Objectives: The current study aimed to find the relation between the changes in the common carotid artery (CCA) diameter and the central venous pressure (CVP) in response to a fluid challenge in spontaneously breathing adult patients. Methods: This study included 65 adult patients aged 20 - 60 years who were admitted to the surgical ICU. The CCA diameter and CVP were measured before and after fluid challenge, and the percentage of increase in the CCA diameter and CVP were calculated. The correlation was assessed between changes in the CVP and CCA diameter. Results: The CCA diameter before fluid administration had a significant strong positive correlation to the CVP (r = 0.8, P value < 0.001); the increase in the CCA diameter after fluid administration had a significant moderate positive correlation with the increase in the CVP (r = 0.4, P value < 0.001). The percentage of increase in CCA diameters was positively correlated to the percentage of increase in CVP (r = 0.589, P value = 0.001) following fluid administration. However, the Receiver Operating Characteristic (ROC) analysis was an invalid test (area under curve 0.513, P value = 0.885). Conclusions: After major surgeries, the change in the CCA diameter was positively correlated with the change in the CVP values in response to fluid administration in the spontaneously breathing adult patients, but the cut-off limit cannot be reached.

Objectives This study compared the efficacy and safety of minimal tourniquet pressure using either determined limb occlusion pressure (LOP) or estimated arterial occlusion pressure (AOP) for elective upper limb surgeries. Methods Forty patients undergone elective upper limb surgery under general hypotensive anesthesia were randomized into groups A and B, where tourniquet pressure was calculated using AOP estimation for group A and LOP determination for group B. AOP, LOP, the time needed to estimate the AOP and determine the LOP and set the tourniquet inflation pressure, tourniquet inflation pressure, initial and maximal systolic blood pressure, heart rate, intraoperative fentanyl requirement, arm circumference, and tourniquet time were recorded. Tourniquet performance was assessed, and signs of tourniquet-related complications were noticed. Results Systolic arterial blood pressure was comparable between the groups. Less time was recorded for measuring AOP or LOP and set the minimal inflation pressure (in second) in group A than in group B (62 ± 2 for group A vs. 120 ± 3 for group B; P < 0.001). The estimated AOP in group A was significantly higher than the determined LOP in group B (118 ± 2 vs. 91 ± 2; P < 0.001). Tourniquet inflation pressures were not significantly different between the groups. Tourniquet performance was excellent or good in all patients in both groups. Conclusions Arterial occlusion pressure estimation or LOP determination methods to set the tourniquet inflation pressure with hypotensive anesthesia can provide effective minimal inflation pressure and satisfactory surgical field for upper extremity surgeries without tourniquet-related complications.