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\begin{document}

\title{PNEUMOMEDIASTINUM SECONDARY TO BAROTRAUMA PRODUCED BY NON-INVASIVE
MECHANICAL VENTILATION IN COVID19}



\author[1]{JJ Vengoechea}%
\author[1]{Rosa Plana}%
\author[1]{Luis Cabrero}%
\author[1]{Carlos A.  Rombolá}%
\author[1]{Ferran Barbe}%
\affil[1]{Hospital Universitari Arnau de Vilanova}%


\vspace{-1em}



  
  \date{May 17, 2024}


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\textbf{Introduction:}

Pneumomediastinum produced by barotrauma is a possible complication from
the mechanical ventilation, since the positive pressure produces
alveolar rupture. The incidence is variable, and increases according to
the indication of mechanical ventilation (1). In a prospective study
with 5183 ICU patients, the overall incidence was 2.9\%, reaching 6.5\%
in patients with acute respiratory distress syndrome (ARDS)(2). The
incidence is higher in invasive ventilation than in non-invasive
ventilation (NIV) or continuous positive airway pressure (CPAP).
Barotrauma risk can be diminished with protective measures, such as
using low support pressure and reduced tidal volumes (1,3).

During the health crisis caused by the COVID-19 coronavirus pandemic, a
high percentage of the severe patients (up to 15.6\% in a review of 1099
patients in Wuhan, China) had respiratory distress (7). In the context
of respiratory failure the first step is conventional oxygen therapy.
Secondly, if it's available, the High-flow Nasal Cannulas (HFNC). And
finally invasive or non invasive ventilation (NIV). This last one should
not postpone intubation (8).

We present the case of a patient with COVID19 positive who, after
starting an NIV, suffered a pneumomediastinum and subcutaneous
emphysema.

\textbf{Case Report:}

The patient was a 60-year-old male with a history of hypothyroidism and
metastatic rectum adenocarcinoma (diagnosed in 2018) with
retroperitoneal, iliac and mediastinal adenopathies and pulmonary
affectation (a 5mm pulmonary nodule in the inferior right lobe), in
active chemotherapy treatment.

He went to the emergency room with a clinic of cough and expectoration
with two weeks of evolution, and fever with progressive dyspnea (finally
at rest) in the last week. On the pulmonary auscultation presented
roncus and diffuse crackles in the left hemithorax.

Analytically the patient had a PCR 67mg/L, a PCT 0,17ng/mL, a leukopenia
(1,75x109) with lymphopenia (0,26x109 {[}14,9\%{]}) and a D-dimer of
2133ng/mL. In the chest X-ray was possible to observe an interstitial
patron, with increased diffuse density in lower left hemithorax. Given
the high suspicion of coronavirus infection as a cause of the condition
of the patient (fever + lymphopenia + pneumonia) a PCR for COVID-19 was
requested, being positive.

In the arterial blood gas was observed a respiratory alkalosis and an
acute respiratory distress (pH 7'51, PaCO\textsubscript{2} 26mmHg,
PaO\textsubscript{2} 51mmHg, and a calculated
PaO\textsubscript{2}/FiO\textsubscript{2} of 60). Due to the palliative
state of the patient, it was decided to treat the acute respiratory
insuficiency with CPAP, excluding an ICU assistance.

During hospitalization, the patient increased respiratory work and the
oxyhemoglobin saturation was \textless{}90\% despite a
FiO\textsubscript{2} of 50\% with Ventimask. It was decided to place a
CPAP of 12 cmH2O, and the patient presented a clinical improve with a
respiratory frequency of 18/min and a 94\% saturation with an additional
oxygen of 15 lpm.

After 24 hours of CPAP treatment, the patient presented a sudden
clinical deterioration, with important desaturation,
(SaO\textsubscript{2} 72\%), with an extensive subcutaneous emphysema in
the anterior thorax, up to the neck and both arms.

Given the suspicion of pneumothorax secondary to barotrauma, the
ventilation was interrupted and an urgent chest X-ray was requested,
which didn't confirm the suspicion. The chest CT scan confirmed a severe
emphysema of thoracic soft parts, important neumomediastinum, right apex
pneumothorax and ground-glass lung opacities in all lung fields,
compatible with COVID-19 infection.'' (Figure 1)

A pleural drainage was placed in the small right pneumothorax. The
patient didn't present any clinical improvement, and maintained
saturations below 80\% with oxygen therapy with Ventimask at
FiO\textsubscript{2} of 50\% and 15 lpm. Due to increased dysneic
sensation, and poor prognosis, it was started a sedation with morphine,
and the exitus occurred in the following hours.

\textbf{Discussion:}

The incidence of pneumomediastinum secondary to NIV is low (1). This
pathology should be suspected in case of subcutaneous emphysema or
dyspneic sensation, mostly if there's a concomitantly pneumothorax. The
risk increases, according to the cause for which mechanical ventilation
is required, in the patient exposed it was secondary to an ARDS
infection by COVID-19.

Due to the vital risk that pneumomediastinum can produce, especially
when accompanied by pneumothorax, it's important to suspect it early and
confirm urgently using imaging techniques. Pneumomediastinum is
associated with increased morbidity and mortality, so avoiding it's
decisive.

To prevent it is crucial to carry out protection strategies during
ventilation, such as maintaining pressure Plateau \textless{} 30cmH2O
(only possible in patients with invasive mechanical ventilation) or
maintaining reduced tidal volumes (between 6 to 8 mL/kg based on the
ideal body weight), or low support pressures (3).

In our patient, COVID-19 positive, even performing mechanical
ventilation with protection strategies, such as keeping volumes reduced,
and being in CPAP mode at 12 cmH\textsubscript{2}O, it was produced a
pneumomediastinum with its consequent worst outcome (6).

Therefore, in addition to the increased risk of pneumomediastinum due to
ARDS caused by the COVID-19 infection, we cannot rule out if this
infection may cause respiratory damage that may increase the risk of
barotrauma, and if those patients should be closely monitored.

There're only two reported cases of spontaneous pneumomediastinum in a
positive COVID patient, who were not submitted to ventilation (4,5).

We still don't have enough information available about all the
phisiopatology of the coronavirus infection and we will have to wait for
more publications and case series studies.

\textbf{Figure:}\selectlanguage{english}
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Figure 1.- Thoracic CT scan: abundant emphysema of thoracic soft parts
and neck base. An important neumomediastinum, without compromise of the
airway or large vessels. A 12 mm right apex pneumothorax. Ground-glass
lung opacities in all lung fields, compatible with COVID-19 infection.

\textbf{References:}

1.- Diaz R, Heller D. Barotrauma And Mechanical Ventilation. {[}Updated
2019 Oct 1{]}. In: StatPearls {[}Internet{]}. Treasure Island (FL):
StatPearls Publishing; 2020 Jan-.

2.- Anzueto, A., Frutos--Vivar, F., Esteban, A., Al\selectlanguage{ngerman}ía, I., Brochard, L.,
Stewart, T., \ldots{} Pelosi, P. (2004). Incidence, risk factors and
outcome of barotrauma in mechanically ventilated patients. Intensive
Care Medicine, 30(4), 612--619. doi:10.1007/s00134-004-2187-7

3.- Epelbaum, O., \& Aronow, W. S. (2017). Mechanical ventilation in the
acute respiratory distress syndrome. Hospital Practice, 45(3), 88--98.
doi:10.1080/21548331.2017.1331687

4.- Sun R, Liu H, Wang X. Mediastinal Emphysema, Giant Bulla, and
Pneumothorax Developed during the Course of COVID-19 Pneumonia. Korean J
Radiol. 2020 Jan;21:e43. https://doi.org/10.3348/kjr.2020.0180

5.- Zhou, C., Gao, C., Xie, Y., \& Xu, M. (2020). COVID-19 with
spontaneous pneumomediastinum. The Lancet Infectious Diseases.
doi:10.1016/s1473-3099(20)30156-0

6.- Xiaobo Yang, Yuan Yu, Jiqian Xu, \ldots{} You Shang. Clinical course
and outcomes of critically ill patients with SARS-CoV-2 pneumonia in
Wuhan, China: a single-centered,

retrospective, observational study. Lancet Respir Med 2020. February 21,
2020 https://doi.org/10.1016/ S2213-2600(20)30079-5

7.- Guan W, Ni Z, Hu Y, Liang W, Ou C, He J, et al. Clinical
Characteristics of Coronavirus Disease 2019 in China. N Engl J Med.
2020;NEJMoa2002032.

8.- Cinesi Gómez, C., Peñuelas Rodríguez, Ó., Luján Torné, M. ., Egea
Santaolalla, C., Masa Jiménez, J. F., García Fernández, J., \ldots{}
Ferrando Ortola, C. (2020). Recomendaciones de consenso respecto al
soporte respiratorio no invasivo en el paciente adulto con insuficiencia
respiratoria aguda secundaria a infección por SARS-CoV-2. Revista
Española de Anestesiología y Reanimación.
doi:10.1016/j.redar.2020.03.006\selectlanguage{english}
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