Pleural effusion decreases left ventricular pre-load and causes haemodynamic compromise: an experimental porcine study

Pleural Effusion and Invasive Hemodynamic Measurements in Advanced Heart Failure

BACKGROUND

Pleural effusion is present in 50% to 80% of patients with acute heart failure, depending on image modality. We aim to describe the association between the presence and size of pleural effusion and central hemodynamics, including pulmonary capillary wedge pressure (PCWP) in an advanced heart failure population.

METHODS

An observational, cross-sectional study in a cohort of patients with advanced heart failure (left ventricular ejection fraction ≤45%) who underwent right heart catheterization at The Department of Cardiology at Copenhagen University Hospital, Rigshospitalet, Denmark, between January 1, 2002 and October 31, 2020. The presence and size of pleural effusion were determined by a semiquantitative score of chest x-rays or computed tomography scans performed within 2 days of right heart catheterization.

RESULTS

In 346 patients (50±13 years; 78% males) with median left ventricular ejection fraction of 20% (15-25), we identified 162 (47%) with pleural effusion. The pleural effusion size was medium in 38 (24%) and large in 30 (19%). Patients with pleural effusion had a 4.3 mm Hg (2.5-6.1) higher PCWP and 2.4 mm Hg (1.2-3.6) higher central venous pressure (P<0.001 for both). Patients with a medium/large pleural effusion had statistically significantly higher filling pressures than patients with a small effusion. Higher PCWP (odds ratio [OR], 1.06 [1.03-1.10]) and central venous pressure (OR, 1.09 [1.05-1.15]) were associated with pleural effusion in multivariable logistic regression adjusted for age, sex, and heart failure medications (P<0.001 for both). In a subgroup of 204 (63%) patients with serum albumin data, PCWP (OR, 1.06 [1.01-1.11]; P=0.032), central venous pressure (OR, 1.14 [1.06-1.23]; P<0.001) and serum albumin level (OR, 0.89 [0.83-0.95]; P<0.001) were independently associated with the presence of a medium/large-sized pleural effusion.

CONCLUSIONS

In patients with left ventricular ejection fraction ≤45% undergoing right heart catheterization as part of advanced heart failure work-up, pleural effusion was associated with higher PCWP and central venous pressure and lower serum albumin.

Acute kidney injury in hospitalized patients with nonmalignant pleural effusions: a retrospective cohort study

BACKGROUND

Nonmalignant pleural effusion (NMPE) is common and remains a definite health care problem. Pleural effusion was supposed to be a risk factor for acute kidney injury (AKI). Incidence of AKI in NMPE patients and whether there is correlation between the size of effusions and AKI is unknown.

OBJECTIVE

To assess the incidence of AKI in NMPE inpatients and its association with effusion size.

STUDY DESIGN AND METHOD

We conducted a retrospective cohort study of inpatients admitted to the Chinese PLA General Hospital with pleural effusion from 2018-2021. All patients with pleural effusions confirmed by chest radiography (CT or X-ray) were included, excluding patients with diagnosis of malignancy, chronic dialysis, end-stage renal disease (ESRD), community-acquired AKI, hospital-acquired AKI before chest radiography, and fewer than two serum creatinine tests during hospitalization. Multivariate logistic regression and LASSO logistic regression models were used to identify risk factors associated with AKI. Subgroup analyses and interaction tests for effusion volume were performed adjusted for the variables selected by LASSO. Causal mediation analysis was used to estimate the mediating effect of heart failure, pneumonia, and eGFR < 60 ml/min/1.73m2 on AKI through effusion volume.

RESULTS

NMPE was present in 7.8% of internal medicine inpatients. Of the 3047 patients included, 360 (11.8%) developed AKI during hospitalization. After adjustment by covariates selected by LASSO, moderate and large effusions increased the risk of AKI compared with small effusions (moderate: OR 1.47, 95%CI 1.11-1.94 p = 0.006; large: OR 1.86, 95%CI 1.05-3.20 p = 0.028). No significant modification effect was observed among age, gender, diabetes, bilateral effusions, and eGFR. Volume of effusions mediated 6.8% (p = 0.005), 4.0% (p = 0.046) and 4.6% (p < 0.001) of the effect of heart failure, pneumonia and low eGFR on the development of AKI respectively.

CONCLUSION

The incidence of AKI is high among NMPE patients. Moderate and large effusion volume is independently associated with AKI compared to small size. The effusion size acts as a mediator in heart failure, pneumonia, and eGFR.

Pleural Pressure Pulse in Patients with Pleural Effusion: A New Phenomenon Registered during Thoracentesis with Pleural Manometry

Pleural manometry enables the assessment of physiological abnormalities of lung mechanics associated with pleural effusion. Applying pleural manometry, we found small pleural pressure curve oscillations resembling the pulse tracing line. The aim of our study was to characterize the oscillations of pleural pressure curve (termed here as the pleural pressure pulse, PPP) and to establish their origin and potential significance. This was an observational cross-sectional study in adult patients with pleural effusion who underwent thoracentesis with pleural manometry. The pleural pressure curves recorded prior to and during fluid withdrawal were analyzed. The presence of PPP was assessed in relation to the withdrawn pleural fluid volume, lung expandability, vital and echocardiographic parameters, and pulmonary function testing. A dedicated device was developed to compare the PPP to the pulse rate. Fifty-four patients (32 women) median age 66.5 (IQR 58.5-78.7) years were included. Well visible and poorly visible pressure waves were detected in 48% and 35% of the patients, respectively. The frequency of PPP was fully concordant with the pulse rate and the peaks of the oscillations reflected the period of heart diastole. PPP was more visible in patients with a slower respiratory rate (p = 0.008), a larger amount of pleural effusion, and was associated with a better heart systolic function assessed by echocardiography (p < 0.05). This study describes a PPP, a new pleural phenomenon related to the cyclic changes in the heart chambers volume. Although the importance of PPP remains largely unknown, we hypothesize that it could be related to lung atelectasis or lower lung and visceral pleura compliance.

When appearances deceive: Echocardiographic changes due to common chest pathology

Most indications for performing echocardiography focus on the evaluation of properties intrinsic to the heart. However, numerous extra-cardiac conditions indirectly convey changes to the echocardiographic appearance through alterations in the governing physiology. Pulmonary embolism increases pulmonary arterial pressure if a sufficient cross-sectional area of the pulmonary vascular bed is occluded. This may result in dilatation of the right ventricle and, in severe cases, concomitant early diastolic septal collapse into the left ventricle. Acute respiratory failure has been shown to yield a similar echocardiographic appearance in experimental conditions due to the resultant pulmonary vasoconstriction. Echocardiography in the presence of pulmonary disease can reveal underlying cardiac pathologies such as pulmonary hypertension that contribute to the clinical severity of respiratory distress. Positive pressure ventilation affects preload, afterload, and compliance of both ventricles. The echocardiographic net result cannot be uniformly anticipated, but provides information on the deciding physiology or pathophysiology. Mediastinal pathology including tumors, herniation of abdominal content, and pleural effusion can often be visualized directly with echocardiography. Mediastinal pathologies adjacent to the heart may compress the myocardium directly, thus facilitating echocardiographic and clinical signs of tamponade in the absence of pericardial effusion. In conclusion, many pathologies of extra-cardiac origin influence the echocardiographic appearance of the heart. These changes do not reflect properties of the myocardium but may well be mistaken for it. Hence, these conditions are essential knowledge to all physicians performing echocardiography across the spectrum from advanced cardiological diagnostics to rapid point-of-care focused cardiac ultrasonography.

Fluid loading and norepinephrine infusion mask the left ventricular preload decrease induced by pleural effusion

Background

Pleural effusion (PLE) may lead to low blood pressure and reduced cardiac output. Low blood pressure and reduced cardiac output are often treated with fluid loading and vasopressors. This study aimed to determine the impact of fluid loading and norepinephrine infusion on physiologic determinants of cardiac function obtained by ultrasonography during PLE.

Methods

In this randomised, blinded, controlled laboratory study, 30 piglets (21.9 ± 1.3 kg) had bilateral PLE (75 mL/kg) induced. Subsequently, the piglets were randomised to intervention as follows: fluid loading (80 mL/kg/h for 1.5 h, n = 12), norepinephrine infusion (0.01, 0.03, 0.05, 0.1, 0.2 and 0.3 μg/kg/min (15 min each, n = 12)) or control (n = 6). Main outcome was left ventricular preload measured as left ventricular end-diastolic area. Secondary endpoints included contractility and afterload as well as global measures of circulation. All endpoints were assessed with echocardiography and invasive pressure-flow measurements.

Results

PLE decreased left ventricular end-diastolic area, mean arterial pressure and cardiac output (p values < 0.001), but fluid loading (20 mL/kg) and norepinephrine infusion (0.05 μg/kg/min) restored these values (p values > 0.05) to baseline. Left ventricular contractility increased with norepinephrine infusion (p = 0.002), but was not affected by fluid loading (p = 0.903). Afterload increased in both active groups (p values > 0.001). Overall, inferior vena cava distensibility remained unchanged during intervention (p values ≥ 0.085). Evacuation of PLE caused numerical increases in left ventricular end-diastolic area, but only significantly so in controls (p = 0.006).

Conclusions

PLE significantly reduced left ventricular preload. Both fluid and norepinephrine treatment reverted this effect and normalised global haemodynamic parameters. Inferior vena cava distensibility remained unchanged.

The haemodynamic significance of PLE may be underestimated during fluid or norepinephrine administration, potentially masking the presence of PLE.

Dobutamine aggravates haemodynamic deterioration induced by pleural effusion: A randomised controlled porcine study

BACKGROUND

Pleural effusion is a common finding in critically ill patients and may contribute to circulatory instability and the need for inotropic support.

OBJECTIVE

We hypothesised that dobutamine would affect the physiological determinants preload, afterload, contractility and changes of inferior vena cava characteristics during experimental pleural effusion.

DESIGN

A randomised, controlled laboratory study.

SETTING

Animal laboratory, conducted from March 2013 to May 2013.

ANIMALS

Twenty-four Landrace and Yorkshire female piglets (21.3 ± 1.7 kg).

INTERVENTION

Twenty piglets were included in the analyses. After inducing bilateral pleural effusion (30 ml kg), the piglets were block randomised to either incremental dobutamine infusion (n = 10) or control (n = 10).

MAIN OUTCOME MEASURES

Ultrasonographic measures of left ventricular end-diastolic area, left ventricular afterload, left ventricular fractional area change and inferior vena cava diameter and distensibility were used to assess the basic physiological effect of incremental dobutamine administration during experimental pleural effusion.

RESULTS

In the dobutamine group, preload, measured as left ventricular end-diastolic area, decreased from 11.3 ± 2.0 cm after creation of the pleural effusion to 8.1 ± 1.5 cm at a dobutamine infusion rate of 20 μg kg min (P < 0.001). In the same period, central venous pressure and the expiratory diameter of the inferior vena cava decreased from 9 ± 3 to 7 ± 4 mmHg (P < 0.001) and from 1.1 ± 0.2 to 0.9 ± 0.1 cm (P = 0.008), respectively.

CONCLUSION

In a porcine model of pleural effusion, dobutamine affected basic haemodynamic determinants substantially by decreasing left ventricular preload. Changes in central venous pressure and inferior vena cava characteristics were minimal, discouraging their use as indices of preload. This study underlines the significance of evaluating basic haemodynamic determinants to avoid inappropriate, potentially harmful treatment.

Transthoracic echocardiography in the perioperative setting

PURPOSE OF REVIEW

A need for further assessment of patients in the perioperative setting and an increasing availability of ultrasonography equipment have facilitated the diffusion of ultrasonography and lately focused transthoracic echocardiography (TTE) in anesthesiology practice. This review will discuss the possible use of focused TTE in the perioperative setting and provides an update on present and future perspectives.

RECENT FINDINGS

Several studies focusing on patient management and diagnostic accuracy of perioperative, focused TTE, have been published recently. Several multidisciplinary guidelines addressing use and educational aspects of focused ultrasonography are available, yet guidelines focusing solely on the use in the perioperative setting are lacking.

SUMMARY

Hemodynamically significant cardiac disease or pathophysiology can be disclosed using TTE. Focused TTE is feasible for perioperative patient management and monitoring and will be an inevitable and indispensable tool for the anesthetist. Future research should focus on the outcome of perioperative TTE performed by anesthetists, using rigorous study designs and patient-centered outcomes such as mortality and morbidity.

Routine pre-operative focused ultrasonography by anesthesiologists in patients undergoing urgent surgical procedures

BACKGROUND

Unexpected cardiopulmonary complications are well described during surgery and anesthesia. Pre-operative evaluation by focused cardiopulmonary ultrasonography may prevent such mishaps. The aim of this study was to determine the frequency of unexpected cardiopulmonary pathology with focused ultrasonography in patients undergoing urgent surgical procedures.

METHODS

We performed pre-operative focused cardiopulmonary ultrasonography in patients aged 18 years or above undergoing urgent surgical procedures at pre-defined study days. Known and unexpected cardiopulmonary pathology was recorded, and subsequent changes in the anesthesia technique or supportive actions were registered.

RESULTS

A total of 112 patients scheduled for urgent surgical procedures were included. Their mean age (standard deviation) was 62 (21) years. Of these patients, 24% were American Society of Anesthesiologists (ASA) class 1, 39% were ASA class 2, 32% were ASA class 3, and 4% were ASA class 4. Unexpected cardiopulmonary pathology was disclosed in 27% [95% confidence interval (CI) 19-36] of the patients and led to a change in anesthesia technique or supportive actions in 43% (95% CI 25-63) of these. Unexpected pathology leading to changes in anesthesia technique or supportive actions was only disclosed in a group of patients above the age of 60 years and/or in ASA class ≥ 3.

CONCLUSION

Focused cardiopulmonary ultrasonography disclosed unexpected pathology in patients undergoing urgent surgical procedures and induced changes in the anesthesia technique or supportive actions. Pre-operative focused ultrasonography seems feasible in patients above 60 year and/or with physical limitations but not in young, healthy individuals.

Point-of-care ultrasonography changes patient management following open heart surgery

OBJECTIVES

Although pericardial effusions (PE) and pleural effusions (PLE) may lead to life-threatening respiratory and circulatory deterioration following open heart surgery the postoperative frequency is not fully recognized. The diagnosis is typically based on ultrasonography, X-ray or computer tomography and often disclosed when circulatory collapse is evident. Point-of-care (POC) ultrasonography protocols constitute a noninvasive evaluation of the cardiopulmonary status. We hypothesized that POC ultrasonography could diagnose unknown PE and PLE.

DESIGN

Patients scheduled for open heart surgery were eligible for inclusion. Baseline evaluation including POC examination and dyspnea score was performed one day prior to surgery and repeated on the 4th and 30th postoperative day.

RESULTS

Eighty patients were included and complete follow-up was 80%. Thirteen patients (19%) had PE on the 4th day postsurgery and 19 patients (30%) had PE on the 30th day. Ultrasonography facilitated change in management in one patient with PE requiring drainage. Forty-nine patients (70%) had PLE on the 4th day following surgery and 19 patients (30%) had PLE on the 30th postoperative day. Ultrasonography facilitated a change in management in seven patients with PLE requiring drainage.

CONCLUSION

POC ultrasonography detected pathology, otherwise undisclosed, and was responsible for a change in management in a considerable number of cases.

Pleural effusion leading to right atrial collapse

Rapid accumulation of pericardial fluid can lead to tamponade, resulting in cardiac chambers' collapse, which can lead to hemodynamic and clinical instability, potentially needing emergent pericardiocentesis. Pleural effusion should also be considered as a potential, if rare, cause of cardiac chambers' collapse and possibly cardiac tamponade. This phenomenon has clinical implications because hemodynamically unstable patients with moderate to large pleural effusion may actually need thoracentesis instead of massive volume resuscitation, inotropic agents, or pericardiocentesis.

The empty azygos fissure

The azygos fissure is typically visible on chest radiography as a right paramediastinal supernumerary line in projection of the right lung apex. The azygos vein, located at the bottom of the fissure, is visible as a teardrop-shaped opacity. The empty azygos fissure is a rare finding. It is the consequence of the displacement of the azygos vein out of the fissure with a close paramediastinal position. This phenomenon, related to lung collapse, has been described in the literature as the migration of the azygos vein due to various etiologies such as increased intrathoracic pressure, spontaneous or iatrogenic pneumothorax, or even during sudden development of kyphosis. In our clinical case, the empty azygos fissure was developed after drainage of a large right pleural effusion. An empty azygos fissure must therefore suggest a history of pulmonary atelectasis related to pneumothorax or large drained effusion.