Jet Ventilation: A Comprehensive Essay

from reportlab.lib.pagesizes import A4
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.units import cm
from reportlab.lib import colors
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, PageBreak
)
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY

OUTPUT = "/home/daytona/workspace/jet-ventilation/Jet_Ventilation_Essay.pdf"

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    title="Jet Ventilation: Definition, Types, Procedure, Indications, Advantages & Disadvantages",
    author="Orris Medical"
)

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story = []

# ── TITLE PAGE ─────────────────────────────────────────────────────────────
story.append(Spacer(1, 1.5*cm))
story.append(Paragraph("JET VENTILATION", title_style))
story.append(Paragraph(
    "Definition &bull; Types &bull; Procedure &bull; Indications &bull; Advantages &bull; Disadvantages",
    subtitle_style
))
story.append(hr())
story.append(sp(2))

# ── SECTION 1: DEFINITION ──────────────────────────────────────────────────
story.append(h1("1. Definition"))
story.append(sp())
story.append(body(
    "Jet ventilation is a technique of mechanical ventilation in which high-pressure gas (oxygen or "
    "an oxygen-air mixture) is delivered into the airway through a narrow-bore catheter or cannula "
    "rather than through a conventional endotracheal tube. The gas is driven as a high-velocity "
    "<b>\"jet\"</b> that directly insufflates the lungs, while expiration occurs passively by elastic "
    "recoil of the lungs and chest wall. The entire system is typically open to the environment, "
    "allowing respiratory gases to escape freely."
))
story.append(body(
    "The distinguishing feature of jet ventilation is that it decouples the need for a cuffed "
    "endotracheal tube from the goal of adequate oxygenation and ventilation. This makes it "
    "uniquely suited to circumstances where an endotracheal tube would either obstruct a surgical "
    "field or be impossible to place safely."
))
story.append(body(
    "<b>High-Frequency Jet Ventilation (HFJV)</b> — the most widely described form — is specifically "
    "defined as the delivery of very small tidal volumes (1–3 mL/kg) from a high-pressure source at "
    "supra-physiological frequencies (1–10 Hz, i.e., 60–600 breaths/min), with passive expiration "
    "between each jet cycle. <i>(Miller's Anesthesia, 10e)</i>"
))
story.append(sp())

# ── SECTION 2: HISTORICAL BACKGROUND ─────────────────────────────────────
story.append(h1("2. Historical Background"))
story.append(sp())
story.append(body(
    "Jet ventilation was first described for rigid bronchoscopy over 40 years ago. Sanders (1967) "
    "described a jet injector attached to a rigid bronchoscope, which became the forerunner of "
    "modern techniques. The Venturi injector concept was later refined into dedicated jet ventilators "
    "capable of high-frequency delivery. Its use has since expanded from bronchoscopy into "
    "microlaryngeal surgery, thoracic procedures, ENT surgery, and emergency airway management."
))
story.append(sp())

# ── SECTION 3: MECHANISM ──────────────────────────────────────────────────
story.append(h1("3. Mechanism of Gas Exchange"))
story.append(sp())
story.append(body(
    "A common misconception is that jet ventilation works through the Venturi effect. In reality, "
    "six mechanisms contribute to gas exchange <i>(Scott-Brown's Otorhinolaryngology, Vol 1)</i>:"
))
mechs = [
    ("Convective (Bulk) Flow", "The primary mechanism at lower frequencies; the jet directly moves gas into distal airways."),
    ("Laminar Flow in Small Airways", "The velocity profile creates a 'cone' of fresh gas that penetrates deep into alveoli."),
    ("Pendelluft", "Asynchronous filling between lung units of different resistance/compliance creates inter-alveolar cross-flow."),
    ("Cardiogenic Mixing", "Cardiac pulsations generate small oscillatory movements facilitating gas mixing."),
    ("Molecular Diffusion", "At very high frequencies approaching alveolar resonance, direct diffusion across the gas column contributes."),
    ("Taylor-Type Dispersion", "Interaction between convection and diffusion along radial concentration gradients amplifies axial gas transport."),
]
for i, (m, d) in enumerate(mechs, 1):
    story.append(Paragraph(f"<bullet>&nbsp;&nbsp;{i}.</bullet> <b>{m}:</b> {d}", bullet_style))
story.append(sp())

# ── SECTION 4: TYPES ──────────────────────────────────────────────────────
story.append(h1("4. Types of Jet Ventilation"))
story.append(sp())

story.append(h2("4.1  Classification by Frequency"))
story.append(sp(0.5))
freq_table = make_table(
    [Paragraph('<b>Type</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white)),
     Paragraph('<b>Rate</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white)),
     Paragraph('<b>Tidal Volume</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white)),
     Paragraph('<b>Notes</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white))],
    [
        ["Low-Frequency JV (LFJV)", "< 60 breaths/min", "5–8 mL/kg", "Delivered via Manujet (VBM); simpler, fewer safety alarms"],
        ["High-Frequency JV (HFJV)", "60–600 breaths/min\n(1–10 Hz)", "1–3 mL/kg", "Requires dedicated electronic jet ventilator with pressure alarms"],
        ["Superimposed HFJV (SHFJV)", "Combination", "Variable", "HFJV superimposed on LFJV; improves end-expiratory lung volumes"],
    ],
    col_widths=[4.5*cm, 3.5*cm, 3*cm, 6*cm]
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story.append(freq_table)
story.append(sp())
story.append(body(
    "LFJV can be delivered by a simple manually operated device such as the Manujet, which is "
    "compact and easy to use but lacks the pressure-alarm safeguards of a high-frequency system. "
    "HFJV requires a purpose-built ventilator (e.g., Monsoon/Acutronic; or the Bunnell Life Pulse "
    "in neonates) with electronic pressure monitoring and cut-off alarms."
))
story.append(sp())

story.append(h2("4.2  Classification by Anatomical Approach"))
story.append(sp(0.5))
story.append(body(
    "Three routes of delivery are recognised, each with distinct advantages and disadvantages:"
))
approaches = [
    ("Supraglottic Jet Ventilation",
     "A jet is directed into the laryngeal inlet from above — typically via a side port in a rigid "
     "laryngoscope or via a catheter placed just above the vocal cords. No tube passes through or "
     "below the glottis. Provides a completely tubeless field."),
    ("Subglottic Jet Ventilation",
     "A narrow-bore jet catheter (e.g., Hunsaker MonJet tube, 14 Fr) is passed through the vocal "
     "cords and positioned in the upper trachea. The catheter lies within the surgical field but is "
     "far smaller than an endotracheal tube. Allows FiO2 control and airway pressure monitoring."),
    ("Transtracheal Jet Ventilation (TTJV)",
     "A cannula (12–16 gauge, kink-resistant, preferably coil-reinforced) is inserted "
     "percutaneously through the cricothyroid membrane by needle cricothyrotomy. Gas is jetted "
     "directly into the subglottic trachea. Used both electively (laryngeal surgery) and as an "
     "emergency 'cannot intubate, cannot oxygenate' (CICO) rescue technique. Listed in the "
     "ASA Difficult Airway Algorithm. (Miller's Anesthesia, 10e)"),
]
for label, desc in approaches:
    story.append(bullet(label, desc))
story.append(sp())

# ── SECTION 5: EQUIPMENT ──────────────────────────────────────────────────
story.append(h1("5. Equipment"))
story.append(sp())
equip = [
    ("Jet ventilator", "High-frequency: Monsoon (Acutronic/Storz); manual: Manujet III (VBM)"),
    ("Driving pressure source", "Wall oxygen pipeline ~55 psi; minimum 15 psi required; regulators built into most ventilators"),
    ("Jet catheter / cannula", "Subglottic: Hunsaker MonJet tube (non-flammable fluoroplastic); TTJV: 14–16G kink-resistant Cook Melker catheter"),
    ("Monitoring", "Pulse oximetry (oxygenation); ABG/transcutaneous PCO₂ or intermittent jet suspension for capnography"),
    ("Ventilator parameters", "Driving pressure (up to 4 bar), frequency (60–600 breaths/min), I:E ratio (<1:2), pause pressure alarm"),
]
for label, val in equip:
    story.append(bullet(label, val))
story.append(sp())
story.append(body(
    "<b>Pause pressure</b> is sensed in the last 10 ms of the expiratory pause and serves as a critical "
    "safety alarm detecting gas trapping. Deaths in a UK audit were confined to departments using "
    "LFJV <i>without</i> pressure-alarm systems, underscoring the importance of proper equipment. "
    "<i>(Scott-Brown's Otorhinolaryngology, Vol 1)</i>"
))
story.append(sp())

# ── SECTION 6: PROCEDURE ──────────────────────────────────────────────────
story.append(h1("6. Procedure"))
story.append(sp())

story.append(h2("6.1  Elective Subglottic HFJV (Microlaryngeal Surgery)"))
steps_elec = [
    "Standard general anaesthesia is induced; full muscle relaxation is achieved (essential to prevent coughing or laryngospasm against the jet).",
    "The surgeon positions the rigid laryngoscope to expose the larynx.",
    "The jet catheter (e.g., Hunsaker MonJet) is introduced through the vocal cords under direct vision and seated in the upper trachea.",
    "The HFJV ventilator is connected; driving pressure, rate, and I:E ratio are set.",
    "Adequacy of chest rise is confirmed visually; SpO₂ is monitored continuously.",
    "Arterial blood gas sampling or transcutaneous CO₂ monitoring verifies ventilation; or the jet is briefly suspended at intervals for ETCO₂ measurement.",
    "The surgeon operates in a tubeless, largely immobile field.",
    "At the end of the procedure the catheter is withdrawn under direct vision and a conventional airway established for emergence.",
]
for i, s in enumerate(steps_elec, 1):
    story.append(Paragraph(f"<bullet>&nbsp;&nbsp;&nbsp;{i}.</bullet> {s}", bullet_style))
story.append(sp())

story.append(h2("6.2  Emergency Transtracheal Jet Ventilation (CICO Scenario)"))
steps_em = [
    "Identify the cricothyroid membrane (CTM) by palpation or ultrasound.",
    "Puncture the CTM with a 14–16G kink-resistant cannula-over-needle directed at 45° caudally.",
    "Aspirate freely to confirm intratracheal placement (free return of air).",
    "Remove the needle; advance the kink-resistant catheter into the trachea.",
    "Connect to jet ventilator or oxygen source (Manujet, or oxygen flowmeter via Luer-lock).",
    "Deliver jet ventilations — ensure upper airway is patent to allow passive expiration through the glottis.",
    "Aim for a definitive airway (surgical tracheostomy or formal intubation) as soon as feasible — TTJV is a temporary bridge.",
]
for i, s in enumerate(steps_em, 1):
    story.append(Paragraph(f"<bullet>&nbsp;&nbsp;&nbsp;{i}.</bullet> {s}", bullet_style))
story.append(sp())
story.append(body(
    "<i>\"Do not perform jet ventilation without the correct equipment ready in advance and without "
    "antecedent practice; one cannot simply put this together at the time of critical need.\" "
    "— Tintinalli's Emergency Medicine</i>"
))
story.append(sp())

# ── SECTION 7: INDICATIONS ────────────────────────────────────────────────
story.append(h1("7. Indications"))
story.append(sp())

story.append(h2("7.1  To Facilitate Surgical Access (ENT / Airway Surgery)"))
ind1 = [
    ("Microlaryngoscopy / laryngeal surgery",
     "Tubeless, largely motionless glottic field for vocal cord and laryngeal procedures — the single most important elective indication."),
    ("Laser laryngeal surgery",
     "Fluoroplastic jet catheters are non-flammable, significantly reducing airway fire risk compared to PVC endotracheal tubes."),
    ("Rigid bronchoscopy",
     "Unobstructed endoscopic view while maintaining continuous oxygenation without apnoeic pauses."),
    ("Panendoscopy",
     "One of five accepted airway approaches for combined laryngoscopy, bronchoscopy and oesophagoscopy. (Miller's Anesthesia, 10e)"),
    ("Tracheal resection and reconstruction",
     "Jet catheter across the anastomosis avoids a bridging endotracheal tube in the operative field."),
    ("Laryngotracheal stenosis",
     "Maintains ventilation during endoscopic dilatation or laser treatment of subglottic/tracheal stenoses."),
    ("Laser treatment of recurrent respiratory papillomatosis (RRP)",
     "Eliminates ETT fire risk and avoids propelling HPV-laden papilloma fragments distally. (Cummings Otolaryngology)"),
    ("Head and neck surgery",
     "Complete exposure of the larynx or pharynx without airway compromise."),
]
for label, desc in ind1:
    story.append(bullet(label, desc))
story.append(sp())

story.append(h2("7.2  To Optimise Pulmonary Function (Thoracic / Critical Care)"))
ind2 = [
    ("One-lung ventilation / thoracic surgery",
     "Selective HFJV maintains oxygenation of the non-operative lung with less haemodynamic compromise than standard one-lung ventilation."),
    ("Interventional radiology",
     "Virtually eliminates respiratory motion at high frequency ('apnoea-equivalent'), enabling precise CT-guided lung biopsies and ablations."),
    ("Pulmonary interstitial emphysema (PIE) in neonates",
     "Neonatal HFJV (Bunnell Life Pulse) is a rescue strategy for PIE refractory to conventional ventilation; shown superior to CMV in an RCT."),
    ("Acute respiratory failure / ARDS rescue",
     "Lower peak airway pressures reduce barotrauma risk, though no mortality benefit over conventional ventilation has been demonstrated. (Murray & Nadel's Respiratory Medicine)"),
    ("Bronchopleural fistula",
     "Small tidal volumes reduce gas loss through the fistula while maintaining adequate oxygenation."),
]
for label, desc in ind2:
    story.append(bullet(label, desc))
story.append(sp())

story.append(h2("7.3  Emergency Airway Rescue"))
ind3 = [
    ("'Cannot Intubate, Cannot Oxygenate' (CICO)",
     "TTJV is a listed ASA emergency technique when conventional intubation and bag-mask ventilation have both failed. (Miller's Anesthesia, 10e)"),
    ("Anticipated difficult airway",
     "Elective TTJV can be pre-planned as a primary strategy in complex airway cases."),
]
for label, desc in ind3:
    story.append(bullet(label, desc))
story.append(sp())

# ── SECTION 8: CONTRAINDICATIONS ─────────────────────────────────────────
story.append(h1("8. Contraindications"))
story.append(sp())
ci_table = make_table(
    [Paragraph('<b>Contraindication</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white)),
     Paragraph('<b>Reason</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white))],
    [
        ["Complete upper airway obstruction", "No egress path for expiration → progressive gas trapping → tension pneumothorax"],
        ["Laryngotracheal trauma / distorted anatomy", "Risk of catheter misplacement, haemorrhage, or false passage creation"],
        ["Severe COPD / status asthmaticus", "Prolonged expiratory time required; gas trapping and barotrauma likely"],
        ["Coagulopathy", "Increased haemorrhage risk at cricothyroid membrane puncture site"],
        ["Tight subglottic stenosis (transtracheal route)", "Stenosis acts as a one-way valve, preventing expiration"],
        ["Untrained personnel / improvised equipment", "High risk of life-threatening complications; must never be improvised"],
    ],
    col_widths=[7*cm, 10*cm]
)
story.append(ci_table)
story.append(sp())

# ── SECTION 9: ADVANTAGES ─────────────────────────────────────────────────
story.append(h1("9. Advantages"))
story.append(sp())
advs = [
    ("Tubeless surgical field",
     "Absence of an ETT provides unobstructed access to the larynx, trachea, and proximal bronchi — the primary reason for its use in airway surgery."),
    ("Reduced vocal cord movement",
     "Small tidal volumes at high frequency produce minimal glottic excursion, facilitating precise microsurgical work on the vocal cords."),
    ("Lower peak airway pressures",
     "HFJV generates lower PAP than conventional volume-cycled ventilation, reducing volutrauma and barotrauma risk while maintaining oxygenation."),
    ("Fire safety",
     "Non-flammable fluoroplastic catheters and the absence of a gas-filled PVC tube in the laser field dramatically reduce airway fire risk."),
    ("Continuous ventilation during bronchoscopy",
     "HFJV via the side port of a rigid bronchoscope allows uninterrupted endoscopic examination without apnoeic pauses."),
    ("Emergency airway rescue",
     "TTJV is rapid, requires minimal equipment, and can be lifesaving in CICO scenarios while a definitive airway is established."),
    ("Reduced respiratory motion",
     "At high frequencies, thoracic excursion is virtually eliminated, improving targeting accuracy for interventional radiology procedures."),
    ("Simultaneous spontaneous breathing (neonates)",
     "HFJV allows coexisting spontaneous respirations more easily than HFOV, improving patient comfort and lung perfusion in neonates."),
    ("Lower mean airway pressure",
     "In many configurations reduces intrathoracic pressure and minimises cardiovascular compromise."),
]
for label, desc in advs:
    story.append(bullet(label, desc))
story.append(sp())

story.append(h2("Advantages by Approach"))
story.append(sp(0.5))
adv_by_approach = make_table(
    [Paragraph('<b>Approach</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white)),
     Paragraph('<b>Key Advantage</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white)),
     Paragraph('<b>Key Disadvantage</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white))],
    [
        ["Supraglottic", "Completely tubeless field; no foreign body below the glottis", "Rapid airway pressure rise; no FiO₂/PAP/ETCO₂ monitoring; more cord movement"],
        ["Subglottic (e.g., Hunsaker)", "FiO₂ control; airway pressure monitoring possible; minimal cardiovascular effect", "Catheter in surgical field (though far smaller than ETT)"],
        ["Transtracheal (TTJV)", "Bypasses glottic/supraglottic obstruction; FiO₂ control", "Highest complication rate; contraindicated with tight stenoses; no ETCO₂"],
    ],
    col_widths=[3.5*cm, 6.5*cm, 7*cm]
)
story.append(adv_by_approach)
story.append(Paragraph("<i>Source: WFSAHQ ATOTW 271 (Conlon, 2012)</i>", source_style))
story.append(sp())

# ── SECTION 10: DISADVANTAGES & COMPLICATIONS ─────────────────────────────
story.append(h1("10. Disadvantages and Complications"))
story.append(sp())

story.append(h2("10.1  Monitoring Limitations"))
disadv1 = [
    ("No reliable capnography",
     "Tidal volumes are smaller than anatomical dead space, making continuous ETCO₂ monitoring impossible during HFJV. Intermittent ABG sampling, transcutaneous PCO₂, or periodic suspension of jetting is required. (Miller's Anesthesia, 10e)"),
    ("No airway pressure waveform",
     "Supraglottic and transtracheal approaches do not allow reliable peak airway pressure monitoring."),
    ("No volume measurement",
     "Delivered tidal volumes cannot be directly measured in an open-circuit jet ventilation system."),
]
for label, desc in disadv1:
    story.append(bullet(label, desc))
story.append(sp())

story.append(h2("10.2  Barotrauma Risk"))
disadv2 = [
    ("Pneumothorax",
     "The highest-stakes complication; caused by gas trapping from inadequate expiratory time or outflow obstruction. In one series of 643 TTJV episodes, a 1% pneumothorax rate was reported (57% requiring drainage). (Scott-Brown's, Vol 1)"),
    ("Pneumomediastinum and subcutaneous emphysema",
     "Particularly with TTJV; surgical emphysema rates up to 8.4% reported in TTJV series. (Scott-Brown's, Vol 1)"),
    ("Breath stacking / gas trapping",
     "If I:E ratio is inadequate or partial airway obstruction exists, sequential jets accumulate, rapidly raising intrathoracic pressure."),
]
for label, desc in disadv2:
    story.append(bullet(label, desc))
story.append(sp())

story.append(h2("10.3  Technical and Practical Disadvantages"))
disadv3 = [
    ("Dependence on patent upper airway",
     "TTJV requires a clear egress path above the cannula for passive expiration — an absolute physiological requirement."),
    ("Aspiration risk",
     "The open system provides no protection against aspiration of gastric contents, blood, or tumour fragments."),
    ("Propulsion of debris distally",
     "Blood, papilloma fragments, and HPV particles can be propelled into the distal airway by the jet. (Cummings Otolaryngology)"),
    ("Mucosal drying",
     "Continuous jetting of cold, dry gas causes tracheal mucosal desiccation, especially in prolonged cases."),
    ("Gastric distension",
     "In small patients, misdirected supraglottic jets can inflate the stomach, impairing ventilation."),
    ("Learning curve",
     "Requires trained operators; complications are significantly higher in inexperienced hands and in departments without pressure-alarm systems."),
    ("Communication demands",
     "Requires constant real-time coordination between surgeon and anaesthetist — obstruction of the surgical field can impair ventilation silently."),
    ("FiO₂ control",
     "Supraglottic open-system jets do not allow reliable control of inspired oxygen fraction as room air is entrained unpredictably."),
]
for label, desc in disadv3:
    story.append(bullet(label, desc))
story.append(sp())

story.append(h2("10.4  Complication Risk Factors"))
story.append(body(
    "From a series of 839 cases using the Hunsaker subglottic tube (Hu et al., cited in Scott-Brown's "
    "Otorhinolaryngology), the overall complication rate was 5.8%. The 47 most common complications "
    "were hypoxia (SpO₂ < 90%) or hypercarbia (CO₂ > 60 mmHg), with 2 cases of barotrauma and "
    "4 cases of airway obstruction. Identified risk factors include:"
))
rf = [
    "Higher BMI",
    "ASA Class 3 or 4",
    "History of cardiac disease",
    "History of previous laryngeal surgery",
    "Longer case duration",
    "Use of laser",
]
for r in rf:
    story.append(Paragraph(f"<bullet>&bull;</bullet> {r}", bullet_style))
story.append(sp())

# ── SECTION 11: HFJV vs CMV TABLE ─────────────────────────────────────────
story.append(h1("11. HFJV vs. Conventional Mechanical Ventilation"))
story.append(sp())
comp_table = make_table(
    [Paragraph('<b>Feature</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white)),
     Paragraph('<b>HFJV</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white)),
     Paragraph('<b>Conventional MV</b>', ParagraphStyle('th', fontName='Helvetica-Bold', fontSize=9, textColor=colors.white))],
    [
        ["Tidal volume", "1–3 mL/kg", "6–8 mL/kg"],
        ["Respiratory rate", "60–600 breaths/min", "12–20 breaths/min"],
        ["Peak airway pressure", "Lower", "Higher"],
        ["Mean airway pressure", "Often lower", "Higher"],
        ["Expiration", "Passive (elastic recoil)", "Active or passive"],
        ["ETCO₂ monitoring", "Not reliably possible", "Continuous, reliable"],
        ["Surgical field access", "Excellent (tubeless possible)", "Limited by ETT"],
        ["Fire risk in laser surgery", "Minimal (fluoroplastic catheter)", "Significant (PVC tube)"],
        ["Humidification", "Difficult", "Easily added"],
        ["Mortality benefit in ARDS", "Not demonstrated", "Standard of care"],
    ],
    col_widths=[5.5*cm, 5.5*cm, 6*cm]
)
story.append(comp_table)
story.append(sp())

# ── SECTION 12: SUMMARY ───────────────────────────────────────────────────
story.append(h1("12. Summary"))
story.append(sp())
story.append(body(
    "Jet ventilation is a flexible and powerful technique that sits at the interface of anaesthesia, "
    "airway surgery, and emergency medicine. Its defining feature — the delivery of small, "
    "high-pressure gas pulses without a conventional endotracheal tube — makes it indispensable for "
    "laryngotracheal and ENT surgery, particularly laser procedures, while also serving as a "
    "lifesaving emergency rescue method in the cannot-intubate cannot-oxygenate scenario."
))
story.append(body(
    "Classification by frequency (LFJV, HFJV, SHFJV) and by anatomical approach (supraglottic, "
    "subglottic, transtracheal) governs the specific indications, monitoring options, and risk "
    "profile of each application. While it offers clear advantages of a tubeless field, lower peak "
    "pressures, and improved surgical access, it demands meticulous monitoring for gas trapping, "
    "careful patient selection excluding complete upper airway obstruction, and a well-trained, "
    "communicating team."
))
story.append(body(
    "Barotrauma — principally pneumothorax — remains its most feared complication and is entirely "
    "preventable with correct technique, appropriate equipment with pressure-alarm safeguards, and "
    "an experienced operator."
))
story.append(sp(2))
story.append(hr())

# ── REFERENCES ────────────────────────────────────────────────────────────
story.append(h1("Key References"))
story.append(sp())
refs = [
    "Scott-Brown's Otorhinolaryngology Head & Neck Surgery, Vol 1 — Chapter 31: Jet Ventilation",
    "Miller's Anesthesia, 10th Edition — Transtracheal Jet Ventilation; Monitoring during HFJV",
    "Murray & Nadel's Textbook of Respiratory Medicine — High-Frequency Jet Ventilation vs HFOV in ARDS",
    "Cummings Otolaryngology Head and Neck Surgery — Jet ventilation in laser laryngology",
    "Tintinalli's Emergency Medicine — Percutaneous Cricothyrotomy and Transtracheal Jet Insufflation",
    "WFSAHQ Anaesthesia Tutorial of the Week 271 — High Frequency Jet Ventilation (Conlon CE, 2012)",
    "Roberts and Hedges' Clinical Procedures in Emergency Medicine — Airway management",
]
for r in refs:
    story.append(Paragraph(f"<bullet>&bull;</bullet> {r}", source_style))

story.append(sp(2))
story.append(Paragraph("Generated by Orris Medical Assistant", ParagraphStyle(
    'footer', parent=styles['Normal'], fontSize=8, textColor=colors.grey, alignment=TA_CENTER
)))

# Build PDF
doc.build(story)
print(f"PDF created: {OUTPUT}")