We describe a bedside arterial blood gas (ABG) monitoring system which uses fluorescent optical sensors in the measurement of blood pH, PCO<SUB>2</SUB> and PO<SUB>2</SUB>. The Point-of-Care Arterial Blood Gas Monitoring System consists of the SensiCath<SUP>TM</SUP> optical sensor unit manufactured by Optical Sensors Incorporated and the Tram<SUP>TM</SUP> Critical Care Monitoring System with ABG Module manufactured by Marquette Electronics Incorporated. Current blood gas measurement techniques require a blood sample to be removed from the patient and transported to an electrochemical analyzer for analysis. The ABG system does not require removal of blood from the patient or transport of the sample. The sensor is added to the patient's existing arterial line. ABG measurements are made by drawing a small blood sample from the arterial line in sufficient quantity to ensure an undiluted sample at the sensor. Measurements of pH, PCO<SUB>2</SUB> and PO<SUB>2</SUB> are made within 60 seconds. The blood is then returned to the patient, the line flushed and results appear on the bedside monitor. The ABG system offers several advantages over traditional electrochemical analyzers. Since the arterial line remains closed during the blood sampling procedure the patient's risk of infection is reduced and the caregiver's exposure to blood is eliminated. The single-use, disposable sensor can be measure 100 blood samples over 72 hours after a single two-point calibration. Quality Assurance checks are also available and provide the caregiver the ability to assess system performance even after the sensor is patient attached. The ABG module integrates with an existing bedside monitoring system. This allows ABG results to appear on the same display as ECG, respiration, blood pressure, cardiac output, SpO<SUB>2</SUB>, and other clinical information. The small module takes up little space in the crowded intensive care unit. Performance studies compare the ABG system with an electrochemical blood gas analyzer. Study results demonstrated accurate and precise blood gas measurement of 100 samples and 72 hour performance without need for re-calibration.
The SensiCath<SUP>TM</SUP> arterial blood gas (ABG) monitoring system allows rapid blood gas and pH measurements using fiber optic sensors in a paracorporeal device. The paracorporeal device location allows blood to be withdrawn from a vascular access, measured and returned to a patient, without direct handling and blood loss associated with traditional sampling techniques. The disposable device contains three fiber optic sensors and one temperature sensor. The sensors are monitored using a three-channel, solid-state instrument of minimal size and weight. Measurements of pH, pCO<SUB>2</SUB>, and pO<SUB>2</SUB> are made at the point of care, on demand, with results available in 60 seconds. Calibration is performed using two prepackaged, sterile, nontoxic, nonpyrogenic solutions. The paracorporeal location allows access for calibration before or during patient utilization, and for quality assurance checks at any time during use. Laboratory data are presented which assess precision and accuracy of the SensiCath system by comparing its performance measured against tonometered gases and a calibrated pH glass electrode. In vivo animal data using a rabbit model indicate the SensiCath system performance is compared against two independent standard blood gas analyzers. The clinical utility of the SensiCath system incorporated into standard arterial lines is discussed.
Ultra low profile (ULP) fiber optic transmitters and receivers have been developed which meet the 0.120 inch height requirement of military avionic applications. Field usable fiber optic connectors have been developed which provide highly efficient fiber coupling from -55 to +125 C. These devices are fabricated using soldering and laser welding techniques to produce packages which contain no organic materials. Both 1300 and 850 nm devices have been built which operate at 1.3 gigabits per second.