Equipment

Question 1

Outline Principle of Cardiopulmonary Excercise Testing

Evaluate role of CPET in a patient undergoing an oesphagectomy

Answer 1

CPET is a non-invasive dynamic test of the cardiopulmonary system

Aims to determine a patients functional capacity

Measures anaerobic thershold, peak O2 consumptions, ventilatory efficiency for CO2

Reduction in these variables is associated with worse post op outcomes

Namely mortality, morbidity , increased hospital and ICU stay

Test uses a electromagnetically braked cycle ergometre

Takes around 10 mins

Predifined program using patients age, weight, height and gender

Measures expired gases, ECG, NIBP, HR, SpO2

Data is entered into nine plot panel to give AT, Vo2 peak and Ve/Vco2

B

USEFUL to risk stratify patients particulary as oesphagectomy is a high risk procedure and post operative complications are increased

Results made help guide MDT decision making eg: proceed to surgery, consider alternatives or prehabilitation (evidence lacking) also for post operative disposition eg ICU/HDU

Question 2

What are the complications associated with residual neuromuscular blockade (30)

Evaluate the methods availiable to assess for residual NMB

Answer 2

INCREASED POSTOPERATIVE PULMONARY COMPLICATIONS

eg hypoxia, aspiration as decreased airway reflexes, poor cough atelectasis

POOR patient experience - phycological distress

Potenial for re-intubation

Increased time in PACU

B)

Methods include clinical judgement, Quantitative and Qualitative Neuromuscular monitoring

Evidence has shown that TOFR >0.9 to be adaquately reversed and minimise risk of PPC

Clinical eg head lift, hand grip is not uselful in determining residual NMB. Studies shown 50% patients have residual blockade

QUALITATIVE - visual or tactile feedback

includes TOF/DBS/PTC

TOF + visual/tactil unable to detect fade TOFR >0.4

DBS + visual/tactile unable to detect fade TOFR >0.6

PTC - used for deep blockage - not appropriate

None of these methods are able to determine TOFR >0.9 so are not useful clinically.

Quatitative with accelomyography eg STIMPOD

most accurate clinical device to objectively determine residual blockade

Main issues - some types require calibration PRIOR to initial NMBD so needs to be placed on for whole case and calibration

Need access to arm, and applied appropraitely,

Question 3

Classify possible causes of awareness under general anaesthesia 70%

Evaluate Evidence for BIS in reducing awareness 30%

Answer 3

Patient

• inadequate drug dose - morbid obesity , tolerance 2nd ETOH, Benzodiazepines
• unable to deliver sufficient dose - unstable patient significant blood loss, trauma, GA emLSCS

Anaesthesia

• human error - wrong dose, unfamiliar drug STP in GA LSCS, NDMB when patient not unconscious or failing to reverse, difficult airway - not delivering anaesthetic - no TIVA, experience , out of hours, fatigue

Equipment, cannnula failure, pump failure, error in monitoring , (failure of titration?)

Awareness is RARE

Cochrane review found that BIS vs clinical signs there was low certaintly that BIS reduced awareness in a general surgical population (B-aware)

In high risk populations BIS (40-60) has been compared to volatile MAC 0.7-1.3 and found no difference in awareness outcomes

Overall, I think BIS is a useful tool if running TIVA using NMBD as although awareness is rare (1:8600 with NDMB) it is a devestating complication

USEFUL TOOL WITH fastidious patient monitoring and preparation