Anesthetic management of staged thoracoscopic repair of bilateral eventration of diaphragm in a neonate.

Congenital eventration of the diaphragm is a rare disorder, the perioperative management of which is challenging. The introduction of thoracoscopic repair of these defects has considerably reduced the perioperative morbidity and mortality in these patients. In spite of the advantages of thoracoscopy which include smaller chest incisions, reduced postoperative pain, and more rapid postoperative recovery compared with thoracotomy, it is still inherent with complications unique to it. A clear understanding of the pathophysiologic changes, potential complications and institution of appropriate monitoring and good planning is essential for the safe conduct of thoracoscopic procedures in neonates. We describe the anesthetic management of staged thoracoscopic repair of bilateral congenital eventration of the diaphragm in a neonate.

INTRODUCTION

Advances in the perioperative management of the newborn with congenital disorders have decreased the morbidity and mortality considerably in this age group. The introduction of thoracoscopy for repair of congenital diaphragmatic hernia or eventration have significant advantages such as a decrease in the pain, surgical stress and immunologic derangement, quicker return to enteral feeds, faster recovery, and shorter hospitalization.[12] Elective surgery, better understanding of the neonatal physiology, effects of anesthetic drugs and innovations in intensive care has resulted in improvement in survival rate for these children.

The reported incidence of congenital diaphragmatic defects is 1 in 2500–4000 live births.[3] The incidence of bilateral congenital diaphragmatic defects is unknown.[4] This case report describes the successful anesthetic management of staged thoracoscopic repair of bilateral congenital eventration of the diaphragm in a neonate.

CASE REPORT

A term 2-day-old female child weighing 3 kg presented to the emergency ward with complaints of respiratory distress. There was no significant antenatal history. Apgar score at birth was 6/10. On examination, the child had rapid breathing with peripheral cyanosis. On auscultation, there was diminished bilateral air entry in lower lung zones. Heart rate was 160/min and respiratory rate was more than 60/min. Oxygen saturation (SpO2) on room air was 92% but improved to 100% with 4 L of oxygen. Blood gas analysis on room air showed pH 7.46, PO2 74 mm Hg and PCO2 40 mm Hg. Chest X-ray revealed bilateral eventration of the diaphragm [Figure 1]. Computed tomography (CT) of the chest showed bilateral eventration of the diaphragm with high placed subdiaphragmatic liver and a gastric lumen in lower thoracic cavity [Figure 2]. There were no congenital heart defects or significant pulmonary hypertension on echocardiography.

Figure 1

Chest X-ray showing bilateral eventration of diaphragm

Figure 2

Computed tomography of chest showed bilateral eventration of diaphragm with high placed subdiaphragmatic liver and gastric lumen in lower thoracic cavity

It was decided to do a staged repair of bilateral eventration of the diaphragm. Thoracoscopic repair of left diaphragmatic eventration was planned on the 2nd day of life. The child was preoxygenated for 3 min with 100% oxygen. Standard American Society of Anaesthesiologists monitoring with an electrocardiogram, noninvasive blood pressure, SPO2, temperature, end-tidal carbon dioxide (EtCO2), and precordial stethoscope over dependent lung was employed. The child was premedicated with intravenous glycopyrrolate 0.05 mg and fentanyl 6 mcg. The child was induced with increasing concentration of sevoflurane from 2% to 4%. Intubation was facilitated by intravenous atracurium 1.5 mg. The child was intubated with 4 mm cuffed endotracheal tube taking care to confirm bilateral equal air entry. Anesthesia was maintained with manual ventilation on air, oxygen and sevoflurane 2–3%. Ventilation with 100% oxygen was attempted whenever SPO2 dropped below 90%.

The child was placed in right lateral decubitus position taking care to protect the pressure areas and confirming bilateral equal air entry. A 5 mm port with 30° telescope was inserted in the midaxillary line at the 4th intercostal space and two 5 mm ports were inserted in anterior and posterior axillary line at the 5th intercostal space. CO2 was insufflated into the left chest at a pressure of 5 mm Hg and flow of 0.5–1 L/min. There was herniation of stomach, left lobe of liver and spleen into the left thoracic cavity which were reduced. The left hemidiaphragm was thin and paper like which was plicated with 2-0 polypropylene interrupted sutures tied extracorporeally and pushed down with knot pusher. No clamp or retractor was used, and the intercostal drain was introduced. The port and drain site was infiltrated with 0.125% bupivacaine. The duration of the surgical procedure was 2 h.

After the reversal, the child was conscious having good respiratory effort. We decided to go for extubation with all precautions. The child tolerated extubation well and had an uneventful immediate postoperative course managing well on oxygen support. The child was started on nasogastric feeds on the 2nd postoperative day (POD), which was well tolerated.

In view of uneventful postoperative course, it was decided to go for thoracoscopic repair of eventration of the right diaphragm 5 days later. A part of the liver was inside the right thoracic cavity which was pushed, and diaphragmatic plication was done. The child had an uneventful postoperative course [Figure 3]. The child was started on nasogastric feeds on 2nd POD, and intercostal drains were removed on 4th POD. The child was discharged on 10th POD and is on regular follow-up.

Figure 3

Postoperative chest X-ray

DISCUSSION

Eventration of the diaphragm is a disorder in which all or part of the diaphragmatic muscle is replaced by fibroelastic tissue. This causes abnormal elevation of intact hemidiaphragm that leads to the paradoxical motion of affected hemidiaphragm during inspiration and expiration. The positive intraabdominal pressure pushes the floppy diaphragm into the chest and the negative intrathoracic pressure during inspiration results in a paradoxical elevation of the viscera toward the ipsilateral chest resulting in compression of the adjacent lung. Eventration of the diaphragm can be congenital or acquired. Congenital eventration of the diaphragm develops from inadequate development of muscles or absence of the phrenic nerve. The common cause of acquired eventration of the diaphragm is an injury to the phrenic nerve, resulting either from traumatic birth injury or surgery for heart disease. The defect in congenital eventration can be partial or diffuse. In the former the defect is localized whereas in the latter the diaphragm is replaced by fibroelastic tissue which is attached peripherally to normal muscle. The diagnosis of diaphragmatic eventration is established by chest radiograph and fluoroscopic investigation of the diaphragm which show an abnormally elevated diaphragm and paradoxical motion of the diaphragm during inspiration and expiration, respectively. Ultrasound, contrast study of the upper gastrointestinal system and CT scan can be used to confirm the diagnosis.

Bilateral eventration of the diaphragm is a rare occurrence that can cause severe respiratory embarrassment. Diaphragmatic plication should be done in all patients to improve lung function. Plication involves a folding of the eventrated diaphragm which is then sutured to correct the excess diaphragm tissue. The conventional repair can be done by a low thoracotomy or laparotomy or both in selected cases. The introduction of thoracoscopy for the repair of diaphragmatic defects has significantly reduced the morbidity and mortality in these patients.

Mouroux performed first thoracoscopic repair[5] and video assisted thoracoscopy was first reported by Van smith et al.[6] To the best of our knowledge, only few references could be gathered about bilateral eventration of diaphragm[47] and none describing thoracoscopic management for bilateral eventration of diaphragm in a new born. Although the advantages of thoracoscopy include smaller chest incisions, reduced postoperative pain, and more rapid postoperative recovery compared with thoracotomy, it is still inherent with complications unique to it. In an attempt to minimize the physiologic insults associated with thoracoscopy multiple anesthetic and surgical techniques have evolved, but none are problem free. Our patient had bilateral eventration of diaphragm with evidence of stomach and spleen in left thoracic cavity and hence we chose to operate on the left side first.

Anesthetic problems

Herniation of abdominal viscera into thoracic cavity leads to pulmonary hypoplasia due to compression by the viscera on developing lungs

High volumes for mask ventilation should be avoided

Concerns of one lung ventilation, which causes ventilation perfusion (V/Q) mismatch, should be addressed. The V/Q mismatch is more in neonates because their compliant chest makes functional residual capacity closer to the residual and closing volumes and makes them prone to atelectasis. The V/Q mismatch is further aggravated by general anesthesia, mechanical ventilation, and neuromuscular blockade

Inhalational anesthetics inhibit hypoxic pulmonary vasoconstriction (HPV). Isoflurane may be preferred due to less attenuation of HPV, although this has not been studied in children

Higher flows and increased inflational pressure can lead to sudden mediastinal shift and cardiovascular collapse

During surgery, high volume or ventilation pressures have to be used carefully as there will be trauma to the healthy lung. We opted for manual ventilation as we had previously managed such cases similarly even though they were unilateral. Manual ventilation may provide useful information to the anesthesiologist about changes in chest compliance or airway resistance and gave us the option of administering inhalational agents intraoperatively[8]

EtCO2 is inaccurate due to increase in dead space and shunt fraction[9]

The continuous insufflation of large volumes of cold, nonhumidified CO2 into the thoracic cavity causes hypothermia in these small children

The oxygen consumption in the neonate of 6–8 ml/kg/min is twice that of an adult. Our patient had eventration of diaphragm on the opposite side as well; hence there were frequent interruptions for achieving acceptable SaO2 and ETCO2

The decision regarding extubation was crucial as a bilateral defect, reduction of contents into the abdominal cavity and the resultant increased intra-abdominal pressure suggested elective ventilation in the postoperative period. We gave a trial of extubation as the child did not require ventilatory support and maintained SpO2 with minimal oxygen support in the preoperative period.

CONCLUSION

It is important for the anesthesiologist to have a clear understanding of the pathophysiologic changes, potential complications, and institute appropriate monitoring and good planning for the safe conduct of thoracoscopic procedures in neonates. A good and constant communication between the anesthesiologist and the surgeon about the intraoperative events is essential in minimizing perioperative morbidity and mortality.

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Conflicts of interest

There are no conflicts of interest