key: cord-0925717-f8023es9
authors: Aguilar-Piedras, María F.; Porres-Aguilar, Mateo; Mukherjee, Debabrata; Cueto-Robledo, Guillermo; Roldan-Valadez, Ernesto; Vargas-Tapia, Patricio A.
title: High flow nasal cannula oxygenation successfully used as bridge therapy for systemic thrombolysis in COVID-19 associated intermediate-high risk pulmonary embolism: HFNC and systemic lysis in acute PE
date: 2021-09-24
journal: Curr Probl Cardiol
DOI: 10.1016/j.cpcardiol.2021.101000
sha: dd0b7a2349265273a08029646985d39276211ca2
doc_id: 925717
cord_uid: f8023es9

The risk of venous thromboembolism (VTE) in COVID-19 patients is a growing problem. Thromboembolic complications are associated with the infection by SARSCoV-2, with an estimated incidence up to 25%-30% of VTE in patients with severe COVID-19 pneumonia. Here in, we present a case of a patient with severe pneumonia due to COVID-19 who is admitted with mild pneumothorax secondary to COVID-19 and high-intermediate-risk pulmonary embolism (PE), who underwent successfully a highflow nasal cannula (HFNC) oxygenation bridge with subsequent successful half-doses of systemic thrombolysis with intravenous alteplase. Prospective studies are warranted in this subset of patients with intermediate-high and high-risk PE, to further explore HFNC oxygenation with or without diverse reperfusion strategies, with the aim to identify the best individualized therapeutic approach in each patient with significant COVID-19 associated VTE and optimize outcomes.

Patients with intermediate-high risk pulmonary embolism (PE) can progress to high-risk requiring hemodynamic support and respiratory support with mechanical ventilation, which could be counterproductive because of positive pressure on venous return 4 . High flow is a modality of ventilatory assistance in patients with respiratory failure, it has taken peak during the COVID-19 pandemic, however, the formation of aerosols has limited its use 5 

53-year-old man with significant past medical history of long-standing type 2 diabetes, occasional smoking, and occasional alcohol use. In May 2021 he received the first dose of vaccination against SARS-CoV-2 (Sputnik); however, by his own decision he did not go to the second dose.

Seventeen days prior to his admission with a dry cough, fever of 37.5 C°, myalgias, arthralgias, stabbing headaches associated with photophobia. He came for evaluation due to rapidly progressive acute dyspnea to mild-moderate efforts, productive cough with greenish expectoration, as well as non-quantified fever for the past 3 days. Oxygen saturation (O2Sat) at room air (RA) was 70%. The rapid test and subsequently the PCR were reported positive for

Vital signs upon admission were heart rate of 117 bpm, respiratory rate of 35 x min, 100/65 mmHg. Temperature 35.8. O2Sat at RA 70%. Neck with subcutaneous emphysema on the right lateral side. Anterior aspect of the right hemithorax with soft tissue crepitation due to subcutaneous emphysema. Respiratory sounds decreased in a generalized way, with bilateral diffuse crackles and rales and increased voice transmission all throughout. Rhythmic heart with tachycardia. Abdomen and extremities without any significant abnormalities. Given the clinical suspicion of pneumothorax, we decided to start respiratory support with a simple mask supplemental O2 at 10 liters x min. A right sided internal jugular ultrasound-guided central venous line was placed.

Laboratories were remarkable for leukocytosis of 13.9 x 10e 3/ uL, mild lymphopenia of 0.83 x10e3 /uL, platelets at 420,000 x mm 3 , hemoglobin 16.2 g/dl, glucose 174 mg / dl, urea 26.9 mg / dl, creatinine 0.59 mg / dl, LDH of 350 U/L. Coagulation profile within normal limits (PT of Despite the increase in the PaO 2 /FiO 2 ratio at10-L simple face mask, tachypnea and tachycardia persisted. Chest radiography showed a small right-sided laminar pneumothorax with pneumopericardium and pneumomediastinum, in addition to bilateral diffuse alveolo-interstitial infiltrates ( Fig. 1-A) . 12-lead electrocardiogram showed sinus tachycardiac with "backward tip pattern", new complete right bundle branch block, as well as late "R" in AVR and presence of "R" wave in lead V-1 (Fig. 1-B) . Computed tomographic angiography (CTA) of the chest for acute PE protocol showed soft tissue range images in the right interlobar pulmonary artery and right basal pulmonary artery trunk up to its bifurcation, as well as in the bifurcation of the left main pulmonary arterial trunk in relation to thrombosis. Severe multi-focal pneumonia with commonly reported findings in SARS-CoV2 pneumonia. Subcutaneous emphysema in the thoracic wall and cervical region, as well as in the right perirenal space. (Fig 1-C and 1-D) .

Rapid multimodality risk stratification classified our patient as intermediate-high risk acute PE, given that it had systolic greater than 90 mmHg, PESI score for Class-III, abnormal biomarkers of myocardial damage and CTA of the chest with objective findings of right ventricular dysfunction with an abnormal RV/LV ratio >0.9, as well as rectification of the interventricular septum. Inferior vena cava reflux corresponds to class II. (Fig. 2-A and 2-B) . Bova score was calculated to be Class-III, implying the possibility of short-term 30-day morbidity and mortality between 20-25%. After multidisciplinary discussion by a designated pulmonary embolism O 2 Sat at 93% (Fig 2-C) , as well as significant improvement and changes in the 12-lead EKG post ST (Fig. 2-D) . ABGs 

HFNC oxygenation therapy represents a cornerstone element for the treatment of acute hypoxemic respiratory failure. Its superiority over non-invasive ventilation and conventional oxygen therapy is well established since it reduces mortality, avoids intubation, shortens days of stay in intensive care and hospitalization in some patients with severe hypoxemia 6, 7 .

The use of HFNC has been described in many clinical scenarios. An early improvement in respiratory distress is reported in terms of oxygenation and respiratory rate, as we were able to observe in our patient. This relief from respiratory failure appears to be the key to the safety and efficacy of HFNC. Several mechanisms explain the benefits of HFNC over conventional oxygenation modalities; among these, being able to provide the necessary flow and being able to 6 graduate the inspired fraction of oxygen unlike low-flow systems 7 . There are few reports of cases of acute PE treated with HFNC, in fact, they are limited to a series of cases and a case report 8, 9 . In PE, mechanical ventilation (MV) increases intrathoracic pressure, which can result in a decrease in RV stroke volume and systemic blood pressure. Therefore, HFNC may have significant advantages: first, although it has been shown that lung volume increases at the end of respiration, this increase is modest and positive pressure is mainly observed during expiration, consequently unwanted hemodynamic effects related to HFNC are not observed 8 Rapid and appropriate risk stratification for both, candidacy for ST as well as for potential major bleedings events post-ST, in combination with a Bova score > 4 points (grade III) which is related to a 30-day mortality between 15%-25% 13 , allowed in our patient to decide for halfdoses of ST with 50 mg IV of Alteplase, with favorable clinical outcomes during his hospital stay.

We strongly believe that the use of HFNC oxygenation in patients with high-risk or intermediatehigh-risk PE could be an attractive option to support acute hypoxemic respiratory failure in this type of patients, to avoid the effects of positive pressure ventilation on the RV, being a feasible option to use HFNC oxygenation as a respiratory therapeutic leverage/bridge if further reperfusion strategies are considered, with the possibility to avoid rapid cardiopulmonary decompensation and the need of MV. Further prospective studies are warranted in the subset of 8 patients with intermediate-high and high-risk PE, to further explore HFNC oxygenation with or without diverse reperfusion strategies, with the aim to identify the best individualized therapeutic approach in each patient with significant COVID-19 associated VTE and optimize outcomes.

Overall, our case suggests that systemic thrombolysis should be considered for the treatment of PE in appropriate patients with COVID-19 14, 15 .

Written and informed consent was obtained from the patient and available for review if needed.

The authors of this case report vouch for accuracy and integrity of the data provided. There is no conflict of interests Position Paper from the National PERT Consortium. Chest. 2020 158 (6) 

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Every single coauthor designed, performed research, helped in writing, crafting, editing and critically reviewing key elements of the manuscript. All coauthors read and approved the final version of the manuscript.