Clinical Pearls (assisted by Dr. Lino Rafael O. Trinidad)

#1 concept: Will be the first warning of trouble in a struggling patient!

Capnography → LEAVE IT ON!! If esophageal, will go BACK to purple

Is the immediate picture of ventilation (SpO2 delayed) Hypoventilation occurs 1-2 minutes before hypoxemia

Ways of Measuring (Is the LAW for conscious sedation ) POC addition to ETT (standard intubation equipment) Sidestream- can add dead space; can underestimate CO2 Mainstream- T-piece adaptor at the airway opening; does not add dead space Mass Spectrometry- CO2 eliminated / O2 consumed



CO2 Waveform

Evaluate for: Height Frequency Rhythm Baseline Shape

Systematic Approach Is CO2 present (waveform) Is the baseline zero Evaluate the: Expiratory upstroke : steep, sloping, prolonged Expiratory (alveolar) plateau : flat prolonged, notched, or sloping Inspiratory downstroke : steep sloping or prolonged Just read the number Check ABG (Try to match the PaCO2, if its not within 5 a problem)



Alpha angle : amount of V/Q mismatch

Beta angle: if >90 degrees → rebreathing occurring

Evaluation of waveform abnormalities:

Waveform regular shape Plateau below normal = CO2 deficiency Hyperventilation Decreased pulm perfusion Hypothermia Decreased metabolism Plateau above normal = CO2 excess Hypoventiltion Absorption of CO2 during laparoscopy Fever Dietary excess Sudden increases: sodium bicarb use, release of tourniquet Watch for Trends:



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