Flank-suspended versus prone percutaneous nephrolithotomy: changes of haemodynamics, arterial blood gases and subjective feelings.

BACKGROUND

The flank-suspended position was adopted in percutaneous nephrolithotomy (PCNL), and haemodynamics, blood gas variables and subjective feelings were examined with an attempt to explore the effect of the operative position in PCNL on the body's inner environment and patient comfort.

OBJECTIVE

The influence of the flank-suspended and prone position on haemodynamics, arterial blood gases and subjective feelings in patients receiving PCNL was examined.

DESIGN, SETTING AND PARTICIPANTS: A total of 100 patients with kidney stones who underwent PCNL during January 2010 to January 2011 were divided into flank-suspended groups (n = 50) and prone groups (n = 50) at random in terms of the operative position. The blood pressure, heart rate, respiratory frequency and oxyhaemoglobin saturation and blood gas variables were determined at different time points (before the operation, after position change, 30 min after the start the operation and immediately after the operation). Visual analogue scale (VAS) scoring system was employed to define the posture comfort, dyspnoea and puncture-site pain 24 h postoperation in the patients. All the measures were compared between patients in different positions at different time points.

STATISTICAL ANALYSIS

Paired t-test was employed in the comparison of measures detected at different time points in the same group. Two-group comparison was subjected to t-test. A p value less than 0.05 was considered statistically significant.

RESULTS AND LIMITATIONS

The blood pressure was decreased within and after the operation in both groups, substantially in the prone group, significantly lower than that before the operation (p<0.05). No significant differences in the heart rate, respiratory frequency and oxyhaemoglobin saturation were noted among the different time points in the same group. Blood gas analysis showed that pH value and base excess were profoundly reduced within and after the operation in the two groups, significantly lower than those before the operation, and the decrease was most manifest in the prone group. There was no difference in the blood sodium and potassium among the different time points in each group. The flank-suspended group was superior to the prone group with regard to posture comfort and dyspnoea degree but not puncture-site pain 24 h postoperation.

CONCLUSIONS

Flank-suspended and prone PCNL affects the haemodynamics, blood gas variables and subjective feelings of patients to a varying degree. The flank-suspended PCNL possesses advantages over prone PCNL such as little influence on haemodynamics and blood gas variables, satisfactory posture comfort, less dyspnoea and easy access to vital sign observation.