how to treat severe pain.

HOW TO TREAT SEVERE PAIN. Self-administered pain relief. An overview based on the PG project work of: Dr Heiko Rudolph

Various methods of pain relief • • • •

Injections, as needed Scheduled injections Epidurals Intra-Venous (IV) infusions (pump or manually administered)

NB:An attentive nurse using the above with 1:1 care is the best possible treatment ! No machine would be needed.

Conventional pain relief P atient needs (P ain) Sedation

Call Nurse

Nurse Res ponds

Relief (Analges ia)

Absorption from Site

"Scr eening"

Injection Given

Sign out Medication P repare Injection

Conventional pain relief

Shortcomings: - Delays in many ways. - Cultural factors - Shyness in asking - Intramuscular: slow

P atient needs (P ain) Sedation

Call Nurse

Nurse Res ponds

Relief (Analges ia)


"Scr eening"

Injection Given


Conventional pain relief Peak and trough effect.

A solution ? • Let the patient control his / her own medication.

• Dr. Philip H. Sechzer “Studies in Pain With Analgesic-Demand

System” 1970,

A solution ! • Let the patient control his / her own medication.

PCA hardware: the pumps • Many PCA pumps are on the market • PCA has been used in hospitals around the world

for the last 15 years

PCA hardware: the pumps

• Modern PCA pumps are safer • Tamper proof (locked front panel)

How PCA works: basic principles • When in pain: The

patient presses the PCA button • A set amount* of pain medication (analgesic) is infused directly into the veins of the patient via a computer controlled infusion pump

* NB: this amount is always conservative !!!

So is the problem solved ? • In theory the problem should be solved.

• Right ?

The solution ! Comparison

So IS the problem solved ? • Well……. (salesperson would say so…. )

• It should be shouldn‟t it ? • But it isn‟t

• The reason is a non-engineering reason. It is a medical,

social, cultural, legal, human reason.

What‟s enough for Peter is not enough for Jane. •.

Problems with conventional PCA

• Most patients

are still in severe pain

Why not just administer more…. ?

Truth and further truth…. • Risk of overdose.

• Social stigma of morphine. • 15 fold variation in sensitivity between people.

• Variation of time within the same person

You CAN give more pain relief but ONLY if you monitor the patient very closely !

Summary: Conventional Patient regulated pain relief Currently PCA suffers from the following problems: 1) Variation in patient demand: Given that patients exhibit an up to 15 fold variation in analgesic requirements the problem in PCA is how to safely administer large amounts of analgesic without endangering those patients who require very little analgesic. 2) Underadministration: Given the variation in patient sensitivity to analgesics: Bolus doses are usually set to a very conservative level. These conservative estimates are then often in practice further reduced by clinical staff leaving the patient with an inadequate range of analgesic i.e. in pain.

A solution ?

Adaptive Patient Controlled Analgesia • Adaptive PCA allows the

patient to take charge of their own pain on a far more precise „sliding scale‟ • Rating pain on the Visual Analogue Scale (VAS) of 1 – 10

The Complete Adaptive PCA System

• Dosage

adjusts over time • Automatic background infusion

Choose how much you need • Greater choice + smart background infusion.

Problem solved ? • Hopefully 90% of the issues are addressed.

• Social, medical, legal, perceptual issues will still have

some influence on the practical “solution”. • It is another step…

CLINICAL TRIALS Trial results on 21 patients in the Royal Melbourne Hospital, Australia

Clinical trial structure Time

Randomly ass igned: 0 - 12 hrs 12 - 24 hrs

Common Handset

Abbott P CA

University of Melbourne and Royal Melbourne Hospital Adaptive PCA

P lacebo

Active Solution

Active Solution

P lacebo

Trial structure

Clinical trial structure

Experimental PCA at the University of Melbourne & Royal Melbourne Hospital 1993- 94

Effects of which system was used first VS questionaire pain scores per 12hour block

Effects of which system was used first VS questionaire pain scores

Effects of which system was used first VS handset pain scores

Effects of which system was used first VS number of Request

Oximeter data

An example button pressing profile, illustrating the way the self-adjusting background infusion responds to various sizes of administered boluses. PCA trial patient 20 Royal Melbourne Hospital May 1995

5 Boluses given

4.5

Background infusion Unfulfilled bolus requests

4

3 2.5 2 1.5 1 0.5

Tim e (10 May - 11 May 1995)

15:36

14:24

13:12

12:00

10:48

08:24 09:36

07:12

06:00

04:48

03:36

02:24

01:12

00:00

22:48

20:24 21:36

19:12

18:00

16:48

15:36

14:24

13:12

12:00

10:48

08:24 09:36

07:12

06:00

04:48

03:36

02:24

01:12

00:00

22:48

20:24 21:36

19:12

18:00

16:48

15:36

0 14:24

mg of morphine

3.5

Clinical trial results

bolus dose (mg)

10 8 6 4 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

time(hour) 4

demands

related to the demand profile, which mirrors the bolus dose profile • Adaptive PCA indicate better pain relief (n=21).

2

1

0 1 2 3 4 5

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

time(hour) 10 8

pain scale

• Pain scores, are

3

6 4 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

ti me (h our)

THE ENGINEERING ASPECT The technology & the algorithm

"...we are not really concerned about risk itself, but the acceptance of risk.” IEAust., Mar. 1993

Typical PCA system with safety monitoring equipment

The expert algorithm and its run-time information sources

The expert system and its run-time information sources- advanced

Handset (P ain score s)

PCA Program

Expe rt Algorithm

Respiration Rate End-Tidal CO2 Sa O2

Infusion Pum p (bolus & ba ckground)

Filter, classify into 4 levels

Knowle dge ba se

Alarm s

P atie nt details (Age ) Fixe d para m eters (Ma x. lim its) Run-tim e statistics

Handset (User fee dba ck)

Adaptive PCA: the analgesic range Bolus amounts (mg) 10 mg

5 mg

High Adaptation. Absolute max. limit (10 mg)

Normal Bolus Range (max. 5mg)

Max. step size 1.0 mg

Bolus amounts any value 0.5 to 5.0 mg 0 mg

Normal Adaptation Range High Adaptation Range

2 Adaptation ranges

Handset to select degree of pain on a pain scale of 1-10

Developed by Mondo Medical PTY LTD, Australia, H. Rudolph et al.

The patient handset for the adaptive PCA system Overlay mask ( visible) Blue

Yellow

GO

Red

0

10 1

2

3

4

5

6

7

8

9

10

Buttons underneath overlay mask ( hidden)

GO

Block diagram of the Adaptive PCA

Display Handset

System Control and Expert Algorithm

Patient Data

Patient

Infusion Pump

Safety & Risk • "...we are not really concerned about risk itself, but

the acceptance of risk.” • IEAust., Mar. 1993

Block diagram of the PCA system Hands et

Display

Capnograph

System Control and Expert System

Oximeter

Patient Data

Patient

Infusion Pump

How PCA works: basic principles Pain Source

• NB: The

patient is part of the control loop

Analgesic

Patient

Analgesic infusor

Button presses

How PCA works: the human control loop • In greater detail: a feedback system

Patient Infusion Pump

Perceived pain

Discomfort (wound)

Desired pain level Button presses

Computer Control

Program structure of the PCA system

User interface graphics routines

PCA control algorithm Expert system

Control & Information processing routines

Handset patient input routines

Oximeter IO routines (String preprocessing, DSP averaging)

Capnograph IO routines (String preprocessing, DSP averaging)

Infusion pump IO & control routines (Command string validation)

Patient input

Safety monitor

Safety monitor

System output

IO Data processing modules

Service Oximeter buf fer Service Capnograph buf fer

Update user interf ace

The main program loop and execution sequence

Drive Drive infusion pump

Service Hands et buf fer

Scan for alarm status

Call expert system Update knowledge bas e

Exte rnal IO de vice s Oximeter Capnograph P ump Handset

The IO Module: Interface between the external devices and the control

PC A control & e xpe rt algorithm P olling Numerical data & flags

Interrupt driven Data string preconditioning

C ircular buffe r P olling

Valid data Invalid data

(Strings)

No data

IO Module

Digital signal P olling proces sing DSP (Averaging) P olling

Set Flag : device unavailable

Cultural influences

Intros pective Emotional Experience of P ain

Hospital environment

A simple conceptual model of the process of quantifying the acute pain experience in order to interface with the PCA system.

Social environment

Family role models

Individual history

Individual personality traits

Mental Model of Expres sing P ain

Augmenting cues

Common societal symbol conventions P CA education

P ain experience trans lated into a form recognizable by the P CA s ys tem - using the handset

GO 0

10 P CA Handset

Clinical experts

Creating and refining the expert system in an iterative manner

References

Inform ation Exchang e

Nursing Staff

Inform ation Exchang e

Knowledge Trans lator/Engineer Evalua tion & Testing

P rototype P CA Sys tem

Mino r a dj ustm e nts

P atient

External IO device

Circular buffe r

Poll circular buffer

String preprocessing to establish validity of IO data

Data string pre conditioning module Data string classification

Valid data string

Invalid data string

No data s tring

If invalid data for > IN VALID_DELA Y seconds device unavailable els e output las t valid data s ample If no data for > NO_DATA seconds, then device unavailable els e output las t valid data s ample Valid data string, convert s tring to numerical value

Valid data , numerical value to DSP Filter

IO device classified as unavailable

Self adjusting variable tap filter for external data samples Alarm O K Alarm 1 Alarm 2 Alarm 3

...

...

•

N/4 Taps

... N/3 Taps

...

N Taps

N/2 Taps

Le s s s mooth ing, fas te r re spon se

To expert system

The screen is divided into information fields

PC A Status

Background infusion graph

Infusion (Green) Bolus (Yellow) Bolus request graph Alarm (Red)

Dat a for clinical nursing charts

Patient monit or dat a (Sa O2, ETCO2, RR)

Block diagram of the patient handset Push buttons 1 to 10 1

2

3

4

5

6

7

8

9

10

LE Ds

Microcontroller MC 68HC11-E2

Serial link Level translation (Max 232 )

Keyboard encoder

RS 232 Serial link to P C

Go

No key press

Wait for keypress. & Loop-back test echo

Loopback echo

Read key, light up LEDs

Flow diagram of the handset software

Turn on "GO" button. Wait for "GO" button press

Send key number to PC All LEDs off

Time out

WHAT IS PAIN ? Can you predict and measure it ?

Patient Controlled Analgesia (PCA) • It is difficult to predict

what level of pain a patient may experience or tolerate. • Even more difficult to determine is the patient‟s tolerance to the analgesic or the likelihood of side effects.

Effects of pain medication • For acute pain the best results are from the strongest

analgesics (pain killers) such as: Morphine & Pethedine (frome the group of: opioid analgesics) • Side effects: inhibit breathing…. which can lead to death if the dose is high enough…. !

Questions: • What population /age group is most sensitive to pain ?

(generally speaking) • ….least sensitive to pain ? • What is pain ?

Variation between patients up to 15 fold !

Frequency of Brain Activation in Highly Sensitive and Insensitive Individuals • The variation between patients to achieve acceptable

pain relief (analgesia) is up to 15 fold !

The dose that is „just right‟ for a young man may kill an elderly lady

Pain-induced Brain Activation in an in-Sensitive person

Pain-induced Brain Activation in a Highly Sensitive person

Patient Controlled Analgesia: ‘the maxim’ • Therefore: Medical staff usually prescribe strong pain

medication conservatively according to the maxim: • “better in pain than dead” :-P • Better he in pain than me sued/loss of reputation

EARLY ANALGESIA IS GOOD Fewer complications, lower morbidity, shorter hospital stays.

The first 6 hours are critical

• Successful analgesia is

especially critical during the first six hours following surgery.

The first 6 hours are critical

• Successful analgesia

leads to: • Fewer complication • Shorter hospital stays • Faster healing

Effects of pre & post surgical analgesia

FEEDBACK LOOP The patient is part of the feedback loop.

The shortcomings associated with conventional analgesic administration P atient needs (P ain) Sedation

Call Nurse

Nurse Res ponds

Relief (Analges ia)


"Scr eening"

Injection Given


How PCA works: basic principles Pain Source

• NB: The

patient is part of the control loop

Analgesic

Patient

Analgesic infusor

Button presses

How PCA works: the human control loop • In greater detail: the control loop

elaborated

Patient Infusion Pump

Perceived pain

Discomfort (wound)

Desired pain level Button presses

Computer Control

Typical PCA system

THE GREATER PICTURE The technology is just one part of many

PCA overview: Pain For the purposes of this presentation I will make the following assumptions. • Pain covers all levels of existence, from physical, to

emotional, mental & spiritual pain/anguish. This is just a complicated way of saying: “It‟s hard to define”. • Pain is what the patient feels it is, not what a doctor or a nurse or machine thinks it is/should be/ might be/could be. • Wound size, injury type, measurable parameters (X-ray, physiological parameters) are not necessarily related to the actual intensity of pain a person feels.

Pain – The uncertainty principle inherent in statistics. • Pain intensity DOES have a statistical profile over a large

population, • This means: age, gender, culture do make a statistical difference.

• In specific individual cases „all bets are off‟ i.e. patient

sensitivity to injury can and does vary wildly regardless of age, gender, culture, perceived degree of injury or “objectively” measurable injury by scientific instruments. i.e. A seemingly minor injury can produce agony, while a seemingly major injury may produce only minor pain.

Elements of pain relief Doctor‟s knowledge of Pain treatment

Better safe than sorry

Legal climate Fear of addiction.

 Pain

free, patient

15 fold variation in Sensitivity

Intrapatient variation

Social perception of “Drugs”

Elements of pain relief : • Up to: 15 fold variation in Sensitivity • Sensitivity to pain medication varies up to 15 fold between

individuals. What is perfect for one person may kill another.

Doctor‟s knowledge of Pain treatment



 Pain free, patient




Elements of pain relief • Intra- patient variation

• Sensitivity of the SAME patient varies over time. • Allergies, & “reactions” may occur.



Legal climate Fear of addition.





Elements of pain relief • Legal climate

• The level of risk of litigation a professional is willing to

make is influenced by the legal climate. • Legal Climate: Commonsense, compensation, VS predatory legal framework, i.e. benefits mainly for larger community VS benefits of individual claimant.








Elements of pain relief: the “better safe than sorry” factor • Better safe than sorry

• When you design a house, bridge, skyscraper, how safe

is safe ? What is the statistical criteria applied ? • A drainage system may be designed to cope with the once in a 100 years flash flood. Legal • Bridges, planes etc…also have Doctor‟s climate knowledge Fear of of Pain addiction. design tolerances treatment

 Pain

A similar process is at work in providing pain relief. Imagine you are a doctor, treating hundreds of patients.


free, patient




Elements of pain relief: the “better safe than sorry” factor • Better safe than sorry

• Let‟s say: To the right of the red line you have a court

case on your hands. • Where do YOU place that line ? • What are your considerations ?

This is really a question of how much risk is a doctor willing to take ? http://upload.wikimedia.org/wikipedia/commons/7/74/Normal_Distribution_PDF.sv

Elements of pain relief • Doctor‟s knowledge of Pain treatment

• Effective pain medication, at whatever dose required

prevents future longer term complications, aids recovery and leads to earlier discharge. Considerations are: • Economic (can work for or against patient)

• Moral and ethical.








Elements of pain relief • Fear of addiction.

• “Drugs are „bad‟ and people get addicted.” • Popular perception VS clinical realities. Non-pain

specialists are still subject to popular mis-conceptions. “Won‟t the patient press the button all the time ?” No. Not really. Real pain relief experiences:

„opioids are not much fun‟

Recreational drug use is different from clinical use








Elements of pain relief • Social perception of “Drugs” - Stigma

• Opioids (morphine etc… ) are “bad”. • As for the “fear of addiction” issue: popular perception VS

clinical realities. Non-pain specialists are still subject to popular mis-conceptions • “drugs” = evil/devil - to be avoided per se !!! • Addiction fears • “Bad name” and social stigma. • Most of the above are overreactions and can be managed clinically very well.








The subjective nature of Pain • When talking about „pain‟ sometimes it may seem that we

know what we are talking about. • But „pain‟ is highly subjective and experiential and like

„pleasure‟ touches all levels of human experience.

Elements of pain relief Under medication: •  Patient in pain. • On average: • Longer recovery • More post-operative complications, chronic conditions • Lower quality of life, • Longer hospital stays.

Elements of pain relief Medication to „reasonable comfort‟: • Patient

.

• On average: • Faster recovery • Less post-operative complications • Higher quality of life, • Shorter hospital stays.

Key: do not let acute/severe pain establish itself. Immediate postoperative analgesia that does not allow pain to gain a foothold has been shown to result in: decreased recovery time, fewer complications, shorter hospital stays and higher quality of life.

Conclusion General: • We don‟t know everything about pain.

• This is an open field. Pain like pleasure is a mysterious

part of life. It is not rational or logical, though sometimes it may seem to be. • This is Heiko‟s personal perspective. PCA results are based on Heiko‟s Postgraduate research & clinical trials on real patients in the Royal Melbourne Hospital, Australia. • Please ask questions.

The end • Questions ? • Email the author:

• [email protected] • or

• [email protected]

PAIN: COMMON MISCONCEPTIONS

Common Misconceptions about Pain • The caregiver is the best judge of pain.

• A person with pain will always have obvious signs such as • • • • •

•

moaning, abnormal vital signs, or not eating. Pain is a normal part of aging. Addiction is common when opioid medications are prescribed. Morphine and other strong pain relievers should be reserved for the late stages of dying. Morphine and other opioids can easily cause lethal respiratory depression. Pain medication should be given only after the resident develops pain. Anxiety always makes pain worse.

From: Missouri Dept of Health & Senior Services health.mo.gov/safety/showmelongtermcare/ppt/PainManagement.ppt

Accessed 24Sep2013.

Consequences of Untreated Pain • • • • • • • • • • •

Poor appetite and weight loss Disturbed sleep Withdrawal from talking or social activities Sadness, anxiety, or depression Physical and verbal aggression, wandering, acting-out behavior, resists care Difficulty walking or transferring; may become bed bound Skin ulcers Incontinence Increased risk for use of chemical and physical restraints Decreased ability to perform ADL‟s Impaired immune function

From: Missouri Dept of Health & Senior Services health.mo.gov/safety/showmelongtermcare/ppt/PainManagement.ppt Accessed 24Sep2013.

Untreated Pain • “Many of us don‟t know what to expect from pain relievers or

how to best advocate for ourselves and our loved ones who have pain,” said Dr. Scott Strassels of the College of Pharmacy.

• Untreated or undertreated pain can rob people of the ability to

function and can cause depression, irritability, sexual dysfunction and disruptions in sleeping, eating and mobility, according to Strassels and Dr. Eun-Ok Im of theSchool of Nursing.

“But what many people don‟t understand is that pain itself can cause harmful side effects and can affect concentration and mental clarity just as profoundly as any drug,” Dr. Scott Strassels From: Univ of Texas at Austin: Untreated pain: Sept. 28, 2009 “Where does it hurt ?” http://www.utexas.edu/features/2009/09/28/pain/

Untreated - Pain in the ICU

From: Guide to pain management in low resource settings. Chapter 37, Pain management in the Intensive Care Unit. Josephine M. Thorp, Sabu James, From The International Association for the Study of Pain http://www.iasppain.org/AM/Template.cfm?Section=Guide_to_Pain_Management_in_Low_Resource_Settings &Template=/CM/ContentDisplay.cfm&ContentID=12200

Marginalization of Pain: Poor pain treatment. Summary Points • Millions worldwide unnecessarily suffer from untreated pain. This burden is highest in the developing world, and among the poor, elderly, mentally ill, children, women, and racial/ethnic minorities. • Both the biomedical and public health approaches to global health marginalize or ignore pain management, viewing it as a drain on resources that would be better spent on cure or prevention. • Reducing global inequalities in untreated pain will require a concerted effort by global health funders, institutions, and organizations to place untreated pain at the top of the list of global health priorities. This effort must attend to the complexity of pain and promote multimodal, multidisciplinary pain management from the outset. King NB, Fraser V (2013) Untreated Pain, Narcotics Regulation, and Global Health Ideologies. PLoS Med 10(4): e1001411. doi:10.1371/journal.pmed.1001411 http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1001411

Pain references List given by U Texas: • American Pain Foundation • Mayday Pain & Society Fellowship • Mayday Fund Pain Management Experts Guide • American Pain Society • International Association for the Study of Pain (IASP) http://www.iasp-pain.org • American Academy of Pain Medicine • Pain Control: Support for people with cancer • Alliance of State Pain Initiatives • Federation of State Medical Boards • Responsible Opioid Prescribing: A Physician‟s Guide • Emerging Solutions in Pain

From: Univ of Texas at Austin: Untreated pain: Sept. 28, 2009 “Where does it hurt ?” http://www.utexas.edu/features/2009/09/28/pain/

Regular assessment + “sedation vacation”

Guide to pain management in low resource settings. Chapter 37, Pain management in the Intensive Care Unit. Josephine M. Thorp, Sabu James, From The International Association for the Study of Pain http://www.iasp-pain.org/AM/Template.cfm?Section=Guide_to_Pain_Management_in_Low_Resource_Settings&Template=/CM/ContentDisplay.cfm&C ontentID=12200

THE END Questions [email protected]

Cellar – HK EA Flyer text •

• • •

• • • •

• •

• • • • •

• •

•

Patients in severe pain press a button connected to a comptuer controlled intra-venous infusion pump and obtain fast pain relief from some of the most powerful drugs available (morphine, pethedine etc..). These devices are standard in hospitals, and known as Patient Controlled Analgesia (PCA). As good as the idea sounds in theory, there are some technical and social shortcomings in practice. This presentation will look at the basic theory and background of self-administered pain relief, and describe some of the medical, social and technical barriers to better pain relief. A seemingly simple problem, turns out to be very complex and wide ranging. Effective pain control is currently subject to negative social perceptions of opiod analgesics, an unequal power relationship between patient and doctor, a litigious legal climate, up to fiveteen fold variations in analgesic sensitivity amongst patients, and a lack of awareness of the long term effects of adequate and in-adequate pain relief on patient recovery. To effectively provide adequate analgesia for the broad population requires economic, social, polictical and technical solutions to work together. A smart device, 'Adaptive Patiend Controlled Analgesia' (A-PCA) is presented and the demonstration software developed under the venture capital company Mondo Medical will be shown. mondo.com.au/adaptive.html The chief shortcomings of current PCA devices, are: - the fixed bolus dose, usually set to cater to the most sensitive segment of the population and leaving a large number of pati ents in servere pain. - inability to adjust to variations in patient profiles and changes within a single profile over time. A-PCA addresses these shortcomings by providing a variable bolus dose and a 'smart algorhythm' to adjust to patient behaviour. A-PCA limitations consist of a greater need for safety monitoring, a modest initially higher capital cost and a perceived greater risk. A-PCA is proposed as the next step in PCA in much the same way that black and white film was largely replaced by colour film. A-PCA claims to provide a much better, but by no means totally successful tradeoff across conflicting parameters.

The Adaptive-PCA device was developed by Dr Heiko Rudolph under the guidance of Prof Jack Cade from the Royal Melbourne Hospital (RMH) (former Director of the RMH's Intensive Care Unit). For those who want to dig deeper, the original thesis can be found here. Speaker: Heiko Rudolph completed his Postgraduate degree (in acute pain-control, medical electronics), at The University of Melbourne, Australia in 1996. A postdoc position in Tokyo in 1997 with Dr Hiroshi Motoyama took him to Asia again until the venture capital company Mondo Medical made an offer too good to refuse: Commericalization of the same pain control device for two years. A three year term in Laos running the annual selection and training of Australian Development Scholarship students for AusAID, added international education to Heiko's experience. An academic at RMIT University since 2003, Heiko helped set up a new Master of Electronic Engineering at RMIT's Vietnam campus in 2011. From August 2012 onwards, Heiko has been resident in Hong Kong as Programme Director for RMIT's Bachelor in Electrical Engineering with HK's Vocational Training Council (VTC) at the Tsing Yi, IVE, campus.