Stroke Volume Variation as a Predictor of Intravascular Volume ...

Stroke Volume Variation as a Predictor of Intravascular Volume ...

Stroke Volume Variation as a Predictor of Intravascular Volume ...


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Annals of Surgical Oncology

DOI: 10.1245/s10434-008-0139-0

Stroke Volume Variation as a Predictor of Intravascular

Volume Depression and Possible Hypotension During

the Early Postoperative Period After Esophagectomy

Makoto Kobayashi, MD, PhD, 1 Masayoshi Koh, MD, 2 Takashi Irinoda, MD, PhD, 1

Eiji Meguro, MD, PhD, 1 Yoshiro Hayakawa, MD, PhD, 1 and Akinori Takagane, MD, PhD 1

1 Surgical Division, Hakodate Goryoukaku Hospital, 38-3 Goryoukaku-cho, Hakodate City, Hokkaido 040-8611, Japan

2 Anesthetic Division, Hakodate Goryoukaku Hospital, 38-3 Goryoukaku-cho, Hakodate City, Hokkaido 040-8611, Japan

Background: Perioperative hypotension during esophagectomy results from hypovolemia

caused by a shift of extracellular fluid from the intravascular to the extravascular compartment.

Fluid management is often difficult to gauge during major surgery because there are no

reliable indicators of fluid status, and some patients still experience cardiorespiratory instability.

In this retrospective study, we evaluated stroke volume variation (SVV), calculated by

using a new arterial pressure-based cardiac output measurement device, as a predictor for fluid

responsiveness after esophageal surgery.

Methods: Eighteen patients undergoing esophagectomy with extended radical lymphadenectomy

were monitored by the FloTrac sensor/Vigileo monitor system during the perioperative

and immediate postoperative period. Fluid responsiveness was assessed and compared

with concurrent SVV and central venous pressure (CVP) values, and routine hemodynamic


Results: Eleven of 18 patients needed additional volume loading within the first 10 postoperative

hours as a result of hypotension. The maximum SVV value of fluid resuscitated

patients was >15% in all cases, whereas six of seven patients without postoperative hypotension

had maximum SVV values of 0.05).

Conclusion: We conclude that SVV, as displayed on the Vigileo monitor, is an accurate

predictor of intravascular hypovolemia and is a useful indicator for assessing the appropriateness

and timing of applying fluid for improving circulatory stability during the perioperative

period after esophagectomy.

Over the past decade, morbidity and mortality

associated with radical esophagectomy have both

improved, 1 whereas postoperative management has

remained problematic. 2 In particular, hypotension

often occurs during the perioperative and immediate

Address correspondence and reprint requests to: Makoto

Kobayashi, MD, PhD; E-mail: neo-coba@mub.biglobe.ne.jp

Published by Springer Science+Business Media, LLC Ó 2008 The Society of

Surgical Oncology, Inc.

postoperative periods associated with major surgery,

such as extended radical lymphadenectomy for

esophageal cancer, and it is almost certainly caused

by hypovolemia. While postoperative hemorrhage

needs to be ruled out, most cases of hypovolemic

hypotension seem to be due to a shift of extracellular

fluid from the central to peripheral compartments,

and it has been suggested that this is a direct consequence

of the development of a third space associated

with increased vascular permeability caused by

hypercytokinemia. 3 The destruction of the lymphatic

tract due to interruption of the pulmonary lymph

outflow tract as a result of mediastinal lymphadenectomy

and removal of the thoracic duct also promotes

deterioration of circulatory dynamics. 4 With

the introduction of minimally invasive surgery, 5 corticosteroid

administration to prevent hypercytokinemia,

6,7 and treatment with a specific neutrophil

elastase inhibitor, 8 postoperative management of

esophageal cancer is safer than ever. However, it is

also true that some patients still experience cardiorespiratory

instability; especially those with poor

preoperative nutrition and those receiving neoadjuvant

chemoradiotherapy. 9,10 Even when it is thought

that sufficient fluid has been administered, it is

sometimes difficult to determine whether intravascular

fluid depression has been relieved by monitoring

routine hemodynamic parameters. An added complication

is that although appropriate fluid transfusion

is often crucial to avoid the deleterious effects of

overresuscitation, underresuscitation, or inappropriate

resuscitation, it is also reported that static indicators

of cardiac preload, such as central venous

pressure (CVP), pulmonary artery occlusion pressure,

and cardiac end-diastolic dimensions, may be unreliable

in detecting volume responsiveness in critically

ill patients. 11

The FloTrac sensor in combination with the Vigileo

monitor (Edwards Lifesciences, Tokyo, Japan) is

a recently introduced arterial pressure-based system

for continuously monitoring cardiac output (CO),

which has applicability in the critical care setting. The

FloTrac sensor is a less invasive hemodynamic

monitoring device than those used for thermodilution

assessment, and it can be used to monitor continuously

CO, stroke volume, and stroke volume variation

(SVV) through a peripheral arterial pressure line.

In addition, other CO devices require calibration to

correct for the patient’s changing vascular tone,

whereas the FloTrac sensor/Vigileo monitor system

needs no calibration because it continuously adjusts

for the patient’s ever-changing vascular tone by use

of a novel algorithm incorporated within the Vigileo

monitor, which is applied to the digitized arterial

pressure wave. 12 The usefulness of SVV in assessing

fluid responsiveness has previously been reported in

patients with reduced cardiac function. 13 We started

routinely using the FloTrac sensor/Vigileo monitor

system during esophageal surgery, including an

assessment of its advantages for perioperative management

after radical esophagectomy, in May 2006.

This followed early findings that indicated that SVV

was very good at predicting the development of

Ann. Surg. Oncol.


hypercytokinemia-induced intravascular hypovolemia

in patients undergoing major surgery.

Here we report retrospective results from the first

18 patients undergoing surgery for esophageal cancer

in whom the FloTrac sensor/Vigileo monitor system

was used to assess fluid responsiveness as an integral

part of routine postoperative management follow-up

and care. In addition, we compared SVV with CVP in

terms of reliability in predicting fluid responsiveness

during the perioperative and postsurgical periods.


Between May 2006 and September 2007, 18 men of

mean ± standard deviation age 66.8 ± 4.8 (range, 61–

73) years underwent perioperative monitoring with

the FloTrac sensor/Vigileo monitor system after

curative esophagectomy for esophageal squamous

cell carcinoma at Hakodate Goryoukaku Hospital.

The tumor, node, metastasis system classification

according to the Guidelines for the Clinical and

Pathologic Studies on Carcinoma of the Esophagus

(Japan Society for Esophageal Diseases, 9th edition)

was as follows: stage I, n = 5; stage II, n = 5; stage

III, n = 4; and stage IVa, n = 4. Tumor location

was upper thoracic esophagus, n = 3; middle thoracic

esophagus, n = 13; and lower thoracic esophagus,

n = 2. Two-field lymph node dissection was

performed in 5 patients and three-field dissection in

13 patients. A combination of general (intravenous

propofol) and epidural (bupivacaine) anesthesia was

used to manage perioperative anesthetic requirements

during surgery. The surgical approach for tumor

resection for all patients was made by intercostal

thoracotomy through a 10- to 12-cm skin incision,

preserving the latissimus dorsi and serratus anterior

muscle. After subtotal esophagectomy and extended

mediastinal lymph node dissection, reconstruction via

stomach and cervical esophagogastrostomy was

performed. All patients were selected for posterior

mediastinal reconstruction via a gastric tube, and a

hand-sutured anastomosis was conducted at the

neck site. During the surgical procedure, fluid was

administered at a rate of 12 to 15 mL/kg/h of crystalloids.

Perioperative dopamine or furosemide was

not permitted.

After surgery, all patients were immediately

transferred to the intensive care unit (ICU) under

tracheal intubation. Mechanical ventilation was

adjusted to supply tidal volumes of 8 to 10 mL/kg of

preoperative body weight with pressure-support

ventilation. Midazolam and morphine were admin-

istrated intravenously for sedation during tracheal


Fluid administration in the early postoperative

period was started at a rate of 3.5 mL/kg/h and

continued until an extravascular to intravascular

shift was observed. Patients were considered to be

hypotensive when systolic blood pressure could not

be maintained above 80 mm Hg for longer than

15 minutes, at which time additional volume loading

was provided. If the serum albumin concentration

dropped below the normal range (3.4 to 5.4 g/dL),

250 mL of 5% plasma protein fraction was administered.

In lieu of corticosteroid treatment to treat

hypercytokinemia, sivelestat sodium hydrate, a specific

neutrophil elastase inhibitor (Elaspol, Ono

pharmacy, Tokyo, Japan), was administrated intravenously

at a rate of 0.2 mg/kg/h on completion of

surgery. To avoid the possibility of intravascular

hypoperfusion, our policy is not to use low-dose

dopamine or loop diuretics to protect against oliguria

until after adjustments have been made for

volume depression. After confirming circulatory

stability and a shift toward diuresis, the rate of

fluid administration was immediately decreased to

1.5 mL/kg/h to avoid congestive heart failure

developing as a consequence of overhydration.

Patients were then weaned from assisted mechanical


Assessment of Hemodynamic Parameters

Before surgery, hemodynamic monitoring was initiated

via a 22-gauge elastic catheter that was inserted

into the radial artery and connected to a FloTrac

sensor. CO and SVV were measured every 20 seconds

according to the algorithm housed within the Vigileo

monitor. Other parameters routinely monitored

included, continuous electrocardiography, pulse

oximetry, end-tidal CO2 and arterial blood pressure

(ABP). A central venous catheter was inserted into

the internal jugular vein, and CVP was measured

continuously during the perioperative period with a

low-pressure transducer. All raw data from the Vigileo

monitor were recorded directly onto a computer

and were subsequently reviewed and analyzed statistically.

To assess hemodynamic variability associated

with volume loading mean SVV, CVP and CO were

determined 30 minutes before and 30 minutes after

fluid administration. To investigate the relation

between changes in preload and postload variables,

changes (D) in SVV, CVP, and CO were calculated by

the following formulas:


DSVVð%Þ ¼preload SVV postload SVV

DCVP ðmm HgÞ ¼postload CVP preload CVP

DCO ¼ðpostload CO preload COÞ=preload CO.

Statistical Analysis

All data are expressed as mean ± SD, unless stated

otherwise. The v 2 test for independence was used to

assess the relationship between SVV and the development

of postoperative hypotension. To determine

whether changes in hemodynamic variables (DSVV,

DCVP) were related to the increased ratio in CO

(DCO) after additional volume loading, both linear

regression and Pearson’s correlation coefficient were

calculated by StatView software (Abacus Concepts,

Berkeley, CA). Values of P < 0.05 were considered

statistically significant.


The mean duration of surgery was 303 ± 58 minutes,

and mean blood loss was 280 ± 320 mL. Postoperatively,

11 of 18 patients required additional

volume loading within the first 10 hours due to

hypotension, and 3 of these received blood transfusions.

The mean duration under mechanical assist

ventilation after surgery was 1.7 ± 0.7 days. The

mean lengths of ICU and hospital stay after surgery

were 3.6 ± 1.4 days and 16.0 ± 3.2 days, respectively.

There was no significant difference in cardiac function,

as assessed by echocardiographically measured

ejection fraction before surgery, in patients who needed

fluid resuscitation after hypotension (69.1 ± 7.2%)

compared with those who did not (66.1 ± 8.8%;

P = 0.390, Mann-Whitney U-test). Furthermore,

there was no statistically significant difference in the

volume of fluid administered (14.1 ± 3.8 vs. 16.1 ± 3.5

mL/kg/h; P = 0.2204, Mann-Whitney U-test), blood

loss (241 ± 165 vs. 427 ± 332 mL; P = 0.092, Mann-

Whitney U-test), or operating time (293 ± 39 vs.

294 ± 70 minutes; P = 0.9025, Mann-Whitney Utest)

between the group requiring fluid resuscitation

versus the group that did not.

Importantly, in this series of patients who had

undergone esophagectomy with extended radical lymphadenectomy

and who developed intravascular volume

depression, ICU management with appropriate

fluid replacement for critical hypotension (as predicted

by SVV changes on the Vigileo monitor) resulted in

resuscitation and recovery in all cases and no clinically

Ann. Surg. Oncol.

FIG. 1. Postoperative SVV, CO, and CVP in a patient with circulatory instability after esophagectomy in a 69-year-old man. Duration of

surgery was 237 minutes; blood loss was 127 mL. Pathological classification according Japanese guidelines (see Materials and Methods) was

pT3 pN0 M0 pIM0; pStage II. SVV, stroke volume variation; CO, cardiac output; CVP, central venous pressure; PPF, plasma protein


important medical problems such as renal dysfunction,

respiratory failure, cardiac insufficiency, or death

occurred. Furthermore, there were no complications

associated with the use of the FloTrac sensor/Vigileo

monitoring system in this cohort of patients.

Figure 1 shows a typical graphical presentation for

SVV, CO, and CVP in a patient who underwent

esophagectomy with three-field lymph node dissection.

This patient experienced postoperative hypotension

and required fluid resuscitation in the ICU.

The initial SVV of the patient at the time of entering

the ICU was 8%, but it gradually increased to 15% to

20% by postoperative hour 4. Shortly thereafter,

systolic ABP decreased to 80 mm Hg, but SVV still increased to 26%. ABP

once again dropped to 20%, and hypotension reoccurred.

After additional fluid resuscitation, the circulation

stabilized, and SVV was finally maintained near 10%.

During these events, CVP values showed almost no

response before or after volume loading, whereas the

change in SVV observed graphically on the Vigileo

monitor clearly predicted hypotension resulting from

intravascular hypovolemia. In contrast, Fig. 2 shows

the typical graphical presentation for SVV, CVP, and

CO in a patient with stable circulation without any

hypotensive events. CO and ABP remained stable,

Ann. Surg. Oncol.


and SVV remained 15% at any stage during the 12 hours after surgery.

In contrast, maximum SVV values in the patient

group with hypotension were >15% in all cases

(n = 11), even though the initial SVV value was

15% is statistically significantly higher

than in patients with maximum SVV of

P = 0.049). In this small cohort of patients, the

correlation between SVV and CO only just achieved

statistical significance, but it did show promise as a

predictor of circulatory instability induced by intravascular

hypovolemia after esophagectomy. In this

regard it, was clearly superior to CVP.


Hypovolemic hypotension induced by hypercytokinemia

is often observed in the early postoperative


FIG. 2. Postoperative SVV, CO, and CVP in a patient with circulatory stability after esophagectomy in a 61-year-old man. Duration of the

operation was 335 minutes; blood loss was 82 mL. Pathological classification was pT2 pN3 M0 IM1, pStage II. SVV, stroke volume variation;

CO, cardiac output; CVP, central venous pressure.

FIG. 3. Initial and maximum intensive care unit (ICU) stroke volume variation (SVV) values. Patients are divided into 2 groups according to

need of fluid resuscitation after postoperative hypotension caused by intravascular hypovolemia. The initial value of SVV on entering the ICU

(j) and the maximum value before fluid resuscitation figures (•) are presented.

period of esophagectomy for esophageal cancer, and

it is reported that >60% of patients develop hypotension

on the operative day. 14 Postoperative hypotension

is often associated with a further reduction in

intravascular volume caused by unusual shift of

extracellular fluid into the third space. 3 Even though

an effective strategy for hypercytokinemia can be

adopted that uses corticosteroids or a specific neutrophil

elastase inhibitor such as sivelestat, and even

though early weaning from mechanical ventilation is

possible, 8 some patients still experience severe circulatory

instability. The usual protocol in our institute

Ann. Surg. Oncol.

FIG. 4. Responsiveness of CO according to changes in CVP and SVV after fluid loading. DSVV (%) = preload SVV - postload SVV; DCVP

(mm Hg) = postload CVP - preload CVP; DCO = (postload CO - preload CO)/preload CO; SVV, stroke volume variation; CO, cardiac

output; CVP, central venous pressure.

for the perioperative management of patients undergoing

esophagectomy is to administer fluid during

anesthesia at a rate of 15 mL/kg/h of crystalloids.

After transfer to the ICU, fluid administration starts

at a rate of 3.5 mL/kg/h. Our strategy for minimizing

effects related to the adverse release of the neutrophil

elastase is to administer sivelestat rather than a corticosteroid,

and we also avoid the use of dopamine

and furosemide. By means of this protocol, in 18

patients with esophageal cancer undergoing radical

esophagectomy, 15 patients (83%) were successfully

extubated within 2 days after surgery without complication,

and the mean period was 1.7 days after

surgery. Seven of 18 patients avoided hypotension

and escaped additional volume loading, but 11 patients

(61%) needed fluid resuscitation to treat

intravascular hypovolemia.

Precise control of fluid balance is a primary goal of

postoperative management after surgery, but traditional

hemodynamic monitoring parameters (heart

rate, mean arterial pressure, and CVP) are often

insensitive and sometimes misleading in the assessment

of circulating blood volume. 15 From May 2006, our

institute introduced the FloTrac sensor/Vigileo monitor

system for tracking SVV during the perioperative

period of esophagectomy. It was reported that SVV

calculated from stroke volume changes within the

respiratory cycle under mechanical ventilation could

be used to assess the volume status and cardiac preload

of critically ill 16 and cardiac surgery patients. 17 Our

early clinical experience of applying the FloTrac sensor/Vigileo

monitor system to patients with esophageal

cancer, also demonstrated that monitoring changes in

Ann. Surg. Oncol.


SVV accurately predicted the development of hypotension

in patients undergoing esophageal surgery.

In our series, the initial value of SVV on entering to

the ICU was15% in all cases, and

the occurrence rate of hypotension was statistically

significantly higher (P = 0.0012) in these patients

(Fig. 3). These data indicate that an increase in SVV

above 15% might usefully be used to predict the

development of hypotension and the need for additional

fluid during the early postoperative period,

even when traditional parameters (e.g., mean arterial

pressure, CVP, heart rate) may not highlight such

changes. In the literature concerning the accuracy of

SVV for estimating fluid responsiveness after cardiac

surgery, it has been reported that real-time monitoring

of SVV is a more sensitive and specific predictor

than CVP and other hemodynamic parameters. 18 Our

SVV-based data is the first pertaining to esophagectomy

patients and confirms that SVV also has excellent

predictive qualities in this group of patients

undergoing esophageal surgery. Comparing CVP and

SVV for their predictability in assessing fluid responsiveness

(Fig. 4) indicated that a decrease in SVV

values was significantly correlated to CO improvement

(r = 0.638, P = 0.049), but no such correlation

between CVP and CO value existed. CVP, which is a

commonly used parameter for the evaluation of

intravascular volume status, 11,17 demonstrated no

predictive value for cardiorespiratory instability during

the perioperative period after esophagectomy.

Although the usefulness of SVV is clearly demonstrated

in our data, the clinical use of this hemodynamic

parameter has certain limitations. First, this

monitoring method can only be used in mechanically

ventilated patients without arrhythmias. Moreover,

severe peripheral constriction and aortic regurgitation

may affect absolute values. Nevertheless, despite

these limitations, we suggest that the FloTrac sensor/

Vigileo monitor system provides marked advantages

over more traditional vital sign monitoring systems

alone in postoperative fluid resuscitation after

esophageal surgery. Because individual responses to

surgical stress from this form of surgery vary and are

difficult to predict, perioperative cardiorespiratory

instability is more unpredictable than after cardiac

surgery. 19 Even though relatively large amounts of

fluid were transfused during the surgical procedures

reported, postoperative hypotension resulting from

intravascular hypovolemia still occurred unexpectedly.

This is a predicament for the physician, who has

difficult decisions to make with regards fluid resuscitation.

Persistent hypotension can lead to serious

tissue hypoperfusion and organ distress, while

excessive fluid replacement may lead to congestive

heart failure and pulmonary edema during volume

resuscitation. To maintain low mortality rates in

esophagectomy, a safer and more exact fluid management

method is required.

On the basis of our experience to date, we conclude

that SVV, as displayed on the Vigileo monitor, is an

accurate predictor of intravascular hypovolemia and

is a useful indicator for assessing the appropriateness

and timing of applying fluid for improving circulatory

stability during the perioperative period after

esophagectomy. A larger, prospective trial is needed

to help ascertain the overall effectiveness of SVV/

Vigileo monitoring.


We thank Steve Clissold, PhD (Content Ed Net),

who provided assistance with English language and

whose work was funded by Edwards Lifesciences,



1. Ando N, Ozawa S, Kitagawa Y, et al. Improvement in the

results of surgical treatment of advanced squamous esophageal


carcinoma during 15 consecutive years. Ann Surg 2000;


2. Fujita H, Kakegawa T, Yamana H, et al. Mortality and

morbidity rates, postoperative course, quality of life, and

prognosis after extended radical lymphadenectomy for esophageal

cancer. Comparison of three-field lymphadenectomy with

two-field lymphadenectomy. Ann Surg 1995; 222:654–62.

3. Ishihara H, Nakamura H, Okawa H, et al. Comparison of

initial distribution volume of glucose and intrathoracic blood

volume during hemodynamically unstable states early after

esophagectomy. Chest 2005; 128:1713–9.

4. Imamura M, Shimada Y, Kanda T, et al. Hemodynamic

changes after resection of thoracic duct for en-bloc resection of

esophageal cancer. Surg Today 1992; 22:226–32.

5. Luketich JD, Alvelo-Rivera M, Buenaventura PO, et al.

Minimally invasive esophagectomy: outcomes in 222 patients.

Ann Surg 2003; 238:486–94.

6. Sayama J, Shineha R, Yokota K, et al. [Control of the excessive

reaction after surgery for esophageal carcinoma with

preoperative administration of the cortico-steriods]. Jpn J

Gasroenterol Surg 1994; 81:49–51.

7. Shimada H, Ochiai T, Okazumi S, et al. Clinical benefits of

steroid therapy on surgical stress in patients with esophageal

cancer. Surgery 2000; 128:791–8.

8. Kobayashi M, Harada O, Shimaya S, et al. [Experiences using

neutrophil elastase inhibitors perioperatively after radical

esophagectomy]. Shinyaku Rinsho 2004; 53:762–5.

9. Bartels H, Stein HJ, Siewert JR. Preoperative risk analysis and

postoperative mortality of oesophagectomy for resectable

oesophageal cancer. Br J Surg 1998; 85:840–4.

10. Reynolds JV, Ravi N, Hollywood D, et al. Neoadjuvant chemoradiation

may increase the risk of respiratory complications

and sepsis after transthoracic esophagectomy. J Thorac Cardiovasc

Surg 2006; 132:549–55.

11. Michard F, Teeboul JL. Predicting fluid responsiveness in ICU

patients: a critical analysis of the evidence. Chest 2002;


12. Manecke GR Jr, Auger WR. Cardiac output determination

from the arterial pressure wave: clinical testing of a novel

algorithm that does not require calibration. J Cardiothorac

Vasc Anesth 2007; 21:3–7.

13. Reuter DA, Felbinger TW, Schmidt C, et al. Stroke volume

variations for assessment of cardiac responsiveness to volume

loading in mechanically ventilated patients after cardiac surgery.

Intensive Care Med 2002; 28:392–8.

14. Suzuki A, Ishihara H, Okawa H, et al. Can initial distribution

volume of glucose predict hypovolemic hypotension after

radical surgery for esophageal cancer? Anesth Analg 2001;


15. Shippy CR, Appel PL, Shoemaker WL. Reliability of clinical

monitoring to assess blood volume in critically ill patients. Crit

Care Med 1984; 12:107–12.

16. Michard F. Changes in arterial pressure during mechanical

ventilation. Anesthesiology 2005; 103:419–28.

17. Hofer CK, Muller SM, Furrer L, et al. Stroke volume and

pulse pressure variation for prediction of fluid responsiveness

in patients undergoing off-pump coronary artery bypass

grafting. Chest 2005; 128:848–54.

18. Rex S, Brose S, Metzelder S, et al. Prediction of fluid responsiveness

in patients during cardiac surgery. Br J Anaesth 2004;


19. Tandon S, Batchelor A, Bullock R, et al. Peri-operative risk

factors for acute lung injury after elective oesophagectomy. Br

J Anaesth 2001; 86:633–8.

Ann. Surg. Oncol.

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