Background <p>Obesity can complicate central venous catheterization by increasing skin-to-vessel depth and impairing ultrasound visualization. Optimizing internal jugular vein (IJV) cross-sectional area (CSA) is a key strategy to facilitate cannulation. Positive end-expiratory pressure (PEEP) is known to promote IJV distension in non-obese individuals and constitutes a component of lung-protective ventilation in obese patients; however, its efficacy for IJV distension and hemodynamic safety in the obese population remain uncertain. This study investigated the association between 10&#xa0;cm H₂O PEEP and right IJV CSA, as well as the hemodynamic tolerability of this intervention, in obese patients under general anesthesia.</p> Methods <p>This prospective observational study enrolled 40 adult patients with body mass index (BMI) &gt; 30&#xa0;kg/m² undergoing elective surgery at Tongren Hospital, Shanghai Jiao Tong University School of Medicine between June and October 2025. Following standardized anesthesia induction and hemodynamic stabilization, each patient underwent ultrasound measurement of right IJV CSA at both zero end-expiratory pressure (ZEEP) and PEEP 10&#xa0;cm H₂O in a randomized, self-controlled design. The outcome assessor was blinded to PEEP levels. Mean arterial pressure (MAP) and heart rate (HR) were recorded concurrently. The primary outcome was the difference in IJV CSA between ZEEP and PEEP 10&#xa0;cm H₂O. Paired Student’s t-tests and Wilcoxon signed-rank tests were used as appropriate, and multivariable linear regression explored factors associated with the change in CSA (ΔCSA).</p> Results <p>All 40 patients (median BMI 32.19 [IQR 31.17–33.59] kg/m²; 52.5% male) completed the study with no dropouts or missing data. PEEP 10&#xa0;cm H₂O was associated with a significant increase in right IJV CSA from 1.33 ± 0.48&#xa0;cm² to 1.62 ± 0.63&#xa0;cm² (mean paired difference [ΔCSA] 0.28 ± 0.42&#xa0;cm², 95% CI 0.15 to 0.42, <i>p</i> &lt; 0.001), representing a relative increase of approximately 21%. MAP showed a modest decrease (median paired difference [ΔMAP] − 7 mmHg, IQR − 13.25 to -2.42, <i>p</i> &lt; 0.001), and HR decreased correspondingly (mean paired difference [ΔHR] 5.68 ± 7.40&#xa0;bpm, 95% CI 3.30 to 8.04, <i>p</i> &lt; 0.001). No patient experienced severe hypotension (MAP &lt; 65 mmHg) or required vasopressor support. Exploratory multivariable regression did not identify significant associations between ΔCSA and BMI, neck circumference, age, sex, or ASA status (all <i>p</i> &gt; 0.05); however, statistical power was limited by the sample size.</p> Conclusions <p>The application of 10&#xa0;cm H₂O PEEP was associated with increased right IJV CSA in moderately obese patients under general anesthesia. This maneuver was well tolerated with clinically acceptable hemodynamic changes in this specific cohort.</p> Trial registration <p>Chinese Clinical Trial Registry, ChiCTR2400091755.</p>

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Effect of 10 cm H₂O positive end-expiratory pressure on right internal jugular vein cross-sectional area in obese patients under general anesthesia: a prospective observational study

  • Xiaofan Zheng,
  • Xiaoqiong Cao,
  • Shiwen Shen,
  • Dongliang Pei

摘要

Background

Obesity can complicate central venous catheterization by increasing skin-to-vessel depth and impairing ultrasound visualization. Optimizing internal jugular vein (IJV) cross-sectional area (CSA) is a key strategy to facilitate cannulation. Positive end-expiratory pressure (PEEP) is known to promote IJV distension in non-obese individuals and constitutes a component of lung-protective ventilation in obese patients; however, its efficacy for IJV distension and hemodynamic safety in the obese population remain uncertain. This study investigated the association between 10 cm H₂O PEEP and right IJV CSA, as well as the hemodynamic tolerability of this intervention, in obese patients under general anesthesia.

Methods

This prospective observational study enrolled 40 adult patients with body mass index (BMI) > 30 kg/m² undergoing elective surgery at Tongren Hospital, Shanghai Jiao Tong University School of Medicine between June and October 2025. Following standardized anesthesia induction and hemodynamic stabilization, each patient underwent ultrasound measurement of right IJV CSA at both zero end-expiratory pressure (ZEEP) and PEEP 10 cm H₂O in a randomized, self-controlled design. The outcome assessor was blinded to PEEP levels. Mean arterial pressure (MAP) and heart rate (HR) were recorded concurrently. The primary outcome was the difference in IJV CSA between ZEEP and PEEP 10 cm H₂O. Paired Student’s t-tests and Wilcoxon signed-rank tests were used as appropriate, and multivariable linear regression explored factors associated with the change in CSA (ΔCSA).

Results

All 40 patients (median BMI 32.19 [IQR 31.17–33.59] kg/m²; 52.5% male) completed the study with no dropouts or missing data. PEEP 10 cm H₂O was associated with a significant increase in right IJV CSA from 1.33 ± 0.48 cm² to 1.62 ± 0.63 cm² (mean paired difference [ΔCSA] 0.28 ± 0.42 cm², 95% CI 0.15 to 0.42, p < 0.001), representing a relative increase of approximately 21%. MAP showed a modest decrease (median paired difference [ΔMAP] − 7 mmHg, IQR − 13.25 to -2.42, p < 0.001), and HR decreased correspondingly (mean paired difference [ΔHR] 5.68 ± 7.40 bpm, 95% CI 3.30 to 8.04, p < 0.001). No patient experienced severe hypotension (MAP < 65 mmHg) or required vasopressor support. Exploratory multivariable regression did not identify significant associations between ΔCSA and BMI, neck circumference, age, sex, or ASA status (all p > 0.05); however, statistical power was limited by the sample size.

Conclusions

The application of 10 cm H₂O PEEP was associated with increased right IJV CSA in moderately obese patients under general anesthesia. This maneuver was well tolerated with clinically acceptable hemodynamic changes in this specific cohort.

Trial registration

Chinese Clinical Trial Registry, ChiCTR2400091755.