Weaning-induced Pulmonary Edema Research Articles

Cardiopulmonary interactions during ventilator weaning.

Weaning a critically-ill patient from the ventilator is a crucial step in global management. This manuscript details physiological changes induced by altered heart-lung interactions during the weaning process, illustrates the main mechanisms which could lead to weaning failure of cardiac origin, and discuss a tailored management based on the monitoring of changes in central hemodynamics during weaning. The transition from positive-pressure ventilation to spontaneous breathing results in abrupt hemodynamic and metabolic changes secondary to rapidly modified heart-lung interactions, sudden changes in cardiac loading conditions, and increased oxygen demand. These modifications may elicit an excessive burden on both the respiratory and cardiovascular systems, result in a rapid and marked increase of left ventricular filling pressure, and ultimately result in a weaning-induced pulmonary oedema (WIPO). The T-piece trial induces the greatest burden on respiratory and cardiocirculatory function when compared to spontaneous breathing trial using pressure support ventilation with positive or zero end-expiratory pressure. Since LV overload is the mainstay of WIPO, positive fluid balance and SBT-induced acute hypertension are the most frequently reported mechanisms of weaning failure of cardiac origin. Although the diagnosis of WIPO historically relied on an abrupt elevation of pulmonary artery occlusion pressure measured during right heart catheterization, it is nowadays commonly documented by echocardiography Doppler. This non-invasive approach is best suited for identifying high-risk patients, depicting the origin of WIPO, and tailoring individual management. Whether this strategy increases the success rate of weaning needs to be evaluated in a population at high risk of weaning failure of cardiac origin.

The Use of Lung Ultrasound in the Diagnosis of Weaning-Induced Pulmonary Oedema in Mechanically Ventilated Patients

Abstract Background Studies dealing with the use of lung ultrasound in the context of weaning have rather calculated lung ultrasound scores with aeration loss (without specifically addressing the issue of weaning induced pulmonary oedema “WIPO”) or assessed post-extubation distress. Our study specifically focuses on WIPO. Advantages of lung ultrasound for diagnosing WIPO are numerous. It provides a non-invasive and direct assessment of lung water accumulation by detecting lung interstitial syndrome (the first stage of haemodynamic pulmonary oedema), lung ultrasound is easier to learn and perform compared to Doppler echocardiography and the acquisition and analysis can be performed within 2 min. Objective To test the ideal profile (increase in the number of B-lines) for diagnosing WIPO using lung ultrasound to avoid the poor outcome of weaning failure. Patients and Methods This study was performed in intensive care units of Ain Shams University hospitals between October 2020 and March 2021. This study was carried out on 51 patients, the final outcome divided this group into three subgroups, successful group include 28 patients (54.9%), failed group without WIPO include 10 patients (19.6%) and failed group with WIPO include 13 patients (25.5%). Results The sensitivity of B-line in predict the successful weaning was 95.0, while the specificity was 90.0% and the accuracy was 92.0% at cut off value 5.0. The sensitivity of B-line in predict the WIPO was 90.0, while the specificity was 84.0% and the accuracy was 87.0% at cut off value 5.5. Conclusion From the results of this study it was concluded that an increase in the number of Blines ≥ 5 on four anterior points during SBT provided the best accuracy for diagnosing WIPO with lung ultrasound. We suggest calling this sign the WIPO profile. These encouraging results must be confirmed by larger series, so that LUCI may empower the non-invasive monitoring tools, including biochemical indices, for the diagnosis of this common problem.

Pressure support and positive end-expiratory pressure versus T-piece during spontaneous breathing trial in difficult weaning from mechanical ventilation: study protocol for the SBT-ICU study

BackgroundSpontaneous breathing trials are performed in critically ill intubated patients in order to assess readiness to be weaned from mechanical ventilation. In patients with difficult weaning (i.e. not extubated after their first SBT), performing SBT using pressure support with or without positive end-expiratory pressure or using T-piece is debated. As ventilatory support during SBT is greater on pressure support than on T-piece and as positive end-expiratory pressure can prevent weaning-induced pulmonary oedema, we hypothesized that their combination and large use of post-extubation non-invasive ventilation may shorten the time until successful extubation as compared with T-piece, without increasing the rate of reintubation.MethodsSBT-ICU is a monocentric prospective open labelled, randomized controlled superiority trial comparing two mechanical ventilation weaning strategies; i.e. daily spontaneous breathing trials using pressure support with positive end-expiratory pressure or T-piece. The primary outcome will be time until successful extubation (defined by as extubation, without reintubation or death within the seven following days).DiscussionThis paper describes the protocol of the SBT-ICU trial. Enrolment of patients in the study is ongoing.Trial registrationClinicalTrials.gov NCT03861117. Registered on March 1, 2019, before the beginning of inclusion.

Diaphragm dysfunction, lung aeration loss and weaning-induced pulmonary oedema in difficult-to-wean patients

BackgroundDiaphragm dysfunction and weaning-induced pulmonary oedema are commonly involved during weaning failure, but their physiological interactions have been poorly reported. Our hypothesis was that diaphragm dysfunction is not particularly associated with weaning-induced pulmonary oedema.MethodsIt was a single-centre and physiological study conducted in patients who had failed a first spontaneous breathing trial and who underwent a second trial. The diaphragm function was evaluated by measuring the tracheal pressure generated in response to a bilateral magnetic phrenic nerves stimulations. Weaning-induced pulmonary oedema was diagnosed in case of failure of the spontaneous breathing trial if patients exhibited signs of plasma concentration or echocardiographic diagnosis of pulmonary artery occlusion pressure elevation.ResultsFifty-three patients were included and 31/53 (58%) failed the spontaneous breathing trial, including 24/31 (77%) patients with weaning-induced pulmonary oedema. Diaphragm dysfunction was present in 33/53 (62%) patients. Diaphragm dysfunction or weaning-induced pulmonary oedema were present in 26/31 (84%) of the patients who failed the spontaneous breathing trial. Weaning-induced pulmonary oedema occurred in 20/33 (61%) patients with a diaphragm dysfunction and in 4/20 (20%) patients without (p = 0.005).ConclusionWeaning-induced pulmonary oedema was three times more frequent in case of diaphragm dysfunction. Even in case of diaphragm dysfunction, physicians might be encouraged to investigate the presence of weaning-induced pulmonary oedema during weaning failure.

Critical illness-related corticosteroid insufficiency during difficult weaning from mechanical ventilation

BackgroundCritical illness-related corticosteroid insufficiency (CIRCI) is common during critical illness and is usually associated with poor outcomes, as prolonged duration of mechanical ventilation (MV) and higher mortality. CIRCI may alter cardiac and vascular functions. Weaning-induced pulmonary oedema (WiPO) is a major mechanism of weaning failure. The aim of this study was to evaluate the role of CIRCI in patients with difficult ventilator weaning and its possible relation with WiPO.MethodsThis is a prospective study conducted in the intensive care of a university hospital in France. Patients under MV for more than 24 h, meeting weaning criteria and having failed the first spontaneous breathing trial (SBT) underwent a corticotropin stimulation test, with assessment of total blood cortisol levels immediately before (T0) 0.25 mg iv of tetracosactrin and 30 and 60 min afterward. Δmax was defined as the difference between the maximal value after the test and T0. CIRCI was defined as T0 < 10 μg/dL (276 nmol/L) and/or Δmax < 9 μg/dL (248 nmol/L) and inadequate adrenal reserve as Δmax < 9 μg/dL. Biomarkers (natriuretic peptide and protidemia) sampling and echocardiograms were performed during the second SBT and were used to diagnose WiPO, which was defined according to two definitions (one liberal and one conservative) derived from recent publications on the topic. Successful extubation was defined as patient alive without reintubation 7 days after extubation. A competing risk analysis was used to assess extubation failure and mortality.ResultsSeventy-six consecutive patients (63 ± 14 years; 49 men) with difficult weaning were enrolled. CIRCI and inadequate adrenal reserve occurred in 25 (33%) and 17 (22%) patients, respectively. The probability of successful extubation was significantly decreased in patients with CIRCI or inadequate adrenal reserve, as compared to their counterparts, and this association persisted after adjustment on severity (SOFA score at first SBT). WiPO occurred in 44 (58%) and 8 (11%) patients, according to the liberal and conservative definition, respectively. WiPO was not associated with CIRCI nor with inadequate adrenal reserve.ConclusionCIRCI was common during difficult weaning and was associated with its prolongation. We did not find a significant association between CIRCI and WiPO.

Left ventricular overloading identified by critical care echocardiography is key in weaning-induced pulmonary edema.

PurposeTo assess the role of left ventricular overload and cumulated fluid balance in the development weaning-induced pulmonary edema (WIPO).MethodsVentilated patients in sinus rhythm with COPD and/or heart failure (ejection fraction ≤ 40%) were studied. Echocardiography was performed immediately before and during a 30-min spontaneous breathing trial (SBT) using a T-tube. Patients who failed were treated according to echocardiography results before undergoing a second SBT.ResultsTwelve of 59 patients failed SBT, all of them developing WIPO. Patients who succeeded SBT had lower body weight (− 2.5 kg [− 4.8; − 1] vs. + 0.75 kg [− 2.95; + 5.57]: p = 0.02) and cumulative fluid balance (− 2326 ml [− 3715; + 863] vs. + 143 ml [− 2654; + 4434]: p = 0.007) than those who developed WIPO. SBT-induced central hemodynamic changes were more pronounced in patients who developed WIPO, with higher E wave velocity (122 cm/s [92; 159] vs. 93 cm/s [74; 109]: p = 0.017) and E/A ratio (2.1 [1.2; 3.6] vs. 0.9 [0.8; 1.4]: p = 0.001), and shorter E wave deceleration time (85 ms [72; 125] vs. 147 ms [103; 175]: p = 0.004). After echocardiography-guided treatment, all patients who failed the first SBT were successfully extubated. Fluid balance was then negative (− 2224 ml [− 7056; + 100] vs. + 146 ml [− 2654; + 4434]: p = 0.005). Left ventricular filling pressures were lower (E/E′: 7.3 [5; 10.4] vs. 8.9 [5.9; 13.1]: p = 0.028); SBT-induced increase in E wave velocity (+ 10.6% [− 2.7/ + 18] vs. + 25.6% [+ 12.7/ + 49]: p = 0.037) and of mitral regurgitation area were significantly smaller.ConclusionIn high-risk patients, WIPO appears related to overloaded left ventricle associated with excessive fluid balance. SBT-induced central hemodynamic changes monitored by CCE help in guiding therapy for successful weaning.Electronic supplementary materialThe online version of this article (10.1007/s00134-020-06061-y) contains supplementary material, which is available to authorized users.

Use of combined cardiac and lung ultrasound to predict weaning failure in elderly, high-risk cardiac patients: a pilot study.

Weaning failure from mechanical ventilation may be due to lung de-recruitment or weaning-induced pulmonary oedema (WIPO). Both can be diagnosed by lung ultrasound (LUS) and transthoracic echocardiography (TTE), respectively. We conducted a prospective observational study, combining TTE and LUS, to determine if LUS alone may identify elderly patients at high risk of weaning or extubation failure. Before and at the end of spontaneous breathing trials (SBT) in 40 elderly patients, we prospectively performed LUS and TTE. Extubation was decided by an independent operator. LUS included global and anterolateral LUS score. TTE included measurement of E/A and E/Ea ratios to determine LV filling pressures. SBT LUS scores for prediction of weaning outcome and for the diagnosis of WIPO were studied. Weaning or extubation failure was observed in 45% (95% CI 28-61) of patients. ROC analysis for ability of global SBT LUS to predict weaning/extubation failure and extubation failure found AUC of 0.80 and 0.81, respectively. AUC for anterolateral SBT LUS to predict weaning/extubation failure and extubation failure was 0.79 and 0.81, respectively. Increased LV filling pressure during SBT was observed without increase of anterolateral LUS score. Inversely, increase of anterolateral LUS was observed without increased filling pressure and was associated with extubation failure. Global and anterolateral SBT LUS were not correlated to E/Ea. In elderly patients, global and anterolateral LUS scores were associated with weaning and extubation failures while echocardiographic indices of filling pressures were not. ClinicalTrials.gov No. NCT03261440.

Lung ultrasound allows the diagnosis of weaning-induced pulmonary oedema.

Detecting weaning-induced pulmonary oedema (WIPO) is important because its treatment might prompt extubation. For this purpose, lung ultrasound might be an attractive tool, since it demonstrates pulmonary oedema through the appearance of B-lines. To test the ideal profile (increase in the number of B-lines) for diagnosing WIPO. Before and at the end of 62 spontaneous breathing trials (SBT) performed in 42 patients, we prospectively assessed lung ultrasound on four anterior chest wall points. B-lines were counted before and at the end of SBT. We looked for the threshold of B-line increase (Delta-B-lines) that provided the best diagnostic accuracy, compared to the reference diagnosis of WIPO established by experts blinded to lung ultrasound. SBT failed in 33 cases. WIPO occurred in 17 cases and all failed. The best diagnostic accuracy was reached with a Delta-B-lines ≥6. Among WIPO, the number of B-lines increased by ≥ 6 in 15 cases (including 13 cases with an increase of ≥ 8 B-lines). Among the 16 cases with SBT failure but without WIPO, the Delta-B-lines was ≥ 6 in two cases. Among the 33 cases with SBT failure, this profile diagnosed WIPO with a sensitivity of 88% (64-98) and a specificity of 88% (62-98) [area under the receiver operating characteristic curve 0.91 (0.75-0.98)]. Among the 29 cases with SBT success, a Delta-B-lines ≥ 6 occurred in two cases. This study suggests that a Delta-B-lines ≥ 6 on four anterior points allows the diagnosis of WIPO with the best accuracy. This should be confirmed in larger populations.

Effect of early negative fluid balance on the early postoperative recovery in children after surgical repair of congenital heart disease with enlarged right ventricle

Objective To estimate the effect of early fluid removal on the early postoperative recovery in children after surgical repair of congenital heart disease with enlarged right ventricle via a randomized trial. Methods One hundred and twenty patients with right-sided complex congenital heart defect who underwent cardiac surgery by cardiopulmonary bypass during January 2017 to June 2017 were enrolled and were divided into two groups, Group-E and Group-C, when the hemodynamics was stable within 3 hours after the surgery.Patients in Group-E were treated with early fluid removal, but Group-C remained conventional therapy.The data of the hemodynamics and outcomes were collected from the postoperative day to the 2nd day post-operation. Results Fluid removal therapy was started in Group-E at (4.39±0.85) h postoperatively vs(10.17±2.77) h in Group-C (P<0.05). Patients in Group-E showed lower extravascular lung water index (ELWI), lower fluid overload and lower NT-proBNP compared with patients in Group-C on the first day of post-operation(P<0.01). Also, the advantages remained in Group-E on the second day but the ELWI showed no remarkable difference.The rate of reintubation(P<0.05), the duration of mechanical ventilation and the length of ICU stay (P<0.01)were significantly reduced in Group-E. Conclusion In patients with right ventricle enlarged complex congenital heart defect who underwent cardiac surgery by cardiopulmonary bypass, utilizing early negative fluid balance when the hemodynamics are stable and the right ventricle is obviously enlarged could achieve negative fluid balance, get extubated and discharge from ICU earlier, also present lower extravascular lung water index, lower incidence of weaning-induced pulmonary edema and reintubation. Key words: Negative fluid balance; Right ventricle enlargement; Congenital heart disease; Cardiac surgery; Early recovery

Cardiovascular failure and weaning.

Cardiac patients are at high risk of weaning failure due to the abrupt burden to the cardiovascular system resulting from the transition from positive-pressure ventilation to spontaneous breathing. Similarly, numerous patients with borderline cardiac function, left ventricular diastolic dysfunction, chronic obstructive pulmonary disease, especially with associated fluid overload or cumulative positive fluid balance, are at high risk of weaning failure of cardiac origin. The diagnosis of weaning-induced pulmonary oedema (WiPO) relies on the measurement of elevated left ventricular filling pressure, or on the presence of a surrogate reflecting pulmonary or cardiac congestion. Plasma concentration of B-type natriuretic peptide and N-terminal proBNP, biological signs of hemoconcentration (increased circulating protein or hemoglobin levels), or measurement of extravascular pulmonary lung water using transpulmonary thermodilution have been proved valuable surrogates for the identification of weaning failure. Nevertheless, studies have not yet compared these indirect methods to precisely determine their respective diagnostic values for the identification of WiPO, especially in heart failure patients. In addition, none of these approaches directly assess left ventricular filling pressure and the mechanism of WiPO. In contrast, critical care echocardiography is ideally suited to establish the diagnosis of weaning failure of cardiac origin. It allows identifying the high-risk population, monitoring hemodynamically the patient at risk, depicting an abrupt increase of left ventricular filling pressure consistent with WiPO when the patient fails weaning, identifying the underlying mechanism of WiPO, and finally it allows tailoring the therapeutic management of the patient who failed weaning. The impact on patient-centered outcomes of such integrated management strategy based on critical care echocardiography deserves to be prospectively tested in a large population of patients at high risk of weaning failure of cardiac origin.

Difficulty in weaning and cardiopulmonary rehabilitation in inoperable severe mitral regurgitation: a case report

Objective: Severe mitral valve insufficiency may lead to heart failure and associated hemodynamic repercussions, such as congestion and weaning-induced pulmonary oedema. This slows weaning from mechanical ventilation, increases the length of the hospital stay, and worsens the patient’s prognosis. Case report: The present report describes one strategy used for cardiopulmonary rehabilitation and to help wean a patient from mechanical ventilation, with prohibitive comorbidities that contra-indicate surgical mitral valve repair, using respiratory and peripheral muscle training associated with positive pressure ventilation. Discussion: The severe dysfunction of the mitral valve was considered to be surgically inoperable by the surgeon team. However, the weaning and rehabilitation challenges in this patient with severe chronic obstructive pulmonary disease, even with weaning-induced pulmonary edema occurrence, were overcome. The strategy to rehabilitate respiratory muscle force during positive pressure ventilation, concomitantly to a cardiopulmonary rehabilitation program, improved peripheral muscle strength and functionality, reducing energetic demand, allowing the weaning from mechanical ventilation. Conclusion: Despite the severity of the disease, with the adopted strategy it was possible to perform weaning of the mechanical ventilation, allowing the patient to survive with his relatives.

Cardiac dysfunction induced by weaning from mechanical ventilation: incidence, risk factors, and effects of fluid removal.

BackgroundWeaning-induced pulmonary oedema (WiPO) is a well-recognised cause of failure of weaning from mechanical ventilation, but its incidence and risk factors have not been reliably described. We wanted to determine the incidence and risk factors in a population of critically ill patients. In addition, we wanted to describe the effects of diuretics when they are administered in this context.MethodsWe monitored 283 consecutive spontaneous breathing trials (SBT; T-piece trial) performed in 81 patients. In cases with cardiac output monitoring (n = 85, 29 patients), a passive leg raising (PLR) test was performed before SBT. Three experts established the diagnosis of WiPO based on various patient characteristics.ResultsSBT failed in 128 cases (45 % of all SBT). WiPO occurred in 59 % of these failing cases. Compared to patients without WiPO (n = 52), patients with at least one WiPO (n = 29) had a higher prevalence of chronic obstructive pulmonary disease (COPD) (38 % vs. 12 %, respectively; p < 0.01), previous “structural” cardiopathy (dilated and/or hypertrophic and/or hypokinetic cardiopathy and/or significant valvular disease, 9 % vs. 25 %, respectively; p < 0.01), obesity (45 % vs. 17 %, respectively; p < 0.01), and low left ventricular ejection fraction (55 % vs. 21 %, respectively; p = 0.01). At logistic regression, COPD (odds ratio (OR) 8.7, 95 % confidence interval (CI) 2.0–37.3), previous structural cardiopathy (OR 4.5, 95 % CI 1.4–14.1), and obesity (OR 3.6, 95 % CI 1.2–12.6) were independent risk factors for experiencing at least one episode of WiPO. In 16 cases with WiPO and a negative PLR at baseline, treatment including diuretics was started. In 9 of these cases, the PLR remained negative before the following SBT. A new episode of WiPO occurred in 7 of these instances, while the two other were extubated. In 7 other cases, the PLR became positive before the following SBT. WiPO did not occur anymore in 6 of these 7 patients who were extubated, while the remaining one was not.ConclusionsIn our population of critically ill patients, WiPO was responsible for 59 % of weaning failures. COPD, previous “structural” cardiopathy, and, to a lesser extent, obesity were the main risk factors. When a treatment including fluid removal had changed preload-independence to preload-dependence, the following SBT was very likely to succeed.

Weaning the cardiac patient from mechanical ventilation.

Because of heart-lung interactions, weaning from mechanical ventilation induces strong hemodynamic changes that can lead to weaning-induced cardiac failure. Cardiac patients are particularly at risk for this complication. In this review, we will summarize the most recent advances concerning the mechanisms, diagnosis and treatment of weaning-induced cardiac failure. The role of left ventricular diastolic abnormalities contributing to weaning-induced pulmonary edema has been recently emphasized. The most important recent findings concern the diagnostic tools that can be used as alternatives to the pulmonary artery catheter for detecting weaning-induced pulmonary edema during a spontaneous breathing trial, such as increase in estimates of left ventricular filling pressure with echocardiography, increase in B-type natriuretic peptide, increase in plasma protein and hemoglobin concentration and increase in extravascular lung water measured by transpulmonary thermodilution. Concerning the treatment, recent data suggest that fluid removal, which is often indicated in such instances, could be guided by the dosage of B-type natriuretic peptide. Nowadays, the diagnosis of weaning-induced pulmonary edema can be easily made. Identifying such an event is important as an appropriate treatment, guided by the suspected mechanisms leading to the cardiac failure, should hasten weaning from mechanical ventilation.

Extravascular Lung Water, B-Type Natriuretic Peptide, and Blood Volume Contraction Enable Diagnosis of Weaning-Induced Pulmonary Edema*

We tested whether the changes in extravascular lung water indexed for ideal body weight could detect weaning-induced pulmonary edema. We also studied the diagnostic value of blood volume contraction indices and B-type natriuretic peptide variations. Prospective study. Twenty-one patients who failed a first spontaneous breathing trial. None. We performed a second 60-minute T-tube spontaneous breathing trial. Before and at the end of spontaneous breathing trial, we recorded pulmonary artery occlusion pressure, the extravascular lung water indexed for ideal body weight, plasma B-type natriuretic peptide level, hemoglobin, and plasma protein concentrations. Weaning-induced pulmonary edema was defined by the association of signs of clinical intolerance and a pulmonary artery occlusion pressure greater than or equal to 18 mm Hg at the end of spontaneous breathing trial. Because some patients performed several spontaneous breathing trial, a primary analysis included all spontaneous breathing trial and a secondary analysis included only the first spontaneous breathing trial of each patient. In primary analysis, 36 spontaneous breathing trials were analyzed, 21 spontaneous breathing trial with weaning-induced pulmonary edema and 15 without. During spontaneous breathing trial, extravascular lung water indexed for ideal body weight increased only in cases with weaning-induced pulmonary edema (25% ± 23%). Plasma protein concentration, hemoglobin concentration, and B-type natriuretic peptide also significantly increased only in cases with weaning-induced pulmonary edema (9% ± 3%, 9% ± 4%, 21% ± 23%, respectively). The areas under the receiver operating characteristics curves to detect weaning-induced pulmonary edema were 0.89 (95% CI, 0.78-0.99) for extravascular lung water indexed for ideal body weight, 0.97 (0.93-1.01) for spontaneous breathing trial-induced changes in plasma protein concentration, 0.96 (0.90-1.01) for changes in hemoglobin concentration, and 0.76 (0.60-0.93) for changes in B-type natriuretic peptide. An increase in extravascular lung water indexed for ideal body weight greater than or equal to 14% diagnosed weaning-induced pulmonary edema with a sensitivity of 67% (95% CI, 43-85%) and a specificity of 100% (95% CI, 78-100%). The secondary analysis confirmed these results. Spontaneous breathing trial-induced increases in extravascular lung water indexed for ideal body weight, plasma protein concentrations, hemoglobin concentration, and B-type natriuretic peptide are reliable alternatives to the pulmonary artery catheter for diagnosing weaning-induced pulmonary edema.

Extravascular lung water, B-type natriuretic peptide and blood volume contraction for diagnosing weaning-induced pulmonary edema

We compared three different methods for diagnosing pulmonary edema induced by weaning from mechanical ventilation: the increase in extravascular lung water index (EVLWI), the increase in B-type natriuretic peptide (BNP) and blood volume contraction, reflected by increases in plasma protein and in hemoglobin concentrations, all observed during a spontaneous breathing trial (SBT).

Echocardiographic diagnosis of pulmonary artery occlusion pressure elevation during weaning from mechanical ventilation*

Weaning-induced pulmonary edema is a cause of weaning failure in high-risk patients. The diagnosis may require pulmonary artery catheterization to demonstrate increased pulmonary artery occlusion pressure (PAOP) during weaning. Transthoracic echocardiography can estimate left ventricular filling pressures using early (E) and late (A) peak diastolic velocities measured with Doppler transmitral flow, and tissue Doppler imaging of mitral annulus velocities including early (Ea) peak diastolic velocity. We tested the hypothesis that E/A and E/Ea could be used to detect weaning-induced PAOP elevation defined by a PAOP > or =18 mm Hg during a spontaneous breathing trial (SBT). We included 39 patients who previously failed two consecutive SBTs. A third SBT was performed over a maximum 1-hour period using a T-piece. The PAOP, E/A, and E/Ea were measured before and during this SBT. Receiver operating characteristic curves were constructed to determine the optimal sensitivity and specificity values of E/A and E/Ea obtained at the end of the SBT for predicting a weaning-induced PAOP elevation. Weaning-induced PAOP elevation occurred in 17 patients. A value of E/A >0.95 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 88% and a specificity of 68%. A value of E/Ea >8.5 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 94% and a specificity of 73%. The combination of E/A >0.95 and E/Ea >8.5 predicted a weaning-induced PAOP elevation with a sensitivity of 82% and a specificity of 91%. At the end of an SBT, the combination of E/A >0.95 and E/Ea >8.5 measured with transthoracic echocardiography allowed an accurate noninvasive detection of weaning-induced PAOP elevation.

Increase in plasma protein concentration for diagnosing weaning-induced pulmonary oedema

Weaning-induced cardiogenic pulmonary oedema is a cause of weaning failure that is classically diagnosed by an increase in pulmonary artery occlusion pressure during a spontaneous breathing trial. During cardiogenic pulmonary oedema, a hypo-oncotic fluid is filtered toward the interstitial space. Thus, we tested whether the changes in plasma protein concentration during a weaning trial could diagnose weaning-induced pulmonary oedema. Prospective study. The 24-bed medical intensive care unit of a university hospital. Forty-six patients who had failed two weaning trials. Weaning-induced pulmonary oedema was diagnosed if a respiratory failure associated with an increase in pulmonary artery occlusion pressure above 18 mmHg occurred during a third weaning trial on a T-tube. The plasma protein concentration was measured before and at the end of the spontaneous breathing trial. During the weaning trial, pulmonary oedema was observed in 24 patients. In these patients, the plasma protein concentration increased by 11% (3-25%). The plasma protein concentration did not change significantly in patients who did not experience weaning-induced pulmonary oedema. An increase in the plasma protein concentration greater than 6% from baseline to the end of the weaning trial allowed detecting a weaning-induced pulmonary oedema with a sensitivity of 87% and a specificity of 95%. The acute changes in plasma protein concentration during a weaning trial represent an alternative method to right heart catheterisation for assessing weaning-induced pulmonary oedema.

How to diagnose weaning-induced pulmonary edema?

How to diagnose weaning-induced pulmonary edema?

Dysfonction cardiaque gauche lors du sevrage de la ventilation mécanique

The transfer from positive pressure mechanical ventilation to negative pressure spontaneous ventilation may induce a left-side cardiac dysfunction that may lead to weaning failure. This left-side cardiac dysfunction results from several pathophysiological mechanisms that are the consequences of heart-lung interaction. In particular, weaning from mechanical ventilation increases the left ventricular afterload and may induce a myocardial ischemia. In patients with a pre-existing heart disease, these phenomena result in an increase in the left ventricular filling pressures. The diagnosis of weaning-induced pulmonary edema is based at best on the measurement of the pulmonary artery occlusion pressure. This measurement also enables to guide therapy that aims at preventing the occurrence of myocardial ischemia and at reducing the left ventricular afterload during weaning.