CPAP Data Interpretation: Reading Device Reports

Modern CPAP devices generate detailed data. Knowing how to interpret it transforms reactive troubleshooting into proactive care.

Key Metrics Overview

Usage Hours

What it measures: Hours the device is running in therapy mode

What it means:

• Reflects patient's sleep time with CPAP
• May be less than total sleep time (removed mask partway)
• Foundation metric for compliance

Target: ≥4 hours/night (Medicare requirement)

Red flags:

• <4 hours average
• Declining trend
• High variability (some nights 0, others 8)

AHI (Apnea-Hypopnea Index)

What it measures: Events per hour of device use

Device AHI includes:

• Obstructive apneas
• Clear airway (central) apneas
• Hypopneas

Target: <5 events/hour (some say <10 acceptable)

Red flags:

• >10 events/hour despite therapy
• Increasing trend
• High proportion of central events

Leak Rate

What it measures: Air escaping from system

Types:

• Intentional (exhaust ports): Normal, ~24 L/min
• Unintentional (mask leak): The problem

Different devices report differently:

• ResMed: Total leak (subtract 24 for unintentional estimate)
• Others: May report unintentional directly

Target: <24 L/min unintentional

Red flags:

• >40 L/min consistently
• Spikes correlating with high AHI
• Patient complaints of air blowing

Pressure Data

What it measures:

• CPAP: Fixed pressure delivered
• APAP: Pressure range and where device operated

Key APAP metrics:

• 90th percentile pressure: Where device spent 90% of time below
• Max pressure reached: Peak therapy pressure
• Min pressure: Lower bound of range

Target: 90th percentile should be well below max, indicating room if needed

Red flags:

• Hitting max pressure frequently
• 90th percentile increasing over time (may need pressure adjustment)

Report Types

Summary Report

Contains: Averages over time period (7, 30, 90 days)

Use for:

• Overall compliance assessment
• Medicare documentation
• Trend identification

Detailed Report

Contains: Night-by-night breakdown

Use for:

• Troubleshooting specific issues
• Identifying patterns
• Correlating with patient reports

Event Report

Contains: Individual apnea/hypopnea events

Use for:

• Understanding event types
• Assessing therapy effectiveness
• Complex troubleshooting

Interpreting Patterns

Pattern: Good Usage, High AHI

Possible causes:

• Pressure too low
• Mask leak undermining therapy
• Central apneas emerging
• Weight gain

Action: Check leak data, review pressure trends, consider titration adjustment

Pattern: Declining Usage

Possible causes:

• Side effects (dry mouth, leak, discomfort)
• Life changes (travel, illness, relationship)
• Lost motivation

Action: Contact patient, identify barriers, address specific issues

Pattern: High Variability

Example: Some nights 7 hours, some nights 1 hour

Possible causes:

• Alcohol use (removes mask, can't tolerate)
• Weekend vs. weekday differences
• Intermittent comfort issues

Action: Look for patterns (day of week, etc.), discuss with patient

Pattern: Early Morning Removal

Example: Usage stops at 3-4 AM consistently

Possible causes:

• REM-related discomfort (higher pressure needs in REM)
• Full bladder waking patient
• Mask discomfort accumulating overnight

Action: Assess EPR settings, check for positional factors, discuss sleep patterns

Pattern: Emergent Central Apneas

What it looks like:

• Low AHI initially
• Central events increasing over weeks
• May indicate treatment-emergent CSA

Action: Monitor closely, may need BiPAP-ST or ASV, discuss with physician

Manufacturer-Specific Notes

ResMed AirSense 10/11

Unique features:

• Detailed event breakdown
• EPR usage data
• Position tracking (11 only)

Data access: AirView cloud platform

React Health Luna G3

Unique features:

• Simple interface
• Direct SD card download option

Data access: Manufacturer portal or SD card

Philips (Historical)

Note: Most Philips devices recalled. Older data still relevant for some patients on alternatives.

Creating Action Plans

For each data review, answer:

1. Is the patient compliant? (≥4 hrs, ≥70% nights)
2. Is therapy effective? (AHI <5)
3. Are there comfort issues? (leak, pressure concerns)
4. What's the trend? (improving, stable, declining)
5. What action is needed? (none, coaching, settings, intervention)

Drift pulls data from all major manufacturers. One dashboard for all your patients. [See data integration →](/support)