"Effect of Pre-Spinal Mindfulness-Based Breathing Exercise on Hemodynamic Response in Elective Cesarean Section" (BREATHE-CS)

"The Effect of a 5-Minute Mindfulness-Based Breathing Exercise Administered Prior to Spinal Anesthesia on Hemodynamic Response in Patients Undergoing Elective Cesarean Section: A Prospective Randomized Controlled Trial"

Spinal anesthesia-induced hypotension is one of the most frequent and clinically significant complications of obstetric anesthesia, occurring in up to 50-80% of parturients undergoing elective cesarean section. Preoperative anxiety has been shown to potentiate hemodynamic instability through autonomic nervous system activation, thereby increasing susceptibility to spinal hypotension.

This prospective, randomized, controlled trial aims to evaluate the effect of a standardized 5-minute mindfulness-based breathing exercise administered immediately prior to spinal anesthesia on the hemodynamic response in pregnant women scheduled for elective cesarean section. Eligible participants will be randomized in a 1:1 ratio into two parallel groups: the Mindfulness-Based Breathing Exercise Group and the Control Group receiving standard preoperative care.

The breathing intervention consists of slow diaphragmatic breathing at a rate of approximately 6 breaths per minute (4-second inhalation through the nose, 6-second exhalation through the mouth), guided by a standardized script delivered by a trained anesthesiologist or nurse. Participants in the intervention group will be instructed to silently repeat the phrase "My body is relaxing as I exhale" with each exhalation, incorporating a mindfulness component.

The primary outcome is the maximum decrease in systolic arterial pressure (SAP) within the first 10 minutes following spinal anesthesia induction. Secondary outcomes include preoperative state anxiety scores (STAI-5), early spinal hypotension incidence, heart rate changes, and vasopressor requirements.

The study will be conducted at Atatürk University Faculty of Medicine, Department of Anesthesiology and Reanimation, Erzurum, Turkey, in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines.

Study Overview

• Status: Recruiting
• Conditions: Hypotension; Cesarean Section; Hemodynamic Instability; Anxiety, Anticipatory
• Intervention / Treatment: Behavioral: Mindfulness-Based Breathing Exercise

Detailed Description

Background and Rationale Spinal anesthesia-induced hypotension is the most common hemodynamic complication in obstetric anesthesia, with reported incidence rates ranging from 50% to 80% in parturients undergoing elective cesarean section. The underlying pathophysiology involves sympathetic blockade-mediated arteriolar and venous vasodilation, resulting in decreased systemic vascular resistance and reduced venous return, further compounded by aortocaval compression exerted by the gravid uterus.

Current prophylactic strategies including left uterine displacement, fluid co-loading, and vasopressor infusion remain the standard of care. However, these pharmacological approaches may be associated with tachycardia, hypertension, and inter-individual response variability, underscoring the need for complementary non-pharmacological interventions.

Preoperative anxiety exerts measurable effects on autonomic nervous system balance, potentially amplifying sympathetic tone and increasing hemodynamic instability following neuraxial blockade. Slow, controlled breathing exercises have been shown to enhance baroreflex sensitivity and augment parasympathetic vagal activity, suggesting that a brief mindfulness-based breathing intervention may attenuate sympathetic hyperactivity through an "autonomic preconditioning" mechanism.

Randomization and Allocation Concealment Participants will be randomized in a 1:1 ratio using a computer-generated random number sequence. Allocation concealment will be ensured through sequentially numbered, opaque, sealed envelopes (SNOSE), opened only after the patient has been transferred to the operating room and immediately before spinal anesthesia induction.

Intervention Protocol Participants in the intervention arm will receive a 5-minute guided mindfulness-based breathing exercise prior to spinal anesthesia, consisting of slow diaphragmatic breathing at approximately 6 breaths per minute (4-second nasal inhalation, 6-second oral exhalation). During each exhalation, participants silently repeat: "My body is relaxing as I exhale."

Anesthesia Management All participants will receive spinal anesthesia in the sitting position with intrathecal administration of 11.2 mg hyperbaric bupivacaine + 15 mcg fentanyl + 150 mcg morphine. Hypotension will be defined as a decrease in systolic arterial pressure (SAP) exceeding 20% from baseline and treated with norepinephrine or ephedrine. Bradycardia will be defined as heart rate ≤50 bpm and treated with intravenous atropine (1 mg).

Statistical Analysis All analyses will be performed using IBM SPSS Statistics (Statistical Package for the Social Sciences) version 20. Normality will be assessed using Shapiro-Wilk and Kolmogorov-Smirnov tests. Between-group comparisons will be performed using independent samples t-test or Mann-Whitney U test as appropriate. Categorical variables will be compared using chi-square test. Statistical significance will be set at p<0.05.

Sample Size Sample size was calculated using G*Power 3.1.9.7 software. A clinically meaningful difference of 4.5 mmHg in maximum SAP decrease (effect size = 0.48) was determined to require 70 participants per group at 80% power and 95% confidence level. Accounting for potential dropout, 150 participants (75 per group) will be enrolled.

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: ESRA DILARA AYBER, MD; Phone Number: +905077794216; Email: esraayber@hotmail.com
• Study Contact Backup: Name: aysenur dostbil, PROF. DR.; Phone Number: +905333676696; Email: adostbil@hotmail.com

Study Locations

• Turkey (Türkiye)
  • Erzurum, Turkey (Türkiye), 25240
    • Recruiting
    • Atatürk University Research Hospital
    • Contact: ESRA DILARA AYBER, MD; Phone Number: +905077794216; Email: esraayber@hotmail.com
    • Principal Investigator: aysenur dostbil, MD
    • Sub-Investigator: esra dilara ayber, MD
    • Sub-Investigator: gamze nur cimilli senocak, MD
    • Sub-Investigator: kamber kaseli

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Pregnant women aged 18-45 years Singleton pregnancy Gestational age 37 weeks or greater American Society of Anesthesiologists (ASA) physical status classification II Scheduled for elective cesarean section under spinal anesthesia Body mass index (BMI) 35 kg/m2 or less Ability to comprehend verbal instructions and perform the breathing exercise Provision of written informed consent

Exclusion Criteria:

Emergency cesarean section Hypertensive disorders of pregnancy (gestational hypertension, preeclampsia, eclampsia, HELLP syndrome) Placenta previa, placental abruption, or active antepartum hemorrhage Multiple pregnancy Contraindications to spinal anesthesia Failed spinal anesthesia requiring conversion to general anesthesia Chronic hypertension or chronic hypotension Known cardiac disease (arrhythmia, valvular disease, cardiomyopathy) Diabetes mellitus with autonomic neuropathy Thyroid dysfunction Chronic pulmonary disease potentially affecting respiratory pattern Body mass index greater than 35 kg/m2 Regular use of beta-blockers, calcium channel blockers, alpha-agonists, or alpha-antagonists Regular use of anxiolytics, antidepressants, sedatives, or chronic opioids Diagnosed anxiety disorder, panic disorder, major depressive disorder, or other psychiatric illness Regular use of psychiatric medications Cognitive impairment or communication difficulties Attention or compliance problems precluding adequate performance of the breathing exercise Prior regular practice of meditation, yoga, or mindfulness-based training

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm 1 Title: Mindfulness-Based Breathing Exercise Group; Participants allocated to this arm will receive a standardized 5-minute mindfulness-based breathing exercise immediately prior to spinal anesthesia induction. The intervention will be administered by a trained anesthesiologist or nurse using a standardized script. The breathing protocol consists of slow diaphragmatic breathing at approximately 6 breaths per minute, with a 4-second nasal inhalation followed by a 6-second oral exhalation. During each exhalation, participants will be instructed to silently repeat the phrase "My body is relaxing as I exhale," incorporating a mindfulness-based cognitive component. The exercise will be performed in a comfortable position in the operating room following establishment of standard monitoring (ECG, non-invasive blood pressure, SpO₂).	Behavioral: Mindfulness-Based Breathing Exercise; "A standardized 5-minute mindfulness-based breathing exercise at approximately 6 breaths per minute (4-second nasal inhalation, 6-second oral exhalation), guided by a trained anesthesiologist or nurse using a standardized verbal script. During each exhalation, participants silently repeat: 'My body is relaxing as I exhale.'"; Other Names: Slow Breathing Exercise; Controlled Deep Breathing; Mindfulness-Based Relaxation Technique
No Intervention: Arm 2 Title: Control Group; Participants allocated to this arm will receive standard preoperative care without any breathing exercise, relaxation technique, or mindfulness-based intervention. Following establishment of standard monitoring (ECG, non-invasive blood pressure, SpO₂) in the operating room, participants will wait for the equivalent duration before spinal anesthesia induction, consistent with routine clinical practice at the study center.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum Decrease in Systolic Arterial Pressure (ΔSAP_max) Following Spinal Anesthesia	he primary outcome is the maximum decrease in systolic arterial pressure (SAP) within the first 10 minutes following spinal anesthesia induction, calculated as the difference between the SAP value measured immediately prior to spinal anesthesia (T1, reference value) and the lowest SAP value recorded during the first 10 minutes post-spinal (SAP_min). Formula: ΔSAP_max = SAP_T1 - SAP_min (mmHg). SAP will be measured non-invasively at 1-minute intervals during the first 10 minutes following spinal induction.	Up to 10 minutes following spinal anesthesia induction"

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Preoperative State Anxiety Score (ΔSTAI-S5)	Change in state anxiety level assessed using the validated Turkish short form of the Spielberger State-Trait Anxiety Inventory (STAI-S5), a 5-item scale scored on a 4-point Likert scale (total score range: 5-20; higher scores indicate greater anxiety). The change score will be calculated as the difference between STAI-S5 scores measured immediately before (T0) and immediately after (T1) the 5-minute breathing exercise.	"Baseline and up to 5 minutes prior to spinal anesthesia induction"
Incidence of Early Spinal Hypotension	Proportion of participants developing hypotension, defined as a decrease in systolic arterial pressure exceeding 20% from baseline, within the first 5 minutes and within the first 10 minutes following spinal anesthesia induction. Reported as the ratio of patients experiencing hypotension to the total number of patients per group.	"Up to 10 minutes following spinal anesthesia induction"
Maximum Heart Rate Decrease (ΔHR_max) Following Spinal Anesthesia	: Maximum decrease in heart rate within the first 10 minutes following spinal anesthesia induction, calculated as the difference between the heart rate measured immediately prior to spinal anesthesia (T1, reference value) and the lowest heart rate recorded during the first 10 minutes post-spinal (HR_min). Formula: ΔHR_max = HR_T1 - HR_min (beats per minute).	"Up to 10 minutes following spinal anesthesia induction"
Time to First Hypotensive Episode	Time elapsed (in minutes) from spinal anesthesia induction to the first recorded hypotensive episode, defined as a decrease in systolic arterial pressure exceeding 20% from baseline value (T1).	"During surgery, up to approximately 60 minutes following spinal anesthesia induction"
Proportion of Participants Requiring Vasopressor Therapy	Proportion of participants in each group requiring administration of norepinephrine or ephedrine for the treatment of spinal anesthesia-induced hypotension within the first 10 minutes following spinal induction. Reported as percentage of patients per group.	"Up to 10 minutes following spinal anesthesia induction"
Total Vasopressor Dose Administered	Total cumulative dose (in micrograms for norepinephrine; in milligrams for ephedrine) of vasopressor agents administered within the first 10 minutes following spinal anesthesia induction for the treatment of hypotension.	"Up to 10 minutes following spinal anesthesia induction"
Lowest Systolic Arterial Pressure (SAP_min) Following Spinal Anesthesia	The lowest systolic arterial pressure value (mmHg) recorded within the first 10 minutes following spinal anesthesia induction, measured by non-invasive blood pressure monitoring at 1-minute intervals.	"Up to 10 minutes following spinal anesthesia induction"

Collaborators and Investigators

• Sponsor: Aysenur Dostbil
• Investigators: Study Director: kamber kaşali, Atatürk University Faculty of Medicine, Department of Biostatistics, Erzurum, Turkey; Study Director: gamze nur cimilli şenocak, MD, Atatürk University Faculty of Medicine, Department of Obstetrics and Gynecology, Erzurum, Turkey

Publications and helpful links

General Publications

• Shaffer F, Ginsberg JP. An Overview of Heart Rate Variability Metrics and Norms. Front Public Health. 2017 Sep 28;5:258. doi: 10.3389/fpubh.2017.00258. eCollection 2017.
• Russo MA, Santarelli DM, O'Rourke D. The physiological effects of slow breathing in the healthy human. Breathe (Sheff). 2017 Dec;13(4):298-309. doi: 10.1183/20734735.009817.
• Walker AP, McCormack ML, Messier J, Myers-Smith IH, Wullschleger SD. Trait covariance: the functional warp of plant diversity? New Phytol. 2017 Dec;216(4):976-980. doi: 10.1111/nph.14853. No abstract available.
• Teixeira AG, Silva AS, Lin FL, Velletri R, Bavia L, Belfort R Jr, Isaac L. Association of complement factor H Y402H polymorphism and age-related macular degeneration in Brazilian patients. Acta Ophthalmol. 2010 Aug;88(5):e165-9. doi: 10.1111/j.1755-3768.2010.01932.x. Epub 2010 Jul 6.

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2026
• Primary Completion (Estimated): March 1, 2028
• Study Completion (Estimated): March 1, 2028

Study Registration Dates

• First Submitted: March 18, 2026
• First Submitted That Met QC Criteria: March 21, 2026
• First Posted (Actual): March 27, 2026

Study Record Updates

• Last Update Posted (Actual): April 1, 2026
• Last Update Submitted That Met QC Criteria: March 27, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Randomized controlled trial; Mindfulness; Hypotension; Cesarean section; Spinal anesthesia; Systolic blood pressure; Breathing exercise; Autonomic nervous system; Heart rate variability; Obstetric anesthesia; Vasopressor; Non-pharmacological intervention; Preoperative anxiety; Hemodynamic response; Baroreflex sensitivity
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Mental Disorders; Anxiety Disorders; Hypotension
• Other Study ID Numbers: B.30.2.ATA.0.01.00/127

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: "Individual participant data will not be shared, as this is an academic thesis study conducted at a single center. Patient confidentiality will be maintained in accordance with applicable data protection regulations. Anonymized aggregate results will be reported in the final publication."

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No