Wiswell T E, Turner B S, Bley J A, Fritz D L, Hunt R E
Division of Medicine, Walter Reed Army Institute of Research, Washington, DC.
Pediatrics. 1989 Aug;84(2):304-11.
It was hypothesized that diverse mechanisms may influence upper airway injury during mechanical ventilation. To assess the roles of several factors in the propagation of such injury, the tracheobronchial histologic changes in 53 newborn piglets were compared following conventional positive pressure ventilation. Eight animals were assigned to each of four positive pressure ventilation groups at "low" settings (an FiO2 of 0.25, a frequency of 10 breaths per minute, a peak inspiratory pressure of 20 cm H2O, a positive end-expiratory pressure of 4 cm H2O, a flow rate of 10 L/min, and an inspiratory time to expiratory time ratio of 1:2): (1) positive pressure ventilation with no hypotension or hypoxemia; (2) positive pressure ventilation with hypotension; (3) positive pressure ventilation with hypoxemia; and (4) positive pressure ventilation with both hypotension and hypoxemia. In addition, eight piglets were assigned to each of two positive pressure ventilation groups at "high" settings (greater frequency [40 breaths per minute], higher peak inspiratory pressure [40 cm H2O], and greater flow rate [17 L/min]): (1) positive pressure ventilation with no hypotension or hypoxemia; and (2) positive pressure ventilation with both hypotension and hypoxemia. The changes were mild and similar among the first three positive pressure groups at low settings. However, the injury scores of the combined hypotension and hypoxemia group (group 4) were greater than those of the former three positive pressure ventilation groups (P less than .004). The piglets receiving positive pressure ventilation at high settings with no hypotension or hypoxemia (group 5) had no more injury than those in the first three groups receiving positive pressure ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)
研究假设认为，多种机制可能会影响机械通气期间的上呼吸道损伤。为了评估若干因素在这种损伤扩散过程中的作用，研究人员比较了53头新生仔猪在接受传统正压通气后的气管支气管组织学变化。将八只动物分配到四个“低”设置的正压通气组中（吸入氧分数为0.25，频率为每分钟10次呼吸，吸气峰压为20 cmH₂O，呼气末正压为4 cmH₂O，流速为10 L/min，吸气时间与呼气时间之比为1:2）：（1）无低血压或低氧血症的正压通气；（2）伴有低血压的正压通气；（3）伴有低氧血症的正压通气；以及（4）伴有低血压和低氧血症的正压通气。此外，将八只仔猪分配到两个“高”设置的正压通气组中（更高的频率[每分钟40次呼吸]、更高的吸气峰压[40 cmH₂O]和更高的流速[17 L/min]）：（1）无低血压或低氧血症的正压通气；以及（2）伴有低血压和低氧血症的正压通气。在低设置的前三个正压组中，变化轻微且相似。然而，低血压和低氧血症联合组（第4组）的损伤评分高于前三个正压通气组（P小于0.004）。在高设置下接受无低血压或低氧血症的正压通气的仔猪（第5组）与接受正压通气的前三个组相比，损伤并不更多。（摘要截取自250字）
