What causes stacking breaths in a patient on mechanical ventilation?

Breath stacking is a way to fill a person’s lungs with more air than the person can usually take in when breathing naturally. Breath stacking helps people who have: Diminished lung capacity due to muscle weakness. Restricted chest movement.

Conclusions: Compared with increasing sedation-analgesia, adapting the ventilator to patient breathing effort reduces breath-stacking asynchrony significantly and often dramatically.

Double-triggering, also named breath-stacking in Assist/Control (A/C) ventilation (37), is characterized by two consecutive ventilator cycles (triggered by the patient) separated by an expiratory time lower than one-half of the mean inspiratory time.

Perhaps most feared among medical complications occurring during mechanical ventilation are pneumothorax, bronchopleural fistula, and the development of nosocomial pneumonia; these entities may owe as much to the impairment of host defenses and normal tissue integrity as to the presence of the ventilator per se.

1. Sit comfortably.
2. Loosen restricting clothing or belts.
3. Take in a full breath through your nose, allowing your stomach and lower ribcage to expand outward.
4. Trap this breath by closing your vocal cords.
5. Take in a smaller second breath and trap it.
6. Take a third breath until your lungs are full.

Breath stacking, also known as double-triggering, is an especially troublesome manifestation of asynchrony in patients on lung-protective ventilation using volume-targeted, assist-control ventilation.

Whereas low-tidal-volume ventilation is strongly advocated, plateau pressure may be a more useful parameter to monitor and better reflects barotrauma risk in these patients. Low tidal volume is an effective ventilation strategy, but clinicians have been somewhat slow to adopt this approach.

When patients trigger a mechanical breath, their spontaneous inspiratory effort is sensed by the machine, usually as a change in airway pressure or airflow. When such a change crosses the trigger-sensitivity threshold, the ventilator delivers the preset tidal volume.

Peak pressure, which reflects resistance to airflow, is measured by the ventilator during inspiration. Plateau pressure is thought to reflect pulmonary compliance and can be measured by applying a brief inspiratory pause after ventilation.

Patient-ventilator asynchronies are a mismatch between the inspiratory and expiratory times of the patient and the ventilator. A common way to detect asynchronies is by examining ventilator waveforms. There are different types of asynchronies, each with a set of characteristics that can be visually recognized.

Double triggering is defined as two ventilator insufflations delivered within one patient inspiratory effort (2). The root cause for this dyssynchrony is a disproportionately shorter inspiratory time (I-time) of the mechanical breath in comparison to patient neural I-time.

Patient-ventilator interaction depends upon the complex interplay of patient pathophysiology and the delivery of a mechanical breath, with the latter integrating the characteristics of the ventilator and the settings chosen by the clinician.

Ventilator-associated pneumonia (VAP) is a life-threatening complication with mortality rates of 33-50%. It is reported to occur in 8-28% of patients given mechanical ventilation. The incidence is 1-4 cases per 1000 ventilator days. The risk of VAP is highest immediately after intubation.

• Bradypnea or apnea with respiratory arrest. …
• Acute lung injury and the acute respiratory distress syndrome.
• Tachypnea (respiratory rate >30 breaths per minute)
• Vital capacity less than 15 mL/kg.
• Minute ventilation greater than 10 L/min.

Some complications developed during intensive care unit stay, such as muscle weakness, pressure ulcers, bacterial nosocomial sepsis, candidemia, pulmonary embolism, and hyperactive delirium, were associated with a significantly higher risk of prolonged mechanical ventilation.