Abstract: Background　In some hemodynamically stable patients with traumatic pneumothorax, conventional vital signs may have limited sensitivity in detecting early disease progression. Quantitative bedside indicators capable of dynamic monitoring are therefore needed. Objectives　To evaluate the ability of a six-zone point-of-care ultrasound (POCUS) counting method to identify a "tension physiology" state in a standardized progressive pneumothorax animal model, and to compare pressure tolerance between left- and right-sided pneumothorax. Methods　Thirty-two adult Bama miniature pigs were randomly assigned to a left-sided pneumothorax group or a right-sided pneumothorax group (16 animals each). Progressive pneumothorax was induced by stepwise air insufflation into the corresponding pleural cavity. Intrapleural pressure (IPP) was gradually increased while cardiac output (CO) and mean arterial pressure (MAP) were continuously monitored. At each pressure level, standardized six-zone POCUS examinations were performed by blinded operators. A reduction in CO of ≥50% from baseline with preservation of an arterial waveform was defined as the operational endpoint of "tension physiology." The relationship between the number of ultrasound-involved zones and hemodynamic changes was analyzed. Results　During stepwise elevation of intrapleural pressure, the right-sided pneumothorax group required significantly lower IPP to reach the same tension physiology endpoint compared with the left-sided group (P＜0.001). Cardiac output declined progressively with increasing pressure, whereas reductions in MAP occurred later. The number of ultrasound-involved zones was significantly negatively correlated with CO (P＜0.001). A threshold of ≥4 involved zones demonstrated the best performance for identifying tension physiology(AUC=0.961). Conclusion　Six-zone POCUS counting may serve as a bedside semi-quantitative indicator of increasing risk of circulatory compromise during progressive pneumothorax. The observed side-dependent differences suggest that the affected side should be considered during clinical assessment of disease progression.