Hemodynamic Effects of Lithotomy Position in Surgical Patients (PH-LITHO) (PIH-LITHO)

May 11, 2026 updated by: Samet Kandemir, Trabzon Karadeniz Teknik Universitesi

Does the Pre-induction Lithotomy Position Reduce Post-induction Hypotension in Geriatric Hypertensive Patients? A Prospective Randomized Study

Anesthesia-induced hypotension is a common occurrence in elderly hypertensive patients and is closely associated with increased postoperative morbidity

  • This study aims to investigate whether the lithotomy position, a non-pharmacological and cost-free approach, can reduce the incidence of post-induction hypotension (PIH) in this high-risk population by increasing venous return

Sixty patients aged 65-80 with a history of hypertension were randomly assigned to either the Supine Group (Group S) or the Lithotomy Group (Group L)

  • In Group L, patients were placed in the lithotomy position 120 seconds before the start of anesthesia induction
  • Blood pressure was monitored every minute for the first five minutes following induction
  • The study evaluates whether this simple positioning strategy can maintain hemodynamic stability, reduce the drop in mean arterial pressure, and decrease the overall need for vasopressor medications like ephedrine

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This prospective, randomized clinical study was conducted at Karadeniz Technical University Faculty of Medicine after receiving ethics committee approval (Protocol No: 2021/268)

  • The study included 60 patients aged 65-80, classified as ASA II-III, who had been diagnosed with hypertension and on stable medication for at least 6 months

Randomization and Blinding: Participants were randomized into two groups (n=30 each) using computer-based random number generation

  • Allocation was concealed using sequentially numbered envelopes
  • Researchers involved in data recording and statistical analysis were blinded to the group assignments

Anesthesia Protocol: All patients received standard monitoring (ECG, SpO₂, and non-invasive blood pressure) and were sedated with intravenous midazolam (0.05 mg/kg) and fentanyl (1 µg/kg)

  • Following a 3-minute rest in the supine position, Group L patients were moved to the lithotomy position for 120 seconds before induction, while Group S remained in the supine position
  • Anesthesia was induced with 3-5 mg/kg thiopental administered over 120 seconds
  • A laryngeal mask airway (LMA) was inserted at the 60th second post-induction
  • Maintenance of anesthesia was achieved with desflurane (BIS target: 40-60) and remifentanil infusion

Hemodynamic Monitoring and Intervention: Non-invasive blood pressure (NIBP) was measured immediately after induction (Minute 0) and every minute thereafter for the first 5 minutes

  • Post-induction hypotension (PIH) was defined as a Mean Arterial Pressure (MAP) falling below 65 mmHg or a decrease of more than 20% from the baseline value
  • In the event of hypotension, 5 mg of intravenous ephedrine was administered as a rescue medication

Statistical Analysis: Sample size was calculated based on a 20% expected difference in PIH incidence, requiring 27 patients per group for 95% power

. Statistical analyses were performed using IBM SPSS v23.0, including t-tests, Mann-Whitney U tests, and Kaplan-Meier analysis for time-to-event (onset of hypotension)

Study Type

Interventional

Enrollment (Actual)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Kalkınma
      • Trabzon, Kalkınma, Turkey (Türkiye), 61100
        • Karadeniz Technical University Faculty of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Aged between 65 and 80 years.
  • American Society of Anesthesiologists (ASA) physical status class II or III.
  • Clinical diagnosis of hypertension.
  • Continuous use of the same antihypertensive medication for at least 6 months.
  • Scheduled for elective surgery requiring the lithotomy position.

Exclusion Criteria:

  • Uncontrolled hypertension.
  • Arrhythmias requiring medical treatment.
  • Left ventricular ejection fraction (LVEF) < 40%.
  • Unstable ischemic heart disease.
  • Physical inability to be placed in the lithotomy position.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Group S (Supine Position Group)
Patients in this group undergo anesthesia induction in the standard supine position
Other: Standard Supine Position

Patients remain in the standard supine position for a 3-minute rest period before induction begins

  • General anesthesia is induced using the same protocol as the experimental group: intravenous midazolam (0.05 mg/kg), fentanyl (1 µg/kg), and thiopental (3-5 mg/kg) administered over a period of 120 seconds
  • Hypotension (defined as MAP < 65 mmHg or >20% drop from baseline) is managed with 5 mg of intravenous ephedrine as rescue therapy
Other Names:
  • Supine Position, Group S
Experimental: Group L (Lithotomy Position Group
Patients in this group are placed in the lithotomy position before the start of anesthesia induction to evaluate its effect on hemodynamic stability
Other: Pre-induction Lithotomy Position

Patients are moved to the lithotomy position 120 seconds prior to the start of anesthesia induction to increase venous return

  • Following this 120-second interval in the lithotomy position, anesthesia is induced with intravenous midazolam (0.05 mg/kg), fentanyl (1 µg/kg), and thiopental (3-5 mg/kg)
  • All inductions are performed at a constant rate over 120 seconds
  • Post-induction hypotension (defined as MAP < 65 mmHg or >20% drop from baseline) is treated with 5 mg of intravenous ephedrine

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of Post-induction Hypotension (PIH)
Time Frame: Within the first 5 minutes following the completion of anesthesia induction (measurements recorded at minutes 0, 1, 2, 3, 4, and 5)
Post-induction hypotension is defined as a Mean Arterial Pressure (MAP) falling below 65 mmHg or a decrease of more than 20% from the baseline value
Within the first 5 minutes following the completion of anesthesia induction (measurements recorded at minutes 0, 1, 2, 3, 4, and 5)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time to Onset of First Hypotension
Time Frame: Within the first 5 minutes after anesthesia induction

The time elapsed from the completion of anesthesia induction until the first occurrence of hypotension (defined as MAP < 65 mmHg or >20% drop from baseline)

  • This measure evaluates the hemodynamic stability duration provided by the positioning
Within the first 5 minutes after anesthesia induction

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Trabzon Karadeniz Teknik Universitesi

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 1, 2021

Primary Completion (Actual)

January 31, 2022

Study Completion (Actual)

January 31, 2022

Study Registration Dates

First Submitted

April 17, 2026

First Submitted That Met QC Criteria

April 17, 2026

First Posted (Actual)

April 23, 2026

Study Record Updates

Last Update Posted (Actual)

May 14, 2026

Last Update Submitted That Met QC Criteria

May 11, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • KTU-PIH-2021
  • Karadeniz Technical University (Other Identifier: Karadeniz Technical University Faculty of Medicine Ethics Approval No: 2021/268.)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared to maintain patient confidentiality and as per institutional policy

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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