Comparing Pleth variability index (PVI) variation induced by passive leg raising and Trendelenburg position in healthy volunteers

Assessment of pleth variability index in volume changes during ultrafiltration process

OBJECTIVES:

Pleth variability index (PVI) has been studied mostly in mechanically ventilated patients, and the role of PVI in predicting volume status and volume changes among spontaneously breathing patients is not clear in the literature. We hypothesized that hemodialysis (HD) can be a valid model for a simulation that can be evaluated the correlation of PVI with fluid changes in various volume states. The aim of this study was to investigate the utility of PVI for assessing volume changes in HD patients who are breathing spontaneously.

METHODS:

This prospective, observational study included patients aged 18 years or older who had end-stage renal failure and presented for routine HD between December 2019 and January 2020. PVI values were measured before and after HD session. Changes in PVI levels were compared according to the amount of ultrafiltration.

RESULTS:

A total of sixty patients were included. Mean PVI level before HD (20.7% ± 5%) showed a statistically significant increase to 27.7% ± 6% after HD session (P < 0.001). According to the amount of fluid removed during HD, the changes in PVI were statistically significant (P = 0.015). There was a strong correlation between ΔPVI and ultrafiltrated volume (r = 0.744, P < 0.001).

CONCLUSION:

The fluid removed by HD caused increase in PVI, and the increase was strongly correlated with the amount of volume change. Bedside monitoring of PVI may provide the clinicians with useful information for monitoring the volume status in critically ill patients with spontaneous breathing.

Use of noninvasive volume assessment methods to predict acute blood loss in spontaneously breathing volunteers

OBJECTIVE

The use of noninvasive volume assessment methods to predict acute blood loss in spontaneously breathing patients remains unclear. We aimed to investigate changes in the pleth variability index (PVI), vena cava collapsibility index (VCCI), end-tidal carbon dioxide (EtCO2), pulse pressure (PP), and mean arterial pressure (MAP) in spontaneously breathing volunteers after acute loss of 450 mL blood and passive leg raise (PLR).

METHODS

This prospective observational study enrolled healthy volunteers in the blood donation center of an academic hospital. We measured the PVI, EtCO2, VCCI, MAP, and PP before blood donation; at the 0th and 10th minute of blood donation; and after PLR. The primary outcome was the changes in PVI, EtCO2, VCCI, MAP, and PP.

RESULTS

We enrolled thirty volunteers. There were significant differences among the four obtained measurements of the PVI, EtCO2, and MAP (P<0.001, P<0.001, P<0.001, respectively). Compared to the predonation values, post-hoc analysis revealed an increase in the PVI at the 0th min postdonation (mean difference [MD], 5.4±5.9; 95% confidence interval [CI], -7.6 to -3.1; P<0.001); a decrease in the EtCO2 and MAP at the 0th and 10th minute postdonation, respectively (MD, 2.4±4.6; 95% CI, 0.019 to 4.84; P=0.008 and MD, 6.4±6.4; 95% CI, 3 to 9.7; P<0.001, respectively). Compared with EtCO2 at the 10th minute, the value increased after PLR (MD, 1.8±3.2; 95% CI, 0.074 to 4.44; P=0.006).

CONCLUSION

The PVI and EtCO2 could detect early hemodynamic changes after acute blood loss. However, it remains unclear whether they can determine volume status in spontaneously breathing patients.

The role of perfusion index and plethysmography variability index for predicting dehydration severity in patients with acute gastroenteritis

Background:

Acute gastroenteritis is a clinical syndrome that may cause severe dehydration in affected individuals and a reason of mortality and morbidity in all age groups. Measurement of perfusion index and plethysmography variability index may provide emergency physicians valuable information about hemodynamics of the patient.

Objectives:

Our study aimed to investigate the role of perfusion index and plethysmography variability index measurement at admission for estimating dehydration severity and determiningthe possible change in those parameters after fluid replacement among patients presenting to emergency department with acute gastroenteritis.

Methods:

This was a prospective cross-sectional study. Patients diagnosed with acute gastroenteritis at the emergency department were consecutively enrolled. The two groups were defined according to the severity of dehydration: mild and moderate/severe dehydration groups. The values of perfusion index and plethysmography variability index of all patients were measured.

Results:

A total of 180 patients were included in the study. As compared with the mild dehydration group, moderate/severe dehydration group had a significantly lower perfusion index value and significantly higher plethysmography variability index value on admission (p < 0.001 for both comparisons). Among moderate/severe dehydration patients, perfusion index value significantly increased and plethysmography variability index significantly decreased after treatment (p < 0.001). There was a significant positive correlation between osmolarity and plethysmography variability index (r = 0.298; p = 0.007) and a significant negative correlation between osmolality and perfusion index (r = −0.259; p = 0.019) in the patients with moderate/severe dehydration.

Conclusion:

The study show that perfusion index and plethysmography variability index may be useful for determining the severity of dehydration in acute gastroenteritis and may be use for assessing the response to fluid replacement especially in patients with severe dehydration at emergency department.