Gas monitor having trend indicators

• US 4,697,450 A
• Filed: 12/29/1986
• Issued: 10/06/1987
• Est. Priority Date: 03/15/1985
• Status: Expired due to Fees

• Current Assignee: Sensormedics Corporation (Becton, Dickinson & Co)
• Original Assignee: Sensormedics Corporation (Becton, Dickinson & Co)
• Inventors: McDavid, Larry S., Bachman, Thomas E., Trueblood, David M.
• Primary Examiner(s): Levy, Stewart J.
• Assistant Examiner(s): ROSKOS, JOSEPH
• Application Number:
  US06/946,685
• Time in Patent Office: 281 Days
• Field of Search: 73/23, 204/406, 204/407, 204/403, 340/632, 340/633, 340/634, 128/635
• US Class Current: 73/23.2
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: G01N 33/0062 concerning the measuring method or the display, e.g. intermittent measurement or digital display

Abstract

An improved device for determining the trend of the partial pressure of a gas, such as oxygen or carbon dioxide, which diffuses outwardly through a patient'"'"'s skin. The device, such as a cutaneous gas monitor, generates over time a series of partial pressure input values that are compared to one another for determining a trend in the partial pressure. This trend is communicated to the operator of the device.

Claims

1. A cutaneous gas monitor system comprising:

means for sampling a gas mixture;

means for determining a substanially current partial pressure of a constituent gas in the gas mixture;

means for recording a series of stored partial pressures;

means for adjustably selecting a historical value using the series of stored partial pressures;

means for inputting at least one adjustably selected reference value to the monitor;

means for comparing the current partial pressure, the historic value and the selected reference value to determine when the trend of the current partial pressure as a function of time exceeds the selected reference value;

a display means for signalling the trend of the current partial pressure when the trend as a function of time exceeds the selected reference value.

2. The monitor system of claim 1 wherein the display means comprises a first and second indicator, the first indicator activating when the trend in the current partial pressure as a function of time exceeds, positively, a first adjustably selected reference value, and the second indicator activating when the trend in the current partial pressure as a function of time exceeds, negatively, a second adjustably selected reference value,

3. The monitor system of claim 1 wherein each sucessively stored partial pressure is a function of the current partial pressure for a selected interval of time proceeding the recording of the stored partial pressure.