Arop Kual, senior anaesthetist at the Princess Marina Hospital in Botswana, and authors, share a case report to address the important key issues relevant to peri-operative anaesthetic management of the obese patient presenting for general surgery
The purpose of this case report is to describe our experience in anaesthetic management of a patient with morbid obesity undergoing general surgery. The obese patient is most likely prone to develop peri-operative impairments of respiratory and cardiovascular functions. Moreover, the obese patient might stand a chance of airway problems at times of tracheal intubation. The difficulties in moving and positioning the patient and difficulties in gaining access for monitoring and venous cannulation add to the problems. Anaesthesia and surgery may present a considerable risk for the obese patient and should not be undertaken lightly without full understanding of the potential’s problems. This case report addresses the important key issues relevant to peri-operative anaesthetic management of the obese patient presenting for general surgery.
Case Report
Anaesthesia in the morbidly obese patient can present many challenges. The concern of most anaesthetists is airway management. It is traditionally thought that obese patients stand a chance of difficult airway or difficult intubation [1]. Besides the many challenges in our settings, such as the limited advance airway equipment for managing a difficult airway scenario; this made the case more interesting and challenging although we had a backup of a fibreoptic video-intubating laryngoscope which we would borrow from the ENT team in case we failed to intubate with the standard ordinary blade laryngoscope.
We describe a 165-Kg morbidly obese female patient (25 years old) whose height was 163.5 cm and {Body mass index (BMI) > 61.1 kg / m2} who underwent ventral hernia repair. The body max index was calculated using the following formula: BMI = body weight (in kg)/height2 (in meters).
Pre-operative anaesthetic evaluation revealed Mallampati Class III with almost an absent neck, the thyromental distance was estimated to be < 6 cm, and there was limited range of motion of her head and neck. All lab variables and vital signs were within normal ranges.
The patient was positioned supine and all monitors were attached (Pulse oximetry, NIBP and ECG). The patient was pre-oxygenated with 100% O2 via facemask. She was then pre-medicated with Metoclopramide 10 mg IV and anaesthetised with Propofol 200 mg IV and Suxamethonium 100 mg IV. The first intubation attempt was unsuccessful as the use of a smaller laryngoscope blade (size 4 Macintosh) could not help in visualising the cords properly. In the second attempt the patient was intubated with size 7.00 mm endotracheal tube (ETT) using size 5 Macintosh blade. A size 3 oropharyngeal airway was also inserted. The patient was ventilated mechanically using a volume control mode with a tidal volume of 1000 mls at a rate of 6mls – 8mls / minute, Sevoflurane 0-3.5 % was given. The peak inspiratory pressure was 35 cmH2O and the I:E ratio of 1:2. A non-depolarising muscle relaxant (Atracurium 50 mg in total) was used during mechanical ventilation.
The patient remained hemodynamically stable during surgery and the emergence from anaesthesia was uneventful. She was ultimately extubated and transferred to Post-Anaesthesia Care Unit (PACU). At the PACU the patient was ventilated with only a nasal cannula without any difficulty post-operatively. The whole anaesthesia course was uneventful.