Respirator apparatus

US4318399A · kind A · utility

Assignee

• Aga Aktiebolag · SE

Inventor

• Christer Berndtsson · Marstrand, SE

Key dates

• Filing date: Nov 28, 1979
• Grant date: Mar 9, 1982
• Expiry date: Nov 28, 1999

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61M2016/0027
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

Respirators work cyclically with an inspiration phase, in which breathing gas is forced into the lungs of a patient, followed by an expiration phase, in which the supply of breathing gas to the patient is stopped and the patient is exhaling by himself. There is a risk that the patient will have difficulty exhaling. In this case the lung pressure of the patient will be too high unless the gas supply is interrupted at the start of the next following inspiration phase. In order to detect too high lung pressure and to provide such interruption, a pressure sensor is arranged to sense the gas pressure in a gas line connected to the breathing catheter introduced into the lung of the patient. This pressure sensor will normally detect a higher pressure during the inspiration phase than during the expiration phase. Therefore, an operating circuit is arranged to sense the state of the pressure sensor in a predetermined phase position only during the expiration phase. When this circuit detects an overpressure in the predetermined position, it feeds an inhibiting signal to the respirator to prevent the commencement of a subsequent inspiration phase.