Transcript Document

 Monitoring
is a human right.
 Anesthetist relies on his/her
natural senses to monitor the
patient.
 Simple aids as stethoscope &
sphygmomanometer help the
anesthetist and may safe the
patient.

Although the anesthetist is generally
careful, conscious and informed, he is
usually blamed if a patient dies during
or shortly after operation.
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However, inappropriate use of monitor
may confuse or mislead the anesthetist
or distracting him by malfunctioning
device.
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At the same time, if the patient dies
during anesthesia and he was
unattached to an available monitoring
device, the anesthetist is legally
indefensible.
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This is because the concept that,
patients who suffer as a result of
negligence should be compensated.
So, it is important to use monitor for:
Safety.
 Conduct of anesthesia.
 ICU practice.
 Research work.
 Assessment of critical conditions.
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Monitor is a Latin word “monere”
which means “to warn”
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Any monitor consists of:
Sensor.
System for data collection.
System for interpretation.
1)
2)
3)
Simple classification of monitoring
devices
Class
I
II
III
IV
sensor
data collect.
Human
Device
Device
Device
Human
Human
Device
Device
interpret.
Human
Human
Human
Device
Degree of invasiveness of
monitoring
Non invasive e.g.
ECG
 Minimally invasive e.g. I.V cannula
 Penetrating e.g.
ECHO
 Invasive e.g.
Arterial cannula
 Highly invasive e.g.
Brain, heart
cannula
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Limitation of monitoring
1)
2)
3)
4)
5)
Delay.
Danger.
Decrease skill.
Doubt of results.
Distracting set up.
How to select monitor
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1)
2)
3)
4)
5)
6)
Depend on
Aim.
Experience.
Type of anesthesia.
Facilities & availability.
Nature of surgery.
General condition of the patient.
CVS monitors
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Peripheral pulse.
Tissue perfusion.
ECG.
Arterial blood pressure.
Central venous catheterization
Pulmonary artery catheterization.
Cardiac output measurement.
TEE.
Blood loss measurement.
Respiratory system monitors
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Clinical monitors.
Airway pressure measurement.
Disconnection alarm.
Stethoscope (pericordial & esophegeal).
Spirometery.
O2 monitoring.
Co2 monitoring.
Anesthetic gas analysis.
H+ ions measurement.
CNS monitors
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Clinical monitoring.
EEG.
Evoked potentials.
Cranial nerve monitoring.
Cerebral blood flow measurement.
Monitoring of cerebral oxygenation.
Monitoring of depth of anesthesia.
Monitoring of metabolism
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Temperature monitoring.
Tissue oxygenation monitoring.
Indirect calorimetry.
Fluid & electrolyte status monitoring.
Blood gases & acid base status monitoring.
Hormonal status monitoring.
Neuromuscular monitoring
Clinical tests:
1)
2)
Conscious patient.
Un Conscious patient.
Peripheral nerve stimulation:
1)
2)
3)
4)
Single twitch.
Train of four twitches.
Tetanic stimulation.
Double burst stimulation.
Blood pressure monitors
ABP= CO×SPR
 MAP= Diastolic BP + 1/3 Pulse pressure
 Pressure units:
mmHg (torr) & Kpa & cm H2O
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(7.6 mmHg= 1 Kpa = 10 cmH2O)
ABP measurement
Non invasive BP monitoring:
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Palpation methode.
Auscultation methode.
Doppler (U/S) probe.
Oscillometry.
Plethysmography (finapress).
Arterial tonometry.
Invasive BP monitoring:
* Indications:
* Contraindications:
* Technique:
- selection of artery:
By (allen & modified allen tests).
- cannulation technique:
- transducer zeroing:
Complications of arterial
cannulation
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Hematoma.
Vasospasm.
Thrombosis.
Embolization of air or thrombus.
Skin necrosis, infection…..
Nerve damage.
Disconnection and fatal blood loss…..
O2 monitoring
(1) Monitor O2 delivery to the patient:
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O2 failure alarm.
O2 conc. In the gas mixture:
* Fuel cell.
* Clark electrode.
* Paramagnetic analyzer.
(2) Monitor O2 delivery to the tissues
A: Global tissue oxygenation:
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1- clinical monitoring e.g.
cap. refilling, state of extremities…
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2- O2 transport monitoring through
measurement of:
COP & Hb level & SaO2 & PaO2
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3- O2 uptake monitoring through:
* measurement of: SvˉO2 by pulmonary
artery oximetry.
* serum lactic acid level.
(B) Regional tissue oxygenation:
1- Oximetry:
* subcutaneous
* intravenous
* cerebral
2- Tonomitry :
gastric intraluminal tonometry.
Value:
1- O2 saturation of arterial blood.
2- Heart rate.
3- Tissue perfusion.
Principles:
Pulse oximeter probe consists of:
-
Photosensor.
Photodetector.
Based on transmission spectrophotometry &
plethysmography.
A- Spectrophotometry:
According to (Lambert-bear Law)
oxy- & reduced Hb differs in their
absorption of red & infrared light.
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Analyzing these changes of light absorption
by microprocessor can identify the value of
O2 saturation.
%saturation =
oxy-Hb /(oxy-Hb +reduced-Hb) × 100
B- Plethysmography:
(SpO2) Used to identify arterial pulsation to
avoid measuring O2 sat. in non-pulsating
blood of viens & tissues.
Disadvantages:
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Inaccuracy…….if O2 sat less than 70%
Insensitivity …..significant decrease in
PaO2 before significant decrease in SaO2 is
detected.
Interference…..
Intrinsic e.g. co-Hb, Met-Hb, I.V dyes,
bilirubine, fetal Hb……
Extrinsic e.g. motion, cautery, nail bed
infection, polish……
CO2 monitoring
A- Excretion of CO2 in the tissues by:
1- CO2 (severinghaus) Elctrode.
2-Transcutaneous partial pressure of CO2
B- Excretion of CO2 in the expired gas by:
Capnography.
 Value:
1- Confirm adequate ventilation.
2- Detect esophegeal intubation.
3- Maintain normocapnia.
4- Indicate quality of perfusion.
5- Diagnosis of air embolism, res.
Obstruction, arrest & quality of
resustation………
6- Prediction of awareness, recovery from MR.
7- Assessment of inspiratory valve
incompetence…
Principles:
Based on infrared absorption
spectrophotometery as CO2 absorb light
strongly at 4260 nm.
Types:
1- Main stream capnography
(Flow through)
2- Side stream capnography
(Aspiration)
Definition:
Simply, hypoxia means decreased O2 any
where; air, blood or tissue.
Hypoxemia is the reduction of O2 in the blood
resulting in:
* PaO2 is < 60 mmHg or
* SaO2 is < 90 %
Mean PaO2 =
102 – 0.33 (age in years) ± 10 mmHg (SD)
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It is an old equation by Marshall and
Whyche in, 1972
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These measures must be:
- At rest
- Breathing room air
NB: Neonates hypoxemia occurs when:
- PaO2 is < 50 mmHg
- SaO2 is < 88 %
With age there is progressive decline of PaO2
That is to say subtracting 1 mmHg from the
minimal PaO2 for adult (80 mmHg) for
every year over 60 years of age.
Types of Hypoxia
1- Hypoxic hypoxia:
When FiO2 < 0.21
 Hypoventilation.
 Pulmonary V/Q mismatch.
 Rt to Lt shunt.
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2- Circulatory Hypoxia
Due to reduced COP.
3- Demand Hypoxia
Due to increased O2 utilization.
4- Hemic Hypoxia
Due to:
decreased Hb content.
decreased Hb function.
5- Histotoxic Hypoxia
Due to inability of cells to utilize O2
e.g. cyanide toxicity.
 C/P
of Hypoxemia:
1- Cyanosis.
2- Sympathetic stimulation in form of:
tachycardia (except….?)
hypertension (except….?)
sweating, arrhythmias, agitation,….
3- Arrest….in sever persistent hypoxia.
4- + C/P of the cause.
 Prevention
and management:
# Prediction from history, exam., investig……
To detect the predisposing factors e.g.
1- Type & site of the surgery….
2- Respiratory diseases…..
3- Smoking
4- Obesity
5- Pregnancy
6- Age…..
# To do what ? ?.........................
Good monitoring.
 Treatment of the cause.
 Sterile equipment.
 Humidified gases.
 Adequate reversal of NMB.
 Proper postoperative analgesia,
physiotherapy.
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# Continue postoperative oxygenation,
reintubation, mechanical ventilation may be
indicated unfortunately in sever cases.
The following information is obtained
Saturday, March 29, 2008 about
21-year-old Dawn Marie Mack
Dawn had an abortion performed at National
Abortion Federation member of Eastern
Women's Center. She was attend, but Dawn
went into cardiorespiratory arrest.
The suit said that Eastern staff failed to
adequately respond to "the precipitous drop
in Plaintiff's blood pressure, cardiac
arrhythmia leading to cardiac arrest and
cessation of respiration."
Dawn was transported to a hospital by
ambulance, where staff tried to resuscitate
Dawn but, She died.
The suit contended that the following
shortcomings caused Dawn's death:
* carelessness in hiring staff
* negligent supervising of staff
* lack of emergency protocol and staff skilled
in treating emergencies
* lack of adequate equipment
* failure to maintain equipment appropriately
* failure to administer timely and properly
dosed medications
* failure to convey to Dawn the risks of
anesthesia
* failure to adequately evaluate Dawn's
condition via exam and medical history
prior to anesthesia
* failure to allow sufficient time to administer
anesthesia and perform the abortion in a
safe and careful manner
* inadequate staff training
* failure to adequately monitor anesthesia
* failure to accurately chart and record
observations and responses
* failure to anticipate potential complications
So, what ! ! ! ! ! ! ! ! ! ! ! !