAP, MPAP, PW, SVR and PVR, but decreased CO. SNP caused a decrease in MAP, MPAP, PW and SVR, while PVR and CO did not change. The main finding of this study was that diaphragmatic strength was not significantly weakened after L-NAME administration, except at 10 Hz, while it did not change after SNP infusion. However, both L-NAME and SNP caused significant decreases in diaphragmatic endurance capacity. The fatigue appearing after L-NAME is probably correlated with a decline in diaphragmatic blood flow, as evidenced by the increase in SVR and the decrease in CO, and consequently in oxygen supply. In contrast, the decrease in endurance capacity after SNP infusion can be attributed to a direct action of NO on skeletal muscle.

EFFECTS OF UPPER OR LOWER ABDOMINAL SURGERY ON DIAPHRAGMATIC FUNCTION

Changes in abdominal (delta AB) and rib cage (delta RC) movements, and in vital capacity, were compared between 23 patients undergoing upper or lower abdominal surgery at 1, 3 and 7 days after surgery. Diaphragmatic index was obtained by measuring the relative abdominal motion (delta AB/delta AB + delta RC) using magnetometers. Electrical activity of abdominal muscles was assessed using needle electrodes after upper abdominal surgery in four additional patients. After upper abdominal surgery, the vital capacity and the diaphragmatic index were markedly reduced for 1 week. No abdominal muscle activity was observed at day 1. After lower abdominal surgery, the vital capacity returned to the normal range within 3 days of operation, without any diaphragmatic impairment. These findings substantiate the role of diaphragmatic dysfunction in postoperative reduction in vital capacity observed after upper abdominal surgery.

The effect of rebreathing CO 2 on ventilation and diaphragmatic electromyography in newborn infants

We tested the hypothesis of whether the reduced ventilatory response to CO 2 in preterm as compared to term infants is related to primary central unresponsiveness, or to mechanical impairment of the respiratory pump. Eleven preterm (n = 19; gestational age 32 ± 0.4 wk) and 14 term (n = 24; GA 40 ± 0.3 wk) infants were studied. Minute integrated diaphragmatic activity (EMG Di × f), and mean inspiratory diaphragmatic activity (EMG Di/T i), were used as indices of central output. After 3 min breathing 21% O 2 (control), infants rebreathed from a bag containing 5% CO 2 in 40% O 2 for 2 to 3 minutes. We measured V e, V t, f, V t/T i. Sleep states were monitored. Preterm infants had a decreased ventilatory response to CO 2 both in quiet sleep (QS) (0.0379 ± 0.067 vs 0.505 ± 0.032 L·(min·kg·kPa P a CO 2 ) −1 ; P < 0.04) and in active sleep (AS) (0.210 ± 0.032 vs 0.331 ± 0.048 L·(min·kg·kPa P a CO 2 ) −1; P < 0.04) . The decrease in response primarily was a function of a lack of increase in tidal volume with CO 2 in QS and a lack of increase in f in AS. Parallel to these changes there were significant correlations between the increases in EMG Di × f and V e with inhaled CO 2 ( r = 0.75; P < 0.001); V t and EMG Di ( r = 0.63; P < 0.01); and between the increases in EMG Di/T i and V t/T i with inhaled CO 2 ( r = 0.64; P < 0.001). The results suggest that ventilatory response to CO 2 is (1) correlated highly diaphragmatic indices of central output; (2) less in active than in quiet sleep; (3) less in preterm than in term infants. We conclude that despite their increased chest wall compliance, preterm infants respond less to CO 2 because of central unresponsiveness.

Effects of aminophylline on diaphragmatic dysfunction after upper abdominal surgery.

The effects of upper abdominal surgery on diaphragmatic function were studied in eight supine patients before and after administration of aminophylline. Changes in pleural (delta Ppl) and gastric pressure (delta Pga) swings were measured with balloon catheter systems. Transdiaphragmatic pressure change (delta Pdi) was calculated as the difference delta Pga-delta Ppl. The ratio delta Pga/delta Pdi, used as an index of the diaphragmatic contribution to the quiet breathing process, decreased significantly as early as 1 h after operation without any further change throughout the 6-h period studied. Administration of aminophylline (6 mg/kg), six hours postoperatively, produced a significant increase in this diaphragmatic index. These data indicate that the early reduced diaphragmatic activity, after upper abdominal surgery, partially may be reversed by administration of aminophylline. The mechanism of its action may involve central nervous stimulation and/or a direct inotropic effect on diaphragmatic muscle. Further studies are needed to evaluate if the correction of altered diaphragmatic motion by aminophylline improves postoperative lung function.