Transcript Climate change – anaesthesia’s part in the problem

Climate change – anaesthesia’s
part in the problem
Dr Stuart White
Royal Sussex County Hospital, Brighton
Climate change
is
a fact.
Man is
responsible
for climate
change.
Why?
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Less/more expensive food
Fewer/more expensive car journeys
No air travel
Higher taxes and costs
Less ‘stuff’
Population restriction
Anaesthetists
• Professional life
• Personal life
Professional life
• Do anaesthetic drugs harm the
environment?
• Does the conduct of anaesthesia harm
the environment?
• How can we minimise the impact of
anaesthesia on the environment?
Anaesthetic gasses
• Evidence limited
• Langbein T et al. Volatile anaesthetics and the
atmosphere: atmospheric lifetimes and atmospheric
effects of halothane, enflurane, isoflurane, desflurane
and sevoflurane. BJA 1999; 82: 66-73
• IPCC
• Summarised in
Axelson U. Climate impact of anaesthetic gases
2008.http://www.miljo.skane.se/eng/U2237_translation.
pdf
Langbein
Inhalational anaesthetic agents contribute to two
environmental problems
• Direct depletion of the ozone layer
• Infrared absorption and global warming
Oxygen-ozone cycle
OO
UV
O
O
O
OO
OO
UV
OOO
OOO
OO OO
l
100
400
MESOSPHERE
STRATOSPHERE
TROPOSPHERE
Ozone depletion potential
Ozone depletion dependent on:
- chlorine and bromine content
- amount of agent that reaches the stratosphere
- longevity of agent remains in the stratosphere
Calculated contribution to stratospheric ozone
depletion
• halothane 1%,
• isoflurane 0.02%
• sevoflurane 0%
• desflurane 0%
Health effects of global warming
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Extreme weather
Rising sea levels
Drought
Crop failure
Resource conflict
Disease
Ozone depletion
Greenhouse gasses
Global warming potentials (GWPs)
• Measure of relative contribution to global
warming of a mass of gas to equivalent mass of
CO2 (GWP 1)
• Calculated according to
- (high) absorption of infrared radiation
- (wide) spectral location of absorbing
wavelengths
- (long) atmospheric lifetime
• Absorption not always linear
Greenhouse gasses
Global warming potential (time horizon, years)
Gas
Lifetime
(years)
GWP20
GWP100
GWP500
Carbon dioxide
Variable
1
1
1
Methane
12
72
25
7.6
HFC 23
270
12000
14800
12200
Sulphur
hexafluoride
3200
16300
22800
32600
Anaesthetic gasses
Global warming potential (time horizon, years)
Gas
Lifetime
(years)
GWP20
GWP100
GWP500
Nitrous oxide
(‘laughing gas’)
114
289
298
153
Isoflurane
2.6
1230
350
106
Sevoflurane
5.2
1980
575
175
Desflurane
2.6
1230
1526
106
BUT ...
Axelson
So N2O is most pollutant, BUT
Greenhouse gasses
6%
Nitrous oxide
20%
Anthropogenic N2O
4%
Specific manufacture
90%
Medicinal N2O
So N2O is most pollutant, BUT
Greenhouse gasses
6%
Nitrous oxide
20%
Anthropogenic N2O
4%
Specific manufacture
90%
Medical N2O
... equivalent to approximately
• 1% atmospheric nitrous
• 0.07% global warming
So not much, BUT ...
• Avoidable
• Secondary health benefits
• I’ve stopped using it
• BUT, have to use nasty gasses at higher MAC
• + more oxygen/air
Adapted from Charlesworth M. How green
is your gas? Anaesthesia News 2009; 267:
22-23.
Agent
MAC
in
100% O2
GWP100
Environmental
factor, EF
(GWPxMAC)
Relative
EF
Isoflurane
1.3
350
455
1
Sevoflurane
2.2
575
1265
2.8
Desflurane
6.0
1526
9156
20.1
Oxygen production
CO2 cost of liquid oxygen
• Air liquefaction
• Cooling
• Transport
= 0.4g CO2 per litre of oxygen
• RAFT: Average amount of oxygen used per case is
594 litres = 238g CO2
• Hip # (GA) = 340 L = 136g CO2
Advice
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Avoid nitrous oxide
Avoid desflurane (+ energy cost of warming)
Care prescribing oxygen
Active scavenging?
Low flow anaesthesia
TIVA
Low flow anaesthesia
Lockwood GG, White DC. Measuring the costs of inhaled
anaesthetics. BJA 2001; 87: 559-63.
• NARKUP
• Hip#, 50kg, SV, CO 4.5, MV 4.5, FRC 1500ml
Cons
Induct
Time
(min)
LOS
(min)
1
2
3
17
80
Flow
induct
(l/min)
Flow
Surg
(l/min)
Sevo
Used
(mls)
Cost
(£.p)
12/4%
5/2%
109
53.63
6/4%
3/2%
56
27.55
6/2%
0.6/2%
13
6.40
TIVA
Stockholm county council
• janusinfo.se, pbtprofiler.net
TIVA (EPA)
Drug
PERSISTENCE
BIOACCUMULATION
Propofol
P
B
T
Alfentanil
P
B
T
Remifentanil
P
B
T
TOXICITY
(fish)
What about regional anaesthesia?
Drug
PERSISTENCE
BIOACCUMULATION
Lignocaine
P
B
T
Bupivacaine
P
B
T
Levo
P
B
T
Ropivacaine
P
B
T
TOXICITY
(fish)
RA v GA
Also cheaper! Hip #
Cost spinal
anaesthesia,
(£)
Cost as %
spinal total
Cost GA
(£)
Cost as % GA
total
Group cost
% total
General
equipment
66.73
37
108.15
42
40
Airway
equipment
1.81
1
25.68
10
6
Personnel
92.85
51
93.71
36
43
Drugs
18.94
10
25.16
10
10
Gasses/
inhalational agents
0.43
<1
6.26
2
2
TOTAL
180.76
257.53*
Medical waste
• double/triple/quadruple packaging! Argh!
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Costs of waste storage set to increase
Incinerator £753/tonne
Domestic £83/tonne
Recycled cardboard, plastic, glass +£17/tonne
Some figures
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Europe 1.3 bn tonnes solid waste (3.5t/person)
UK 100 million tonnes solid waste
85%  9901 landfill sites
Incineration limited by EU Directive
NHS waste 408,000t/year (4%)
29% is clinical waste
< 10% of total NHS waste is recycled.
Hutchins DCJ, White S. Coming round to
recycling. BMJ 2009; 338: 609
• 2300kg of anaesthetic waste/theatre/year
• 40% of anaesthetic theatre waste is
potentially recyclable
• 4% of sharps bin waste was appropriate
Barriers
Social
Logistical
Legal
environment and wastes
health and safety
transport
6R
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Responsibility
Reduce
Reuse
Recycle
Rethink
Research
Responsibility
Central
Professional
Personal
Travel
2010 update of NHS Carbon Reduction strategy
(NHS SDU)
• 2004 18.6Mt CO2 (25% public sector, 3% UK)
• 2007 21 Mt CO2
• 2008 Climate Change Act
- reduce by 10% 2015 (19Mt!)
- reduce by 80% 2050 (4.2Mt)
22%
RAFT environmental audit
Patient + theatre staff + anaesthetists
=
108.7 miles of car usage
=
17.2kg CO2 (+ the rest!)
Cycle/walk/run to work
ESA Milan 2009
• From LGW (BA)=
225kg CO2 (stratosphere)
• Mean SE UK = 8.8t
CO2/person @
• ie 2.5% of @ production in
0.0006% of a year
• ie 43 times the usual rate
ESA Amsterdam 2011
Research
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Update inhalational work
Evaluate inhalational vs TIVA vs regional
Life cycle analysis of anaesthetic equipment
Evaluate the monetary and environmental
cost of recycling equipment
• Fully calculate the carbon cost of oxygen/air
• Green alternatives
• Decontamination and sterilisation
BUT
1 year Brighton East REC paper audit
• 68 REC applications + research conduct of
successful 55
• 176,150 sheets of A4 paper
- 879kg, £658, + £2078 PC
• equivalent national annual estimate
- 11.5m sheets A4
- 88 tonnes
- 2100 trees
Top tips
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Don’t use nitrous oxide
Use low flow anesthesia
Use regional anaesthesia
REDUCE, reuse, recycle, responsibility
Cycle to work
Stay informed
Agitate
[email protected]
[email protected]