Hyperdynamic circulation is abnormally increased circulatory volume. Systemic vasodilation

Vasodilation

Vasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...

 and the associated decrease in peripheral vascular resistance results in decreased pulmonary capillary wedge pressure

Pulmonary capillary wedge pressure

The pulmonary capillary wedge pressure or PCWP is the pressure measured by wedging a pulmonary catheter with an inflated balloon into a small pulmonary arterial branch.Physiologically, distinctions can be drawn among pulmonary venous pressure, pulmonary artery pressure, pulmonary...

 and decreased blood pressure

Blood pressure

Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...

, often presenting with a collapsing pulse

Pulse

In medicine, one's pulse represents the tactile arterial palpation of the heartbeat by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed against a bone, such as at the neck , at the wrist , behind the knee , on the inside of the elbow , and near the...

. In effort to compensate the heart will increase cardiac output

Cardiac output

Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...

 and heart rate

Heart rate

Heart rate is the number of heartbeats per unit of time, typically expressed as beats per minute . Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep....

, which accounts for the decreased pulse pressure

Pulse pressure

Pulse Pressure is most easily defined as being the amount of pressure required to create the feeling of a pulse. Measured in millimeters of mercury , the pressure difference between the systolic and diastolic pressures give you the amount of pressure change to create the pulse, which is the pulse...

 and sinus tachycardia

Sinus tachycardia

Sinus tachycardia is a heart rhythm with elevated rate of impulses originating from the sinoatrial node, defined as a rate greater than 100 beats/min in an average adult. The normal heart rate in the average adult ranges from 60–100 beats/min...

. The condition sometimes accompanies septic shock

Septic shock

Septic shock is a medical emergency caused by decreased tissue perfusion and oxygen delivery as a result of severe infection and sepsis, though the microbe may be systemic or localized to a particular site. It can cause multiple organ dysfunction syndrome and death...

, preeclampsia, and other physiological and psychiatric conditions.

Possible causes

• Renal disease
• Volume expansion
  Volume expansion
  Volume expansion may refer to:*Thermal expansion*Increase of fluid in the blood. When reaching abnormally high levels, it is termed hypervolemia...
  
  
• Anemia
  Anemia
  Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
  
  
• Anxiety
  Anxiety
  Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
  
  
• AV fistulae
  Arteriovenous fistula
  An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein. It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial aneurysm....
  
  
• Beriberi
  Beriberi
  Beriberi is a nervous system ailment caused by a thiamine deficiency in the diet. Thiamine is involved in the breakdown of energy molecules such as glucose and is also found on the membranes of neurons...
  
  
• Erythroderma
  Erythroderma
  Erythroderma is an inflammatory skin disease with erythema and scaling that affects nearly the entire cutaneous surface....
  
  
• Exercise
• Hepatic failure
  Liver failure
  Acute liver failure is the appearance of severe complications rapidly after the first signs of liver disease , and indicates that the liver has sustained severe damage . The complications are hepatic encephalopathy and impaired protein synthesis...
  
  
• Hydrocephalus
  Hydrocephalus
  Hydrocephalus , also known as "water in the brain," is a medical condition in which there is an abnormal accumulation of cerebrospinal fluid in the ventricles, or cavities, of the brain. This may cause increased intracranial pressure inside the skull and progressive enlargement of the head,...
  
  
• Hypercapnia
  Hypercapnia
  Hypercapnia or hypercapnea , also known as hypercarbia, is a condition where there is too much carbon dioxide in the blood...
  
  
• Paget's disease
  Paget's disease
  Sir James Paget, a surgeon and pathologist, described several diseases, including:* Paget's disease of bone * Paget's disease of the breast* Paget-Schroetter disease* Extramammary Paget's disease...
  
  
• Portal hypertension
  Portal hypertension
  In medicine, portal hypertension is hypertension in the portal vein and its tributaries.It is often defined as a portal pressure gradient of 10 mmHg or greater.-Causes:Causes can be divided into prehepatic, intrahepatic, and posthepatic...
  
  
• Pregnancy
  Pregnancy
  Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
  
  
• Pyrexia
• Thyrotoxicosis
• Vasodilator drugs