MAP Rechner - Mittlerer Arterieller Druck
Berechnen Sie Ihren Mittleren Arteriellen Druck (MAD) sofort. Verstehen Sie die Organperfusion und kardiovaskuläre Gesundheit.
Normalbereich: 90-140 mmHg
Normalbereich: 60-90 mmHg
Häufig Gestellte Fragen
Warum ist MAD wichtiger als systolischer oder diastolischer Druck?
MAD reflektiert den Gewebeperfusionstatus besser als systolischer oder diastolischer Druck: (1) Umfassend: MAD repräsentiert den durchschnittlichen Druck während des gesamten Herzzyklus, nicht nur die systolische oder diastolische Phase. (2) Perfusionindikator: MAD reflektiert direkt den Perfusionsdruck lebenswichtiger Organe, der beste Indikator für Gewebeperfusion. (3) Behandlungsziel: MAD wird als Behandlungsziel und Überwachungsindikator im Schockmanagement verwendet. (4) Autoregulation: Die zerebrale Blutflussautoregulation wird hauptsächlich durch MAD beeinflusst, nicht durch systolischen oder diastolischen Druck. Während systolischer und diastolischer Druck für Hypertoniediagnose wichtig sind, wird MAD für Gewebeperfusionsbewertung und Intensivführung verwendet.
Warum ist MAD 60 mmHg ein wichtiger Schwellenwert?
MAD 60 mmHg ist der minimale Schwellenwert zur Aufrechterhaltung der Perfusion lebenswichtiger Organe, weil: (1) Zerebrale Perfusion: Unter diesem Wert kann die zerebrale Blutflussautoregulation versagen, was zu zerebraler Ischämie führt. (2) Koronare Perfusion: Koronararterien perfundieren hauptsächlich während der Diastole, was ausreichenden diastolischen Druck erfordert (eng verwandt mit MAD). (3) Nierenfunktion: Nieren benötigen ausreichenden Perfusionsdruck zur Aufrechterhaltung der glomerulären Filtrationsrate. (4) Klinische Forschung: Zahlreiche Studien bestätigen, dass MAD < 60 mmHg mit akuter Nierenschädigung und erhöhter Mortalität assoziiert ist. Daher ist die Aufrechterhaltung von MAD ≥ 65 mmHg ein wichtiges Behandlungsziel in der Schockreanimation und Intensivmedizin.
Sollten MAD-Ziele für chronische Hypertoniepatienten höher sein?
Ja, chronische Hypertoniepatienten können einen höheren MAD benötigen: (1) Rechtsverschobene Autoregulationskurve: Langzeitbluthochdruck verursacht eine Rechtsverschiebung der zerebralen Blutflussautoregulationskurve. (2) Höheren MAD tolerieren: Die Gehirne chronischer Hypertoniepatienten sind an höhere Perfusionsdrücke gewöhnt. (3) Reduktionsrisiko: Die Reduktion von MAD auf "normale" Werte kann eine Hypoperfusion lebenswichtiger Organe verursachen. Klinische Empfehlungen: Für bekannte chronische Hypertoniepatienten kann das MAD-Ziel auf höheren Werten festgelegt werden müssen (z.B. 75-85 mmHg). Individualisieren Sie Ziele unter Berücksichtigung des Basisblutdrucks des Patienten. Vermeiden Sie rasche substantielle Blutdrucksenkung zur Vermeidung einer Beeinträchtigung der Organperfusion.
Wie wird niedriger MAD erhöht?
Methoden zur MAD-Erhöhung hängen von der Hypotonieursache ab. Hypovolämie (am häufigsten): Flüssigkeitsreanimation mit Kristalloiden (physiologische Kochsalzlösung, Ringer-Laktat) oder Kolloiden; Bluttransfusion bei aktiver Blutung oder schwerer Anämie. Kardiogen: Inotrope Medikamente wie Dobutamin, Milrinon; Vasopressoren wie Norepinephrin (erhöht Blutdruck und verbessert Perfusion). Distributiver Schock (z.B. septischer Schock): Vasopressoren wie Norepinephrin (Erstwahl), Vasopressin, Epinephrin; Simultane Flüssigkeitsreanimation erforderlich. *Die Behandlung sollte unter ärztlicher Anleitung erfolgen, Auswahl des geeigneten Plans basierend auf der Ätiologie.
Was ist die Beziehung zwischen MAD und Hypertonie?
MAD ist ein wichtiger Indikator zur Bewertung des Hypertonieschweregrads und kardiovaskulären Risikos: (1) Kardiovaskuläres Risiko: MAD-Erhöhung ist eng mit erhöhtem kardiovaskulärem Ereignisrisiko assoziiert. (2) Zielorganschaden: Anhaltend hoher MAD führt zu Zielorganschäden an Herz, Nieren, Blutgefäßen. (3) Behandlungsüberwachung: Ziel der antihypertensiven Behandlung ist die Reduktion von MAD in den Normalbereich. (4) Pulsdruck: Sowohl Pulsdruck (SBP-DBP) als auch MAD sind Indikatoren zur Bewertung des kardiovaskulären Risikos. Normaler Blutdruck: SBP < 120 und DBP < 80, MAD etwa 70-93 mmHg. Hypertonie: SBP ≥ 130 oder DBP ≥ 80, MAD normalerweise > 95 mmHg. *Hypertoniediagnose sollte auf mehreren Messungen und umfassender Bewertung basieren, nicht nur eine einzelne MAD-Berechnung.
Wie wird MAD berechnet?
MAD wird unter Verwendung der Standardformel berechnet: MAD = (2 × DBP + SBP) / 3. Warum diese Formel? Die Diastole macht etwa 2/3 des Herzzyklus aus, die Systole etwa 1/3. Daher ist MAD näher am diastolischen Druck als am systolischen Druck. Diese empirische Formel nähert sich eng der präzisen Berechnung (MAD = DBP + (SBP - DBP) / 3), ist aber für schnellere klinische Berechnung und Verwendung einfacher. Berechnungsbeispiele: Blutdruck 120/80 mmHg: MAD = (2 × 80 + 120) / 3 = 280 / 3 = 93,3 mmHg (Normal). Blutdruck 90/60 mmHg: MAD = (2 × 60 + 90) / 3 = 210 / 3 = 70 mmHg (Normal-niedrig). Blutdruck 160/100 mmHg: MAD = (2 × 100 + 160) / 3 = 360 / 3 = 120 mmHg (Schwer erhöht).
Medizinischer Haftungsausschluss
This calculator provides results for reference only and cannot replace professional medical diagnosis. MAP calculation is an auxiliary tool for assessing hemodynamic status and should not be used alone for diagnosis or treatment decisions. MAP targets should be individualized based on specific patient conditions. If you have abnormal blood pressure or related symptoms, please consult a doctor. Seek immediate medical attention in emergencies.
Mean arterial pressure (MAP) is the average pressure driving blood through the arteries over one full heartbeat cycle. Because the heart spends roughly twice as long in diastole (relaxed) as in systole (contracting) at a typical resting heart rate, MAP is weighted toward the diastolic pressure rather than sitting exactly halfway between the systolic and diastolic readings.
Die Formel
MAP = DBP + (SBP - DBP) / 3 - SBP = systolic blood pressure in mmHg, the higher number in a blood pressure reading
- DBP = diastolic blood pressure in mmHg, the lower number in a blood pressure reading
- equivalent form: MAP = (SBP + 2 x DBP) / 3
Standard hemodynamic approximation based on the relative durations of systole and diastole at resting heart rate
How the calculation works
A single blood pressure reading gives two numbers: systolic pressure, the peak pressure when the heart contracts, and diastolic pressure, the pressure while the heart relaxes and refills between beats. Neither number alone describes the average pressure organs are exposed to over a full cardiac cycle, which is what actually drives blood flow into tissue.
Because diastole lasts about twice as long as systole at a normal resting heart rate, the true time-averaged pressure sits closer to diastolic pressure than to the midpoint between the two readings. The formula captures this by adding only one third of the difference between systolic and diastolic pressure to the diastolic value, rather than averaging the two numbers directly.
How to read your result
A MAP in the typical adult range generally indicates that major organs are receiving adequate blood flow, assuming normal blood vessel resistance and no localized blockages. Values outside this range warrant clinical context rather than an isolated interpretation.
| MAP (mmHg) | General interpretation |
|---|---|
| Below 60 | Often considered inadequate to reliably perfuse the brain, kidneys, and coronary arteries |
| 60-70 | Lower end of adequate perfusion for most adults; closely monitored in acutely ill patients |
| 70-100 | Typical range for a healthy resting adult |
| 100-110 | Above typical resting range; may reflect elevated blood pressure or acute stress |
| Above 110, especially if sustained | Suggests hypertension requiring evaluation; very high sustained values raise concern for a hypertensive emergency |
MAP in acute and critical care
MAP is used at the bedside far more than in routine outpatient care because it summarizes perfusion pressure in a single number that clinicians can track and target directly, including with an arterial line for continuous, beat-to-beat measurement in critically ill patients. A MAP of about 60 mmHg is commonly cited as a rough floor below which the brain, kidneys, and heart are at growing risk of inadequate blood flow, though the precise threshold for an individual depends on their baseline blood pressure and the resistance in their blood vessels.
In septic shock specifically, sepsis treatment guidelines have set an initial resuscitation target of a MAP of 65 mmHg or higher, achieved through intravenous fluids and, if needed, vasopressor medications, with the target reassessed and sometimes raised for patients who have chronic high blood pressure. Outside acute or critical illness, MAP is used less often than the standard systolic and diastolic readings, since it does not by itself distinguish isolated systolic hypertension from other blood pressure patterns.
MAP versus pulse pressure
Pulse pressure is a different number calculated from the same two readings: pulse pressure = systolic pressure - diastolic pressure, in mmHg. Where MAP describes the average pressure driving blood flow over a full cardiac cycle, pulse pressure describes the swing between peak and trough, driven mainly by stroke volume, arterial stiffness, and how quickly blood ejected during systole runs off into the periphery during diastole. Because MAP is a weighted blend of both readings, two people can share an identical, normal MAP while having very different pulse pressures, so the two numbers answer different clinical questions and are read together, not as substitutes.
A normal resting pulse pressure is roughly 40 mmHg, and pulse pressure is often expressed as a fraction of systolic pressure, with a pulse pressure below about 25 percent of systolic pressure considered narrow. A narrow pulse pressure, such as 90/76 mmHg (pulse pressure 14 mmHg), can signal a low stroke volume, as seen in cardiogenic shock, hypovolemia, cardiac tamponade, or severe aortic stenosis, even when the calculated MAP still falls in a seemingly reassuring range. A wide pulse pressure, such as 170/70 mmHg (pulse pressure 100 mmHg), is common with stiffened, less elastic arteries in older adults with isolated systolic hypertension, and is also characteristic of aortic regurgitation, where blood ejected in systole leaks back into the left ventricle during diastole and lets diastolic pressure fall unusually low.
- Pulse pressure = systolic pressure - diastolic pressure, in mmHg
- MAP reflects average perfusion pressure; pulse pressure reflects stroke volume and arterial stiffness
- A normal MAP does not rule out an abnormal pulse pressure, and both are assessed together, not interchangeably
- A narrowing pulse pressure in a deteriorating patient can be an early clue to falling stroke volume before blood pressure itself drops
| Pulse pressure pattern | Typical finding | Associated with |
|---|---|---|
| Narrow | Below about 25 percent of systolic pressure, e.g. under 25-30 mmHg | Low stroke volume: cardiogenic shock, hypovolemia, cardiac tamponade, severe aortic stenosis |
| Normal | Roughly 30 to 50 mmHg at rest | Typical for a healthy resting adult |
| Wide | Above roughly 60 to 100 mmHg | Arterial stiffness and isolated systolic hypertension in older adults, aortic regurgitation, severe anemia, hyperthyroidism |
Grenzen
- This formula is an approximation that assumes a roughly normal resting heart rate; at fast heart rates, diastole shortens disproportionately more than systole, so the calculated MAP can diverge from the true time-averaged pressure measured directly from an arterial waveform.
- A single cuff blood pressure reading has natural variability from measurement technique, cuff size, position, recent activity, and anxiety; averaging two or three readings taken a minute apart gives a more reliable input than one isolated measurement.
- In critically ill patients, an intra-arterial catheter provides a continuously measured, more accurate MAP than one calculated from cuff readings, particularly in shock states or with irregular heart rhythms.
- Irregular heart rhythms, such as atrial fibrillation, can make cuff-based systolic and diastolic readings themselves unreliable, which in turn affects the accuracy of a MAP calculated from them.
- Normal MAP ranges and clinically important thresholds established in adults have not been validated for children, whose normal blood pressure and heart rate differ substantially by age.
Häufige Fragen
Why is MAP not just the average of systolic and diastolic pressure?
A simple average would assume the heart spends equal time in systole and diastole, but diastole normally lasts about twice as long. Weighting diastolic pressure more heavily gives a better estimate of the true time-averaged pressure driving blood flow.
What MAP is considered normal?
A MAP of roughly 70 to 100 mmHg is typical for a healthy resting adult, though the number that matters for any individual depends on their usual blood pressure and clinical situation.
Why does sepsis treatment target a MAP of 65?
Clinical trials in septic shock have generally not shown added benefit from targeting a higher MAP, while a MAP below about 65 mmHg is associated with a higher risk of inadequate organ perfusion, so 65 mmHg is used as a practical initial resuscitation target.
Can MAP be normal even with abnormal systolic or diastolic pressure?
Yes. Because MAP is a weighted combination of both numbers, it is possible for MAP to fall in a typical range even when systolic pressure alone is elevated, such as in isolated systolic hypertension, which is why MAP does not replace looking at both numbers individually.
What is pulse pressure and how is it different from MAP?
Pulse pressure is systolic pressure minus diastolic pressure, in mmHg, and reflects stroke volume and arterial stiffness rather than average perfusion pressure. A normal resting pulse pressure is roughly 40 mmHg. MAP and pulse pressure are calculated from the same two readings but describe different aspects of the cardiac cycle, so both are typically reviewed together.
What does a narrow pulse pressure mean?
A pulse pressure under roughly 25 percent of the systolic reading is considered narrow and can suggest a low stroke volume, seen in conditions such as cardiogenic shock, hypovolemia, cardiac tamponade, or severe aortic stenosis. A narrowing pulse pressure in someone being monitored closely can be an early warning sign even before their MAP itself falls.
Quellen
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