1. Monitoring in anesthesia
Done By: Amer Al-Salamat

2. Objectives
Cyanosis.
O2-Hb dissociation curve.
Ventilation monitoring.

3. Cyanosis 
Is the bluish discoloration of the skin or mucous membranes due to the tissues near the skin surface having low oxygen saturation.
Defined as the presence of 5 gm/dL of deoxygenated hemoglobin (deoxy Hb) or greater.
Since estimation of hypoxia is usually now based either on arterial blood gas measurement or pulse oximetry.

4. the presence of cyanosis is dependent upon there being an absolute quantity of deoxyhemoglobin, the bluish color is more readily apparent in those with high hemoglobin counts than it is with those with anemia.
Cyanosis is divided into two main types:
Central(around the core,lips,and tongue).
Peripheral(only the extremities or fingers).

5. When signs of cyanosis first appear, such as on the lips or fingers, intervention should be made within 3–5 minutes because a severe hypoxia or severe circulatory failure may have induced the cyanosis.
The name cyanosis literally means the blue disease or the blue condition.

6. An oxygen saturation of 66% corresponds to an arterial oxygen tension (paO2)= of approximately 35 mmHg , the oxygen tension (PaO,) at which cyanosis is detected will be even lower.
Assume for example that the patient's Hb is now 10 gm/dL. The saturation at which we will detect cyanosis (ie., when the DeoxyHb = 5 gm/dL).
In severely anemic patients, oxygen saturation at which cyanosis is detectable will be lower than in normal patients.

7. O2-Hb dissociation curve
Sigmoidal in character- describes the relationship between oxygen tension (PaO2) and binding (saturation).

8. When PaO2 is low ( PaO2<60%), the hemoglobin affinity to oxygen falls rapidly, explaining the sharp sloping.
The lowest acceptable O2 saturation level is 90%.
Shifting in the curve is a normal process depending on the site of circulation.
Right shift: Hb releases oxygen to tissues; muscles and placenta, more rapidly.
Left shift: Hb has a higher affinity for oxygen in the lungs
Causes of shifting Include changes in PaCO2, Ph, temperature and [2,3 DPG].

11. Ventilation monitoring
As we known before we must monitor a patient to ensure adequate ventilation of the patient .
Clinically, we monitor it through a correctly positioned endotracheal tube, also observing chest expansion, and breath sounds over both lungs
Quantitively by capnography and ETCO2 analysis, and by Arterial blood gas analysis for assessing both oxygen and ventilation.

12. What is Capnography?
Continuous CO2 measurement displayed as a waveform sampled from the patient’s airway during ventilation.
What is EtCO2 ?
A point on the capnogram,which is the final measurement at the endpoint of the patient’s expiration before inspiration begins .
It is usually the highest CO2 measurement during ventilation.

13. Phases of the capnogram :
Inspiratory baseline
3. Expiratory Plateau
5. Expiratory Downstroke
2. Expiratory Upstroke
4. End-tidal ( EtCO2)

14. 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.
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.
Normal range: mmHg.

15. Thank You