Ludemann R, Krysztopik R, Jamieson G G, Watson D I
Department of Surgery, University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
Surg Endosc. 2003 Dec;17(12):1985-9. doi: 10.1007/s00464-003-8126-9. Epub 2003 Oct 23.
Pneumothorax is a known complication of laparoscopy, with most pneumothoraces diagnosed postoperatively with conventional chest x-ray. Electrocardiogram (ECG) conduction changes are associated with pneumothorax. In a sheep model, ECG changes were evaluated as a potential indicator of intraoperative pneumothorax. Additionally, resolution rates of helium (He) and carbon dioxide (CO2) pneumothorax were also evaluated in this model.
Under general anesthesia, 10 sheep had known volumes (20-100 cc) of either He or CO2 introduced into the left hemithorax. A 12-lead ECG recorded changes associated with the induced pneumothorax. After changes in the ECG plateaued, the gas volume in the hemithorax was increased to 2 L and the resultant pneumothorax was followed for a 2-h period using fluoroscopy to determine resolution rates for the different gas pneumothoraces. Gas volumes were aspirated after 2 h and ECGs were again recorded.
Pneumothorax volumes as low as 20 cc produced consistent ECG changes. The amplitude of the precordial QRS complex was seen to diminish, and this lowering of the QRS amplitude continued as pneumothorax volume increased up to 100 cc. The ECG returned to prepneumothorax patterns with aspiration of the left chest. For different gas pneumothoraces, CO(2) pneumothorax showed almost complete resolution in the 2-h period, whereas He pneumothorax was unchanged.
Precordial ECG changes appear to be a very sensitive indicator of pneumothorax, with very small pneumothorax (<100 cc) consistently being detected by reduction of the QRS complex amplitude. Intraoperative use of precordial ECG leads could result in rapid identification of pneumothorax during laparoscopic surgery. Carbon dioxide pneumothorax shows near 100% resolution in a 2-h period. This supports recommendations of expectant management in asymptomatic patients with CO(2) pneumothorax. However, He pneumothorax does not resolve spontaneously quickly and may require aspiration even in asymptomatic patients.
气胸是腹腔镜手术已知的并发症，大多数气胸在术后通过传统胸部X线诊断。心电图（ECG）传导变化与气胸有关。在绵羊模型中，评估心电图变化作为术中气胸的潜在指标。此外，还在该模型中评估了氦气（He）和二氧化碳（CO₂）气胸的消散率。
在全身麻醉下，向10只绵羊的左半胸引入已知体积（20 - 100 cc）的He或CO₂。用12导联心电图记录与诱发气胸相关的变化。在心电图变化趋于平稳后，将半胸内的气体体积增加到2 L，并使用荧光透视法对由此产生的气胸进行2小时的跟踪，以确定不同气体气胸的消散率。2小时后抽出气体体积并再次记录心电图。
低至20 cc的气胸体积产生了一致的心电图变化。胸前导联QRS波群的振幅减小，并且随着气胸体积增加至100 cc，QRS振幅的降低持续存在。通过抽吸左胸，心电图恢复到气胸前的模式。对于不同的气体气胸，CO₂气胸在2小时内几乎完全消散，而He气胸则无变化。
胸前导联心电图变化似乎是气胸非常敏感的指标，通过QRS波群振幅降低可始终检测到非常小的气胸（<100 cc）。术中使用胸前导联心电图可能会在腹腔镜手术期间快速识别气胸。CO₂气胸在2小时内显示近100%的消散率。这支持了对无症状CO₂气胸患者进行观察处理的建议。然而，He气胸不会迅速自发消散，即使是无症状患者也可能需要抽吸。
