Ultrasound Machine Components and Controls — Flashcards

Flashcard 1: Which anesthetic equipment malfunction is characterized by a capnography waveform showing an **elevated baseline** and a **prolonged Phase III** (alveolar plateau)?

Answer: Expiratory valve malfunction

Extra: Incompetence of either the inspiratory or expiratory valve results in rebreathing of CO2, manifested as an **elevated baseline** (the CO2 level does not return to zero during inspiration). An **expiratory valve malfunction** specifically results in a prolonged Phase III (alveolar plateau) and an elevated baseline because exhaled gas is drawn back from the expiratory limb during inspiration.

Flashcard 2: Pressure regulator is a part of the _____ pressure system of the anesthesia machine

Answer: high

Flashcard 3: Which condition is characterized by a capnograph trace showing either a flat line or small CO2 peaks that rapidly decrease in height immediately following intubation?

Answer: Esophageal intubation

Extra: In esophageal intubation, the capnograph typically shows a flat line (no CO2). If CO2 was forced into the stomach during bag-mask ventilation, small waveforms may be seen initially, but these will rapidly decrease in height and disappear within a few breaths.

Flashcard 4: Rhythmic ripples on the expiratory plateau of a capnogram that coincide with the heart rate represent: _____

Answer: Cardiac oscillations

Extra: Cardiac oscillations are rhythmic ripples seen on the capnography waveform (usually in the expiratory plateau or descending limb) that coincide with the patient's heart rate. They are caused by the mechanical action of the heart beating against the lungs, causing small volumes of gas to move. They are more common in pediatric patients and those with slow respiratory rates.

Flashcard 5: Which catheter is used to measure pulmonary capillary wedge pressure (PCWP) and cardiac output via thermodilution?

Answer: Swan-Ganz catheter (Pulmonary artery catheter)

Extra: The Swan-Ganz catheter is a multi-lumen flow-directed catheter with a balloon at the tip. It is used to measure: 1. Right atrial pressure (CVP) 2. Right ventricular pressure 3. Pulmonary artery pressure 4. Pulmonary capillary wedge pressure (PCWP) 5. Cardiac output (via thermodilution)

Flashcard 6: Which condition is characterized by a 'shark-fin' appearance on a capnography waveform?

Answer: Bronchospasm (e.g., Asthma, COPD)

Flashcard 7: The incidence of PDPH is _____ when the needle bevel is placed in the long axis of the neuraxis

Answer: lesser (more/less)

Flashcard 8: A biphasic or "dual-peak" capnography waveform (double-sloped expiratory plateau) is characteristic of:

Answer: Single lung transplant

Extra: A biphasic or "dual-peak" capnogram (double-sloped expiratory plateau) occurs in single-lung transplant patients because the native and transplanted lungs have different compliance and resistance (different time constants), leading to asynchronous emptying.