Quantitative Monitoring of Neuromuscular Blockade

Your opportunity to improve clinical outcomes

TetraGraph is a quantitative neuromuscular transmission monitor which is easy to use and features gold standard EMG technology for accurate measurements, bringing confidence to your anesthesiology practice.

Through the accurate meaurements, TetraGraph supports your neuromuscular blockade management from start to finish during the surgical procedure and helps you to confirm a train-of-four ratio ≥ 0.9 prior to extubation.

In addition, the monitor has a quick start up-time and does not require calibration. The patient’s arm can be tucked under surgical drape and can thus be used in all types of procedures.

Grounded in science to improve patient safety

It started with a patient who had RNMB.

As a young trainee, Dr. Brull had a patient with residual blockade. He could not stop thinking about what could have been done differently and how this could have been prevented. There was a huge unmet need for an accurate and simple to use neuromuscular monitor.

A R&D project was initiated to develop an EMG-based, portable train-of-four monitoring system. In 2018, the TetraGraph system received CE mark. In November 2019, TetraGraph received FDA 510 clearance.

Since the market introduction of TetraGraph, we have helped thousands of users to prevent the preventable and make anesthesia practice safer.

“We can do better for our patients. Nothing should stop us now when we have the tools we need.“

Sorin J. Brull, MD FCARCSI (Hon) Professor Emeritus of Anesthesiology and Perioperative Medicine, Mayo Clinic

ASA Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade

Based on the type of technology recommended by ASA

ASA’s new guidelines recommend against clinical assessment alone to avoid residual neuromuscular blockade when neuromuscular blocking drugs are administered, and also strongly recommends quantitative monitoring over qualitative assessment to avoid residual neuromuscular blockade.

In addition, the guidelines state a recommendation of confirming a train-of-four ratio greater than or equal to 0.9 before extubation.

TetraGraph is a quantitative neuromuscular monitor, based on state-of-the-art EMG technology, enabling you as a clinican to make confident decisions from start to finish of a procedure.

Designed to fit your needs

  • Usable in all types of surgery, as the patient’s arm can be tucked
  • No hand or thumb access needed
  • Small and portable, connected to mains power or battery operated
  • Gold standard EMG technology for accuracy and patient safety
  • Can be used anytime during the surgical procedure
  • Can be used in a variety of locations: OR, PACU, ICU, NORA
  • Integrates with anesthesia monitors and EMR systems

Your partner in the intensive care unit (ICU)

The TetraGraph is an effective tool to address the daily challenges of paralytic monitoring in the intensive care setting and provides continuous and accurate results.

Make confident titrations with our reliable device, by knowing your patient’s depth of paralysis.

Easy to use. Consistent results. Let the TetraGraph be your trusted partner in paralytic management.

Modes of Operation

TOF mode is the TetraGraph’s main mode of operation. A sequence of four stimuli, at a frequency of 2 Hz, referred to as Train-of-Four (TOF) is delivered to the peripheral nerve and the Train-of-Four Ratio (TOFR, or the ratio of the amplitude of the fourth twitch T4, to that of the first twitch, T1) and the TOF Count (TOFC, or the number of discernable twitches) of the evoked EMG responses are calculated and displayed.

TOF stimulation is used to assess the depth of neuromuscular blockade and gauge the degree of recovery after reversal. Other operating modes are Post-Tetanic Count (PTC), which is used to determine NMBA management during surgeries that require deep block, and Single Twitch, which is used to deliver a single stimulus and display a single muscle response in millivolt (mV).


Mode of Action

TOF Interval 20 sec – 60 mins
Automatic stimulus setup Automatic detection of maximal current. Supramaximal current 20% above maximal current
Train-of-Four (TOF Ratio & TOF Count) 4 pulses of 200 or 300 µs duration at 2 Hz repeated at user selected frequency of 20 s, 1 min, 5 min, 15 min or 60 min
Post-tetanic Count (PTC) PTC consists of Tetanic Stimulation, a set of 250 pulses (1 pulse at 50 Hz over 5s) fixed at 50 mA, 200 µs;
followed by up to 20 ST pulses at 1 Hz
Single Twitch (ST) Pulse of 200 or 300 µs duration at 0.1 Hz



Renew et al, Neuromuscular blockade management in the critically ill, J Intensive Care, 37 (2020)


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