Dr Sangram Patil, Specialist Registrar in ITU,
Morriston Hospital, Swansea, SA6 6PU.
A 55-year gentleman with weight 220Kg presented to hospital with increasing shortness of breath for few weeks. His background medical history was type 2 diabetes mellitus, right-sided heart failure, chronic type 2 respiratory failure, sleep apnoea, recent increase in lower limb swelling, orthopnea and paroxysmal nocturnal dyspnoea. His regular medications were furosemide, simvastatin, metformin and co-codamol.
The reason for his presentation to hospital was probably non-infective exacerbation of type 2 respiratory failure. His blood gas in casualty department showed hypoxia with respiratory acidosis (pH7.30, pO2 7.6 kPa, pCO2 10.8 kPa). His bicarbonate level was 12.7mmol/L. Soon he deteriorated on respiration and blood gases deteriorated to pH 7.1, pO2 7.82 and pCO2 14.5 kPa. This patient was referred to ITU team for consideration for non-invasive ventilation.
On admission to ITU the patient was supported with non-invasive ventilation BiPAP- PEEP of 10 mbar and pressure support of 22 mbar on 70% inspired oxygen concentration. He had very poor air entry in chest bilaterally. In spite of high non-invasive support he continued to deteriorate. His pCO2 reached to 15.6 mbar. His airway assessment showed almost no neck, Mallampatti class 4 view of pharynx, very little neck extension, inability to identify cricoid and thyroid cartilages.
Decision was taken to invasively ventilate this patient. Awake fiberoptic ventilation was planned. After local anaesthesia to airway with lignocaine spray and jelly, fiberoptic scope was passed down the nose. The patient started bleeding in his nose and became uncooperative. It became difficult to suck out the throat and visualize larynx. So, the decision was taken to transfer him to theatre and perform fiberoptic intubation under inhalational induction.
Meanwhile, patient received two boluses of furosemide 80mg to offload his right heart. He was transferred to theatre with full monitoring. Inhalational induction with sevofluorane and 100% oxygen was done. Direct laryngoscopy performed when patient was sufficiently under anaesthesia showed grade 2 view of larynx. He was intubated with size 7 ETT due to difficulty in getting a bigger size tube into his trachea. The patient was transferred back to ITU and ventilated with BiPAP mode.
This gentleman posed very difficult technical problems on ITU. It was almost impossible to move him for any procedures on ITU for example for chest X-ray. Transthoracic echocardiography did not show any sensible view at all. He needed high level of ventilatory support with 100% oxygen and PEEP of 18 mbar to keep his oxygen saturations at around 90%. Due to his agitation he was started on remifentanyl and propofol sedation. He developed hypotension from sedation. So, we switched him to midazolam sedation.
After multiple failed attempts at confirming right placement of nasogastric tube, pH method of NG aspirate was used to confirm the placement, as it was impossible to X-ray his chest due to massive size of his chest.
This patient subsequently developed chest infection and deteriorated chest wise. It was decided after a week of intensive therapy that, due to irreversible nature of his cardio respiratory condition, it was not appropriate to resuscitate this patient in case of cardiac arrest. We put limits to his treatment and decided not to escalate his management any further. The plans to perform trans-oesophageal echo were cancelled due to eminent technical problems with it.
This patient continued deteriorating and did not respond to intensive interventions at any point during his ITU stay. The decision was made to withdraw life supports. The patient died immediately after withdrawal of intensive therapy.
Clinical investigations addressing the care of the critically ill, morbidly obese patient are scarce.
Extreme obesity is frequently associated with life-threatening cardiopulmonary disease and presents substantial obstacles to the delivery of routine care.
Morbidly obese patients dedicate a disproportionately high percentage of total O2 to conduct respiratory work, even during quiet breathing. This relative inefficiency suggests a decreased ventilatory reserve and a predisposition to respiratory failure in the setting of even mild pulmonary or systemic insults.1
Duarte, Alexander G et al in their study on outcome in morbidly obese ventilated patients have shown increased mortality if the patients did not respond well to NIV and needed invasive ventilation.2A total of 33 patients were treated with non-invasive ventilation (NIV), of which 21 avoided intubation (NIV success) and 12 required intubation (NIV failure). Mean body mass index for the NIV success group was significantly less than for the NIV failure group. Significant improvements in pH and Paco2 were noted for the invasive mechanical ventilation and NIV success groups. No improvements in gas exchange were noted in the NIV failure group. Of patients treated with NIV, 36% required intubation.
In a case report by Masashi Nishikawa et al concluded that basic problem leading to respiratory failure in their patient was morbid obesity, body weight reduction was considered to be mandatory. The caloric intake of a morbidly obese patient was limited to 1000 kcal·day−1, resulting in body weight reduction by 50kg during the patient's stay on the intensive care unit. The patient was successfully extubated on ICU day 35. 3
Philippe Juvin et al have reported a difficult intubation rate of 15.5% in obese patients and 2.2% in lean patients.4 Llimited neck mobility and mouth opening accounted for most cases of difficult intubation in obese subjects.5 Short sternomental distance, receding mandible, and prominent teeth have been advanced as potential causes for difficult intubation.
The potential problems with critical care of morbidly obese patients are 6-
Difficult airway management
Difficult IV access
Pharmacological considerations especially for sedation
Radiological procedures and transfer difficulties
From our case report we conclude that morbidly obese critically ill patients present with many technical and management issues. They are difficult to handle physically due to their size and it may be very difficult to transfer, investigate and nurse these patients. They might present with medical problems associated with morbid obesity which puts them at high risk of adverse outcome. Management of this group of patients needs a careful team approach and additional technical support.
1. John P Kress et al, The impact of morbid obesity on oxygen cost of breathing at rest. Am. J. Respir. Crit. Care Med., Volume 160, Number 3, September 1999, 883-886
2. Duarte, Alexander G et al, Outcomes of morbidly obese patients requiring mechanical ventilation for acute respiratory failure. Critical Care Medicine. 35(3):732-737, March 2007.
3. Masashi Nishikawa et al- Respiratory failure due to morbid obesity in a patient with Prader-Willi syndrome: an experience of long-term mechanical ventilation, Volume 20, Number 4 / November, 2006, 300-303.
4. Philippe Juvin et al, difficult tracheal intubation is more common in obese than in Lean Patients, Anesth Analg 2003;97:595-600.
5. Williamson JA, Webb RK, Szekely S, Gillies ER, Dreosti AV. The Australian Incident Monitoring Study. Difficult intubation: an analysis of 2,000 incident reports. Anaesth Intensive Care 1993;21:602-607.
6. Clinical Approach to the Critically III, Morbidly Obese Patient American
Journal of Respiratory and Critical Care Medicine, Mar 1, 2004 by El-
Solh, Ali A.