DISCUSSION
We present a patient with ARDS due to acute lung injury related to
Midwakh. Dokha is manufactured by drying tobacco leaves, mixed with
herbs and spices to enhance the flavor. It is smoked through a small
pipe called Midwakh, which has three parts, a mouthpiece, a stem, and a
bowl (image 1). The bowl can contain approximately 0.5 grams of dry
tobacco, enough to finish one session in 2 inhalations; Therefore, an
individual ends up smoking Midwakh 20-25 times a day.
Smoking Midwakh is increasing in the Gulf and particularly in the
UAE7, among the adolescent and school
students1.It is the most commonly used ATP in UAE,
next only to Cigarette on overall tobacco use8.
Nicotine levels in Midwakh tobacco products were 170.76%, 218.07%,
128.57%, and 193.33% higher in comparison with cigarettes, chewing
tobacco, snuff tobacco, and electronic cigarettes respectively and its
tar content is the highest when compared to shisha and
cigarettes2. Midwakh tobacco products contains harmful
levels of cobalt, chromium, cadmium, iron, and lead. In addition to
these, carcinogens and Central nervous system (CNS) depressants were
found9,10 .Traditional Midwakh pipes contain no
filters; hence these toxicants can quickly enter the lungs. Midwakh
smokers may add herbs, spices, dried flowers, fruits, bark, and leaves
of native plants (like the Damas tree leaves) to tobacco. Nevertheless,
the effects on these combinations and the byproducts on combustion have
never been reported.
Toxic inhalational lung injury may result in a spectrum of respiratory
disorders like bronchopneumonia, pulmonary edema, interstitial lung
disease, reactive airways dysfunction syndrome, obstructive airway
disease, and Bronchiolitis Obliterans Organizing Pneumonia (BOOP), as
the triggering agents could be single or multiple. Fatal cases following
significant exposure were associated with laryngeal edema, airway
obstruction, non-cardiogenic pulmonary edema/ARDS, and secondary
infection in the setting of the diffuse airway and pulmonary parenchymal
damage11. They also described the resolution of
initial acute pneumonia to be followed by the gradual onset of airway
obstruction, which has to be watched during the follow-up.
The clinical presentation and radiological findings, including CT scans,
were quite similar to the E‐cigarette/Vaping‐associated Lung Injury
(EVALI) outbreak in the USA. Patients with EVALI present with acute,
severe respiratory distress with findings typical of a chemical-induced
pneumonitis after using E-Cigarette or vaping
products12. Symptoms like cough, shortness of breath,
fever can rapidly worsen within 24-48 hours of initial presentation, as
happened in our case13.
In addition to antibiotics, patients with EVALI were treated by systemic
steroids to reduce the inflammatory response. As per the CDC, steroids
showed an improvement in the clinical condition in almost 82% of
patients treated14. CDC recommends follow up at 1-2
weeks (SpO2 and chest x-ray). Some patients have relapsed during
corticosteroid tapering, and some have had persistent hypoxemia (SpO2
<95%) requiring home oxygen at discharge14.
ARDS has an incidence of 30–80 cases per 100,000
populations15. It is divided into three categories as
per Berlin definition from 2012 according to severity of hypoxemia as
mild (PaO2 /FiO2 200–300 mmHg), moderate (PaO2/FiO2 100–200 mmHg) and
severe (PaO2/FiO2 < 100 mmHg) forms of ARDS.
Despite a much-improved understanding of ARDS pathophysiology, the
efficacy of used therapeutic approaches is limited. In our case, poor
compliance of the lungs despite the low requirement of FiO2 up to 50%
was remarkable. For a set tidal volume of 5 ml/kg, his peak inspiratory
pressure was reaching up and beyond 35 cm H2O. Thus we resort to
ultra-protective lung ventilation with tidal volumes of 4 to 5 ml/kg as
required to avoid barotrauma. Prone positioning was useful especially in
the acute phase of severe ARDS, by enabling better ventilation/perfusion
matching, more homogenous distribution of ventilation with reduction of
Ventilator-induced lung injury and recruitment of dorsal
regions16.
The use of neuromuscular blocking agents (NMBA) improves
patient-ventilator synchrony and reduces oxygen consumption leading to
improved survival17. However, when given alone with
steroids, it can exacerbate weakness due to critical illness myopathy
and polyneuropathy18.In our case, it could not be
avoided as we had to balance the risk of ICU-acquired weakness with the
potential benefit of neuromuscular blockers and systemic glucocorticoids
in the severe lung injured patient.
Lee et al. highlighted various new outcomes that need to be studied in
Pediatric Acute Respiratory Distress Syndrome (PARDS) like long term
pulmonary function, risk of pulmonary hypertension, nutrition status and
growth, PICU acquired weakness, neurocognitive development, functional
status and Health-related quality of life (HRQOL)19. A
cohort study conducted on 316 mechanically ventilated pediatric patients
concluded that 23% developed new morbidities due to residual organ
dysfunction, treatment complications etc20.
There have been numerous studies on long term outcomes in adult ARDS.
One study with potential application to pediatrics illustrated that half
of the patients had persistent functional disability 12 months after
discharge21. The 6-minute walk test (6MWT) helps
assess global physical function, i.e., lung and cardiac function and
muscle strength. The mean distance walked in the 6MWT increased
significantly over the first year when followed up at three months and
9-12 months after discharge22.
Our patient had significantly reduced spirometry parameters upon
discharge from the PICU, which got almost normalized within three months
post-discharge from the hospital.