Pleural Pressure - Factors, Management, and Precautions

Introduction

Pleural pressure is also referred to as intrapleural pressure. In the thoracic cavity, the visceral and parietal pleura form a division and divides the lungs from the thoracic wall. There is a region that is sandwiched between two layers that is referred to as a pleural cavity. It is clinically of great importance, but also many infections arise as a result of fluid accumulation in this cavity. The pleural cavity also sustains a negative intrapleural pressure, which is helpful in restriction of the lungs’ natural tendency to collapse and enhances proper functioning during the respiration process.

What Are Intrapleural Pressures and Intrapulmonary Pressures?

Intrapleural pressure means the force the gasses exert in the pleural cavity during respiration. Intrapulmonary pressure means the force the gasses exert within the alveoli of the lungs during the respiration process. In most cases, the intrapleural pressure is negative because it performs the role of suction to keep the lungs in position and inflated.

What Are the Factors Which Affect the Intrapleural Pressure?

The following are the factors that affect intrapleural pressure:

• The first factor is during inhalation and exhalation; there are alterations in the intrapleural pressure. In the inhalation process, there is a contraction of the diaphragm and the intercostal muscles. As a result of this, there is an enlargement of the thoracic cavity. Due to enlargement, the intrapleural pressure decreases. And in exhalation, there is a reduction in the thoracic cavity, which lead to an elevation in the intrapleural pressure.

• The lungs are elastic in nature, and alveoli (tiny sacs in the lungs) these two factors affect intrapleural pressure. The lungs have the capacity to recoil, and the walls of the chest expand. Due to this, negative pressure is formed, and this keeps the lungs in position.

• The fluid accommodation between the visceral and parietal pleura is called pleural fluid. This fluid helps to sustain the negative pleural pressure. This is helpful to relieve friction and allows for smooth movement of the lung during breathing.

• Asthma also causes alterations in pleural pressure.

• The chronic obstructive pulmonary disease also causes fluctuations in pleural pressure.

• Pulmonary fibrosis affects intrapleural pressure.

• Normal activities which alter the intra-abdominal pressure also show their effect on the pleural pressure. These actions involve sneezing, severe cough, and straining. This causes elevation of pleural pressure.

What Is the Normal Pleural Pressure?

The normal pleural pressure at rest position is estimated at -3 to -5 cmH2O (centimeters of water). The value is always negative so that the expansion of the lungs is sustained and air movement during the respiratory process is facilitated.

1. Alveolar Pressure: This is the pressure inside the alveoli of the lungs. During normal breathing, it is usually equal to atmospheric pressure (around 0 cmH2O or 0 mmHg) during exhalation and inhalation.

2. Intrapleural Pressure: This is the pressure within the pleural space. It is calculated to be about -4 cmH2O (-3 mmHg) during normal breathing. The negative pressure is created by the elastic recoil of the lungs pulling against the chest wall and by the surface tension of the fluid in the pleural space.

The intrapleural pressure can be estimated indirectly by subtracting the alveolar pressure from the atmospheric pressure. For example, if atmospheric pressure is 0 cmH2O and alveolar pressure is 4 cmH2O, then the estimated intrapleural pressure would be -4 cmH2O. This is an approximation, and actual measurements may vary.

What Is the Management of Intrapleural Pressure Alterations?

The management of intrapleural pressure changes relies on the underlying medical condition causing the alteration. Intrapleural pressure refers to the pressure within the pleural cavity, the space between the two layers of pleura that surround the lungs. Alterations in intrapleural pressure can occur in various medical conditions, such as pneumothorax (collapsed lung) or pleural effusion (accumulation of fluid in the pleural cavity).

What Are the Precautions That Are Recommended for the Alterations in Pleural Pressure?

The precautions that are recommended for the alterations in pleural pressure are as follows:

• Seek Medical Evaluation: If there are alterations in intrapleural pressure or experience any respiratory symptoms, it is crucial to consult a physician for proper diagnosis and management.

• Ensure to Follow Treatment Plan: If the condition that is diagnosed affects intrapleural pressure, such as pneumothorax or pleural effusion, follow the treatment plan prescribed by their physician. This may include medicines, procedures, or surgery.

• Avoid Risky Activities: Engagement in activities that minimize the trauma or injury to the chest, as it can lead to alterations in intrapleural pressure. Inhibit contact sports or activities with an elevated risk of injury.

• Prevent Infections: Infections like pneumonia can worsen intrapleural pressure alterations. Practice good hygiene, get vaccinated as recommended, and inhibit close contact with individuals who have respiratory infections.

• Respiratory Support: In some cases, individuals with alterations in intrapleural pressure may require respiratory support. This could involve using supplemental oxygen or mechanical ventilation. Follow the physician's instructions regarding the use of respiratory support devices.

• Posture Maintenance: Maintaining an upright posture can help optimize lung function and reduce the strain on the chest. Ensure good posture when sitting, standing, and sleeping to enhance respiratory mechanics.

• Breathing Exercises: Engage in breathing exercises recommended by a physician or respiratory therapist. These exercises are helpful to improve lung capacity, promote efficient breathing, and support respiratory health.

• Monitor Signs: Need attention to any alterations in respiratory symptoms, such as shortness of breath, chest pain, or persistent cough. They are suggested to speak to their physician promptly.

• Inhibit Smoking: Smoking and exposure can further damage the respiratory system and aggravate conditions affecting intrapleural pressure. Quit smoking if they are a smoker, and inhibit environments where smoking is prevalent.

• Maintain Health: Follow a healthy lifestyle by consuming a balanced diet, exercising frequently, getting adequate sleep, and managing stress.

Conclusion

Intrapleural pressure, as used in physiology, describes the pressure inside the pleural cavity. In most cases, the pleural cavity experiences negative pressure, which is a little bit lower than air pressure. When the pleural cavity is injured or torn, the intrapleural pressure rises to a level higher than the surrounding air pressure. So it is recommended to sustain correct pleural pressure, and alterations should be managed correctly.