Effects of steep head-down position on pulse pressure variation

BACKGROUND: The effects of head-down position on dynamic hemodynamic variables remain without full understanding. We evaluated the effects of steep head-down position on the pulse pressure variation (PPV). METHODS: Forty patients were positioned at 30degrees head-down position after anesthesia induction. We measured the heart rate (HR), arterial blood pressure (BP) and PPV before and 2 minutes after the position change. RESULTS: PPV and HR decreased (9.3 +/- 3.2% to 4.6 +/- 1.8%, 67.2 +/- 11.4 to 62.4 +/- 7.8, respectively) after steep head-down position, whereas the BP increased. Baseline PPV was related with decreases of PPV (r2 = -0.83, P < 0.0001). An 8% PPV threshold discriminated the patients with more than 5% decreases of absolute PPV value. The area under the receiver operating characteristic curve was 0.98 (95% CI = 0.88 to 1.00, P < 0001). CONCLUSIONS: Steep head-down position caused decreases in PPV. Higher PPV at the supine position decreased more after the position change. Further investigations are required to assess the significance, the duration and the relationship with fluid responsiveness of this change.

Respiratory Effects of Laparoscopic Operation under General Anesthesia / 대한마취과학회지

As laparoscopic operation has become more widely practiced, the full spectrum of effects associated with this technique must be realized. The purpose of this study is to investigate the cardiovascular effects, blood gas changes and especially changes in respiratory variables during laparoscopic operation. We studied 10 patients undergoing elective laparoscopic cholecystectomy (group I) and another 10 patients undergoing elective laparoscopic salpingectomy (group II). In both groups, mean arterial pressure and PaCO2 were increased and pH was decreased. But there was no significant change in PaO2. The changes of respiratory variables in group I were not significant. But in group II, peak airway pressure was increased and compliances significantly decreased (p<0.05) owing to more head-down position. In condusion, patients who are undergoing laparoscopic operatian may require careful monitormg about hemodynamic changes, oxygenation and CO2 retention during anesthetic management.