{"id":59358,"date":"2016-03-15T17:47:03","date_gmt":"2016-03-15T15:47:03","guid":{"rendered":"http:\/\/wpcalc.com\/?p=59358"},"modified":"2026-10-26T09:24:08","modified_gmt":"2026-10-26T06:24:08","slug":"systemic-vascular-resistance","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/medical\/systemic-vascular-resistance\/","title":{"rendered":"SVR Calculator \u2013 Systemic Vascular Resistance"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 id=\"calculator-title\" class=\"text-lg font-display font-bold\">SVR Estimator Using MAP, CVP, and CO<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"59358\" data-favorite-title=\"Systemic Vascular Resistance (SVR)\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/medical\/systemic-vascular-resistance\/\" data-favorite-excerpt=\"Estimate Systemic Vascular Resistance (SVR) from mean arterial pressure (MAP), central venous pressure (CVP), and cardiac output (CO). Enter three values in mmHg and L\/min to get SVR in dyn\u00b7s\/cm\u2075.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-flask\">\n    <span class=\"icon icon-shape-star-empty\" aria-hidden=\"true\"><\/span>\n  <\/button>\n  <div class=\"calcdash-favorite__tip\" aria-hidden=\"true\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n  <span class=\"sr-only\" role=\"status\" id=\"favorite-status\"><\/span>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/en\/medical\/systemic-vascular-resistance\/\" method=\"POST\" class=\"calculator\" id=\"calculator-59358\" data-post=\"59358\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">Mean Arterial Pressure (MAP)<\/label><div class=\"term\">MAP<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"mean_arterial_pressure_map\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"1\" value=\"90\"\/><div class=\"unit\" id=\"calc-unit-1\">mmHg<\/div><small id=\"calc-info-1\">Mean arterial pressure<\/small><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-2\">Central Venous Pressure (CVP)<\/label><div class=\"term\">CVP<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"central_venous_pressure_cvp\" id=\"field-2\" aria-describedby=\"calc-unit-2 calc-info-2\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"5\"\/><div class=\"unit\" id=\"calc-unit-2\">mmHg<\/div><small id=\"calc-info-2\">Central venous pressure<\/small><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-3\">Cardiac Output (CO)<\/label><div class=\"term\">CO<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"cardiac_output_co\" id=\"field-3\" aria-describedby=\"calc-unit-3 calc-info-3\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0.1\" value=\"5\"\/><div class=\"unit\" id=\"calc-unit-3\">L\/min<\/div><small id=\"calc-info-3\">Cardiac output<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"59358\">Calculate<\/button><button type=\"reset\">Reset<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calculate automatically<\/label><small>If enabled, the result will update automatically when you change any value.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> Your Results<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>Systemic Vascular Resistance<\/span><span class=\"result-term\">SVR<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"dyn\u00b7s\/cm\u2075\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copy Result\" aria-label=\"Copy Result\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><\/div><div class=\"result-actions\"><button type=\"button\" class=\"copy-link\"><svg viewBox=\"0 0 20 20\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z\"\/><path d=\"M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z\"\/><\/svg><span class=\"copy-link__text\">Copy link to this calculation<\/span><\/button><span class=\"sr-only\" role=\"status\" id=\"copy-link-status\"><\/span><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Leave a Comment<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"59358\" aria-live=\"polite\" aria-labelledby=\"calc-reactions-title\"><p id=\"calc-reactions-title\" class=\"text-sm text-gray-500 text-center mb-2\">How did this result make you feel?<\/p><div role=\"group\" aria-labelledby=\"calc-reactions-title\" class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">Like <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">Helpful <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confused <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">Disappointed <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\u274c <\/span><span class=\"reaction-description font-medium\">Inaccurate <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><div class=\"calcdash-ad not-prose calcdash-ad--calc_result calcdash-ad--in-article\"><ins class=\"adsbygoogle\" style=\"display:block\" data-ad-client=\"ca-pub-1721569815777345\" data-ad-slot=\"6317458308\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/div>\n<style id=\"wpcoderpro-inline-1\">.formula-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>Systemic Vascular Resistance Formula<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">Formula<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n\\[ SVR = 80 \\cdot \\frac{MAP - CVP}{CO} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(SVR\\) \u2014 systemic vascular resistance (dyn\u00b7s\/cm\u2075)<\/li>\n<li>\\(MAP\\) \u2014 mean arterial pressure (mmHg)<\/li>\n<li>\\(CVP\\) \u2014 central venous pressure (mmHg)<\/li>\n<li>\\(CO\\) \u2014 cardiac output (L\/min)<\/li>\n<li>\\(80\\) \u2014 conversion factor from mmHg\u00b7min\/L (Wood units) to dyn\u00b7s\/cm\u2075<\/li>\n<\/ul>\n<p>The formula follows from the hemodynamic analogy of Ohm's law: the pressure drop across the systemic circulation (\\(MAP - CVP\\)) divided by the flow through it (\\(CO\\)) gives the resistance.<\/p>\n<p>\r\n<\/section>\n<style id=\"wpcoderpro-inline-459\">.calculation-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>Systemic Vascular Resistance \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> a critically ill patient has a mean arterial pressure of 90 mmHg, a central venous pressure of 5 mmHg, and a cardiac output of 5 L\/min.<\/p>\n<p>\\[ SVR = 80 \\cdot \\frac{90 - 5}{5} = 80 \\cdot \\frac{85}{5} = 80 \\cdot 17 = 1360 \\text{ dyn\u00b7s\/cm}^5 \\]<\/p>\n<p><strong>Result:<\/strong> SVR = 1360 dyn\u00b7s\/cm\u2075, which is above the typical reference range and suggests increased vascular tone (vasoconstriction).<\/p>\n<p>\n\r\n<\/section>\n<h2>How to Use the SVR Calculator<\/h2>\n<ol>\n<li>Enter the <strong>Mean Arterial Pressure (MAP)<\/strong> in mmHg. If you only have systolic and diastolic pressures, use the <a href=\"https:\/\/wpcalc.com\/en\/medical\/mean-arterial-pressure\/\">Mean Arterial Pressure calculator<\/a> first.<\/li>\n<li>Enter the <strong>Central Venous Pressure (CVP)<\/strong> in mmHg, measured with a central venous catheter. If no value is available, a typical value of 5\u20138 mmHg is often assumed.<\/li>\n<li>Enter the <strong>Cardiac Output (CO)<\/strong> in L\/min. You can obtain this from thermodilution or estimate it with the <a href=\"https:\/\/wpcalc.com\/en\/medical\/cardiac-output\/\">Cardiac Output (Fick Method) calculator<\/a>.<\/li>\n<li>Read the <strong>Systemic Vascular Resistance<\/strong> result in dyn\u00b7s\/cm\u2075.<\/li>\n<\/ol>\n<h2>What Is Systemic Vascular Resistance?<\/h2>\n<p>Systemic vascular resistance is the resistance that the systemic blood vessels oppose to the blood flow generated by the left ventricle. In clinical terms, it is the quantitative expression of <em>afterload<\/em>: the load the left heart must overcome with every contraction. SVR is determined mainly by the diameter of the arterioles \u2014 the small resistance vessels \u2014 which constrict or dilate under sympathetic, hormonal, and local metabolic control.<\/p>\n<p>The concept comes directly from Ohm's law applied to the circulation: pressure equals flow times resistance. Rearranging gives resistance as the pressure drop across the vascular bed divided by the flow through it. Here the pressure drop is the difference between the mean arterial pressure (the pressure at the origin of the systemic circuit) and the central venous pressure (the pressure at its return), and the flow is the cardiac output.<\/p>\n<p>Because resistance cannot be measured directly, it is always a <em>derived<\/em> value. That means its accuracy depends entirely on the accuracy of the three inputs \u2014 particularly the cardiac output, which appears in the denominator, so small measurement errors in CO produce proportionally larger errors in SVR.<\/p>\n<h2>Interpreting SVR Values<\/h2>\n<p>In adults, a typical reference range is roughly <strong>800\u20131200 dyn\u00b7s\/cm\u2075<\/strong> (about 10\u201315 Wood units). Ranges vary between laboratories and patient populations, so always interpret SVR in the context of the clinical picture and the reference values used in your institution.<\/p>\n<p><strong>Elevated SVR<\/strong> (above roughly 1200 dyn\u00b7s\/cm\u2075) indicates vasoconstriction. Common causes include hypovolemic or cardiogenic shock (where the body compensates by clamping down the vessels), late septic shock, hypertension, and vasopressor therapy. A high SVR with a low cardiac output is the classic pattern of cardiogenic shock.<\/p>\n<p><strong>Low SVR<\/strong> (below roughly 800 dyn\u00b7s\/cm\u2075) indicates vasodilation, most characteristically in early septic shock, but also in anaphylaxis, neurogenic shock, liver failure, and after vasodilator drugs. The typical septic picture is a low SVR with a high cardiac output \u2014 the heart pumps strongly, but the vessels offer too little resistance to maintain pressure.<\/p>\n<p>SVR is most useful when read together with cardiac output and filling pressures rather than in isolation. For example, the same elevated SVR can reflect compensatory vasoconstriction in a hypovolemic patient or pathological vasoconstriction in heart failure. For a related measure of cardiac performance, see the <a href=\"https:\/\/wpcalc.com\/en\/medical\/ejection-fraction\/\">Ejection Fraction calculator<\/a>.<\/p>\n<h2>Units, Assumptions and Limitations<\/h2>\n<ul>\n<li><strong>Units.<\/strong> The factor 80 converts the result from mmHg\u00b7min\/L (Wood units) to dyn\u00b7s\/cm\u2075, the traditional clinical unit. In SI units, resistance is expressed in MPa\u00b7s\/m\u00b3 (1 mmHg\u00b7min\/L \u2248 8 MPa\u00b7s\/m\u00b3).<\/li>\n<li><strong>Assumed inputs.<\/strong> The formula assumes steady-state flow. In rapidly changing hemodynamic states (arrhythmias, ongoing resuscitation), a single set of values may not represent the patient's average condition.<\/li>\n<li><strong>Estimating missing values.<\/strong> If CVP is not measured, clinicians often assume a value of 5 mmHg; this introduces error, especially when the true CVP is far from that assumption. MAP derived from a non-invasive cuff pressure is less accurate than an arterial line, particularly in shock.<\/li>\n<li><strong>Not a standalone diagnosis.<\/strong> SVR is a derived index intended to support, not replace, clinical assessment. Treatment decisions should rest on the full hemodynamic profile and the patient's overall condition.<\/li>\n<li><strong>Special populations.<\/strong> Reference ranges differ in children, during pregnancy, under anesthesia, and in patients on mechanical ventilation or vasoactive drugs.<\/li>\n<\/ul>\n<p>For broader cardiovascular risk context, you may also find the <a href=\"https:\/\/wpcalc.com\/en\/medical\/framingham-risk-score\/\">Framingham Heart Disease Risk calculator<\/a> useful.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Estimate Systemic Vascular Resistance (SVR) from mean arterial pressure (MAP), central venous pressure (CVP), and cardiac output (CO). Enter three values in mmHg and L\/min to get SVR in dyn\u00b7s\/cm\u2075.<\/p>\n","protected":false},"author":70,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[8],"tags":[50],"class_list":["post-59358","post","type-post","status-publish","format-standard","hentry","category-medical","tag-diagnostics"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59358","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/users\/70"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/comments?post=59358"}],"version-history":[{"count":4,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59358\/revisions"}],"predecessor-version":[{"id":67529,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59358\/revisions\/67529"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=59358"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=59358"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=59358"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}