Monitoring in Anesthesia Dr.Arkan Jaafar, M.D. Anesthesiologist,Medical college of Mosul

OXYGENATION Oxygenation is monitored clinically by providing adequate illumination of the patient's color and by pulse oximetry pulse oximeter measure : 1. The oxygen saturation of haemoglobin in arterial blood - which is a measure of the average amount of oxygen bound to each haemoglobin molecule. The percentage saturation is given as a digital readout together with an audible signal varying in pitch depending on the oxygen saturation 2. The pulse rate - in beats per minute.

VENTILATION Ventilation is monitored clinically by verification of a correctly positioned endotracheal tube as well as by observing chest excursions, reservoir bag displacement, and breath sounds over both lung fields. Ventilation is quantitatively monitored using end tidal carbon dioxide (ETCO2) analysis as well as an audible disconnection alarm on all mechanically ventilated patients

CIRCULATION palpation of the pulse auscultation of heart sounds Blood pressure measurement : -Automated non-invasive BP measurements NIBP -lnvasive BP monitoring :The radial artery at the wrist is the most common site for an arterial catheter insertion. The femoral, brachial, and dorsalis pedis arteries are alternative sites A central venous pressure (CVP) catheter provides an estimate of the right atrial and right ventricular pressures. The CVP reflects the patients blood volume, venous tone, and right ventricular performance. CVP mmHg

Electrocardiogram (ECG) The ECG monitors the conduction of electrical impulses through the heart. It is used to determine the heart rate and to detect and diagnose arrhythmias, myocardial ischemia, pacemaker function, and electrolyte abnormalities

Temperature : - Core temperature: measured through tympanic membrane, nasopharynx, esophagus,rectal, urinary bladder, pulmonary artery. - Peripheral temperature Urinary output : should be monitored hourly Oliguria:- urinary output <0.5 ml/kg/h Peripheral nerve stimulator : Monitoring neuromuscular function of patient receiving neuromuscular blocking agent

Arterial Blood Gas Interpretation ABG Acid- base disturbances are indicators of serious underlying pathology Arterial blood gas examination is a useful investigation in patients with suspected respiratory or metabolic disease serial blood gas investigation can monitor the progress or treatment of the underlying disease. PH is the negative log of the H+ ion concentration PH is important because H+ ions react highly with cellular proteins resulting in alterations in their function. Therefore, avoiding acidemia and alkalemia by tightly regulating [H+] is essential for normal cellular function

Blood samples : Radial artery Brachial a. Axillary a. Dorsalis pedis a. Femoral a

Blood gas normal values PH: ; measures blood acidity & concentration of hydrogen ions PaCO2: mm Hg; measures partial pressure of carbon dioxide HCO3: mEq/L; measures amount of bicarbonate Base excess (BE) (-2.0 to +2.0 mEq/L) The base deficit (BD) is the number of mEq/L of base (or acid) needed to titrate a serum pH back to normal at 37°C while the PaCO2 is held constant at 40 mmHg, thus eliminating the respiratory component.Therefore, the BD represents only the metabolic component of an acid-base disorder PaO2: mm Hg; measures partial pressure of oxygen (at sea level, FiO2 = 21%, Age-dependent) SaO %

ABG provides an assessment of the following : Oxygenation (PaO2, O2 saturation). The PaO2 is the amount of oxygen dissolved in the blood and therefore provides initial information on the efficiency of oxygenation. Ventilation (PaCO2). The adequacy of ventilation is inversely proportional to the PaCO2, so that when ventilation increases, PaCO2 decreases, and when ventilation decreases, PaCO2 increases. Acid-base status (pH, HCO3, and base deficit).

The Terms ACIDS Acidemia Acidosis ↓ PH –Respiratory  CO 2 –Metabolic  HCO 3 BASES –Alkalemia –Alkalosis –↑ PH Respiratory  CO 2 Metabolic  HCO 3

ABG PH → 7.35 – 7.45 PaCO2 → 35 – 45 mmHg HCO3 → 22 – 26 mEq/L BE → - 2 ─ +2 PaO2 → 80 – 100 mmHg (at sea level, FiO2 = 21%) SaO2 → 93 – 98%