The Effects of Intrathoracic Pressure During Continuous Two‐Lung Ventilation for Thoracoscopy on the Cardiorespiratory Parameters in Sevoflurane Anaesthetized Dogs

Abstract

The cardiopulmonary effects of different levels of carbon dioxide insufflation (3, 5 and 2 mm Hg) under two-lung ventilation were studied in six sevoflurane (1.5 minimum alveolar concentration; MAC) anaesthetized dogs during left-sided thoracoscopy. An arterial catheter, Swan-Ganz catheter and multianaesthetic gas analyser were used to monitor the cardiopulmonary parameters during the experiment. Baseline data were obtained before intrathoracic pressure elevation and the measurements were repeated at intervals after left lung collapse induced by insufflation with carbon dioxide gas. The intrapleural pressure levels used were 3, 5 and 2 mm Hg. Arterial blood pressures, cardiac index, stroke index, left and right ventricular stroke work index, arterial haemoglobin saturation, arterial oxygen tension and systemic vascular resistance decreased significantly during hemithorax insufflation, whereas heart rate, right atrial pressure, mean, systolic and diastolic pulmonary arterial pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance and arterial carbon dioxide tension significantly increased during intrapleural pressure elevation. Although carbon dioxide insufflation into the left hemithorax with an intrapleural pressure of 2-5 mm Hg compromises cardiac functioning in 1.5 MAC sevoflurane anaesthetized dogs, it can be an efficacious adjunct for thoracoscopic procedures. Intrathoracic view was satisfactory with an intrapleural pressure of 2 mm Hg. Therefore, the intrathoracic pressure rise during thoracoscopy with two-lung ventilation should be kept as low as possible. Additional insufflation periods should be avoided, since a more rapid and more severe cardiopulmonary depression can occur.

Pressure-Controlled versus Volume-Controlled One-Lung Ventilation for MIDCAB

“…This might be caused by higher intrathoracic pressure as a result of higher inspiratory peak pressure in the VCV mode. In consequence, we found a higher MPAP (significant ΔMPAP at OLV in our study) and PAOP during OLV with VCV [13]. …”

Cardiopulmonary effects of thoracoscopy in anesthetized normal dogs

“…Insufflation of CO 2 beyond an intrathoracic pressure of 3 mm Hg produces significant detrimental effects on cardiac output (CO) in dogs (Daly et al. 2002; Polis et al. 2002).…”

Evaluation of echocardiographic variables of morphometry and function in horses submitted to minimally invasive partial pericardiotomy

“…The intrathoracic pressure used during thoracoscopy may cause hemodynamic and respiratory changes in the patient, but they do not cause postoperative clinical sequelae (Barash et al, 2013), provided that it is used during short periods (Polis et al, 2002). Owing to the great discrepancy of pneumothorax values established by the literature among the different species, in the present study we opted for the pressure of 4mmHg, which provided good visualization and adequate working space for the surgeon and team.…”