1. Monitoring in Anesthesia
Dr. Med. Khaled Radaideh
Department of Anesthesiology
Faculty of Medicine
Jordan University of Science and Technology
September 18
Dr. Med. Khaled Radaideh, Facharzt

2. Monitoring in Anesthesia
OBJECTIVES:
1. Guidelines to the practice of anesthesia and patient monitoring
2. Elements to monitor (Anesthesia depth, Oxygenation, Ventilation, Circulation, Temperature)
2.1. ECG
2.2. Pulse Oximetry ( Function, Values, Limitations)
2.3. Blood Pressure (methods, indications, limitations, Insertion sites, values)
2.4. central venous line and pressure (methods, indications, limitations, Insertion sites and it's advantages, Complications, values)
September 18
Dr. Med. Khaled Radaideh, Facharzt

3. Monitoring in Anesthesia
OBJECTIVES:
2.5. Capnography and EtCO2 (Uses, Measurement, values, factors affecting EtCO2)
2.6. Cyanosis
2.7. The oxyhemoglobin dissociation curve (interpretation, causes of Left and right shifting , key values, O2-Content of Blood)
2.8. Temperature ( Methods, Values, sites)
3. Normal values for a healthy adult undergoing anesthesia
September 18
Dr. Med. Khaled Radaideh, Facharzt

4. Dr. Med. Khaled Radaideh, Facharzt
Guidelines to the practice of anesthesia and patient monitoring: Monitoring in the Past
Visual monitoring of respiration and overall clinical appearance
Finger on pulse
Blood pressure
September 18
Dr. Med. Khaled Radaideh, Facharzt

5. Guidelines to the practice of anesthesia and patient monitoring:
1. Qualified anesthesia personnel shall be present in the room throughout the conduct of all general anesthetics, regional anesthetics and monitored anesthesia care.
2. A completed pre-anesthetic checklist.
(history, physical exam, lab investigations, NPO policy)
September 18
Dr. Med. Khaled Radaideh, Facharzt

6. Guidelines to the practice of anesthesia and patient monitoring:
3. An anesthetic record. ( In general, major regional anesthesia, or monitored IV conscious sedation HR and BP should be measured every 5 min. Also time, dose and route of drugs and fluids should be charted ) 4. During all anesthetics, the patient’s oxygenation, ventilation, circulation and temperature shall be continually evaluated.
September 18
Dr. Med. Khaled Radaideh, Facharzt

7. Dr. Med. Khaled Radaideh, Facharzt
MONITORING HR
O2 sat RR BP
Temp
MAP
September 18
Dr. Med. Khaled Radaideh, Facharzt

8. Dr. Med. Khaled Radaideh, Facharzt
Elements to Monitor :
I. Anesthetic Depth:
Patients with local or regional anesthesia provide verbal feedback regarding well being.
Onset of general anesthesia signaled by lack of response to verbal commands, in addition to loss of blink reflex to light touch.
Inadequate anesthesia can be signaled by : Facial grimacing or movement of arm or leg. But with muscle relaxants ( fully paralysis), it can be signaled by : Hypertension, tachycardia, tearing or sweating.
Excessive anesthesia can be signaled by : Cardiac depression, bradycardia, and Hypotension. And also may result in hypoventilation, hypercapnia and hypoxemia when muscle relaxants is not given.
September 18
Dr. Med. Khaled Radaideh, Facharzt

9. Dr. Med. Khaled Radaideh, Facharzt
Elements to Monitor :
II. Oxygenation:
Clinically, monitored by patient color ( with adequate illumination ) and pulse oximetry.
Quantitavely monitored by using oxygen analyzer, equipped with an audible low oxygen concentration alarm.
III. Temperature
Continuous temperature measurements monitoring is mandatory if changes in temperature are anticipated or suspected.
September 18
Dr. Med. Khaled Radaideh, Facharzt

10. Dr. Med. Khaled Radaideh, Facharzt
Elements to Monitor :
IV. Circulation:
Clinically, monitored by pulse palpation, heart auscultation and monitoring intra-arterial pressure or oximetry.
Quantitavely using ECG signals and arterial blood pressure measurements every 5 min.
V. Ventilation
Clinically, monitored through a correctly positioned endotracheal tube, also observing chest excursions, reservoir bag displacement, and breath sounds over both lungs.
Quantitavely by ETCO2 analysis, equipped with an audible disconnection alarm.
Arterial blood gas analysis for assessing both oxygen and ventilation.
September 18
Dr. Med. Khaled Radaideh, Facharzt

11. Monitoring: Electrocardiogram ECG:
A 3 or 5 lead electrode system is used for ECG monitoring in the OR.
The 3 lead system has electrodes positioned on the right arm, left arm and chest position. ( placed in the left anterior axillary line at the 5th interspace, referred to as V5 ). Lead 2 is usually monitored by this system.
The 5 lead system adds a right leg and left leg electrodes, which allows monitoring v1, v2, v3, AVR, AVL, AVF and V5.
September 18
Dr. Med. Khaled Radaideh, Facharzt

12. Monitoring: Electrocardiogram ECG:
Identification of P waves in lead 2 and it’s association with the QRS complex is useful in distinguishing a sinus rhythm from other rhythms.
Analysis of ST segment is used as an indicator of MI. ( Dep.-ischemia / elev.-infarction )
Over 85% of ischemic events can be detected by monitoring ST seg. of leads 2 and V5.
September 18
Dr. Med. Khaled Radaideh, Facharzt

13. Monitoring: Pulse Oximetry:
Allows beat to beat analysis of oxygenation.
Depends on differences in light absorption between oxyHb and deoxyHb.
Red and Infra-red light frequencies transmitted through a translucent portion. (finger-tip or earlobe)
Microprocessors then analyze amount of light absorbed by the 2 wavelengths, comparing measured values, then determining concentrations of oxygenated and deoxygenated forms. (oxy- and deoxy-)
September 18
Dr. Med. Khaled Radaideh, Facharzt

14. Monitoring: Pulse Oximetry:
After all data is processed, oxygen saturation can be calculated.
Pulse plethysmograph (visual analysis of pulse waveform), while an audible form (auditory assessment of oxygenation status).
Pulse oximetry (SpO2) measures oxy-, deoxy-, met-, and carboxyHb.
CO poisoning gives an overestimation of the true O2 saturation(SaO2). E.g. Burn victims.
Inaccurate measurements seen in poor tissue perfusion (shock or cold extremities), movement, dysrhythmias, or when electrical interference is present (surgical cautery unit).
September 18
Dr. Med. Khaled Radaideh, Facharzt

15. Monitoring: Blood Pressure BP:
Methods of BP measurement:
1. Simplest method of BP measurement, estimating the SBP, is by palpating the return of arterial pulse as cuff is deflated.
2. auscultation of the Kortokoff sounds on deflation (providing both SBP and DBP)
Mean Arterial Pressure (MAP) = DBP + 1/3(SBP – DBP)
September 18
Dr. Med. Khaled Radaideh, Facharzt

16. Monitoring: Blood Pressure BP:
Methods of BP measurement:
3. Automated non-invasive BP measurements.
METHODOLOGY: a microprocessor controlled oscillometer (Dinamap®) which is used routinely intraoperatively. It allows automatic inflation of the BP cuff at preset time intervals, sending readings into a pressure transducer that digitalizes them. This technique gives rapid, accurate (± 9 mmHg) measurements of SBP, DBP, MAP and HR several times a minute. LIMITATIONS: Errors occur due to movements, arrhythmias or BP fluctuations due to respiration. 3 – 5 minutes intervals is recommended to prevent compressive peripheral nerve injury due to repeated rapid measurements.
September 18
Dr. Med. Khaled Radaideh, Facharzt

17. Monitoring: Blood Pressure BP:
Methods of BP measurement:
4. Invasive BP measurements. (Arterial BP):
Indications:
Rapid moment to moment BP changes
Frequent blood sampling
Major surgeries (cardiac, thoracic, vascular)
Circulatory therapies: vasoactive drugs, deliberate hypotension
Failure of indirect BP: burns, morbid obesity
Sever metabolic abnormalities
Major trauma
The radial artery at the wrist is the most common site for an arterial catheter. Alternatives are femoral, brachial and dorsalis pedis.
September 18
Dr. Med. Khaled Radaideh, Facharzt

18. Central Venous line and Pressure (CVP)
Catheter inserted into the SVC providing an estimate of the right atrial and ventricular pressures.
Serial CVP measurements are more useful than a single value in order to assess blood volume, venous tone and right ventricular performance. HR, BP and CVP response to a volume infusion (100 – 500 ml) is also a useful test of right ventricular performance.
September 18
Dr. Med. Khaled Radaideh, Facharzt

19. Central Venous line and Pressure (CVP)
Indications:
CVP monitoring provides Right Atrial and Right Ventricle pressures
Advanced Cardiopulmonary disease + major operation
Secure vascular access for drugs
Secure access for fluids + traumatic pts
Aspiration of entrained air: sitting craniotomies
Inadequate peripheral IV access
September 18
Dr. Med. Khaled Radaideh, Facharzt

20. Central Venous Line: PERFORMANCE of Right Internal Jugular Vein
Internal jugular (Int. Jug.) vein lies in groove between sternal and clavicular heads of sternocleidomastoid muscle
It is lateral and slightly anterior to carotid artery
Aseptic technique, head down
Insert needle towards ipsilateral nipple
Seldinger method: 22 G finder; 18 G needle, guide-wire, scalpel blade, dilator and catheter
Observe ECG and maintain control of guide-wire
Ultrasound guidance; Chest-Xray post insertion.
September 18
Dr. Med. Khaled Radaideh, Facharzt

21. Advantages of Right Int. Jug. vein
Consistent, predictable anatomic location
Readily identifiable landmarks
Short straight course to Superior Vena Cava
Easy access for anesthesiologist at patient’s head
High success rate, 90-99%
September 18
Dr. Med. Khaled Radaideh, Facharzt

22. Complications of Central lines (jugular):
Bleeding
Injury to surrounding structures as carotid artery
Pneumothorax
Arrhythmia
September 18
Dr. Med. Khaled Radaideh, Facharzt

23. Central Venous line Alternative Sites
Subclavian vein:
Easier to insert versus Int. Jug. vein
Better patient comfort v. Int. Jug.
Higher Risk of pneumothorax- 2%
External jugular:
Easy to cannulate if visible.
no risk of pneumothoroax,
high risk or bleeding
20%: cannot access central circulation
September 18
Dr. Med. Khaled Radaideh, Facharzt

24. Central Venous Pressure (CVP ) Monitoring
Reflects pressure at junction of vena cava + RA
CVP is driving force for filling RA + RV
CVP provides estimate of:
Intravascular blood volume
RV preload
Trends in CVP are very useful
Measure at end-expiration
Central Venous Pressure (CVP): 1-10 mmHg
September 18
Dr. Med. Khaled Radaideh, Facharzt

25. Dr. Med. Khaled Radaideh, Facharzt
Capnography and EtCO2
Capnometry: is the numerical measurement of CO2 concentration during inspiration and expiration.
Capnogram: refers to the continuous display of the CO2 concentration waveform sampled from the patient’s airway during ventilation.
Capnography: is the continuous monitoring of a patient’s capnogram.
September 18
Dr. Med. Khaled Radaideh, Facharzt

26. Dr. Med. Khaled Radaideh, Facharzt
Capnography and EtCO2
End-tidal CO2 monitoring is standard for all patients undergoing GA with mechanical ventilation.
It is an important safety monitor and a valuable monitor of the patient’s physiologic status, and it has been an important factor in reducing anesthesia-related mortality and morbidity.
Co2 monitoring is considered the best method for verifying successful intubation and extubation procedures.
It helps in assessment of the adequacy of ventilation and an indirect estimate of PaCO2.
Also it aids in diagnosis of PE, recognition of a partial airway obstruction, and indirect measurement of airway reactivity (bronchospasm).
ETCO2 levels have also been used to predict outcome of resuscitation.
September 18
Dr. Med. Khaled Radaideh, Facharzt

27. Dr. Med. Khaled Radaideh, Facharzt
Capnography and EtCO2
Measurement of ETCO2
Sampling the patient’s respiratory gases near the airway.
Using infra-red gas analysis or mass spectrometry on the values and concentrations obtained.
Provided that when sampling, inspired CO2 value should be near zero. (i.e. ETCO2 value is a function of CO2 production, alveolar ventilation and pulmonary circulation; excluding inspired CO2).
During general anesthesia, with absence of ventilation perfusion abnormalities, difference between PaCO2 and ETCO2 is about 5 mm Hg (PaCO2 = 40 mmHg, ETCO2 = 35 mmHg)
Increases or decreases in ETCO2 values maybe the result of increases or decreases in production and elimination.
September 18
Dr. Med. Khaled Radaideh, Facharzt

28. Changes in CO2 Production Changes in CO2 Elimination
Capnography and EtCO2 Factors affecting ETCO2:
Increased ETCO2
Decreased ETCO2
Changes in CO2 Production
Hyperthermia
Sepsis
Thyroid storm
Malignant Hyperthermia
Muscular Activity
Hypothermia
Hypometabolism
Changes in CO2 Elimination
Hypoventilation
Rebreathing
Partial airway obstruction
Exogenous CO2 absorption (laparoscopy)
Hyperventilation
Hypoperfusion
Embolism
Transient increases in ETCO2 may be noted after: IV bicarbonate administration, release of extremity tourniquets, or removal of vascular cross-clamps.
September 18
Dr. Med. Khaled Radaideh, Facharzt

29. Dr. Med. Khaled Radaideh, Facharzt
Cyanosis:
Defined as the presence of 5 gm/dL of deoxygenated hemoglobin (deoxy Hb).
i.e. Hb level = 15 gm/dL, 5 gm/dL release O2
which leaves 10 gm/dL of oxyhemoglobin
SaO2 = OxyHb / (OxyHb + DeoxyHb)
= 10 / (10 + 5)
= 66%
SAO2 of 66% corresponds to PaO2 of 35mmHg.
In anemic patients the oxygen tension at which cyanosis is detectable will be even lower.
i.e. Hb level = 10 gm/dL, 5 gm/dL release O2
SaO2 = OxyHb / (oxyHb + DeoxyHb)
= 5 / (5 + 5)
= 50%
SAO2 of 50% corresponds to PaO2 of only 27 mmHg.
September 18
Dr. Med. Khaled Radaideh, Facharzt

30. The oxyhemoglobin dissociation curve
It is a sigmoid curve that describes the relationship between oxygen tension (PaO2) and binding (SpO2).
When PaO2 is low, the hemoglobin affinity to oxygen falls rapidly , explaining the sharp sloping .(PaO2< 60 mmHg)
September 18
Dr. Med. Khaled Radaideh, Facharzt

31. Left And Right Shifts of the Oxyhemoglobin Dissociation Curve
A decrease in PaO2 of less than 60 mmHg (corresponding to SpO2 90 %) results in a rapid fall in the oxygenation saturation.
The lowest acceptable O2 saturation level is 90%.
Left And Right Shifts of the Oxyhemoglobin Dissociation Curve
Right
Left
Decreased affinity of Hb for O2.
Increased affinity of Hb for O2.
Causes:
Inc. PCO2
Hyperthermia
Acidosis
Increased altitude
Increased 2,3-DPG
Sickle Cell Anemia
Inhalational anesthetics
Dec. PCO2
Hypothermia
Alkalosis
Fetal hemoglobin
Decreased 2,3-DPG
Carboxyhemoglobin
Methemoglobin
September 18
Dr. Med. Khaled Radaideh, Facharzt

32. Oxygen content of blood:
The oxyhemoglobin dissociation curve
Key Values:
At PO2 100 mmHg, Hb 100% saturation.
At PO2 40 mmHg, Hb 75% saturation.
At PO2 27 mmHg, Hb 50% saturation.
Oxygen content of blood:
is the total amount of O2 carried in blood, including bound and dissolved O2.
O2 content = (O2-binding capacity * % saturation) + O2 dissolved
O2-binding capacity = maximal amount of O2 bound to Hb at 100 % sat.
The dissolved O2 isn’t measured by oximetry but by blood gas analysis.
September 18
Dr. Med. Khaled Radaideh, Facharzt

33. Monitoring Temperature
Objective
aid in maintaining appropriate body temperature
Application
readily available method to continuously monitor temperature if changes are intended, anticipated or suspected
Methods
thermostat
temperature sensitive chemical reactions
September 18
Dr. Med. Khaled Radaideh, Facharzt

34. Monitoring Temperature
Potential heat loss or risk of hyperthermia necessitates continuous temperature monitoring
Normal heat loss during anesthesia averages C per hour, but usually not more that C
Temperature below 34C may lead to significant morbidity
September 18
Dr. Med. Khaled Radaideh, Facharzt

35. Monitoring Temperature
Hypothermia develops when thermoregulation fails to control balance of metabolic heat production and environment heat loss
Normal response to heat loss is impaired during anesthesia
Those at high risk are elderly, burn patients neonates, spinal cord injuries
September 18
Dr. Med. Khaled Radaideh, Facharzt

36. Monitoring Temperature
Hyperthermia Causes
Malignant hyperthermia
Endogenous pyroxenes (IL1)
Excessive environmental warming
Increases in metabolic rate secondary to:
Thyrotoxicosis
Pheochromocytoma
September 18
Dr. Med. Khaled Radaideh, Facharzt

37. Monitoring Temperature
Monitoring Sites
Tympanic
Esophagus
Rectum
Nasopharynx
September 18
Dr. Med. Khaled Radaideh, Facharzt

38. Dr. Med. Khaled Radaideh, Facharzt
Normal values for a healthy adult undergoing anesthesia
Systolic Blood Pressure
Diastolic Blood Pressure
Heart Rate
Respiratory Rate
Oxygen sat. by oximetry
End Tidal Carbon Dioxide tension
Skin appearance
Color
Temperature
Urine Production
SBP
DBP HR RR
SpO2
ETCO2
85 – 160
50 – 95
50 – 100
8 – 20
95 – 100
33 – 45
warm, dry
pink
36 – 37.5
>= 0.5
mmHg
bpm
rpm %
O C
ml.kg-1.min-1
Central Venous Pressure
Pulmonary Artery Pressure
Pulmonary Capillary Wedge Pressure
Mixed venous oxygen saturation
Cardiac Output
Mean Arterial Pressure
*MAP = DBP + 1/3 ( SBP – DBP )
CVP
PAP (mean)
PCWP
SvO2 CO
MAP
1 – 10
10 – 20
5 – 15 75
4.5 – 6
80 – 120
1.Min-1
September 18
Dr. Med. Khaled Radaideh, Facharzt

39. Monitoring in Anesthesia
Dr. Med. Khaled Radaideh
THANK YOU
Department of Anesthesiology
Faculty of Medicine
Jordan University of Science and Technology
September 18
Dr. Med. Khaled Radaideh, Facharzt