Related Experiment Video
Updated: May 21, 2026

Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation
Published on: February 26, 2013
Negative pressure versus loss of resistance technique for interpleural block
Pankaj Kundra1, Karuppiah Ajeetha
1Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, Tamil Nadu, India.
Background:
Loss of resistance is a commonly practiced technique among the trainees. But, for performing interpleural block (IPB), negative-pressure identification techniques have been popularized. This study was designed to evaluate the two techniques in trainee anaesthetists.
Methods:
Sixty American society of anaesthesiologist (ASA) grade 1 and 2 women scheduled for elective breast surgeries under general anaesthesia were recruited for the study. The patients were randomly assigned to receive IPB (25 mL of 0.5% bupivacaine with adrenaline 5 mg/mL) with either loss of resistance technique (group LR, n=45) or the negative-pressure technique (group NP, n=45). The success rate and ease of performance was evaluated by the number of attempts and time taken.
Results:
Higher first attempt success rate was observed in group LR (90%) when compared with group NP (80%), with a significantly shorter mean time to successful identification of interpleural space in the group LR (5 min) than in the group NP (5.8 min), P<0.01log rank test. All patients had satisfactory IPB and the median numbers of segments blocked were 7 (5-9) and 6 (5-7) in groups LR and NP, respectively. No significant complications were observed in any of the patients.
Conclusion:
Both techniques are safe and effective, but the loss of resistance technique is associated with a higher first attempt success rate performed in a shorter time by trainee anaesthetists.
Related Concept Videos
Pressure Relationships in Thoracic Cavity
Breathing Mechanisms
Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs during...
Pulmonary Ventilation: Inhalation
Boyle's law becomes particularly pertinent when examining respiratory...
Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation (NIPPV)
Pneumothorax II: Pathophysiology
Local Anesthetics: Clinical Application as Intravenous Regional Anesthesia
One of the advantages of...
Mechanical Ventilation II: Invasive Ventilation
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
