Use of high-flow nasal cannula for emergency pericardiocentesis in a case of anterior mediastinal mass.

Sir,

We report a case of a 3-year-old child with mediastinal mass requiring emergency pericardiocentesis.

The patient presented with a history of fatigue and enlarged neck veins without orthopnea, dysphagia, cyanosis, and syncope. Computed tomography (CT) confirmed large lobulated heterogeneous mass measuring 9.7 cm × 9.5 cm × 6.8 cm in anterior mediastinum with superior vena cava compression and collapse of the left upper lobe with concomitant pleural and pericardial effusion [Figure 1]. He was scheduled for elective CT-guided biopsy on following day. However, he became drowsy, irritable with sinus tachycardia (156/min), blood pressure 60/40 mmHg, and SpO2 90% on room air soon after admission. He was refractory to fluid bolus (20 ml/kg) and inotropic support. Focused two-dimensional transthoracic echo demonstrated collapsing right ventricle due to pericardial effusion [Figure 1] mandating emergency pericardiocentesis. Difficult airway cart containing flexometallic tubes and rigid bronchoscope was kept on standby. In a 45° propped up position, titrated doses of intravenous ketamine/propofol combination was used and oxygenation was provided using Airvo™ (Fisher and Paykel Healthcare Limited, Panmure, Auckland, New Zealand) which delivered 100% FiO2 at the rate of 25 L/min. Supplemental local anesthesia was given at pericardiocentesis site and 150 ml straw-colored fluid was aspirated. Hemodynamics improved immediately after the pericardial tap. The patient maintained 100% saturation throughout the procedure. Flow cytometry of aspirated pericardial fluid established the diagnosis of T-cell acute lymphoblastic leukemia, obviating the need for CT-guided biopsy.

Figure 1

Computed tomography image sagittal reconstruction (A), horizontal section (B), two-dimensional echo (C). The mediastinal mass (a), compressed superior vena cava (b), pericardial effusion (c), compressed left upper lobe (d), pleural effusion (e). RV: Right ventricle, RA: Right atrium

Patients with mediastinal masses may develop airway obstruction and life-threatening hypoxia following anesthesia, despite maintenance of spontaneous ventilation.[1] These risks are due to decreased functional residual capacity (FRC) in supine position, reduced inspiratory muscle tone, loss of transpleural pressure gradient secondary effect on diaphragm, and increased compressibility of the airways because of relaxation of the tracheobronchial tree under anesthesia.[2]

High-flow nasal cannula (HFNC) combines the benefits of “classical” apneic oxygenation with continuous positive airway pressure and gaseous exchange through flow-dependent dead space flushing.[3] Hypopharyngeal pressure increases in proportion to increasing gas flow, and positive mean airway pressure created by HFNC can serve as a bridge to conventional positive pressure ventilation.[4] In our opinion, high oxygen flow provided by Airvo™ along with its proposed benefits, might have created supra-atmospheric intraluminal airway pressures, and splinted the airway. Maintaining a propped up position (to minimize effect on FRC) and spontaneous ventilation was equally important in successful outcome of the case.

This case demonstrates the usefulness of the HFNC and applying it to new paradigms in ventilatory assistance to patients with respiratory distress due to anterior mediastinal mass. However, the current case does not allow us to quantify the success rate of this technique. We believe that administration of high-flow nasal oxygen can be a useful tool for such diagnostic/therapeutic interventions.

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Conflicts of interest

There are no conflicts of interest.