The Use of Tidal Volume Challenge of Dynamic Parameters During Laparoscopic Surgery

Study Overview
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Brief Summary
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Laparoscopy is increasingly used for major abdominal and pelvic surgery. As this approach is also recommended in elderly patients with serious comorbidities, optimal fluid therapy guidance during this procedure is important. Many studies have reported that less invasive dynamic indices such as pulse pressure variation (PPV) and stroke volume variation (SVV), which are derived from the arterial pressure waveform, are superior to static indices to predict fluid responsiveness. PPV and SVV are based on the heart-lung interaction and reflect cyclic changes in stroke volume induced by mechanical ventilation in the closed-chest condition. Therefore, their ability to predict fluid responsiveness can be affected by factors that influence the arterial tone or the compliance of the respiratory system. Laparoscopic surgery for the abdominal visceral organs requires pneumoperitoneum and the Trendelenburg position to optimize surgical conditions, and can reduce cardiac output and respiratory compliance. Accordingly, the usefulness of PPV and SVV in predicting fluid responsiveness during laparoscopic surgery under these conditions may be questioned. It has been clearly shown that the values of dynamic parameters are significantly correlated with the magnitude of VT. Min et al. reported that augmentation of PPV and SVV via a temporary increase in VT from 8 to 12 ml/kg improved their predictive power in the inconclusive zone with respect to fluid responsiveness (PPV values of 9% and 13%, respectively). Another recent study reported that on increasing VT from 6 to 8 ml/kg, augmented PPV and SVV, as well as their absolute changes, predicted fluid responsiveness with high sensitivity and specificity, even in critically ill patients receiving low VT. Therefore, the aim of the current study was to investigate whether increasing VT from 6 to 8 ml/kg would improve the predictive power of PPV and SVV in patients undergoing robot-assisted laparoscopic surgery in the Trendelenburg position under lung-protective ventilation. We also assessed the ability of absolute changes in PPV and SVV values induced by a temporary increase in VT from 6 to 8 ml/kg to predict fluid responsiveness.

Official Title
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The Use of Tidal Volume Challenge to Improve the Reliability of Dynamic Parameters (Pulse Pressure Variation and Stroke Volume Variation) During Pneumoperitoneum and Laparoscopic Surgery

Conditions
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Laparoscopic Surgery

Intervention / Treatment
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* Other: tidal volume challenge
* Other: volume expansion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients who performed robot assisted laparoscopic surgery under Trendelenburg position Exclusion Criteria: preoperative arrhythmia Severe bradycardia Moderate to severe valvular disease left ventricular ejection fraction < 50% Poorly controlled hypertension (systolic BP > 160 mmHg) Patients with renal insufficiency (creatinine > 1.5 mg/dL) Moderate to severe liver disease BMI >.30 or < 15 kg/ m2 preexisting pulmonary disease FEV1 < 60% of predicted value contraindications to oesophageal Doppler (OED) monitoring probe insertion (i.e. oesophageal stent, carcinoma of the oesophagus or pharynx, previous oesophageal surgery, oesophageal stricture, oesophageal varices, pharyngeal pouch, and severe coagulopathy)

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: tidal volume challenge|transiently increasing tidal volume from 6 to 8 mL/kg predicted body weight (tidal volume challenge)|
|Other: volume expansion|give 6ml/kg (predicted body weight) volulyte for 10min|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PPV8 | augmented pulse pressure variation using a temporary increase in VT | 3min after tidal volume challenge | 
| SVV8 | augmented stroke volume variation using a temporary increase in VT | 3min after tidal volume challenge | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ΔPPV6-8 | The changes in pulse pressure variation obtained by transiently increasing tidal volume | 3min after tidal volume challenge | 
| ΔSVV6-8 | The changes in stroke volume variation obtained by transiently increasing tidal volume | 3min after tidal volume challenge | 
| PPV6 | The value of pulse pressure variation when protective ventilation applied | Before fluid expansion | 
| SVV6 | The value of stroke volume variation when protective ventilation applied | Before fluid expansion | 
| PPV_fb | The change in PPV after giving the fluid expansion | 5min after fluid expansion | 
| SVV_fb | The change in SVV after giving the fluid bolus | 5min after fluid expansion |