INTRODUCTION:

Amongst many congenital heart defects, Patent ductus arteriosus (PDA) is a condition where the natural opening in the fetal heart, called, ductus arteriosus which lies between the proximal descending aorta and pulmonary artery remains patent/open causing the flow of oxygenated blood return to the lung itself instead of getting circulated to the rest of body parts, thus compromising the heart and lung function. Under normal circumstances,soon after birth this vessel closes as a natural process, in function and by days to few weeks in anatomical configuration or it becomes tiny within the first few days of life. The overall incidence is 5%-10% of all congenital heart diseases (CHD)¹. Around 8/1000 live births are found to have CHD². World Health Organization reported in Health statistics and information that within 4 weeks of birth about 3,03,000 new borns die worldwide because of congenital anomalies.³

Cardiac catheterization, a minimally-invasive non-surgical procedure, where a small device, a transcatheter PDA closure, is implanted in the vessel (PDA) to close the patent ductus arteriosus.⁴

The treatment for chronic suppurative otitis media is tympanomastoidectomy. In January 2023, in our institution, a rural hospital medical college, a tympanomastoid exploration was undertaken under general anaesthesia (GA) in a child having a device implanted for PDA correction. With the aim to discuss our experience along the course of anaesthesia viz during induction/intubation, maintenance and also during immediate and late post operative period, the case is being presented.

CASE REPORT:

The patient, a 14year old girl,weighing 36kg of BMI 15.2kg/m² having implanted PDA closure device in situ was undertaken for right sided (R) tympanomastoid exploration done endoscopically.

From the department of paediatrics, the systemic clinical examinations, investigations of complete blood count, kidney function test, liver function test, X-ray chest PA view, ECG were done, and found to be within normal limit. The pre-anaesthetic check up, done the previous day of the anaesthetic procedure, the patient was found to be fit for anaesthesia clinically.No history of any drug intake was there.

A written and informed consent was obtained from the parents after counselling.

Fasting protocol was maintained, the patient was not allowed clear fluid from 2hrs pre- anaesthetic period. A 20-gauge peripheral cannula was secured and ringer lactate drip started as per Holliday -Segar regime.⁵ Intraoperative monitoring included continuous oxygen saturation with pulse-oxymeter, noninvasive blood pressure, temperature monitoring, ECG, pulse rate, end tidal CO₂[EtCO₂] recorded every 5mins. Forced air warmer was used to keep the patient warm. To prevent hypothermia warm saline for flushing and fluid warmer for fluid management of crystalloid infusions was used in our case. Adequate hydration needs to be done to reduce viscosity of blood.

On the operation table, 6 liters 100% oxygen for 3 minutes supplied through bag mask spontaneous ventilation as preoxygenation. Induction of anaesthetia was done with intravenous (IV) fentanyl 2μg kg^-1, ketamine 2mg kg^-1, midazolam 0.04mg kg^-1, glycopyrrolate 0.004mg kg^-1, vecuronium 0.08mg kg^-1 . Endotracheal intubation was done with size (ID 6) portex endotracheal tube (ETT) using Macintosh Laryngoscope. The tube was secured at left angle of mouth, position was confirmed, the chest was auscultated for equal bilateral breath sound and EtCO₂. Anesthesia was maintained in volume controlled mode adjusting the mechanical ventilator setting with tidal volume (Vt) 8ml^-1, respiratory rate 16/min maintaining EtCO₂ in the range of 35-45mmHg. Fresh gas flow (FGF) of oxygen, air (50:50) avoiding nitrous oxide, sevoflurane 0.8-1.6% to maintain MAP [systolic blood pressure < 85mmHg] between 65-67mmHg and intermittent time bound maintenance doses of vecuronium at 0.05mg kg^-1 IV every 20mins but discontinued minutes before facial nerve monitoring as requested by the surgeons . To provide a bloodless surgical field an infusion of dexmedetomidine, an α2-adrenoceptor agonist which also serves as a sedative and analgesic agent, was started in a dose of 0.2μg/kg/hr after induction and establishment of mechanical ventilation and the dose was then titrated accordingly as per the response of the patient. Dexmedetomidine can be an adjunct for invasive procedures. It has minimal effect on respiration^6,7with a dose depended property of analgesia and sedation.⁸Vitals were stable throughout intra operative period of 180mins. Infusion of dexmedetomidine was stopped about 30mins before and inhalation of sevoflurane discontinued around 15mins prior to skin closure. For reversal from neuromascular block neostigmine 0.05mg^-1and glycopyrrolate 0.02 mg/kg was given IV. Extubation was done once the child responded to commands with full recovery of consciousness and SpO2 on air 98%. For unprecedented difficult airway, emergency transtracheal ventilation set were kept ready.

At the end of the procedure ondansetron was administered in the dose of 0.1mg kg^-1IV to prevent nausea and vomiting in the postoperative period. In our patient neither postoperative shivering nor emergence agitation was observed.

While the patient was under GA, the surgeon infiltrated the surgical field with a local anaesthetic agent containing adrenalin in dilution of (1:200000), with the aim to limit the bleeding in surgical field besides, in combination with paracetamol, NSAIDs and/or oral opioids in titrated dose, it could aid postoperative analgesia.

Application of topical local anaesthetics and the practice of putting a pack of sterile malleable haemostatic gelatine sponge soaked in betadine ointment along with 2% lidocaine solution in external auditory canal are followed at the author's institution.

Figure 1: Deformed pinna (oblique arrow), tragus (horizontal arrow)

CONCLUSION:

For anaesthetizing these patients, a detailed preoperative assessment with a knowledge and wisdom of pharmacology of anaesthetic agents which are likely to come across in relation to the abnormal physiology of CHD, is essential. The contributory factors related to morbidity in such children include surgery in younger age group patients; compared with other surgeries, procedural time is longer; drilling and suction–irrigation which is a caloric vestibular stimulant, done adjacent to the inner ear cause direct stimulation of the vestibular system.

The ideal anaesthetic procedure for middle ear surgery demands an optimal blood less surgical field without excessive arterial hypotension especially in the present case scenario of a device implanted correction of patent ductus arteriosus. A fruitful anaesthetic outcome can be attained if these factors are aimed at and that is what we have achieved administering an adjunct, α2-adrenoceptor agonist along with G.A

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Received on 27.09.2023 Modified on 11.12.2023

Research J. Pharm. and Tech 2024; 17(7):3305-3307.

DOI: 10.52711/0974-360X.2024.00516