Question 13

College Answer

Maintain ABCs

• Monitoring of vital signs
• SpO2 and ABGs for PCO2
• Use of CPAP post op if required. May use patient’s own CPAP device but issues with leak, need for oxygen supplementation, etc. may require ICU machine usage
• Monitor electrolytes especially K+, urine output

Maintain hydration

• Appropriate fluids can be Hartmanns, 5% glucose, dextrose saline all of which will provide an energy substrate and avoid starvation ketosis

Maintain euglycaemia (BSL 4-10)

• Insulin either as an intravenous infusion or intermittent sub-cut bolus to maintain BSL 4-10. No evidence even in this group to support tight BSL control

Avoid starvation ketosis

• Post-operative oral fluids or diet should be discussed with surgical team and appropriate diet commenced as soon as practical

Housekeeping

• Adequate analgesia avoiding opioids
• DVT prophylaxis- mechanical prophylaxis for all with low molecular weight heparin if no contraindications.

Positioning

• Ensure appropriate posture/positioning in bed to optimize respiratory function and minimize gastro-oesophageal reflux and for pressure care
• Early mobilization is essential. Goals should be set in conjunction with physiotherapy staff including, for example, sitting out of bed within 18 hours, walking within the next 24 hours.
• Special bariatric beds required and may also need large chairs so patients can be sat out of bed. Hoists etc. / manual handling training for staff

Surgical

• Test for leak as per surgical protocol e.g. ice water test, gastrograffin swallow.

Additional Examiners’ Comments:

Candidates who scored well mentioned specific challenges and considerations (rather than just generic “ABCs”) and suggested strategies to address these.

Discussion

The best resource for this was actually the UpToDate article on bariatric surgery. The college answer had some fairly generic suggestions (eg. "Monitoring of vital signs", "appropriate diet commenced as soon as practical") - as if without such recommendations the trainees would leave their bariatric patients unfed and unmonitored.

In trying to separate these generic issues from the real unique problems of post-operative care for the super-obese patient, the following summary was formed:

Avoidance of opiate excess

• Already the medulla is less sensitive to hypoxia and hypercapnea, from years of sleep apnoea.
• The addition of opiates is likely to upset this further
• The use of remifentanil may be appropriate while the patient is intubated, to avoid a residual opiate respioratory drive depression when it comes time to extubate them.

Mechanical ventilation for the morbidly obese patient

• The weight of the chest wall contributes to a decreased respiratory compliance
• A higher PEEP and P_aw is the expected norm.
• Still, one should try to keep the P_plat under 35 cmH₂O
• Oesophageal manometry may help to calculate the actual transpulmonary pressure
• You need a higher PEEP than you think. A recent study (Pirrone et al, 2016) found poorer lung compliance with clinician-set PEEPs (10-14 cmH₂O) among  patients who were all of horrendous size (BMI >50). The best PEEP settings were actually around 20cmH₂O.

Staged extubation

• If the elective airway was genuinely difficult, emergent re-intubation may be impossible.
• A hollow exchange catheter may be used to make re-intubation possible
• After the endotracheal tube is removed, the exchange catheter guidewire may remain in situ for some hours
• If the patient is breathing comfortably and a satisfactory period has passed, the guidewire may be removed.

Extubation on to NIV

• CPAP after extubation improves lung function by preventing post-extubation atelectasis (Neligan et al, 2009)
• The patient may already be on CPAP nocturnally, or at least have a CPAP machine with which they are noncompliant
• It would be helpful to extubate the patient on to their own CPAP machine
• Alternatively, post-extubation NIV could be titrated to a "normal" PaO₂ / PaCO₂  for the patient.

Logistics of mobilisation postural positioning and pressure area care

• They will need a special bed and a special chair to sit in
• The nurses who turn them will need a special air mattress to change the position of the patient
• The pressure area care requires more staff
• Manual handling techniques need to be reinforced by educators
• Lifting and cleaning may require specialised hoists
• Mobilising them will require extra physiotherapy staff and additional equipment

Akinnusi, Morohunfolu E., Lilibeth A. Pineda, and Ali A. El Solh. "Effect of obesity on intensive care morbidity and mortality: A meta-analysis*." Critical care medicine 36.1 (2008): 151-158.

Marik, Paul, and Joseph Varon. "The obese patient in the ICU." CHEST Journal113.2 (1998): 492-498.

Ling, Pei-Ra. "Obesity Paradoxes—Further Research Is Needed!*." Critical care medicine 41.1 (2013): 368-369.

Gross, Neil D., et al. "‘Defatting’tracheotomy in morbidly obese patients." The Laryngoscope 112.11 (2002): 1940-1944.

Brodsky, Jay B., et al. "Morbid obesity and tracheal intubation." Anesthesia & Analgesia94.3 (2002): 732-736.

Neligan, Patrick J., et al. "Continuous positive airway pressure via the Boussignac system immediately after extubation improves lung function in morbidly obese patients with obstructive sleep apnea undergoing laparoscopic bariatric surgery." The Journal of the American Society of Anesthesiologists 110.4 (2009): 878-884.

Pirrone, Massimiliano, et al. "Recruitment Maneuvers and Positive End-Expiratory Pressure Titration in Morbidly Obese ICU Patients." Critical Care Medicine 44.2 (2016): 300-307.

Robinson, Malcolm K., et al. "The Relationship Among Obesity, Nutritional Status, and Mortality in the Critically Ill*." Critical care medicine 43.1 (2015): 87-100.

Amundson, Dennis E., Svetolik Djurkovic, and Gregory N. Matwiyoff. "The obesity paradox." Critical care clinics 26.4 (2010): 583-596.

Hutagalung, Robert, et al. "The obesity paradox in surgical intensive care unit patients."Intensive care medicine 37.11 (2011): 1793-1799.

Curtis, Jeptha P., et al. "The obesity paradox: body mass index and outcomes in patients with heart failure." Archives of internal medicine 165.1 (2005): 55-61.

Gruberg, Luis, et al. "The impact of obesity on the short-term andlong-term outcomes after percutaneous coronary intervention: the obesity paradox?." Journal of the American College of Cardiology 39.4 (2002): 578-584.

Fonarow, Gregg C., et al. "An obesity paradox in acute heart failure: Analysis of body mass index and inhospital mortality for 108927 patients in the Acute Decompensated Heart Failure National Registry." American heart journal 153.1 (2007): 74-81.

Sasabuchi, Yusuke, et al. "The dose-response relationship between body mass index and mortality in subjects admitted to the ICU with and without mechanical ventilation."Respiratory care 60.7 (2015): 983-991.

Marik, Paul Ellis. "Obesity in the ICU." Evidence-Based Critical Care. Springer International Publishing, 2015. 787-795.