Understanding the Scatter Plot & Heatmap

The data visualized here come from two key domains in the operating room:

• Patient Vitals: Physiologic signals continuously measured from the patient: heart rate, blood pressure, oxygen saturation, and CO₂ levels.
• Ventilator & Infusion Settings: Clinician-controlled parameters such as inspired oxygen (FiO₂), PEEP, anesthetic concentration (MAC), and tidal volume.

These two domains are naturally interrelated. Clinicians respond to patient vitals by adjusting settings, and interventions may directly affect physiologic signals.

A quick guide to what each selected parameter represents:

Patient Vitals

• Arterial BP: Mean arterial pressure (mmHg)
• Diastolic BP: Lowest arterial pressure (mmHg)
• End-Tidal CO₂: Exhaled CO₂ at the end of a breath (mmHg)
• Heart Rate: Heartbeats per minute (bpm)
• NIBP Mean BP: Non-invasive mean blood pressure (mmHg)
• Oxygen Saturation: Percent of hemoglobin saturated with oxygen (SpO₂)
• Pleth HR: Heart rate derived from plethysmograph waveform
• Systolic BP: Peak pressure during heartbeat (mmHg)

Ventilator & Infusion Settings

• ETCO2: End-tidal carbon dioxide sensor reading (mmHg)
• FiO₂ Setting: Fraction of inspired oxygen delivered to patient
• Insp Time Setting: Duration of inhalation phase (sec)
• MAC: Minimum alveolar concentration of anesthetic gas
• Minute Ventilation: Volume of air exhaled per minute (L/min)
• PEEP: Positive end-expiratory pressure (cmH₂O)
• Tidal Volume: Air moved per breath (mL)

Heatmap Summary

The Global Correlation Heatmap below shows how pairs of these parameters tend to behave across all surgical cases. Each square displays the average Pearson correlation (r) between two signals:

• Deep red: Strong positive correlation (e.g., both rise together)
• Deep blue: Strong negative correlation (e.g., one rises, the other falls)
• White or pale tones: Little or no consistent relationship

Notable Observations:

• Arterial BP and Diastolic BP: These are two ways of measuring blood pressure, so it makes sense they rise and fall together.
• End-Tidal CO₂ and ETCO₂: These both track the amount of carbon dioxide a patient breathes out and closely match.

On the other hand, several parameter pairs show little or no correlation, such as:

• Pleth HR and FiO₂ Setting and MAC and Stroke Volume

Overall Summary: This time-series dataset offers a view into both patient physiology and clinician behavior in the operating room. Together, these time-synchronized data streams form a comprehensive record of intraoperative care.

Click on a heatmap square to view the trend above!