RCP 110: Patient Monitoring

Vocabulary practice flashcards covering respiratory care monitoring principles, capnography, pulse oximetry, co-oximetry, transcutaneous monitoring, hemodynamics, and mechanical ventilation monitoring.

Monitoring

The clinical practice of repeatedly or continuously observing patient data over time to detect whether values are stable, improving, or worsening.

Patient Assessment Priority

The rule that when a monitored value suddenly changes, the clinician must always assess the patient first before checking the equipment, signal, or alarms.

Capnography

A monitoring modality that uses infrared absorption to measure exhaled carbon dioxide ($\text{ECO}_2$, $\text{ETCO}_2$, or $\text{PetCO}_2$).

Return of Spontaneous Circulation (ROSC)

The restoration of effective cardiac perfusion during CPR, identified on a capnograph by a sudden, sustained rise in $\text{ETCO}_2$.

Causes of Rising ETCO2

A physiological increase in exhaled carbon dioxide that commonly occurs with hypoventilation.

Causes of Falling ETCO2

A physiological decrease in exhaled carbon dioxide caused by hyperventilation or reduced pulmonary blood flow, such as in a pulmonary embolism.

Pulse Oximeter

The most appropriate noninvasive technique for continuous monitoring of arterial oxygen saturation ($\text{SpO}_2$) and pulse, operating by transmitting light pulses through capillary beds.

Factors Impairing Pulse Oximeter Accuracy

Conditions interfering with light transmission or pulse detection, including poor peripheral perfusion (shock, hypotension), skin pigmentation, nail products, motion, bright ambient light, and carbon monoxide poisoning.

Overnight Oximetry

Continuous recording of oxyhemoglobin saturation and pulse set to the shortest time interval overnight, used to screen for sleep-related breathing disorders or evaluate treatment response in obstructive sleep apnea.

Polysomnography

A formal sleep study indicated when overnight oximetry detects episodes of desaturation below $89\%$.

Co-Oximeter (Hemoximetry)

An invasive, non-continuous laboratory instrument that uses a blood sample and multiple wavelengths of light to measure oxyhemoglobin ($\text{O}_2\text{Hb}$), carboxyhemoglobin ($\text{COHb}$), and methemoglobin ($\text{MetHb}$).

Carboxyhemoglobin (COHb)

Hemoglobin bound to carbon monoxide; normal levels are $0 - 1\%$, smoker levels range from $2 - 12\%$, and levels exceeding $20\%$ indicate carbon monoxide poisoning.

Methemoglobin (MetHb)

A form of non-functional hemoglobin accurately differentiated and measured using a co-oximeter rather than a standard pulse oximeter.

Transcutaneous PO2 and PCO2 Monitoring

A continuous, non-invasive method using modified Clark ($\text{O}_2$) and Severinghaus ($\text{CO}_2$) electrodes applied directly to the skin surface to estimate arterial blood gases.

Transcutaneous Electrode Heating Temperature

Warming the skin beneath the electrode to $43 - 45\,^\circ\text{C}$ to increase local capillary perfusion and promote gas diffusion through the skin.

Transcutaneous Electrode Site Placement

Application of the electrode over flat areas with good perfusion, normally on the chest beneath the center of the right or left clavicle, rotated every $4\,\text{hours}$ to avoid erythema or blistering.

Transcutaneous Calibration Standards

Quality control calibration using room air ($\text{PO}_2\text{ }150\,\text{torr}$) for high $\text{PO}_2$, electronic zeroing for low $\text{PO}_2$, $10\%\,\text{CO}_2$ for high $\text{PCO}_2$, and $5\%\,\text{CO}_2$ for low $\text{PCO}_2$.

Air Leak (Transcutaneous Monitoring)

An inadequate sensor seal that exposes the electrode to ambient air, causing transcutaneous oxygen ($\text{TcPO}_2$) to falsely read higher than arterial oxygen ($\text{PaO}_2$).

Hemodynamics

The study and monitoring of blood movement through the cardiovascular system and the pressures and forces involved, commonly including heart rate, blood pressure, and mean arterial pressure (MAP).

Pulmonary Mechanics

Monitored ventilator variables—specifically airway pressure, volume, and flow—that describe the dynamic interactions between the patient and mechanical ventilator.

Artificial-Airway Cuff Pressure Monitoring

Routine monitoring of an endotracheal or tracheostomy tube cuff to ensure an adequate airway seal while preventing tracheal wall injury.