Datex-Ohmeda 3770/3775

The Datex-Ohmeda 3770/3775 models are pulse oximeters made by GE’s Datex-Ohmeda division. GE Healthcare acquired Instrumentarium’s Datex-Ohmeda division in 2003. The division produces anesthesia, respiratory, and monitoring equipment. The Datex Ohmeda brand is still branded on select GE equipment. Pulse oximeters are non-invasive devices used to monitor a patient’s oxygen saturation.

The 3770/3775 pulse oximeters both operate on power from a battery pack. When attached to a nickel-cadmium battery back, the oximeters can be placed in the battery charger monitoring station and powered by the station’s DC power supply. The saturated oxygen and pulse rate values are updated each second. The plethysmographic waveform is updated every four seconds.

The 3770 model is designed for spot-checking saturated oxygen levels and pulse rates. It is not intended for continuous monitoring and does not include alarms or user-definable parameters.

The 3775 model is designed for spot-checking and providing short- and long-term continuous saturated oxygen and pulse rate monitoring. This model can print to an optional Hewlett-Packard (HP) printer through an infrared link.

Both the 3770 and 3775 models include the name “Datex-Ohmeda” printed on the front face of the device. Each model includes a digital display. The 3775 includes a dial-like wheel at the bottom of the device that can be used to scroll through menu options.

Visual displays and indicators:

The displayed SpO2 and pulse rate values are updated every second. The plethysmographic waveform sweep is updated every 4 seconds.

Main display: 8-character alpha-numeric; green; variable intensity dependent on ambient light conditions

Waveform display: 8 green LEDs

Signal strength indicator bar: 4 LEDs (1 dark green, 1 yellow green, 1 yellow, and 1 orange)

Low battery indicator: 1 orange LED

Alarm bar (3775 only): red

Display update interval: 0.5 seconds

Display hold interval: 12 seconds

Dimensions:

* Height: 18.54 cm (7.3 inches; 9.5 inches including FlexConnect™)

* Width: 7.62 cm (3.0 in.)

* Depth: 5.33 cm (2.1 in.)

* Weight: 0.33 kg (9.6 oz.) without battery pack

Power:

* Typical consumption: 1.6 W

• Typical current: 180 mAmps

Circuitry:

* Microprocessor controlled

* Automatic self-test at power on

* Automatic setting of default parameters (3775 only)

* Automatic alarm messages

• Automatic/continuous system diagnostics

Sensor emitter wavelength ranges:

* Red LED peak wavelength range: 650 to 665 nm

* Infrared (IR) LED peak wavelength range: 930 to 950 nm

• Average power: ≤ 1 mW

(3775 only) Audio indicators:

• Alarm volume: On (default) and off

* Pulse rate volume: On and off (default)

* Pitch modulation to reflect changing SpO2 levels

* Alarm silence (120 seconds)

* Low- and high-SpO2 out-of-limits alarm

* Sensor condition alarms

* System failure alarms

SpO2:

• Range: 0 to 100%

* Accuracy (±1 standard deviation)

** 80 to 100%: ± 2%

** 60 to 79%: ± 3%

** Below 60%: unspecified

Calibration: fractional

Interfering substances:

• Carboxyhemoglobin may erroneously increase readings. The level of increase is approximately equal to the amount of carboxyhemoglobin present. Dyes, or substances containing dyes, that change usual arterial pigmentation may cause erroneous readings.

(3775 only) Alarm limits:

* Low = 60 to 99%

* High = 61 to 100% and OFF

Pulse rate:

• Range: 40 to 235 beats per minute
• Accuracy: ± 1.7% of current reading (accuracy calculations assume a constant pulse rate)

Wikipedia: Pulse Oximeter

Datex-Ohmeda 3770/3775 Service Manual

Datex-Ohmeda 3770/3775 Replacement Batteries from Amazon.com