Re-Expansion Pulmonary Edema Following Minimally Invasive Cardiac Surgery: A Case Report.

ABSTRACT: Re-expansion pulmonary edema (RPE) is a rare complication of minimally invasive cardiac surgery (MICS). We present a case of RPE following atrial septal defect (ASD) closure using a thoracotomy approach and cardiopulmonary bypass (CPB). REP contributes to significant morbidity and extends the length of stays in the intensive care unit. Understanding the pathophysiology and risk factors of RPE allows us to prevent or minimize the incidence.

Identifying Early Risk Factors for Postoperative Pulmonary Complications in Cardiac Surgery Patients.

Background and Objectives: Postoperative pulmonary complications (PPCs) are common in patients who undergo cardiac surgery and are widely acknowledged as significant contributors to increased morbidity, mortality rates, prolonged hospital stays, and healthcare costs. Clinical manifestations of PPCs can vary from mild to severe symptoms, with different radiological findings and varying incidence. Detecting early signs and identifying influencing factors of PPCs is essential to prevent patients from further complications. Our study aimed to determine the frequency, types, and risk factors significant for each PPC on the first postoperative day. The main goal of this study was to identify the incidence of pleural effusion (right-sided, left-sided, or bilateral), atelectasis, pulmonary edema, and pneumothorax as well as detect specific factors related to its development. Materials and Methods: This study was a retrospective single-center trial. It involved 314 adult patients scheduled for elective open-heart surgery under CPB. Results: Of the 314 patients reviewed, 42% developed PPCs within 12 h post-surgery. Up to 60.6% experienced one PPC, while 35.6% developed two PPCs. Pleural effusion was the most frequently observed complication in 89 patients. Left-sided effusion was the most common, presenting in 45 cases. Regression analysis showed a significant association between left-sided pleural effusion development and moderate hypoalbuminemia. Valve surgery was associated with reduced risk for left-sided effusion. Independent parameters for bilateral effusion include increased urine output and longer ICU stays. Higher BMI was inversely related to the risk of pulmonary edema. Conclusions: At least one PPC developed in almost half of the patients. Left-sided pleural effusion was the most common PPC, with hypoalbuminemia as a risk factor for effusion development. Atelectasis was the second most common. Bilateral effusion was the third most common PPC, significantly related to increased urine output. BMI was an independent risk factor for pulmonary edema development.

Prognostic Significance of Lactate Clearance in Cardiogenic Pulmonary Edema in the Emergency Department.

Background and Objectives: Acute cardiorespiratory failure disrupts the delicate balance of energy supply, demand, and consumption, with elevated lactate levels and decreased blood pH serving as crucial indicators. Acute cardiogenic pulmonary edema (ACPO), a common cause of acute respiratory failure, poses a substantial mortality risk. Lactate, a byproduct of pyruvate reduction, is a pertinent marker in perfusion assessment. Lactate clearance (LC) has proven prognostic efficacy in various conditions but lacks consensus on its predictive power in acute cardiogenic pulmonary edema. Materials and Methods: This prospective observational study, conducted in a metropolitan area's third-level emergency department, involved patients with cardiogenic pulmonary edema from May 2021 to August 2023. The inclusion criteria specified acute cardiogenic pulmonary edema, excluding patients with incomplete data or other respiratory conditions. Lactate clearance, calculated at presentation and after 6 h, served as the primary outcome predictor. Our data analysis employed logistic regression, the ROC curve, and statistical tests. Results: The cohort of 106 patients revealed that a lactate clearance below 14.29% was significantly associated with mortality. While 51.6% of survivors were discharged, LC's predictive success for discharge was inconclusive. Logistic regression underscored the significance of lactate clearance, with a one-unit increase yielding a 5.55-fold probability of survival. The AUC for LC was 0.759. Conclusions: This study pioneers the exploration of lactate clearance in patients with acute cardiogenic pulmonary edema. LC below 14.29% signifies a poor prognosis, emphasizing its potential as an early treatment initiation marker. While acknowledging this study's limitations, we advocate for further multicenter research to refine the understanding of lactate clearance in this context.

Lung ultrasound diagnosis of pulmonary edema resulting from excessive fluid absorption during hysteroscopic myomectomy: a case report.

BACKGROUND: Hysteroscopic surgery is a safe procedure used for diagnosing and treating intrauterine lesions, with a low rate of intraoperative complications. However, it is important to be cautious as fluid overload can still occur when performing any hysteroscopic surgical technique. CASE PRESENTATION: In this case report, we present a unique instance where lung ultrasound was utilized to diagnose pulmonary edema in a patient following a hysteroscopic myomectomy procedure. The development of pulmonary edema was attributed to the excessive absorption of fluid during the surgical intervention. By employing lung ultrasound as a diagnostic tool, we were able to promptly identify and address the pulmonary edema. As a result, the patient received timely treatment with no complications. This case highlights the importance of utilizing advanced imaging techniques, such as lung ultrasound, in the perioperative management of patients undergoing hysteroscopic procedures. CONCLUSIONS: This case report underscores the significance of early detection and intervention in preventing complications associated with fluid overload during hysteroscopic myomectomy procedures.

When anaphylactic shock meets epinephrine and blood lactate increases: A case report.

RATIONALE: Anaphylactic shock, a severe and rapid systemic allergic reaction, poses significant treatment challenges. Epinephrine, the first-line treatment, effectively reverses symptoms but can complicate the clinical picture by elevating lactate levels, blurring the distinction between shock-induced hypoperfusion and drug-induced metabolic effects. PATIENT CONCERNS: A 26-year-old female presented with anaphylactic shock following an antibiotic infusion, experiencing chest tightness, hypotension, and pulmonary edema, without significant past medical history apart from a noted allergy to fish and shrimp. DIAGNOSES: Anaphylaxis was diagnosed based on clinical presentation and supported by imaging that revealed pulmonary edema, despite normal troponin levels and electrocardiogram. INTERVENTIONS: Treatment included 0.5 mg of intramuscular epinephrine and 5 mg of intravenous dexamethasone, with subsequent intubation and mechanical ventilation in the intensive care unit. An intravenous epinephrine infusion was also administered for hemodynamic support. OUTCOMES: While epinephrine resolved the pulmonary edema and stabilized circulation, it led to a significant, albeit transient, increase in lactate levels, which normalized following discontinuation of epinephrine, indicating the metabolic effect of the drug rather than ongoing tissue hypoperfusion. LESSONS: This case illustrates the importance of recognizing epinephrine-induced lactate elevation in anaphylactic shock, necessitating a nuanced interpretation of lactate dynamics. Clinicians must differentiate between lactate elevations due to tissue hypoperfusion and those arising from epinephrine's pharmacologic effects to optimize patient care.

Moderate-Flow Perfusion is Superior to Low-Flow Perfusion in Ex Situ Lung Perfusion.

BACKGROUND: Full-flow perfusion during prolonged ex situ lung perfusion (ESLP) results in unacceptable pulmonary edema formation. Clinical ESLP at 30% to 50% predicted cardiac output (CO) supports acceptable physiologic outcomes; however, progressive pulmonary edema still develops. Lower flow rates may provide equivalent physiologic preservation with less edema formation due to reduced hydrostatic pressures. We report our results of moderate-flow (MF; 30% CO) vs low-flow (LF; 10% CO) negative pressure ventilation (NPV)-ESLP with transplantation. METHODS: Twelve pig lungs underwent 12-hours of NPV-ESLP with 30% or 10% CO (n = 6/group). Three left lungs per group were transplanted post-ESLP and assessed in vivo over 4 hours. Lung function was assessed by physiologic parameters, weight-gain, and pro-inflammatory cytokine profiles. RESULTS: Results are MF vs LF (mean ± SEM). All lungs demonstrated acceptable oxygenation post-ESLP (454.2 ± 40.85 vs 422.7 ± 31.68, P = .28); however, after transplantation, the MF lungs demonstrated significantly better oxygenation (300.7 ± 52.26 vs 141.9 ± 36.75, P = .03). There was no significant difference in compliance after ESLP (21.38 ± 2.28 vs 16.48 ± 2.34, P = .08); however, pulmonary artery pressure (PAP; 10.89 ± 2.28 vs 21.11 ± 0.93, P = .06) and pulmonary vascular resistance (PVR; 438.60 ± 97.97 vs 782.20 ± 162.20, P = .05) were significantly higher in the LF group. Weight gain (%) post-ESLP and post-transplant was similar between groups (29.42 ± 5.72 vs 24.17 ± 4.42, P = .24; and 29.63 ± 7.23 vs 57.04 ± 15.78, P = .09). TNF-α and IL-6 were significantly greater throughout LF ESLP. CONCLUSIONS: The MF NPV-ESLP results in superior lung function with less inflammation compared to LF NPV-ESLP.

Torsemide in the Management of Pulmonary Edema.

Pulmonary edema, either cardiogenic or noncardiogenic, is caused by fluid accumulation in the alveolar spaces. Cardiogenic pulmonary edema (CPE), one of the causes of congestive heart failure (CHF), is treated with loop diuretics. Torsemide and furosemide were found to be useful in the treatment of CHF-associated pulmonary edema due to their ability to lower pulmonary capillary pressure and left ventricular end-diastolic pressure, respectively. Pharmacological features of torsemide, such as greater bioavailability, higher absorption rate, and efficacy, make it a better alternative for treating pulmonary edema than the regularly used loop diuretic, furosemide. Torsemide administered intravenously was found to be both efficacious and well tolerated in CPE. However, more research is needed to determine its usefulness in non-CPE.

Efficacy of Lung Ultrasound vs Chest X-Ray in Detecting Lung Consolidation and Edema in Premature Infants in the NICU.

BACKGROUND The incidence of lung diseases in premature newborns is significantly higher than in full-term newborns due to their underdeveloped lungs. Ultrasound and X-ray are commonly-used bedside examinations in neonatology. This study primarily compares the efficacy of chest X-ray (CXR) and lung ultrasound (LUS) images in evaluating lung consolidation and edema in premature newborns at Neonatal Intensive Care Units (NICU). MATERIAL AND METHODS A retrospective analysis was conducted on LUS and CXR examination results, along with clinical records of premature newborns admitted to our hospital's NICU from November 1, 2019, to December 31, 2021. CXR and LUS scans were performed on the same newborn within a day. We evaluated the consolidations and edema by interpreting the CXR and LUS images, then compared the findings. RESULTS Out of 75 cases, 34 showed lung consolidations on LUS (45%), while only 14 exhibited consolidations on CXR (19%). The detection rate of consolidations by LUS was significantly higher compared to CXR (34/75 vs 14/75, P<0.001). Differences were observed between the 2 bedside examinations in identifying consolidations, with some cases seen only on LUS. CXR struggled to accurately assess the severity of lung edema visible on LUS, showing significant disparity in detecting interstitial edema (53/75 vs 21/75, P<0.001). CONCLUSIONS LUS outperforms chest CXR for bedside assessment of lung consolidation and edema in premature newborns.

Cardiomiopatia de Takotsubo associada a feocromocitoma: um caso atípico e complexo / Takotsubo cardiomyopathy associated with pheochromocytoma: an atypical and complex case

INTRODUÇÃO Cardiomiopatia (CMP) induzida por estresse, como a cardiomiopatia de Takotsubo, pode ter características clínicas semelhantes à isquemia miocárdica, como elevação de troponinas, alterações no Eletrocardiograma (ECG), mas sem obstrução coronariana ou lesões isquêmicas. Semelhante, a CMP induzida por Feocromocitoma possui sintomas também semelhantes a CMP hipertrófica, hipertensão e edema pulmonar devido a fatores cardiogênicos ou não cardiogênicos. Ambas supracitadas podem ter associação com excesso de catecolaminas, mas raramente estão associadas. RELATO DO CASO Paciente masculino, 46 anos, diabético, com história de estresse por situações familiares importantes, recentemente. Chega no serviço de emergência, com queixas de dispnéia, náuseas e êmese, iniciados há 1 dia, associado a retenção urinária e parestesia em mãos e paraparesia de membros inferiores. Refere também tratamento com Amoxicilina + Clavulanato há um mês por Colecistite Aguda. Na chegada, paciente se encontrava taquicárdico, taquipneico e saturando 98% em uso de óculos nasal a 2l/min, além de acidose metabólica. Realizou-se uma tomografia computadorizada de abdome, que evidenciou uma massa em Adrenal, sugestivo de Feocromocitoma, bem como metanefrinas urinárias e catecolaminas positivas. Ainda na emergência, evoluiu com insuficiência respiratória aguda por edema agudo de pulmão, necessitando de manejo com Nitroglicerina e 03 ampolas de Furosemida e uso de máscara não reinalante a 10l/min. Foi encaminhado para Unidade de Terapia Intensiva, onde foi realizado um ECG com alterações primárias da repolarização, seguido de alterações nos valores de Troponina e alterações no Ecocardiograma (ECO) de acinesia apical, hipocinesia de todos os segmentos médios e contratilidade preservada em segmentos basais. Cateterismo cardíaco com achados semelhantes ao ECO e presença de balonamento na ventriculografia, além de ausência de lesões obstrutivas em coronárias. CONCLUSÃO A excepcionalidade desse caso diz respeito ao quadro de síndrome coronariana aguda com dois motivos plausíveis e evidenciados na condução do caso, sendo eles: CMP de Takotsubo e a induzida por Feocromocitoma. Fica evidente, pela evolução do quadro, a gravidade do mesmo e a importância de considerar diagnósticos diferenciais, inclusive os menos comuns.

The pathophysiology of patent foramen ovale and its related complications.

The foramen ovale plays a vital role in sustaining life in-utero; however, a patent foramen ovale (PFO) after birth has been associated with pathologic sequelae in the systemic circulation including stroke/transient ischemic attack (TIA), migraine, high altitude pulmonary edema, decompression illness, platypnea-orthodeoxia syndrome (POS) and worsened severity of obstructive sleep apnea. Importantly, each of these conditions is most commonly observed among specific age groups: migraine in the 20 to 40s, stroke/TIA in the 30-50s and POS in patients >50 years of age. The common and central pathophysiologic mechanism in each of these conditions is PFO-mediated shunting of blood and its contents from the right to the left atrium. PFO-associated pathologies can therefore be divided into (1) paradoxical systemic embolization and (2) right to left shunting (RLS) of blood through the PFO. Missing in the extensive literature on these clinical syndromes are mechanistic explanations for the occurrence of RLS, including timing and the volume of blood shunted, the impact of age on RLS, and the specific anatomical pathway that blood takes from the venous system to the left atrium. Visualization of the flow pattern graphically illustrates the underlying RLS and provides a greater understanding of the critical flow dynamics that determine the frequency, volume, and pathway of flow. In the present review, we describe the important role of foramen ovale in in-utero physiology, flow visualization in patients with PFO, as well as contributing factors that work in concert with PFO to result in the diverse pathophysiological sequelae.

Cardiovascular effects of breath-hold diving at altitude.

Hypoxia, centralization of blood in pulmonary vessels, and increased cardiac output during physical exertion are the pathogenetic pathways of acute pulmonary edema observed during exposure to extraordinary environments. This study aimed to evaluate the effects of breath-hold diving at altitude, which exposes simultaneously to several of the stimuli mentioned above. To this aim, 11 healthy male experienced divers (age 18-52y) were evaluated (by Doppler echocardiography, lung echography to evaluate ultrasound lung B-lines (BL), hemoglobin saturation, arterial blood pressure, fractional NO (Nitrous Oxide) exhalation in basal condition (altitude 300m asl), at altitude (2507m asl) and after breath-hold diving at altitude. A significant increase in E/e' ratio (a Doppler-echocardiographic index of left atrial pressure) was observed at altitude, with no further change after the diving session. The number of BL significantly increased after diving at altitude as compared to basal conditions. Finally, fractional exhaled nitrous oxide was significantly reduced by altitude; no further change was observed after diving. Our results suggest that exposure to hypoxia may increase left ventricular filling pressure and, in turn, pulmonary capillary pressure. Breath-hold diving at altitude may contribute to interstitial edema (as evaluated by BL score), possibly because of physical efforts made during a diving session. The reduction of exhaled nitrous oxide at altitude confirms previous reports of nitrous oxide reduction after repeated exposure to hypoxic stimuli. This finding should be further investigated since reduced nitrous oxide production in hypoxic conditions has been reported in subjects prone to high-altitude pulmonary edema.

Venovenous ECMO for Acute Chronic Heart Failure after Bilateral Lung Transplantation.

ABSTRACT: Venovenous (VV) ECMO is rarely used during decompensated circulatory states. Although VA ECMO is the routine option, VV ECMO may be an option in selected patients. We present a case of pulmonary edema due to acute heart failure in a patient 4- and 12-year post-lung transplantation who received VV ECMO. Using a thoughtful cannulation strategy, VV ECMO, and aggressive ultrafiltration, the patient was successfully decannulated, extubated, and discharged from the hospital. In cardiogenic pulmonary edema, VV ECMO represents an additional, and likely under-utilized tool, especially in patients who are at high risk for ventilator-associated lung injury. Cannula location and size should be given additional consideration to potentially transition to V-AV ECMO configuration if necessary.

The acute effects of furosemide in acute heart failure assessed by remote dielectric sensing. A protocol.

INTRODUCTION: Intravenous loop diuretics have been a key component in treating pulmonary oedema since the 1960s and have a Class 1 recommendation in the 2021 guidelines for acute heart failure (AHF). While the diuretic effect of loop diuretics is well established, it remains unclear how furosemide influences pulmonary congestion and cardiac filling pressures in the hyperacute phase before significant diuresis occurs. METHODS: This was a prospective study of adult patients with AHF and objective signs of pulmonary congestion admitted to the cardiac ward. Remote dielectric sensing (ReDS) will directly measure lung fluid content, and cardiac filling pressures will be assessed by echocardiography with Doppler and strain analysis. CONCLUSIONS: This study will examine if furosemide leads to a hyperacute reduction in pulmonary congestion assessed by ReDS independent of diuretic effects in patients with AHF. We hypothesise that the haemodynamic effect of furosemide shown on pulmonary congestion may explain the subjective instant relief in patients with AHF receiving furosemide. FUNDING: Dr. Grand's salary during this project is supported by a research grant from the Danish Cardiovascular Academy funded by Novo Nordisk Foundation grant number NNF20SA0067242 and by the Danish Heart Foundation. TRIAL REGISTRATION: This protocol was approved by the Scientific Ethical Committee, H-23029822, and the Danish Data Protection Agency P-2013-14703. The protocol was registered with ClinicalTrial.org on 29 August 2023 (Identifier: NCT06024889).

Biophysical properties of alveolar surfactant in drever dogs with hunting associated pulmonary edema.

BACKGROUND: A syndrome of acute non-cardiogenic pulmonary edema associated with hunting is prevalent in the drever breed, but etiology of this syndrome is currently unknown. Alveolar surfactant has a critical role in preventing alveolar collapse and edema formation. The aim of this study was to investigate, whether the predisposition to hunting associated pulmonary edema in drever dogs is associated with impaired biophysical properties of alveolar surfactant. Seven privately owned drever dogs with recurrent hunting associated pulmonary edema and seven healthy control dogs of other breeds were included in the study. All affected dogs underwent thorough clinical examinations including echocardiography, laryngeal evaluation, bronchoscopy, and bronchoalveolar lavage (BAL) as well as head, neck and thoracic computed tomography imaging to rule out other cardiorespiratory diseases potentially causing the clinical signs. Alveolar surfactant was isolated from frozen, cell-free supernatants of BAL fluid and biophysical analysis of the samples was completed using a constrained sessile drop surfactometer. Statistical comparisons over consecutive compression expansion cycles were performed using repeated measures ANOVA and comparisons of single values between groups were analyzed using T-test. RESULTS: There were no significant differences between groups in any of the biophysical outcomes of surfactant analysis. The critical function of surfactant, reducing the surface tension to low values upon compression, was similar between healthy dogs and affected drevers. CONCLUSIONS: The etiology of hunting associated pulmonary edema in drever dogs is not due to an underlying surfactant dysfunction.

Periprocedural acute haemodynamic decompensation during substrate-based ablation of scar-related ventricular tachycardia: a rare and unpredictable event.

AIMS: Patients with structural heart disease (SHD) undergoing catheter ablation (CA) for ventricular tachycardia (VT) are at considerable risk of periprocedural complications, including acute haemodynamic decompensation (AHD). The PAINESD score was proposed to predict the risk of AHD. The goal of this study was to validate the PAINESD score using the retrospective analysis of data from a large-volume heart centre. METHODS AND RESULTS: Patients who had their first radiofrequency CA for SHD-related VT between August 2006 and December 2020 were included in the study. Procedures were mainly performed under conscious sedation. Substrate mapping/ablation was performed primarily during spontaneous rhythm or right ventricular pacing. A purposely established institutional registry for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated using the source medical records. Acute haemodynamic decompensation triggered by CA procedure was defined as intraprocedural or early post-procedural (<12 h) development of acute pulmonary oedema or refractory hypotension requiring urgent intervention. The study cohort consisted of 1124 patients (age, 63 ± 13 years; males, 87%; ischaemic cardiomyopathy, 67%; electrical storm, 25%; New York Heart Association Class, 2.0 ± 1.0; left ventricular ejection fraction, 34 ± 12%; diabetes mellitus, 31%; chronic obstructive pulmonary disease, 12%). Their PAINESD score was 11.4 ± 6.6 (median, 12; interquartile range, 6-17). Acute haemodynamic decompensation complicated the CA procedure in 13/1124 = 1.2% patients and was not predicted by PAINESD score with AHD rates of 0.3, 1.8, and 1.1% in subgroups by previously published PAINESD terciles (<9, 9-14, and >14). However, the PAINESD score strongly predicted mortality during the follow-up. CONCLUSION: Primarily substrate-based CA of SHD-related VT performed under conscious sedation is associated with a substantially lower rate of AHD than previously reported. The PAINESD score did not predict these events. The application of the PAINESD score to the selection of patients for pre-emptive mechanical circulatory support should be reconsidered.

Altitude illnesses.

Millions of people visit high-altitude regions annually and more than 80 million live permanently above 2,500 m. Acute high-altitude exposure can trigger high-altitude illnesses (HAIs), including acute mountain sickness (AMS), high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). Chronic mountain sickness (CMS) can affect high-altitude resident populations worldwide. The prevalence of acute HAIs varies according to acclimatization status, rate of ascent and individual susceptibility. AMS, characterized by headache, nausea, dizziness and fatigue, is usually benign and self-limiting, and has been linked to hypoxia-induced cerebral blood volume increases, inflammation and related trigeminovascular system activation. Disruption of the blood-brain barrier leads to HACE, characterized by altered mental status and ataxia, and increased pulmonary capillary pressure, and related stress failure induces HAPE, characterized by dyspnoea, cough and exercise intolerance. Both conditions are progressive and life-threatening, requiring immediate medical intervention. Treatment includes supplemental oxygen and descent with appropriate pharmacological therapy. Preventive measures include slow ascent, pre-acclimatization and, in some instances, medications. CMS is characterized by excessive erythrocytosis and related clinical symptoms. In severe CMS, temporary or permanent relocation to low altitude is recommended. Future research should focus on more objective diagnostic tools to enable prompt treatment, improved identification of individual susceptibilities and effective acclimatization and prevention options.

Pulmonary edema after naloxone administration for opioid reversal: a systematic review of case reports and causality assessment using the Naranjo scale.

INTRODUCTION: Pulmonary edema is a rare complication occurring after naloxone administration, but the causal relationship remains insufficiently investigated. We aimed to determine the likelihood of naloxone as the causative agent in published cases of pulmonary edema. METHODS: A literature search was conducted across multiple databases, utilizing database-specific search terms such as "pulmonary edema/chemically induced" and "naloxone/adverse effects." Each case report was evaluated using the Naranjo scale, a standardized causality assessment algorithm. RESULTS: We identified 49 published case reports of pulmonary edema following naloxone administration. The median total dose of naloxone was 0.2 mg for patients presenting following a surgical procedure and 4 mg for out-of-hospital opioid overdoses. Based on the Naranjo scale, the majority of cases were classified as "possible" (n = 38) or "probable" (n = 11) adverse reactions, while no "definite" cases of naloxone-induced pulmonary edema were identified. Many patients were classified as "possible" due to limited patient information or other potential risks, such as fluid administration or airway obstruction. Forty-six of 49 patients survived (94 percent). DISCUSSION: Pulmonary edema may occur after both low and high doses of naloxone; however, low doses were primarily reported in the surgical population. Despite this complication, the majority of patients survived. Furthermore, no case report in our analysis was classified as a "definite" case of naloxone-induced pulmonary edema which limits the establishment of causality. Future studies should explore patient risk factors, including surgical versus outpatient setting and opioid-naïve versus opioid-tolerant for developing pulmonary edema and employ a causality assessment algorithm. CONCLUSIONS: These case reports suggest pulmonary edema can occur following naloxone administration, irrespective of dose. According to the Naranjo scale, there were no definite cases of naloxone-induced pulmonary edema. Overall, we suggest the benefits of naloxone administration outweigh the risks. Naloxone should be administered to treat opioid overdoses while monitoring for the development of pulmonary edema.