Dr rowan molnar anaesthetics study guide part ii Identification of patient requiring procedure Referral to perioperative service Screening for level of workup required Pre-anaesthetic assessment/plan Referral & investigations as required. Admission at appropriate pre-op interval Post-operative drug/fluid/other therapy Appropriate post op level of care & stay Discharge at earliest appropriate point Dr Rowan Molnar, Dr Rowan Molnar Anaesthetics, Dr Rowan

1. DR ROWAN MOLNAR PART II:
PERIOPERATIVE MEDICINE
“THE WAY OF THE FUTURE”

2. WHAT IS PERIOPERATIVE MEDICINE?
“Integrated multidisciplinary
management of the surgical
or procedural patient’s
hospital admission & stay.”

3. PERIOPERATIVE SYSTEM INCLUDES:
 Identification of patient requiring procedure
 Referral to perioperative service
 Screening for level of workup required
 Pre-anaesthetic assessment/plan
 Referral & investigations as required.
 Admission at appropriate pre-op interval
 Post-operative drug/fluid/other therapy
 Appropriate post op level of care & stay
 Discharge at earliest appropriate point

4. BUT WHY?
 Minimize unnecessary pre-op bed days.
 Minimize preoperative cancellations
 Enable more predictable bed occupancy
 Minimize pseudo-urgent blood tests & other
investigations
 Improve post operative care & shorten post operative
stay

5. THE PRE-ANAESTHETIC CONSULTATION
 What? Targeted history & examination, &
formulation of anaesthetic/perioperative plan.
 Who? Ideally by the anaesthetist for the procedure
(not always possible).
 Whom? All patients should have some form of this.
 When? At the earliest appropriate opportunity
(Obviously this varies on a case by case basis)
 Why? To enable optimimum pre-anaesthetic
preparation, risk minimisation, informed consent,
and allaying of anxiety.

6. PRE-OPERATIVE PREPARATION MAY
INCLUDE PREMEDICATION
Use if required, not “one size fits all”
Aims:
1. Ameliorate anxiety
Usually with a benzodiazepine such as
temazepam
2. Relieve pain – predominantly in the acute setting –
usually with narcotics.
3. Prevent reflux/aspiration - in at risk patient
Usually (a) H2 blocker or PPI 6-8 hrs preop if
possible, then (b) non particulate antacid
immediately preop.
4. Treat other medical conditions
e.g. asthma prophylaxis.

7. MOST REGULAR MEDICATIONS ARE CONTINUED,
INCLUDING ON THE DAY OF SURGERY
Exceptions include:
(a) Oral hypoglycaemics
(b) Antithrombotic agents (mostly)

8. ASA PHYSICAL STATUS
 ASA 1 – Healthy patient
 ASA 2 – Mild or controlled systemic disease
 ASA 3 – Significant systemic disease
 ASA 4 – Severe systemic disease – current or
constant threat to life
 ASA 5 – Moribund patient unlikely to survive with or
without procedure
 ASA 6 – Brain dead patient (organ donor)
+/- E = Emergency procedure

9. RELEVANCE OF THIS?
 Risk stratification
 Workload/resource utilisation planning
 Remuneration aspects

10. PERIOPERATIVE (PREANAESTHETIC)
CLINIC
Surgical clinic
Nurse Clinic
Checked up, satisfied
as fit & suitable
Decides to proceed
with planned time,
date & procedure
Not certain;sends
only case notes to
anaesthetist to review it
Satisfied with it;
decides to send
it back to her
for mx
Not quite satisfied;
takes over review & mx
Decides to further
investigate. May cancel,
postpone, refer case or
decide to do it
Surgeon refers case

11. Preanaesthetic Clinic
 The Doctor takes a quick history, leading
questions are allowed as major
diagnoses should already be known
 Asks for hypertension, diabetes,
asthma,epilepsy, previous anaesthetics,
allergies, complications, medications
being used
 A quick examination is done, Ix like Xray,
ECG, UES & Blood ix are done
 ASA categorised, anaesthesia decided
 Explained to patient about anaesthetics,
risks, PCA & possible complications

12. Preanaesthetic Clinic
Based on: History
Examination, Investigation . . .
Decision:
To do the
planned
procedure
To postpone the
procedure till fully
investigated
optimised
To cancel the
procedure

13. CASE STUDY II
Perioperative management

14. DIABETIC PATIENT FOR
VASCULAR SURGERY

15. HISTORY
 65 year old man, BMI 35
 Type II DM, 15 yrs, on OHGs, poor control
 Smoker 60+ pack years
 Hypertension
 Hypercholesterolaemia
 Ischaemic heart disease
 Diabetic nephropathy, (eGFR ~ 30mls/min)
For (R) femoro-popliteal bypass

16. What are the issues and risks here?

17. 1.What are the issues and risks here?
2. How can we optimise him preoperatively?

18. 1. What are the issues and risks here?
2. How can we optimise him preoperatively?
3. What are our anaesthetic options & problems?

19. 1. What are the issues and risks here?
2. How can we optimise him preoperatively?
3. What are our anaesthetic options & problems?
4. How do we manage him postoperatively?

20. PART III:
SAFETY & MONITORING
IN ANAESTHESIA

21. SAFETY IN ANAESTHESIA IS PARAMOUNT
“When it goes right, no-one remembers. . . When it goes wrong,
no-one forgets”
. . . So the aim is to make anaesthesia as forgettable as possible!

22. SAFETY INITIATIVES IN ANAESTHESIA
Anaesthetists have been the leaders in safety initiatives
in medicine – e.g. :
 Privileged reporting & investigation of deaths under or
associated with anaesthesia in most states.
 Systematic reporting of incidents and near misses
 Collegial policies on minimum standards for facilities,
equipment, monitoring, staffing, & training.
 Publication of algorithms – e.g: difficult airway
management; malignant hyperthermia
 Simulation & contingency training e.g. difficult airway
workshops, emergency management of anaesthetic
crises (EMAC) course.

23. PRINCIPLES OF SAFETY
 Recognise risk – pre anaesthetic consultation
 Avoid risk if possible – e.g. can procedure be
done under LA?
 Mitigate risk – optimise patient condition, select
safest technique/agents/resources – e.g “cardiac”
anaesthetic & postop ventilation.
 Plan & be prepared for emergencies – e.g.
predrawn emergency drugs, backup airway plan.
 Observe/monitor for deviations & crises.
 Respond in a timely& appropriate fashion.
 Call for help/backup if required.

24. “THE PRICE OF SAFETY IS ETERNAL
VIGILANCE”
“Clinical observation is the cornerstone of patient
monitoring”
- ANZCA Policy statements (several)
OR . . .
“The best patient monitor is still the one between
your ears – so make sure it’s switched on”
– my take on the above.

25. MONITORING IN ANAESTHESIA
Basic (all/most patients)
 Pulse oximetry
 ECG
 Noninvasive (cuff) BP
 Capnography
 Oxygen concentration
 Agent monitoring
 Airway pressures
 Temperature
Others as indicated
 Invasive arterial BP
 Precordial stethescope
 Ventilator alarm(s)
 Nerve stimulator
 BIS/entropy
 Spirometry
 CVP
 “Swann Ganz” (PAP)
 Transoesophageal echo

26. PULSE OXIMETRY
 First monitor I put on most patients & first I
usually look at.
 If this is OK, then patient has a pulse, a
survivable blood pressure (at least 60/) and is
oxygenating their blood.
 But if it’s not right, it’s not very specific – i.e. it
may be as simple as a dislodged probe, or as
serious as a cardiac arrest.
 Doesn’t guarantee tissue oxygenation – may
be relatively normal in extreme anaemia,
carboxy- haemoglobinaemia, cyanide
posoning, etc.

27. ELECTROCARDIOGRAM
 Good monitor for:
 Arrhythmias/ectopics
 Some electrolyte abnormalities (K+ & Ca++)
 Ischaemic/strain changes
(Provided leads are placed correctly!)
 Does not monitor:
 Volume status
 Cardiac output
 Blood pressure
Remember: it is entirely possible to die
with a relatively normal ECG!

28. NONINVASIVE ARTERIAL BLOOD
PRESSURE (NIBP) MONITORING
 Usually automated
 Convenient but not reliable:
 Dependant on correct cuff size & position
 Not continuous
 Usually under-estimates true hyper-& over-
estimates true hypotensive values.
 Interferes with IV infusions & pulse oximetry
 Should not be placed on limb with AV fistula or
lymphoedema.

29. CAPNOGRAPHY
“Gold standard” for verification of ETT
placement.
Can also give information on:
 Dead space/V-Q mismatching
 Adequacy of ventilation
 Spontaneous respiratory effort during controlled
vent’n.
 Rebreathing: circuit problems or inadequate gas
flow.
 Venous return, RV function & pulmonary blood
flow e.g. thrombotic, gas or fat embolism

30. OXYGEN MONITORING
 Monitors machine rather than patient.
 The only specific monitor of oxygen supply
(Other safety features assume/depend on the
gas from O2 outlets & cylinders actually
being oxygen)
N.B. Before adoption/mandating of oxygen
monitoring, all reported (& thankfully very
rare) “wrong gas” anaesthetic incidents
(misconnected pipelines or incorrectly
filled cylinders) resulted in the death of the
first patient exposed in every case.

31. ANAESTHETIC AGENT MONITORING
 Identifies (hopefully confirms!) anaesthetic agent
being used
 Measures inspiratory & expiratory
concentrations
 Expiratory (alveolar) concentration enables
calculation of MAC fraction or multiple – i.e.
estimation of anaesthetic depth.
 Now mandatory when inhalational anaesthetic
agents are used.

32. TEMPERATURE MONITORING
 Anaesthesia promotes hypothermia by:
 Decreased metabolic rate -> decreased heat production
 Redistribution of blood flow -> increased heat loss
 Patients may need temperature support
 Passive (prevent heat loss)
 Active warming: forced air/ heated IV fluids
 What you support you must monitor
 Ideally monitor core temperature:
Nasopharyngeal/oesophageal/bladder/PV
Better than
Skin/axillary/oral/rectal

33. Airway manometry
 Usually analogue gauge
on circle circuit
 Monitors inflation
pressure
 With IPPV can help
identify:
Airway obstruction
Bronchospasm
Circuit leaks/faults
Ventilator monitor
 Mandatory when
mechanical IPPV
employed.
 Usually integrated into
ventilator w/automatic
activation.
 High (overpressure) &
low (disconnect)
functions

34. Precordial stethescope
 “Traditional” monitor
 Still used in some
paediatric cases
 Can monitors:
Heart & respiratory rate
Breath sounds presence &
quality.
Only as good as the
person listening to it!
Direct arterial pressure
monitoring
Invasive procedure, but:
 Gold standard for real
time haemodynamic
assessment
 Accurate, reliable.
 Immediate warning of
hypo/hypertension of
any aetiology.

35. Nerve stimulator
 Used with muscle relaxants
(neuromuscular blockers):
 Electrical stimulus to nerve
then observation of innervated
muscle.
 Commonest site: Ulnar nerve
 Nondepolarising block
characterised by “fade” –
weakening of contraction with
(4) successive impulses “train
of four.”
 Assesses: - Density of
block
- Return of function
- Point of safe reversal
Depth of Anaesthesia
monitoring
 Uses simplified EEG recording
& algorithm to produce
number related to level of
conciousness (lower
no=deeper anaesthesia)
 Two methods: bispectral edge
(“BIS”) and entropy.
 Role/value still controversial
 Probably indicated for:
 TIVA (as no MAC to
monitor)
 Patient with a history of
awareness
 Where lightest possible
plane of anesthesia
essential

36. OTHER MONITORS
 Central venous line.
- Mostly used for drug
infusions but can also
measure CVP as a (not
very accurate) guide to
volume status.
 Pulmonary artery (Swann
Ganz) catheter
- Can estimate LV filling
pressure (preload) – a
better guide to functional
volume status than CVP
- Also can measure cardiac
output by thermodilution.
 Trans-Oesphageal Echo-
cardiography (TOE)
Has become the gold
standard cardiac function
monitor. Able to estimate:
- Ejection fraction/stroke
volume/cardiac output
- LV & RV Preload/pressures
- Diastolic dysfunction (early
index of ischaemia)
 Spirometry
Measurement of pressure
volume loops & hence work
of breathing in controlled,
spont. & ass’t’d ventilation