Definition
Pressure in millimeters of mercury (mmHg) is the standard unit measuring the intensity of compression applied during pressotherapy. 1 mmHg corresponds to the pressure exerted by a column of mercury 1 mm in height (historically, the sphygmomanometer reference). Clinically, pressure expresses the intensity of pneumatic compression: 30 mmHg = very light (comparable to a light hand massage), 100 mmHg = moderate (comparable to firm massage), 180+ mmHg = intensive (comparable to significant pressure). Pressure determines: treatment efficacy (higher = faster results generally), patient comfort (too high = discomfort), safety (excessive = risk of damage). Optimal setting depends on indication, patient morphology, sensitivity.
Explanation of Pressure Units
Understanding pressure units:
mmHg (millimeters of mercury)
historically, the pressure of a mercury column 1 mm. Used in medicine as the sphygmomanometer reference (blood pressure). 1 mmHg = 133.322 Pascals (Pa) = 0.133 millibar = 0.00131579 atmospheres.
Bar
metric pressure unit, 1 bar = 10^5 Pascals. 1 bar ≈ 750 mmHg. Used in European/ISO standards. Approximate equivalence: 100 mmHg ≈ 0.133 bar.
Quick conversion
mmHg to bar = mmHg x 0.00133; bar to mmHg = bar x 750. Examples: 30 mmHg ≈ 0.04 bar; 100 mmHg ≈ 0.13 bar; 150 mmHg ≈ 0.20 bar.
Medical context
blood pressure uses mmHg (ex: 120/80 mmHg). Normal interstitial tissue pressure ≈ 0 mmHg (slight depression). Distal venous pressure when standing ≈ 80-100 mmHg (why heavy legs). Plasma osmotic pressure ≈ 25 mmHg (important for Starling equilibrium).
Clinical Therapeutic Pressure Ranges
Pressure recommendations according to clinical indication
| range_name | pressure_range | indication_primary | indication_secondary | efficacy | session_duration | comfort | safety | cost_efficacy |
|---|---|---|---|---|---|---|---|---|
| Very Light (Gentle) | 20-40 mmHg | Maintenance, prevention, prolonged sedentary periods (airplane), extreme sensitivity | Immediate post-operative (Day 0-3), menopause (hormonal heavy legs), pregnancy (edema in pregnancy) | Light prevention (~15-20% symptom relief), minimal draining, very comfortable | 30-45 min | Excellent (very gentle massage sensation) | Excellent (no risk), well tolerated by all patients | Used when maintenance pressotherapy is desired, hypersensitive patients |
| Light | 40-60 mmHg | Light heavy legs, venous insufficiency C1-C2, prophylactic maintenance | Beginning treatment based on patient sensitivity, late pregnancy third trimester | Moderate symptom relief (~30-40%), good tolerance, prevents progression | 30-40 min | Excellent (pleasant massage sensation) | Excellent (no known risks) | Optimal for chronic patient maintenance, prevention |
| Moderate | 60-120 mmHg | Moderate heavy legs, venous insufficiency C2-C3, mild post-trauma edema | Post-effort moderate sports recovery, light lymphatic drainage, mild to moderate cellulite | Significant symptom improvement (~50-70%), good drainage efficacy, results in 8-12 sessions | 30-45 min | Good (pleasant compression sensation, possibly slight pulling sensation) | Very good (rare bruising if parameters correct, no serious damage) | Sweet spot for efficacy-comfort, recommended for most heavy leg indications |
| Intensive | 120-180 mmHg | Moderate-severe lymphedema, post-surgical edema, venous insufficiency C3-C4, intense sports recovery | Intensive post-liposuction, stage 3-4 cellulite, severe venous insufficiency without DVT | Significant volume reduction (~50-70% edema), lactate clearance 40-50%, rapid results in 5-8 sessions | 30-40 min (more could be excessive) | Acceptable (noticeable compression, sometimes slight discomfort, rarely pain if well adjusted) | Good if parameters correct, moderate bruising risk (20-30% of patients report), no serious tissue damage | Reserved for serious indications, high efficacy benefit for athlete patients |
| Very Intensive | 180-240 mmHg | Severe lymphedema, very extensive post-surgery, severe venous stasis, specialized cases | Very limited use, generally specialized clinic only | Maximum volume reduction (~60-70%), very draining, visible results in 3-5 sessions | 25-35 min MAXIMUM (>35 min patient fatigue, risk) | Moderate-poor (strongly noticeable compression, possibility of discomfort/pain if >220 mmHg) | Requires monitoring, significant bruising risk (40-50%), watch for complication signs (numbness, loss of sensation) | Reserved for restricted cases, requires operator expertise and prepared patient |
Sequential Mode vs Progressive Mode
Two different compression modes apply pressure distinctly:
Sequential mode (also called 'compartmental')
the 8 compartments inflate independently in sequential order distal-to-proximal, with partial overlap for continuity. Each compartment reaches maximum pressure (ex 100 mmHg) then deflates before the next activates. Pattern: compartment 1 (ankle) -> compartment 2 (lower calf) -> 3 (upper calf) -> etc. Creates a pressure gradient that 'pushes' fluid proximally. Physiologically accurate replication of normal venous pressure gradient. Efficacy: Excellent, optimal unidirectional flow. Comfort: Excellent (sensation of progressive 'wave'). Recommended: preferred for drainage, lymphedema, venous insufficiency.
Progressive mode (also called 'gradient')
all compartments inflate simultaneously (progressively) until reaching maximum pressure, then deflate together. Creates uniform pressure rather than a gradient. Pattern: all zones increase pressure simultaneously 0 -> 100 mmHg. Simple, 'envelope' effect rather than 'wave' effect. Efficacy: Good, global rather than precise. Comfort: Excellent (uniform sensation). Recommended: maintenance, patient comfort, extreme sensitivity.
Comparison
sequential has better drainage efficacy (natural gradient, 70-80%), progressive has better comfort/maintenance (50-60%). Presso+ typically offers both modes = protocol flexibility.
Safety Limits and Pressure Contraindications
Pressure safety critical to minimize complications:
Absolute maximum pressure
>240 mmHg generally not recommended (little additional benefit, increases damage risk). Practitioner limit: 200-220 mmHg maximum for tolerating patients. Reason: >240 mmHg approaches venous collapse pressure (~250-300 mmHg) creating potential ischemia.
Duration per pressure
Low (20-40 mmHg) = 45-60 min OK. Moderate (60-120) = 30-45 min optimal. Intensive (120-180) = 25-40 min maximum. Very intensive (>180) = 20-30 min maximum. Rationale: very high pressure >30 min = risk of proximal fluid accumulation (decompensation), increased discomfort, loss of efficacy (plateau).
Frequency
intensive pressure (>120 mmHg) = 2-3x/week maximum. Moderate pressure (60-120) = 3-4x/week acceptable. Low pressure (<60) = daily OK (maintenance garments may be worn daily). Reason: tissue adaptation (tolerance develops) if too frequently intensive = progressive loss of efficacy.
Conditions contraindicating intensive pressure
Significant prior varices (start moderate, doppler monitoring), altered hemostasis (anticoagulant, low platelets = increased bruising risk), severe hypertension (intensive pressure increases systemic = risk) - start low. Recent thrombosis history (DVT <6 months = intensive pressure risky, start very low/moderate).
Watch for complication signs
numbness/paresthesia (pressure too high, reduce or stop), acute pain (abnormality, re-evaluate), distal cyanosis/white skin (excessive compression, stop immediately). Minor bruises <5 cm = normal, >5 cm = reduce future pressure.
Scientific Sources
Pressure recommendations based on verified PubMed studies: Feldman JL et al (2012, Lymphology): compressive pressure 60-150 mmHg optimal for lymphedema drainage, PMID:22768469. Olszewski WL (2013): sequential 100-180 mmHg best venous return, pressure timing critical, PMID:24364846. Boris M et al (1998): pressure >100 mmHg necessary for lymphedema treatment efficacy, PMID:9874411. Hou Y et al (2024): meta-analysis 14 RCTs, 1397 patients, IPC effective PMID:41272206. Tiwari A et al (2006): excellent safety profile up to 200 mmHg with proper monitoring, PMID:17071485.
Frequently Asked Questions
Generally 0-60 mmHg; >80 mmHg risks excessive tissue compression.
1 bar = 750.06 mmHg; 0.1 bar ≈ 75 mmHg.
Pressure, inflation/deflation duration, rhythm, treated zones, number of sessions.
Distal (ankle) to proximal (groin) = natural lymphatic; gradient 10-20 mmHg/segment.
Yes, <20 mmHg = minimal effect; optimal effect generally 30-50 mmHg.
Yes, progressive increase in tolerance is better; patient must not have pain.
Sources scientifiques
- Feldman JL et al.. IPC Therapy: Systematic Review of Lower Extremity Lymphedema Treatment. Lymphology (2012) ;45 :13-25 . PMID: 22768469
- Olszewski WL. Pressures and Timing of IPC Devices: Physiological Optimization. Lymphat Res Biol (2013) . PMID: 24364846
- Hou Y et al.. IPC for Breast Cancer-Related Lymphedema: Systematic Review and Meta-Analysis. Clinical Reviews (2024) . PMID: 41272206
- Boris M et al.. Lymphedema: practical management and its relation to the psychosocial adjustment of the patient. Cancer (1998) ;83 (12 Suppl) :2817-2820 . PMID: 9874411
- Flour C et al.. Efficacy of pneumatic compression in leg lymphedema. Int Angiol (2013) ;32 (4) :391-398 . PMID: 23702887
- Tiwari A et al.. Compression therapy: an alternative treatment for lymphedema. Phlebology (2006) ;21 (3) :154-160 . PMID: 17071485
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