EIT Evaluation of Pulmonary Ventilation With Different Ropivacaine Concentrations in Intercostal Nerve Blockade

Fudan University

Status: Not yet enrolling

Conditions: Surgical Procedures, Operative; Anesthesia, Local; Breast Neoplasms; Pulmonary Ventilation; Intercostal Nerve Block

Treatments: Drug: 0.5% Ropivacaine; Drug: 0.375% Ropivacaine; Drug: 0.25% ropivacaine

Study type: Interventional

Funder types: Other

Identifiers

NCT07079436

XTJLBTNDLPKA-1

Details and patient eligibility

About

This study aims to find out how different strengths of the anesthetic drug ropivacaine affect lung breathing function when used in intercostal nerve block (a type of local anesthesia) for breast quadrantectomy surgery. Researchers will use a non-invasive imaging technique called electrical impedance tomography (EIT) to monitor lung ventilation in real time.

Why is this study being done? Intercostal nerve block is a common anesthesia method for breast surgeries, but the ideal strength of ropivacaine that balances effective pain relief with safety for lung function is not fully clear. EIT can help measure how each drug strength affects breathing by showing changes in lung airflow.

What will happen in the study? Participants: 72 adults scheduled for breast quadrantectomy, aged 18-80, will be randomly assigned to receive one of three ropivacaine strengths (0.25%, 0.375%, or 0.5%) during intercostal nerve block.

Procedures: After anesthesia, EIT will monitor lung ventilation before and after the block. Researchers will measure:

How much each lung side contributes to breathing during quiet and deep breaths. How quickly the anesthesia works, pain levels during surgery, and any side effects (like difficulty breathing or allergic reactions).

Who can join? Adults having elective breast quadrantectomy. ASA physical status I-II (generally healthy to mildly ill). BMI <35 kg/m². No history of nerve block allergies, breathing problems, or certain lung diseases.

What are the possible benefits? The study may help doctors choose the best ropivacaine strength to ensure good pain control while minimizing risks to lung function, especially for same-day surgery patients.

What are the risks? Potential risks include rare side effects from the anesthetic (like allergic reactions or low blood pressure) or temporary breathing changes, which will be closely monitored.

How is the study designed? This is a double-blind, randomized trial (neither patients nor doctors know which drug strength is used) at Fudan University Shanghai Cancer Center.

Full description

The purpose of this study is to explore the impact of different concentrations of ropivacaine on pulmonary ventilation function and anesthetic efficacy during intercostal nerve block, so as to provide a reference for clinical medication selection.

This is a single-center, prospective, randomized controlled trial, with the research subjects being patients scheduled to undergo breast quadrant resection under intercostal nerve block anesthesia. Eligible patients will be randomly assigned to three groups, receiving 0.25%, 0.375%, or 0.5% ropivacaine for intercostal nerve block respectively (4ml injected into each intercostal space, blocking the 2nd to 6th intercostal nerves). The procedure will be performed by experienced anesthesiologists under ultrasound guidance, with a double-blind design where neither the anesthesiologists nor the patients are aware of the grouping and drug concentration information.

In the study, Electrical Impedance Tomography (EIT) will be used for real-time, non-invasive monitoring of changes in patients' pulmonary ventilation function before and after the block. Meanwhile, indicators related to anesthetic efficacy such as the onset time of anesthesia and block success rate will be evaluated. The entire research process includes preoperative screening, intraoperative intervention, and postoperative follow-up, aiming to clarify the relationship between ropivacaine concentration, its impact on pulmonary ventilation function, and anesthetic efficacy, so as to provide a basis for optimizing the clinical application of ropivacaine in intercostal nerve block.

Enrollment: 72 estimated patients

Sex: Female

Ages: 18 to 80 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients scheduled for elective breast quadrantectomy;
• Aged 18-80 years;
• American Society of Anesthesiologists (ASA) physical status I-II;
• Body mass index (BMI) <35 kg/m².

Exclusion criteria

• Contraindications for nerve block: infection at the puncture site, local anesthetic allergy, coagulation dysfunction or bleeding risk;
• Patients with unilateral diaphragmatic paralysis;
• Patients with severe ventilatory or gas exchange dysfunction;
• Complicated with acute or chronic pulmonary and bronchial diseases, sleep apnea syndrome;
• Mental disorders;
• Patients who refuse to participate;
• Patients whom the researchers consider unsuitable for the clinical trial, with reasons to be specified.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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72 participants in 3 patient groups

Arm A: 0.25% Ropivacaine for Intercostal Nerve Blockade

Experimental group

Description:

The in-plane technique was adopted, with the needle inserted 5 mm away from the long axis of the probe. During the operation, the long axis of the needle and the needle tip were displayed in real time. When the needle tip reached the extrapleural space, between the internal intercostal muscle (internal intercostal membrane) and the innermost intercostal muscle at the lower edge of the rib, and no blood was aspirated, ropivacaine (Naropin 10ml:75mg) of corresponding concentration and volume was injected into each group. Anechoic fluid was observed to spread under the internal intercostal muscle, and as the volume of the injected fluid increased, the local parietal pleura gradually descended. Inject 4 ml of 0.25% ropivacaine into each intercostal space.

Treatment:

Drug: 0.25% ropivacaine

Arm B: 0.375% Ropivacaine for Intercostal Nerve Blockade

Experimental group

Description:

The in-plane technique was adopted, with the needle inserted 5 mm away from the long axis of the probe. During the operation, the long axis of the needle and the needle tip were displayed in real time. When the needle tip reached the extrapleural space, between the internal intercostal muscle (internal intercostal membrane) and the innermost intercostal muscle at the lower edge of the rib, and no blood was aspirated, ropivacaine (Naropin 10ml:75mg) of corresponding concentration and volume was injected into each group. Anechoic fluid was observed to spread under the internal intercostal muscle, and as the volume of the injected fluid increased, the local parietal pleura gradually descended. Inject 4 ml of 0.375% ropivacaine into each intercostal space.

Treatment:

Drug: 0.375% Ropivacaine

Arm C: 0.5% Ropivacaine for Intercostal Nerve Blockade

Experimental group

Description:

The in-plane technique was adopted, with the needle inserted 5 mm away from the long axis of the probe. During the operation, the long axis of the needle and the needle tip were displayed in real time. When the needle tip reached the extrapleural space, between the internal intercostal muscle (internal intercostal membrane) and the innermost intercostal muscle at the lower edge of the rib, and no blood was aspirated, ropivacaine (Naropin 10ml:75mg) of corresponding concentration and volume was injected into each group. Anechoic fluid was observed to spread under the internal intercostal muscle, and as the volume of the injected fluid increased, the local parietal pleura gradually descended. Inject 4 ml of 0.5% ropivacaine into each intercostal space.

Treatment:

Drug: 0.5% Ropivacaine