Asymptomatic tension pneumothorax in a child.

Sir,

In paediatric patients regional anaesthesia is always very challenging. We report the occurrence of asymptomatic tension pneumothorax in a child 4 days after administration of ultrasound guidance supraclavicular brachial plexus block.

A 7-month-old baby weighing 10 kg was diagnosed with a rhabdomyosarcoma of the right forearm and scheduled for tumour excision under general anaesthesia followed by ultrasound guided right supraclavicular block for postoperative pain relief.

The airway was secured with i- gel® size 1.5 and anaesthesia was maintained with oxygen, sevoflurane, fentanyl and atracurium with Intermittent positive pressure ventilation IPPV. Supraclavicular block was performed when child was undergoing IPPV and intraoperative period was uneventful. The brachial plexus was identified using the Sonosite Edge II ultrasound system (Sonosite Edge II™, Bothell, WA, USA) with a 13-6 MHz 25-mm high-frequency linear transducer (L25 × 13-6 MHz Sono Site). Depth, mode and exam type used were 1.5 cm, penetration and nerve, respectively. The probe was placed in the coronal-oblique plane in the supraclavicular fossa and the puncture was in-plane from the lateral to medial. The brachial plexus was identified lateral to the subclavian artery above the first rib and the plexus was blocked using 0.5 ml/kg of injection bupivacaine 0.25%. On the fourth postoperative day, slight subcutaneous emphysema was noted over the right-mid axillary area with no significant symptoms such as pain or dyspnoea and it was associated with normal respiration rate and stable vital signs. A chest X-ray was ordered which suggested right-sided tension pneumothorax, where the upper mediastinum (trachea) and lower mediastinum (heart) were shifted to the left side as shown in Figure 1.

Figure 1

Chest X-ray showing asymptomatic right-sided tension pneumothorax

On examination, there was a slight tracheal shift to the left side which in turn is considered as a late sign in the course of tension pneumothorax development.

The risk of pneumothorax is greater in infants and small children because the apex of the lung is situated in a more rostral position[1] and complete avoidance of this complication is difficult, even using an ultrasound-guided technique.[2] A faulty image-setting, poor views of the needle and the needle tip during the entire process of advancement may also be contributory factors for the cause of pneumothorax. Image settings that do not show the first rib lying below the subclavian artery in the corner pocket may result in the needle being advanced into an area where the pleura is no longer protected by the overlying first rib.[3] At times it is very difficult to get the plexus over the first rib due to specific neck and shoulder anatomy especially in paediatric patients. Although we tried to visualise the needle and pleural dome throughout the procedure, there were instances when our needle tip was not clearly visible. Owing to low margin of error and less space available for probe placement in infants, the needle might have punctured the pleura. These are the patients in whom we have to be very careful. Hence, always visualise the tip of the needle while advancing the needle. Routine use of postoperative chest X-ray may be suggested after brachial plexus block, however, it is not always mandatory. The risk of pneumothorax can further be decreased by putting the probe in the anterior posterior direction rather than parallel to the clavicle as it helps in getting the plexus over the first rib.[4]

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Conflicts of interest

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