The following example shows a sequence of images in a pressure support mode. In the first image, the pressure-time scalar shows a progressive increase in the inspiratory pressure drop during the trigger phase, indicating increasing patient inspiratory effort. Correspondingly, there is an increase in both peak inspiratory flow and tidal volume. Over the next few breaths, a gradual reduction in inspiratory effort is observed, reflected by decreasing peak inspiratory flow and ti

In volume control mode, flow and tidal volume are independent variables, while pressure is a dependent variable. The peak pressure alarm serves as a safety mechanism to prevent excessive airway pressures that could cause barotrauma. When the airway pressure reaches the preset alarm limit, the ventilator terminates the inspiratory phase to avoid further pressure rise- a process known as pressure cycling.

Breaths 2 and 5 in the following waveforms demonstrate a marked pressure drop below baseline, accompanied by higher peak inspiratory flow and a rapid return of flow to baseline compared to the surrounding breaths. When such brief, strong inspiratory efforts are observed, it is important to consider hiccups as the cause, since hiccups generate sudden, short-duration diaphragmatic contractions that produce this characteristic waveform pattern

Rise time is the interval required for the ventilator to achieve the target pressure in pressure control or pressure support modes. It is also referred to as the pressurization rate, and it directly influences the peak inspiratory flow delivered to the patient. When the rise time is set too slow, the pressure increases gradually rather than promptly. This can be uncomfortable for patients who are breathing rapidly or have strong inspiratory drive, because the ventilator flow

A pressure spike at the end of inspiration is sometimes misinterpreted as delayed (late) cycling. However, it is important to recognize that a similar spike can occur simply due to relaxation of the inspiratory muscles, even without active expiratory effort. When a strong inspiratory effort suddenly stops, the ventilator may not immediately compensate, leading to a brief overshoot in airway pressure. Thus, not all end-inspiratory pressure spikes indicate late cycling; some ma

Hiccups are brief, strong, and involuntary diaphragmatic contractions. In this example, one of the breaths shows a greater pressure drop during the trigger phase compared to the surrounding breaths, along with a higher peak inspiratory flow, and the breath is very short in duration. This distinct pattern reflects a sudden, forceful inspiratory effort characteristic of a hiccup. Therefore, these abnormal short breaths are most consistent with hiccup-induced diaphragmatic contr

When there is an auto-PEEP/ air trapping, the expiratory flow-time scalar fails to reach the baseline before the next breath (abrupt termination of expiration).  Auto PEEP occurs when there is an increased airway resistance and/ or inadequate time for exhalation.

During the expiratory phase, the inspiratory valve remains closed while the expiratory valve stays open. Normal expiration is typically a passive process driven by the elastic recoil of the respiratory system, resulting in an expiratory flow-time graph that exhibits an exponential decay pattern. However, when a patient briefly initiates an inspiratory effort within the expiratory phase, it can lead to a reduction or absence of gas returning to the exhalation valve, causing a