Simple Leg Raise Assesses 'Tank' in Septic Shock

SAN FRANCISCO – Before reaching for vasopressors to treat a patient in septic shock, physicians want to know that the patient has received enough fluid. Two traditional ways of assessing the patient’s "tank" both have limitations, but a relatively simple bedside procedure can predict the need for a fluid bolus.

Observing respiratory variations in arterial wave form analysis while health care workers raise a supine patient’s legs into a sitting position helps assess the volume status, also known as the pre-load or "the tank," in a patient with septic shock, Dr. Peter M. C. DeBlieux said at the annual meeting of the American College of Emergency Physicians.

"What that requires is a simple arterial line placed in either the radial or femoral artery, and then that’s transduced" and observed on a monitor with the heart rate, he said. Changes greater than 12%-15% in the pulse amplitude of the arterial wave form during either physiologic or mechanical breathing predicts that the patient would benefit from a fluid bolus, said Dr. DeBlieux, professor of medicine at Louisiana State University and professor of surgery at Tulane University, both in New Orleans.

This is more easily seen by raising the legs of a supine patient with septic shock. The patient’s head may be at a 45-degree angle, but the legs should start flat on the table. Two health care workers on either side of the bed should raise the patient’s legs to 90-degree angles at the hips and knees, as if the patient was in a sitting position, while observing the arterial tracing. If the arterial tracing shows at least a 12%-15% increase in pulse pressure, that warrants a fluid bolus.

"It’s a pretty simple thing to do at the bedside that changes management," he said.

Previously, volume status in patients with septic shock has been assessed by central venous pressure monitoring. Bedside ultrasound also has been used, focusing on the inferior vena cava and the collapsibility of the vena cava during normal respiratory cycles. A collapse of 20%-50% indicates that a fluid bolus would be beneficial. Both of these measures can give false elevations, however, if the patient has preexisting acute or chronic heart or lung disease.

Although an elevated central venous pressure (CVP) or collapsing inferior vena cava (IVC) on ultrasound during respiration indicated the need for a fluid bolus, "once the CVP is elevated or if you have a plethoric IVC, you’re left scratching your head," Dr. DeBlieux said. "Remember that any cardiac or pulmonary dysfunction gets immediately transmitted to the great vein," so the CVP may be high, or the IVC may look plethoric on ultrasound, but the patient may still need a fluid bolus.

"You would say that the tank is full, but you don’t know. I don’t know. We don’t know," he said.

Managing the tank corresponds with the first of three steps in the Surviving Sepsis Campaign's perfusion goals in early goal-directed therapy in acute care of septic shock. Dr. DeBlieux and some other educators refer to these as the tank, the hose and the pump for teaching purposes.

The tank goal is a CVP of 8-12 mm Hg through treatment with serial crystalloid fluid infusions.

The hose is marked by systemic vascular resistance. After addressing the tank, if the mean arterial blood pressure is lower than 65 mmHg, administer norepinephrine, dopamine or epinephrine to bring it up to 65 mm Hg. The medical literature supports any one of those three choices, but norepinephrine will produce fewer tachyarrhythmic events, he said.

In reality, managing the tank and hose may happen simultaneously because physicians may not want to wait for hours until the CVP gets to goal before administering vasopressors, he added.

The pump reflects oxygen delivery and utilization. After addressing the tank and hose, if the lactate level is greater than 4 mmol and central venous oxygen saturation (ScvO₂) is less than 70%, consider giving dobutamine in the setting of left ventricular dysfunction, start invasive mechanical ventilation, and/or blood transfusion if the hemoglobin/hematocrit is less than 10/30 within 6 hours.

Dr. DeBlieux said he has no relevant conflicts of interest.

SAN FRANCISCO – Before reaching for vasopressors to treat a patient in septic shock, physicians want to know that the patient has received enough fluid. Two traditional ways of assessing the patient’s "tank" both have limitations, but a relatively simple bedside procedure can predict the need for a fluid bolus.

Observing respiratory variations in arterial wave form analysis while health care workers raise a supine patient’s legs into a sitting position helps assess the volume status, also known as the pre-load or "the tank," in a patient with septic shock, Dr. Peter M. C. DeBlieux said at the annual meeting of the American College of Emergency Physicians.

"What that requires is a simple arterial line placed in either the radial or femoral artery, and then that’s transduced" and observed on a monitor with the heart rate, he said. Changes greater than 12%-15% in the pulse amplitude of the arterial wave form during either physiologic or mechanical breathing predicts that the patient would benefit from a fluid bolus, said Dr. DeBlieux, professor of medicine at Louisiana State University and professor of surgery at Tulane University, both in New Orleans.

This is more easily seen by raising the legs of a supine patient with septic shock. The patient’s head may be at a 45-degree angle, but the legs should start flat on the table. Two health care workers on either side of the bed should raise the patient’s legs to 90-degree angles at the hips and knees, as if the patient was in a sitting position, while observing the arterial tracing. If the arterial tracing shows at least a 12%-15% increase in pulse pressure, that warrants a fluid bolus.

"It’s a pretty simple thing to do at the bedside that changes management," he said.

Previously, volume status in patients with septic shock has been assessed by central venous pressure monitoring. Bedside ultrasound also has been used, focusing on the inferior vena cava and the collapsibility of the vena cava during normal respiratory cycles. A collapse of 20%-50% indicates that a fluid bolus would be beneficial. Both of these measures can give false elevations, however, if the patient has preexisting acute or chronic heart or lung disease.

Although an elevated central venous pressure (CVP) or collapsing inferior vena cava (IVC) on ultrasound during respiration indicated the need for a fluid bolus, "once the CVP is elevated or if you have a plethoric IVC, you’re left scratching your head," Dr. DeBlieux said. "Remember that any cardiac or pulmonary dysfunction gets immediately transmitted to the great vein," so the CVP may be high, or the IVC may look plethoric on ultrasound, but the patient may still need a fluid bolus.

"You would say that the tank is full, but you don’t know. I don’t know. We don’t know," he said.

Managing the tank corresponds with the first of three steps in the Surviving Sepsis Campaign's perfusion goals in early goal-directed therapy in acute care of septic shock. Dr. DeBlieux and some other educators refer to these as the tank, the hose and the pump for teaching purposes.

The tank goal is a CVP of 8-12 mm Hg through treatment with serial crystalloid fluid infusions.

The hose is marked by systemic vascular resistance. After addressing the tank, if the mean arterial blood pressure is lower than 65 mmHg, administer norepinephrine, dopamine or epinephrine to bring it up to 65 mm Hg. The medical literature supports any one of those three choices, but norepinephrine will produce fewer tachyarrhythmic events, he said.

In reality, managing the tank and hose may happen simultaneously because physicians may not want to wait for hours until the CVP gets to goal before administering vasopressors, he added.

The pump reflects oxygen delivery and utilization. After addressing the tank and hose, if the lactate level is greater than 4 mmol and central venous oxygen saturation (ScvO₂) is less than 70%, consider giving dobutamine in the setting of left ventricular dysfunction, start invasive mechanical ventilation, and/or blood transfusion if the hemoglobin/hematocrit is less than 10/30 within 6 hours.

Dr. DeBlieux said he has no relevant conflicts of interest.

SAN FRANCISCO – Before reaching for vasopressors to treat a patient in septic shock, physicians want to know that the patient has received enough fluid. Two traditional ways of assessing the patient’s "tank" both have limitations, but a relatively simple bedside procedure can predict the need for a fluid bolus.

Observing respiratory variations in arterial wave form analysis while health care workers raise a supine patient’s legs into a sitting position helps assess the volume status, also known as the pre-load or "the tank," in a patient with septic shock, Dr. Peter M. C. DeBlieux said at the annual meeting of the American College of Emergency Physicians.

"What that requires is a simple arterial line placed in either the radial or femoral artery, and then that’s transduced" and observed on a monitor with the heart rate, he said. Changes greater than 12%-15% in the pulse amplitude of the arterial wave form during either physiologic or mechanical breathing predicts that the patient would benefit from a fluid bolus, said Dr. DeBlieux, professor of medicine at Louisiana State University and professor of surgery at Tulane University, both in New Orleans.

This is more easily seen by raising the legs of a supine patient with septic shock. The patient’s head may be at a 45-degree angle, but the legs should start flat on the table. Two health care workers on either side of the bed should raise the patient’s legs to 90-degree angles at the hips and knees, as if the patient was in a sitting position, while observing the arterial tracing. If the arterial tracing shows at least a 12%-15% increase in pulse pressure, that warrants a fluid bolus.

"It’s a pretty simple thing to do at the bedside that changes management," he said.

Previously, volume status in patients with septic shock has been assessed by central venous pressure monitoring. Bedside ultrasound also has been used, focusing on the inferior vena cava and the collapsibility of the vena cava during normal respiratory cycles. A collapse of 20%-50% indicates that a fluid bolus would be beneficial. Both of these measures can give false elevations, however, if the patient has preexisting acute or chronic heart or lung disease.

Although an elevated central venous pressure (CVP) or collapsing inferior vena cava (IVC) on ultrasound during respiration indicated the need for a fluid bolus, "once the CVP is elevated or if you have a plethoric IVC, you’re left scratching your head," Dr. DeBlieux said. "Remember that any cardiac or pulmonary dysfunction gets immediately transmitted to the great vein," so the CVP may be high, or the IVC may look plethoric on ultrasound, but the patient may still need a fluid bolus.

"You would say that the tank is full, but you don’t know. I don’t know. We don’t know," he said.

Managing the tank corresponds with the first of three steps in the Surviving Sepsis Campaign's perfusion goals in early goal-directed therapy in acute care of septic shock. Dr. DeBlieux and some other educators refer to these as the tank, the hose and the pump for teaching purposes.

The tank goal is a CVP of 8-12 mm Hg through treatment with serial crystalloid fluid infusions.

The hose is marked by systemic vascular resistance. After addressing the tank, if the mean arterial blood pressure is lower than 65 mmHg, administer norepinephrine, dopamine or epinephrine to bring it up to 65 mm Hg. The medical literature supports any one of those three choices, but norepinephrine will produce fewer tachyarrhythmic events, he said.

In reality, managing the tank and hose may happen simultaneously because physicians may not want to wait for hours until the CVP gets to goal before administering vasopressors, he added.

The pump reflects oxygen delivery and utilization. After addressing the tank and hose, if the lactate level is greater than 4 mmol and central venous oxygen saturation (ScvO₂) is less than 70%, consider giving dobutamine in the setting of left ventricular dysfunction, start invasive mechanical ventilation, and/or blood transfusion if the hemoglobin/hematocrit is less than 10/30 within 6 hours.

Dr. DeBlieux said he has no relevant conflicts of interest.