Appraising pulmonary edema using supine chest roentgenograms in ventilated patients

Prediction of hemodynamic tolerance of intermittent hemodialysis in critically ill patients: a cohort study

The evaluation and management of fluid balance are key challenges when caring for critically ill patients requiring renal replacement therapy. The aim of this study was to assess the ability of clinical judgment and other variables to predict the occurrence of hypotension during intermittent hemodialysis (IHD) in critically ill patients. This was a prospective, observational, single-center study involving critically ill patients undergoing IHD. The clinical judgment of hypervolemia was determined by the managing nephrologists and critical care physicians in charge of the patients on the basis of the clinical data used to calculate the ultrafiltration volume and rate for each dialysis treatment. Seventy-nine (31.9%) patients presented with hypotension during IHD. Patients were perceived as being hypervolemic in 109 (43.9%) of the cases by nephrologists and in 107 (43.1%) by intensivists. The agreement between nephrologists and intensivists was weak (kappa = 0.561). Receiver operating characteristic curve analysis yielded an AUC of 0.81 (95% CI 0.75 to 0.84; P < 0.0001), and a cutoff value of 70 mm for the vascular pedicle width (VPW) had the highest accuracy for the prediction of the absence of hypotension. The clinical judgment of hypervolemia did not predict hypotension during IHD. The high predictive ability of the VPW may assist clinicians with critical thinking.

Interdependence of VA-ECMO output, pulmonary congestion and outcome after cardiac surgery

BACKGROUND

Venoarterial-extracorporeal membrane oxygenation (VA-ECMO) is a life-saving method for patients with low-output failure after cardiac surgery. However, VA-ECMO therapy may increase left ventricular afterload due to retrograde blood flow in the aorta, which may lead to progression of pulmonary congestion. We examined the predictive value of pulmonary congestion in patients that need VA-ECMO support after cardiovascular surgery.

METHODS

We enrolled a total of 266 adult patients undergoing VA-ECMO support following cardiovascular surgery at a university-affiliated tertiary care centre into our single-center registry. Pulmonary edema was assessed on bedside chest X rays at day 0, 3, 5 after VA-ECMO implantation.

RESULTS

Median age was 65 (57-72) years, 69% of patients were male and 30-day survival was 63%. At ICU-admission 20% of patients had mild, 54% had moderate and 26% showed severe pulmonary congestion. Pulmonary congestion at day 0 was not associated with outcome (adjusted HR 1.31; 95%-CI 0.89-1.93;P = 0.18), whereas pulmonary congestion at day 3 (adj. HR 2.81; 95%-CI 1.76-4.46;P<0.001) and day 5 (adj. HR 3.01;95%-CI 1.84-4.93;P<0.001) was significantly associated with survival. Linear regression revealed that out of left ventricular function, cardiac output, central venous saturation, maximum dobutamine and norepinephrine dose as well as fluid balance solely ECMO rotation was associated with the evolution of pulmonary congestion (P = 0.007).

CONCLUSIONS

Pulmonary edema three and five days after ECMO implantation are associated with poor survival. Interestingly, a high VA-ECMO output was the most important determinant of worsening pulmonary congestion within the first five days.

Simple quantitative chest CT for pulmonary edema

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Quantitative CT is a highly accurate but underutilized method for identifying pulmonary edema on CT.

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There is a moderatelystrong correlation between CT HUs and CXR pulmonary edema grade in every lobe with correlation coefficients ranging from 0.585−0.685.

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CT Hounsfield unit measurement yields excellent accuracy in differentiating no edema from mild to severe edema, with AUCs up to 0.995 in the LUL.

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Qualitative CT with a % versus 84 % and specificity 95 % versus 78 Qualitative CT with a HU cut-off of -825 in the LUL is more sensitive (100% vs 84%) and specific (95% vs 78%) than qualitative CT.

Purpose

To determine the accuracy of quantitative CT to diagnose pulmonary edema compared to qualitative CT and CXR and to determine a threshold Hounsfield unit (HU) measurement for pulmonary edema on CT examinations.

Method

Electronic medical records were searched for patients with a billing diagnosis of heart failure and a Chest CT and CXR performed within three hours between 1/1/2016 to 10/1/2016, yielding 100 patients. CXR and CT examinations were scored for the presence and severity of edema, using a 0–5 scale, and CT HU measurements were obtained in each lobe. Polyserial correlation coefficients evaluated the association between CT HUs and CXR scores, and receiver operating characteristic (ROC) curve analysis determined a cutoff CT HU value for identification of pulmonary edema.

Results

Correlation between CT HU and CXR score was moderately strong (r = 0.585−0.685) with CT HU measurements demonstrating good to excellent accuracy in differentiating between no edema (grade 0) and mild to severe edema (grades 1–5) in every lobe, with AUCs ranging between 0.869 and 0.995. The left upper lobe demonstrated the highest accuracy, using a cutoff value of -825 HU (AUC of 0.995, sensitivity = 100 % and specificity = 95.1 %). Additionally, qualitative CT evaluation was less sensitive (84 %) than portable CXR in identifying pulmonary edema. However, quantitative CT evaluation was as sensitive as portable CXR (100 %) and highly specific (95 %).

Conclusions

Quantitative CT enables the identification of pulmonary edema with high accuracy and demonstrates a greater sensitivity than qualitative CT in assessment of pulmonary edema.

ERS statement on chest imaging in acute respiratory failure

Chest imaging in patients with acute respiratory failure plays an important role in diagnosing, monitoring and assessing the underlying disease. The available modalities range from plain chest X-ray to computed tomography, lung ultrasound, electrical impedance tomography and positron emission tomography. Surprisingly, there are presently no clear-cut recommendations for critical care physicians regarding indications for and limitations of these different techniques.The purpose of the present European Respiratory Society (ERS) statement is to provide physicians with a comprehensive clinical review of chest imaging techniques for the assessment of patients with acute respiratory failure, based on the scientific evidence as identified by systematic searches. For each of these imaging techniques, the panel evaluated the following items: possible indications, technical aspects, qualitative and quantitative analysis of lung morphology and the potential interplay with mechanical ventilation. A systematic search of the literature was performed from inception to September 2018. A first search provided 1833 references. After evaluating the full text and discussion among the committee, 135 references were used to prepare the current statement.These chest imaging techniques allow a better assessment and understanding of the pathogenesis and pathophysiology of patients with acute respiratory failure, but have different indications and can provide additional information to each other.

The PCQP Score for Volume Status of Acutely Ill Patients: Integrating Vascular Pedicle Width, Caval Index, Respiratory Variability of the QRS Complex and R Wave Amplitude

Introduction

Techniques for measuring volume status of critically ill patients include invasive, less invasive, or noninvasive ones. The present study aims to assess the accuracy of noninvasive techniques for measuring volume status of critically ill patients.

Patients and Methods

A total of 111 critically ill patients admitted to the emergency department and undergoing central venous catheterization were included in the study. Five parameters were measured including vascular pedicle width (VPW), diameter of inferior vena cava, caval index, respiratory changes in QRS, and P wave amplitude. Patients with risk factors which could decrease the accuracy of central venous pressure (CVP) value were excluded from study. We compared these parameters with static CVP parameter. Finally, based on the afore-mentioned parameters, PCQP role in criteria was designed.

Results

In detecting loss of circulating blood volume, area under the curve of VPW was 0.92 (90%, confidence interval [CI]: 0.85-0.99), diameter of inferior vena cava was 0.82 (90%, CI: 0.72-0.91), caval index was 0.9 (90%, CI: 0.82-0.98), and changes in QRS and P waves were 0.88 (95%, CI: 0.81-0.95) and 0.73 (95%, CI: 0.63-0.82), respectively. PCQP role in criteria was designed according to these parameters, and at its best cutoff point (score 6), VPW had a sensitivity of 97.4% (95%, CI: 84.57-99.99) and specificity of 83.6% (95%, CI: 72.65-90.86) for the detection of loss of circulating blood volume (<8 cmH₂O).

Conclusion

PCQP score could be a reliable and noninvasive technique for the assessment of volume status in critically ill patients.

Imaging of nontraumatic thoracic emergencies

PURPOSE OF REVIEW

Acute chest symptoms form an important incentive for imaging in the emergency setting. This review discusses the radiologic features of various vascular and pulmonary diseases leading to acute respiratory distress and recent developments on important emergency radiologic examinations.

RECENT FINDINGS

Recently, triple-rule-out computed tomography protocol was introduced in diagnosis of chest pain, and advancing computed tomography technology and knowledge have led to discussion on treatment of pulmonary embolism. Diffuse pulmonary opacities remain a diagnostic dilemma in the emergency setting and although imaging findings can often be nonspecific, they help in guiding toward accurate diagnosis and timely management.

SUMMARY

Though promising, triple-rule-out is not yet justified because of low incidence of additional findings compared with conventional computed tomography angiography in chest pain, but it might be suited for clinical practice in the near future. Relevance of isolated subsegmental pulmonary embolism is unknown and research on this topic is needed and on its way. We provided some key findings in differentiating diffuse pulmonary opacities and describe the additional value of chest ultrasound in this clinical dilemma. A brief sidestep to pneumothorax is made, as this is also a frequent finding in the acute dyspneic patient, as well as in patients with acute chest pain.

Introduction to the Interpretation of Chest Radiographs during Donor Care

Organ procurement coordinators often provide independent interpretations of chest radiographs during donor care. Catheter or tube position, lobar atelectasis, extra-alveolar air, air bronchograms, pleural fluid, and other findings are important throughout donor care and when deciding if a lung is acceptable for transplantation. Technical factors, features of a normal chest radiograph, and abnormal radiographic findings are reviewed and examples are presented.

Measurement of the vascular pedicle width predicts fluid repletion: a cross-sectional comparison with inferior vena cava ultrasound and lung comets

Background

Determination of a patient’s volume status remains challenging. Ultrasound assessments of the inferior vena cava and lung parenchyma have been shown to reflect fluid status when compared to the more traditional static and dynamic methods. Yet, resource-limited intensive care units (ICUs) may still not have access to bedside ultrasound. The vascular pedicle width (VPW) measured on chest radiographs remains underutilized for fluid assessment. In this study, we aimed to determine the correlation between ultrasound assessment and vascular pedicle width and to identify a discriminant value that predicted a fluid replete state.

Methods

Eighty-four data points of simultaneous VPW and inferior vena cava measurements were collected on mechanically ventilated patients. VPW measurements were compared with lung comet scores, fluid balance, and a composite variable of inferior vena cava diameter greater than or equal to 2 cm and variability less than 15 %.

Results

A VPW of 64 mm accurately predicted fluid repletion with a positive predictive value equal to 88.5 % and an area under the curve (AUC) of 0.843, 95 % CI 0.75–0.93, p < 0.001. VPW closely correlated with inferior vena cava diameter (Pearson’s r = 0.64, p = <0.001). Poor correlations were observed between VPW and lung comet score, Pearson’s r = 0.12, p = 0.26, fluid balance, Pearson’s r = 0.3, p = 0.058, and beta natriuretic peptide, Pearson’s r = 0.12, p = 0.26.

Conclusions

This study shows a high predictive ability of the VPW for fluid repletion, as compared to an accepted method of volume assessment. Given the relationship of fluid overload and mortality, these results may assist fluid resuscitation in resource-limited intensive care units.

Imaging of acute respiratory distress syndrome

IMPORTANCE OF THE FIELD

Acute respiratory distress syndrome (ARDS) describes a relatively common and frequently lethal syndrome at the severe end of the spectrum of acute lung injury. Onset of symptoms is usually within 72 h of the inciting event and complicates a wide variety of clinical disorders, ranging from infection to trauma. It may be defined as resistant hypoxaemia in the clinical setting of one of the group of recognised causes, in association with bilateral pulmonary infiltrates and in the absence of left atrial hypertension. Accurate diagnosis and differentiation from other treatable conditions is crucial.

AREAS COVERED IN THIS REVIEW

This publication addresses the clinical and radiological features of ARDS, a review of the imaging technology with illustrations and differential diagnosis.

WHAT THE READER WILL GAIN

This paper will give insight into the strengths and weaknesses of imaging modalities used in the management of patients with ARDS.

TAKE HOME MESSAGE

Imaging plays a vital role in the assessment of acute respiratory syndromes. Computed tomography is much more sensitive compared with chest radiography, and relatively under-utilised. Other methods, such as bedside ultrasound and impedance tomography, may have roles to play in the future.

Revisiting Clinical Utility of Chest Radiography and Electrocardiogram to Determine Ischemic Stroke Subtypes: Special Reference on Vascular Pedicle Width and Maximal P-Wave Duration

BACKGROUNDS

It is often difficult to diagnose stroke subtypes at admission, particularly in sinus rhythm cases. Vascular pedicle width (VPW) on chest X-ray (CXR) and maximal P-wave duration (P-max) on electrocardiogram (ECG) are again realized as useful parameters reflecting intravascular volume and atrial conduction status, respectively. We investigated the utility of VPW and P-max as a tool for differentiating ischemic stroke subtypes.

METHODS

We studied 343 acute stroke patients showing sinus rhythm on admission. Dividing the patients into cardioembolic (CE) stroke (n = 57) and non-CE (n = 286) groups, we compared clinical backgrounds including VPW on CXR, and P-max in lead II and premature atrial contraction (PAC) on 12-leads ECG. Then, we investigated the independent factors for CE.

RESULTS

Independent factors associated with CE were VPW (≥59.3 mm) (p < 0.001; odds ratio (OR), 10.12; 95% confidence interval (CI), 4.13-24.8), P-max in lead II (≥120 ms) (p < 0.001; OR, 8.61; 95% CI, 3.96-18.7), PAC (p = 0.002; OR, 7.35; 95% CI, 2.14-25.3) and D-dimer level (≥1.11 µg/ml) (p = 0.016; OR, 2.57; 95% CI, 1.20-5.51).

CONCLUSIONS

VPW, P-max, PAC and D-dimer are useful parameters for diagnosing CE stroke in patients with sinus rhythm at admission.

Percutaneous left atrial decompression in patients supported with extracorporeal membrane oxygenation for cardiac disease

OBJECTIVES

Left atrial decompression using cardiac catheterization techniques has been described at centers with extracorporeal membrane oxygenation programs. Left atrial decompression can decrease cardiogenic edema, minimize ventricular distension, and allow myocardial recovery. We describe Boston Children's Hospital's experience with percutaneous left atrial decompression techniques, acute outcomes, and clinical impact of left atrial decompression in extracorporeal membrane oxygenation patients.

SUBJECTS

Patients supported with extracorporeal membrane oxygenation undergoing percutaneous left atrial decompression were identified and assigned to two groups 1) myocarditis/suspected myocarditis or 2) nonmyocarditis cardiac disease.

INTERVENTIONS

Three techniques including vent placement, static balloon dilation, and stent implantation were used.

MEASUREMENTS AND MAIN RESULTS

Change in left atrial pressure and severity of pulmonary edema on chest radiography pre and post procedure, impact of timing and technique of left atrial decompression on resolution of left atrial hypertension, and extracorporeal membrane oxygenation survival were evaluated. Furthermore, we evaluated the presence of residual atrial septal defect during follow-up. Percutaneous left atrial decompression was performed in 44 of 419 extracorporeal membrane oxygenation cases (10.5%) and was frequently used for myocarditis (22 of 44 patients; 50%). Techniques included 25 vents, 17 static balloon dilations, and two stents. All techniques were equally successful and significantly reduced left atrial pressure and pulmonary edema. Survival to hospital discharge was not associated with extracorporeal membrane oxygenation duration prior to left atrial decompression, change in left atrial pressure, or technique used. Persistent atrial septal defect was noted in five surviving patients (excluding transplant recipients and deceased), two required closure.

CONCLUSIONS

Left atrial decompression can be performed effectively in children on extracorporeal membrane oxygenation using various percutaneous techniques. Reduction in pulmonary venous congestion is usually evident by chest radiography within 48 hours of intervention. Persistent atrial septal defect may require closure at the time of extracorporeal membrane oxygenation decannulation or during long-term follow-up.

Validation of the vascular pedicle width as a diagnostic aid in critically ill patients with pulmonary oedema by novice non-radiology physicians-in-training

Assessing intravascular volume status in the critically ill patient remains a challenge for intensivists, and the accuracy of such estimation based on bedside examination alone is reported to be nearly a coin toss. In this retrospective study we sought to validate a previously recommended chest radiographic vascular pedicle width (VPW) ≥70 mm for identifying cardiogenic pulmonary oedema (CPO). We additionally assessed whether novice physicians-in-training can reliably measure the VPW. The study included intensive care patients with an existing pulmonary artery catheter. Three independent raters performed measurements of VPW from chest radiographs obtained within three hours of pulmonary artery occlusion pressure measurements. In 80 patients enrolled, a VPW cut-off of ≥70 mm had a 55% sensitivity, 88% specificity, 81% positive predictive value, 69% negative predictive value and 73% accuracy for identifying patients with CPO. Receiver operating characteristic curve analysis showed an area under the curve of 0.72 (95% confidence interval 0.61 to 0.84) for VPW in discriminating CPO from non-cardiogenic pulmonary oedema. Kappa statistics for inter-rater reliability showed Kappa=0.41, 0.42 and 0.85 for each pair of the three raters. In conclusion, the previously accepted VPW cut-off of ≥70 mm is reasonably accurate in discriminating CPO from non-cardiogenic pulmonary oedema. VPW can be measured by physicians-in-training with a comparable performance to previous studies utilising expert radiologists.

Assessment of intravascular volume status and volume responsiveness in critically ill patients

Accurate assessment of a patient's volume status, as well as whether they will respond to a fluid challenge with an increase in cardiac output, is a critical task in the care of critically ill patients. Despite this, most decisions regarding fluid therapy are made either empirically or with limited and poor data. Given recent data highlighting the negative impact of either inadequate or overaggressive fluid therapy, understanding the tools and techniques available for accurate volume assessment is critical. This review highlights both static and dynamic methods that can be utilized to help in the assessment of volume status.

Vascular pedicle width on chest radiograph as a measure of volume overload: meta-analysis

INTRODUCTION

Vascular pedicle width (VPW), a measurement obtained from a chest radiograph (CR), is thought to be an indicator of circulating blood volume. To date there are only a handful of studies that demonstrate a correlation between high VPW and volume overload, each utilizing different VPW values and CR techniques. Our objective was to determine a mean VPW measurement from erect and supine CRs and to determine whether VPW correlates with volume overload.

METHODS

MEDLINE database, Web of Science, and the Cochrane Central Register of Controlled Trials were searched electronically for relevant articles. References from the original and review publications selected electronically were manually searched for additional relevant articles. Two investigators independently reviewed relevant articles for inclusion criteria and data extraction. Mean VPW measurements from both supine and erect CRs and their correlation with volume overload were calculated.

RESULTS

Data from 8 studies with a total of 363 subjects were included, resulting in mean VPW measurements of 71 mm (95% confidence interval [CI] 64.9-77.3) and 62 mm (95% CI 49.3-75.1) for supine and erect CRs, respectively. The correlation coefficients for volume overload and VPW were 0.81 (95% CI 0.74-0.86) for both CR techniques and 0.81 (95% CI 0.72-0.87) for supine CR and 0.80 (95% CI 0.69-0.87) for erect CR, respectively.

CONCLUSION

There is a clinical and statistical correlation between VPW and volume overload. VPW may be used to evaluate the volume status of a patient regardless of the CR technique used.

[Thoracic radiology in the intensive care unit]

The clinical evaluation of the intensive care unit patient is based upon multiple parameters, including portable chest x-ray examination. Knowledge of the methods, capabilities, and limitations is prerequisite for a legally correct and medically reasonable approach. This report provides basic knowledge about pleural und pulmonary pathologies, e.g., pneumothorax, pleural effusion, atelectasis, aspiration, pneumonia, lung edema, and acute respiratory distress syndrome.

Vascular pedicle width in acute lung injury: correlation with intravascular pressures and ability to discriminate fluid status

INTRODUCTION

Conservative fluid management in patients with acute lung injury (ALI) increases time alive and free from mechanical ventilation. Vascular pedicle width (VPW) is a non-invasive measurement of intravascular volume status. The VPW was studied in ALI patients to determine the correlation between VPW and intravascular pressure measurements and whether VPW could predict fluid status.

METHODS

This retrospective cohort study involved 152 patients with ALI enrolled in the Fluid and Catheter Treatment Trial (FACTT) from five NHLBI ARDS (Acute Respiratory Distress Syndrome) Network sites. VPW and central venous pressure (CVP) or pulmonary artery occlusion pressure (PAOP) from the first four study days were correlated. The relationships between VPW, positive end-expiratory pressure (PEEP), cumulative fluid balance, and PAOP were also evaluated. Receiver operator characteristic (ROC) curves were used to determine the ability of VPW to detect PAOP < 8 mmHg and PAOP ≥ 18 mm Hg.

RESULTS

A total of 71 and 152 patients provided 118 and 276 paired VPW/PAOP and VPW/CVP measurements, respectively. VPW correlated with PAOP (r = 0.41; P < 0.001) and less well with CVP (r = 0.21; P = 0.001). In linear regression, VPW correlated with PAOP 1.5-fold better than cumulative fluid balance and 2.5-fold better than PEEP. VPW discriminated achievement of PAOP < 8 mm Hg (AUC = 0.73; P = 0.04) with VPW ≤67 mm demonstrating 71% sensitivity (95% CI 30 to 95%) and 68% specificity (95% CI 59 to 75%). For discriminating a hydrostatic component of the edema (that is, PAOP ≥ 18 mm Hg), VPW ≥ 72 mm demonstrated 61.4% sensitivity (95% CI 47 to 74%) and 61% specificity (49 to 71%) (area under the curve (AUC) 0.69; P = 0.001).

CONCLUSIONS

VPW correlates with PAOP better than CVP in patients with ALI. Due to its only moderate sensitivity and specificity, the ability of VPW to discriminate fluid status in patients with acute lung injury is limited and should only be considered when intravascular pressures are unavailable.

Radiographic measures of intravascular volume status: the role of vascular pedicle width

PURPOSE OF REVIEW

A valid, low-cost, high-yield instrument to assess intravascular volume status in critically ill patients does not exist. The portable chest X-ray is a common part of any intensivist's or chest clinician's daily rounds.

RECENT FINDINGS

A simple, objective, valid measure of intravascular volume status, the vascular pedicle width, remains underappreciated in the medical literature. While more invasive, more expensive, and less common technologies are looked upon to assist in the clinical evaluation of volume status among critically ill patients, the vascular pedicle width stands alone in its low-cost, nearly risk-free potential to impact clinical practice. Even as the daily chest X-ray has become less common in practice, the role of measuring vascular pedicle width is potentially significant, particularly among mechanically ventilated patients. A standardized approach to reading the portable chest X-ray (supine or erect) is needed to facilitate interpretation of complex medical problems among the critically ill. Prospective evaluation of its appropriate use, particularly as compared with other, typically more invasive measures of intravascular volume, is warranted.

SUMMARY

Vascular pedicle width measurement using a standardized approach to daily chest X-ray interpretation represents untapped potential for improving the non-invasive assessment of volume status in critically ill patients.

Simple vs complex radionuclide methods of assessing capillary protein permeability for diagnosing acute respiratory distress syndrome

PURPOSE

Using injection of gallium Ga 67 transferrin, technetium Tc 99m red cells, probes over the lungs, and blood samples, a pulmonary leak index (PLI) and pulmonary transcapillary escape rate (PTCER) for transferrin can be measured. This may help differentiating between cardiogenic pulmonary edema (CPE) and permeability (noncardiogenic) pulmonary edema of the acute respiratory distress syndrome (ARDS). The purpose of the study was to evaluate the relative importance of red cell labeling, blood sampling, and probe measurements in this assessment.

MATERIALS AND METHODS

Analysis of radionuclide data obtained in consecutive patients with radiographic evidence for pulmonary edema, classified as ARDS (n = 13), CPE (n = 8), or mixed (n = 5), was performed. The latter patients met ARDS criteria except for a high pulmonary capillary wedge pressure.

RESULTS

The PLI, PTCER, and the (67)Ga-lung/blood radioactivity increase (without (99m)Tc-red cell data) were specific and sensitive indices to differentiate ARDS/mixed from CPE. The blood transcapillary escape rate (TER) of (67)Ga-transferrin was about 2- to 6-fold higher in ARDS and mixed than in CPE. The TER had similar diagnostic value as the PLI, PTCER, and the (67)Ga-lung/blood radioactivity ratio increase.

CONCLUSIONS

The diagnostic value of the simple blood TER of (67)Ga-transferrin is similar to that of complex methods, using (99m)Tc-red cells and probe measurements over the lungs, because the complex methods largely depend on the blood TER. Simplification of the method without red cell labeling and probes may facilitate bedside use to diagnose permeability edema of ARDS, particularly in the absence of a pulmonary artery catheter.

Clinical relevance of time of onset, duration, and type of pulmonary edema after liver transplantation

We investigated the clinical significance of time of onset, duration, and type of pulmonary edema after orthotopic liver transplantation by retrospectively reviewing 93 consecutive recipients. Pulmonary edema was diagnosed by means of radiographic criteria and Pao(2)/Fio(2) ratio <300. Type was identified by pulmonary artery wedge pressure (hydrostatic, >18 mm Hg; permeability, < or =18 mm Hg). Of 91 evaluable patients, 44 (48%) had no pulmonary edema, 23 (25%) had immediate pulmonary edema resolving within 24 hours, 8 (9%) had late pulmonary edema (developing de novo in the first 16 to 24 hours), and 16 (18%) had persistent pulmonary edema (developing immediately and persisting for at least 16 hours). At 16 to 24 hours, mean arterial pressure was lower with persistent permeability-type edema than without pulmonary edema (75 versus 87 mm Hg, P <.01). Patients with persistent permeability-type edema had higher mean pulmonary arterial pressure (23 versus 16 mm Hg, P <.01) and higher pulmonary vascular resistance (103 versus 53 dyn. second. m(-5), P <.05), consistent with a resistance-dependent mechanism. Patients with persistent hydrostatic-type edema did not differ from those without edema in mean arterial pressure (84 versus 87 mm Hg, P >.05) or pulmonary vascular resistance (67 versus 53 dyn. second. m(-5), P >.05), but had increased mean pulmonary arterial pressure (27 versus 16, P <.01), suggesting a flow volume-dependent mechanism. Duration of mechanical ventilation, intensive care, and hospital stay were prolonged in patients with late or persistent permeability-type edema but not in patients with immediate pulmonary edema of any type. In conclusion, immediate pulmonary edema resolving within 24 hours after liver transplantation had little clinical consequence; persistent permeability-type pulmonary edema portended a worse outcome.

Findings on the portable chest radiograph correlate with fluid balance in critically ill patients

STUDY OBJECTIVES

Fluid balance concerns occur daily in critically ill patients, complicated by difficulties assessing intravascular volume. Chest radiographs (CXRs) quantify pulmonary edema in acute lung injury (ALI) and total blood volume in normal subjects. We hypothesized that CXRs would reflect temporal changes in fluid balance in critically ill patients.

DESIGN

Standardized scoring of 133 supine, portable, anteroposterior CXRs. Outcomes included subjective and objective measures of intravascular volume and pulmonary edema.

SETTING

Academic university medical center and affiliated Veterans Affairs hospital.

PATIENTS

Thirty-seven patients with ALI receiving mechanical ventilation blindly randomized to treatment with diuretics and colloids or dual placebo for 5 days.

MEASUREMENTS AND RESULTS

Treated patients experienced a 3.3-L diuresis and 10-kg weight loss during the 5-day period. A significant correlation was observed in all patients between changes in vascular pedicle width (VPW) and net intake/output (r = 0.50, p = 0.01) or weight (r = 0.51, p = 0.01). The correlation between VPW and fluid balance was greatest for weight changes in the treatment group alone (r = 0.71, p = 0.005). Pulmonary artery occlusion pressure correlated highly with changes in VPW (r = 0.70, p < 0.001). After day 1, CXRs revealed significant between-group differences in VPW without changes in cardiothoracic ratio or subjective measures of edema. The proportion of patients with VPW < 70 mm did not differ at baseline but was significantly more in the treatment group on all subsequent days (p < 0.05).

CONCLUSIONS

We conclude that temporal fluid balance changes are reflected on commonly utilized portable CXRs. Objective radiographic measures of intravascular volume may be more appropriate indicators of fluid balance than subjective measures, with VPW appearing most sensitive. If systematically quantitated, serial CXRs provide a substantial supplement to other clinically available data for the purpose of fluid management in critically ill patients.

Using the chest radiograph to determine intravascular volume status: the role of vascular pedicle width

Due to concerns about the efficacy and safety of using pulmonary artery catheterization to evaluate hemodynamic status, noninvasive diagnostic testing has gained increased importance. This article focuses on both the supportive evidence and the limitations of applying the vascular pedicle width (VPW), which is the mediastinal silhouette of the great vessels, as an aid in the assessment of patients' intravascular volume status. The objective measurement of the VPW obtained from either upright or supine chest radiographs (CXRs which are often already available though not fully utilized) can increase the accuracy of the clinical and radiographic assessment of intravascular volume status by 15 to 30%, and this value may be even higher when VPW is used serially within the same patient. Regardless of the presence or absence of pulmonary edema, the best VPW cutoff for differentiating a high vs normal to low intravascular volume status is 70 mm. Patients with a VPW of > 70 mm coupled with a cardiothoracic ratio of > 0.55 are more than three times more likely to have a pulmonary artery occlusion pressure > 18 mm Hg than are patients without these radiographic findings. We suggest a management algorithm for utilizing the VPW, and whether or not such an approach will offer superior patient outcomes requires prospective investigation. Reappraisal of the VPW and other roentgenographic signs should be incorporated into newly implemented studies of the Swan-Ganz catheter, ICU echocardiography, portable CT scans, and other costlier technologies. While such investigations may refine the optimum application of the portable CXR, conventional and digital supine radiographs should retain an important role in the diagnosis and management of critically ill patients. Lastly, the measurement of the VPW should be incorporated into the training of chest clinicians and radiologists.

The pulmonary physician in critical care 1: pulmonary investigations for acute respiratory failure

This is the first in a series of reviews of the role of the pulmonary physician in critical care medicine. The investigation of mechanically ventilated patients is discussed, with particular reference to those presenting with acute respiratory failure and diffuse pulmonary infiltrates.

Radiologic determination of intravascular volume status using portable, digital chest radiography: a prospective investigation in 100 patients

OBJECTIVE

To answer the following questions: Can the digital chest roentgenogram (CXR) be used to differentiate patients' volume status? Do clinical data alter radiologists' accuracy in interpreting the digital CXR?

DESIGN

Prospective cohort study.

SETTING

Nine adult intensive care units of a tertiary care medical center.

PATIENTS

One hundred thirty-five consecutive patients with pulmonary artery catheters, of whom 35 were excluded because of unacceptable pulmonary artery occlusion pressure (PAOP) tracings.

METHODS

Each patient had a portable, anteroposterior, supine digital CXR. Clinicians evaluated volume status and then measured hemodynamic data within 1 hr of the CXR. Digital CXRs were independently interpreted on two separate occasions (with and without clinical information) by three experienced chest radiologists, and these interpretations were compared with hemodynamic data.

RESULTS

Of the 100 patients, 39 had PAOP >18 mm Hg, whereas 61 had PAOP <18 mm Hg. Radiologists' accuracy in differentiating volume status increased with incorporation of clinical data (56% without vs. 65% with clinical data, p =.009). Using objective receiver operating characteristic-derived cutoffs of 70 mm for vascular pedicle width and 0.55 for cardiothoracic ratio, radiologists' accuracy in differentiating PAOP >18 mm Hg from PAOP <18 mm Hg was 70%. The intrareader and the inter-reader correlation coefficients were very high. The likelihood ratio of the CXR in determining volume status using the objective vascular pedicle width and cardiothoracic ratio measures was 3.1 (95% confidence interval, 1.9-6.0), significantly higher than subjective CXR interpretations with and without clinical data (p <.001).

CONCLUSIONS

Differentiating intravascular volume status with portable, supine, digital CXRs may be improved by using objective cutoffs of vascular pedicle width >70 mm and cardiothoracic ratio >0.55 or by incorporating clinical data.