Polysomnography Module

Complete polysomnography tracking for basal and titration sleep studies

Overview

The Polysomnography module tracks comprehensive sleep study data for patients with sleep apnea. It consists of two distinct study types:

Basal Study

Initial diagnostic polysomnography to assess baseline sleep apnea severity

Titration Study

Pressure titration study to determine optimal CPAP/BiPAP settings

Both study types are linked to the patient’s active admission (ingreso) to ensure proper data organization across treatment cycles.

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Basal Polysomnography

Model: PolisomnografiaBasal

The basal study establishes the patient’s baseline sleep apnea metrics before treatment begins.

Location: apps/exams/models.py:184-224

Data Fields

fecha_basal · DateField · required

Date when the basal sleep study was conducted

Form Label: “Fecha de Estudio Basal”

iah · DecimalField · required

Apnea-Hypopnea Index (AHI) - The number of apnea and hypopnea events per hour of sleep

• Format: Decimal (5 digits, 2 decimal places)
• Form Label: “Índice de Apneas (IAH)”
• Clinical Significance: Primary diagnostic metric for sleep apnea severity

severidad_apnea · CharField · required

Clinical severity classification based on AHI score

Available Choices:

• NORMAL - Normal (no sleep apnea)
• LEVE - Mild (AHI 5-15)
• MODERADA - Moderate (AHI 15-30)
• GRAVE - Severe (AHI > 30)

Form Label: “Severidad de Apneas”

ido · DecimalField · required

Oxygen Desaturation Index (ODI) - Average number of oxygen desaturation events per hour

• Format: Decimal (5 digits, 2 decimal places)
• Form Label: “IDO”
• Clinical Significance: Measures oxygen deprivation during sleep

eficiencia · DecimalField · required

Sleep Efficiency - Percentage of time in bed actually spent sleeping

• Format: Decimal (5 digits, 2 decimal places)
• Form Label: “Eficiencia(%)”
• Range: 0-100%

Relationships

ingreso · ForeignKey

Links to the patient’s active admission record

Related Name: polisomnografias_basales

registrado_por · ForeignKey

User who registered this basal study

Related Name: polisomnografias_basales_registradas

Registration Workflow

View: register_basal (apps/exams/views.py:217-242)

def register_basal(request, patient_id):
    patient = get_object_or_404(Patient, id=patient_id)
    ingreso_actual = patient.ingresos.filter(estado='ACTIVO').first()
    
    if request.method == 'POST':
        form = BasalForm(request.POST)
        if form.is_valid():
            basal = form.save(commit=False)
            basal.ingreso = ingreso_actual  # Link to active admission
            basal.registrado_por = request.user
            basal.save()
            return redirect('patient_clinical', patient_id=patient.id)

The basal IAH value is automatically used as a reference in the Monitoring module to calculate treatment correction percentage.

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Titration Polysomnography

Model: PolisomnografiaTitulacion

The titration study determines the optimal pressure settings and mask configuration for PAP therapy.

Location: apps/exams/models.py:228-289

Data Fields

fecha_titulacion · DateField · required

Date when the titration study was conducted

Form Label: “Fecha de Estudio de Titulación”

tipo_titulacion · CharField

Type of positive airway pressure therapy titrated

Available Choices:

• CPAP - Continuous Positive Airway Pressure
• BPAP - Bilevel Positive Airway Pressure
• BPAP ST - BiPAP with Spontaneous/Timed backup rate

Form Label: “Tipo de Titulación”

presion_ipap · DecimalField · required

Inspiratory Positive Airway Pressure - Pressure delivered during inhalation

• Format: Decimal (5 digits, 2 decimal places)
• Unit: cmH₂O
• Form Label: “Presión IPAP en Titulación”
• Clinical Note: For CPAP mode, IPAP = EPAP (single pressure)

presion_epap · DecimalField

Expiratory Positive Airway Pressure - Pressure maintained during exhalation

• Format: Decimal (5 digits, 2 decimal places)
• Unit: cmH₂O
• Form Label: “Presión EPAP en Titulación”
• Optional: Only applicable for BiPAP modes

frecuencia_respiratoria · IntegerField

Respiratory Rate - Breaths per minute for BiPAP ST mode

• Unit: Respirations per minute (rpm)
• Form Label: “Frecuencia Respiratoria”
• Optional: Only applicable for BiPAP ST mode
• Help Text: “Respiraciones por minuto (rpm)“

Mask Configuration

tipo_mascara · CharField · required

Type of interface mask used during titration

Available Choices:

• PILLOW NASAL - Nasal pillow (minimalist, inserted into nostrils)
• NASAL - Nasal mask (covers nose only)
• ORONASAL - Full face mask (covers nose and mouth)

Form Label: “Tipo Mascara” Default: “No especificado”

talla_mascara · CharField · required

Size of the mask fitted to the patient

Available Choices:

• SMALL - Small
• MEDIUM - Medium
• LARGE - Large

Form Label: “Talla Mascara” Default: “No especificado”

Relationships

ingreso · ForeignKey

Links to the patient’s active admission record

Related Name: polisomnografias_titulaciones

registrado_por · ForeignKey

User who registered this titration study

Related Name: polisomnografias_titulaciones_registradas

Registration Workflow

View: register_titulacion (apps/exams/views.py:247-272)

def register_titulacion(request, patient_id):
    patient = get_object_or_404(Patient, id=patient_id)
    ingreso_actual = patient.ingresos.filter(estado='ACTIVO').first()
    
    if request.method == 'POST':
        form = TitulacionForm(request.POST)
        if form.is_valid():
            titulacion = form.save(commit=False)
            titulacion.ingreso = ingreso_actual
            titulacion.registrado_por = request.user
            titulacion.save()
            return redirect('patient_clinical', patient_id=patient.id)

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Clinical Workflow

Step 1: Basal Study (Diagnostic)

Purpose: Establish baseline sleep apnea severity

1. Conduct overnight polysomnography without treatment
2. Record AHI, ODI, and sleep efficiency
3. Classify severity (Normal/Mild/Moderate/Severe)
4. Determine if PAP therapy is indicated

Key Metric: AHI determines treatment eligibility and severity classification

Step 2: Titration Study (Treatment Planning)

Purpose: Determine optimal PAP settings and mask fit

1. Trial different pressure levels during sleep
2. Test various mask types and sizes for comfort
3. Record optimal IPAP/EPAP pressures
4. Document respiratory rate for BiPAP ST if needed

Output: Prescription for home PAP therapy with specific settings

Step 3: Equipment Assignment

After titration, the determined settings are used to:

• Configure the patient’s home PAP device (see Medical Equipment)
• Provide the appropriately sized mask
• Begin ongoing monitoring (see Monitoring)

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Data Retrieval

Accessing Polysomnography Data

View: patient_clinical (apps/exams/views.py:12-58)

# Get all basal studies for active admission
basales = PolisomnografiaBasal.objects.filter(
    ingreso=ingreso_actual
).order_by('-id')

# Get all titration studies for active admission
titulaciones = PolisomnografiaTitulacion.objects.filter(
    ingreso=ingreso_actual
).order_by('-id')

# Get most recent basal IAH for monitoring reference
psg = PolisomnografiaBasal.objects.filter(
    ingreso=ingreso_actual
).last()
valor_basal = psg.iah if psg else 0

All polysomnography data is filtered by the patient’s active admission (estado='ACTIVO') to ensure data isolation between treatment cycles.

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Clinical Significance

Apnea-Hypopnea Index (AHI)

The AHI is the gold standard for diagnosing and classifying sleep apnea:

Severity	AHI Range	Clinical Significance
Normal	< 5	No sleep apnea
Mild	5-15	Minimal symptoms, lifestyle modifications may suffice
Moderate	15-30	Significant symptoms, PAP therapy recommended
Severe	> 30	High cardiovascular risk, immediate PAP therapy required

Oxygen Desaturation Index (ODI)

Measures how often blood oxygen drops ≥3% or ≥4% per hour:

• Correlates with cardiovascular complications
• Higher ODI indicates more severe oxygen deprivation
• Used to assess treatment urgency

Sleep Efficiency

Percentage of time in bed actually spent sleeping:

• Normal: 85-95%
• Poor: < 85% (indicates sleep fragmentation)
• Low efficiency suggests frequent awakenings from apnea events

The basal IAH value is automatically propagated to the Monitoring module at /exams/views.py:78-79, where it’s used to calculate treatment correction percentage.

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Related Modules

Monitoring

Track treatment effectiveness using basal IAH as reference

Medical Equipment

Assign PAP devices using titration pressure settings

Pulmonology

Specialist consultations for complex cases