PMC8165976_01
Respiratory variables, distribution of ventilation, and 'silent spaces' in Case 1. (A) High PEEP, Supine; (B) Low PEEP, Supine; (C) High PEEP, Prone; and (D) Low PEEP, Prone. In low PEEP. +. supine position, oxygenation was worst and the largest amount of '. silent spaces'. was observed, suggesting a massive lung collapse in dependent lung regions (B). High PEEP improved oxygenation, reduced the amount of '. silent spaces'. (A). Prone position by itself reduced the amount of silent spaces in dependent lung regions without increasing PEEP (D). The combination of high PEEP with prone position achieved highest oxygenation, least amount of '. silent spaces'. (C). PEEP =. positive end-expiratory pressure; Crs = respiratory system compliance.
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fig1
The combination of high PEEP with prone position achieved highest oxygenation, highest respiratory system compliance, least amount of silent spaces (Fig. 1).
PMC8165976_02
Respiratory variables, distribution of ventilation, and 'silent spaces' in Case 2. (A) High PEEP, Supine; (B) Low PEEP, Supine; (C) High PEEP, Prone; and (D) Low PEEP, Prone. Regardless of position, the amount of '. silent spaces'. in non-dependent lung increased, oxygenation deteriorated, and respiratory system compliance reduced by increasing PEEP, suggesting PEEP induced overdistension, (A, C). Prone position at low PEEP had the least amount of 'silent spaces' in non-dependent lung, achieving the highest value of oxygenation (D). PEEP = positive end-expiratory pressure; Crs = respiratory system compliance.
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PEEP, all of which suggest higher PEEP overdistended non-dependent lung regardless of position. Prone position at low PEEP (vs. supine at low PEEP) reduced the amount of silent spaces in the dependent lung from 12% to 8% and it also had the least amount of silent spaces in the non-dependent lung, achieving the highest value of oxygenation (Fig. 2).