Tacker W A, Balldin U I, Burton R R, Glaister D H, Gillingham K K, Mercer J R
Aviat Space Environ Med. 1987 Jan;58(1):69-75.
Acceleration atelectasis is the absorptional collapse of alveoli in the dependent lung due to increased accelerative forces. It is exacerbated by breathing 100% oxygen and, during +Gz exposure, by the use of an anti-G suit. Experiments were conducted on 12 subjects using simulated aerial combat maneuvers (SACM) with G profiles having peak exposures of either 4.5 G or 9 G. Decreases in vital capacity (VC) measurements were used as quantification of atelectasis, two types of reduction being identified and described. Labile reductions in VC were readily restored by a deep breath or cough. Such reduction approximated 28% following the 4.5-G SACM and 25% following the 9-G SACM. More persistent (so called) stable reductions were of lesser degree, values of -20% being seen following both 9 G and 4.5 G maneuvers. Acceleration atelectasis causes symptoms of chest pain, coughing, and shortness of breath. Subjective ratings of the severity of these symptoms were obtained from the subjects, and these were much greater following the 4.5-G SACM exposures than after the 9-G runs. Acceleration atelectasis was reduced by dilution of the inspired oxygen concentration by argon and nitrogen (evaluated at 95, 82.5, 70, 50, and 20% oxygen); the addition of unassisted positive pressure at 30 mm Hg (4 kPa) to the breathing mask; or the performance of the anti-G straining maneuver (AGSM).
加速度性肺不张是由于加速力增加导致下垂肺区肺泡吸收性萎陷。吸入100%氧气会使其加重，在 +Gz 暴露期间，使用抗荷服也会加重。对12名受试者进行了实验，采用模拟空战机动动作（SACM），其过载曲线的峰值暴露分别为4.5 G或9 G。肺活量（VC）测量值的下降被用作肺不张的量化指标，识别并描述了两种类型的下降。肺活量的不稳定下降可通过深呼吸或咳嗽轻易恢复。在4.5 G的模拟空战机动动作后，这种下降约为28%，在9 G的模拟空战机动动作后为25%。更持久（所谓的）稳定下降程度较小，在9 G和4.5 G的机动动作后均出现了 -20% 的值。加速度性肺不张会导致胸痛、咳嗽和呼吸急促等症状。从受试者那里获得了这些症状严重程度的主观评分，4.5 G的模拟空战机动动作暴露后的评分比9 G运行后的评分高得多。通过用氩气和氮气稀释吸入氧气浓度（在95%、82.5%、70%、50%和20%氧气浓度下评估）、在呼吸面罩上添加30 mmHg（4 kPa）的无辅助正压或进行抗荷紧张动作（AGSM），可减轻加速度性肺不张。
