Clinical Outcomes of Low-Risk Patients Undergoing Beating-Heart Surgery With or Without Pulmonary Artery Catheterization

OBJECTIVE

For patients who undergo off-pump coronary artery bypass (OPCAB) surgery, pulmonary artery catheterization (PAC) has been proposed as a useful intraoperative monitoring tool. This study was designed to determine if the choice of PAC versus central venous pressure monitoring (CVP) had any effect on outcome after OPCAB. This study compared these 2 methods of hemodynamic monitoring in low-risk patients undergoing beating-heart surgery via a median sternotomy and evaluated their effect on morbidity and in-hospital mortality.

DESIGN

Retrospective database and medical record review.

SETTING

Tertiary care teaching hospital.

PARTICIPANTS

Low-risk patients who had coronary revascularization via a median sternotomy on the beating heart.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A population of 2,414 low-risk patients who had beating-heart coronary revascularization between January 2000 and December 2003 was reviewed. Most patients (1,671 or 69.2%) received a PAC, whereas 743 (30.8%) had CVP monitoring. Risk-adjusted logistic regression analyses were performed to investigate the effect of each technique on clinical outcomes. The groups were comparable in both baseline characteristics and Parsonett's mortality risk (1.5 +/- 0.9, p = 0.58). Univariate analysis failed to show a difference in operative mortality (p = 0.76), on-pump conversion rate for completion of aortocoronary bypasses (p = 0.82), postoperative low cardiac output (p = 0.10), or prolonged inotropic agent use (p = 0.22). Similarly, in the multivariate analysis, both groups had a similar rate of conversion to an on-pump procedure for completion of coronary artery grafting (p = 0.91), intraoperative intra-aortic balloon pump use (p = 0.69), low cardiac output state (p = 0.16), or in-hospital mortality (p = 0.51).

CONCLUSIONS

This single-institution, retrospective study suggests that in low-risk patients undergoing beating-heart surgery, CVP monitoring may be sufficient.

Clinical Outcomes in Patients Undergoing Elective Coronary Artery Bypass Graft Surgery With and Without Utilization of Pulmonary Artery Catheter–Generated Data

OBJECTIVE

The purpose of this study was to determine the frequency of pulmonary artery catheter (PAC) quantitative data requirements for modifying patient management during and after elective coronary artery bypass graft (CABG) surgery.

DESIGN

A prospective observational clinical trial.

SETTING

University tertiary referral center.

PARTICIPANTS

Two hundred patients undergoing elective CABG surgery.

INTERVENTIONS

Attending anesthesiologist and surgeon were blinded to PAC numeric values. These data could be revealed in the presence of at least 2 of the following criteria: (1) systolic blood pressure <90 mmHg, (2) central venous pressure >15 mmHg, (3) urine output <0.5 mL/kg/h, (4) pH <7.35/HCO(3) <18 mmol/L, (5) SaO(2) <95%/F(I)O(2) >80%, and (6) ST changes +/- 2 mm if the empiric treatment failed to restore normal hemodynamics within 10 minutes. All patients were classified into either blinded or unblinded PAC groups.

MEASUREMENTS AND MAIN RESULTS

PAC data were unblinded in 46 (23%) patients. Preliminary diagnosis was confirmed in 28 (14%), and treatment was modified in 18 (9%) of these patients. Four (2%) patients were given additional fluid challenges, 10 (5%) patients received a combination of fluid challenges and inotropic support, 3 (1.5%) patients were started on vasoconstrictors, and 1 (0.5%) patient required insertion of an intra-aortic balloon pump. Patients in the unblinded PAC group had a higher prevalence of perioperative myocardial infarction, atrial fibrillation, and inotropic support; longer intubation times; and increased intensive care unit (ICU) and hospital lengths of stay.

CONCLUSIONS

This study confirmed the contention that insertion of a PAC can be safely delayed until the clinical need arises either in the operating room or in the ICU after elective CABG surgery.

Fluid challenge revisited

OBJECTIVE

To discuss the rationale, technique, and clinical application of the fluid challenge.

DATA SOURCE

Relevant literature from MEDLINE and authors' personal databases.

STUDY SELECTION

Studies on fluid challenge in the acutely ill.

DATA EXTRACTION

Based largely on clinical experience and assessment of the relevant published literature, we propose that the protocol should include four variables, namely 1) the type of fluid administered, 2) the rate of fluid administration, 3) the critical end points, and 4) the safety limits.

CONCLUSIONS

A protocol for routine fluid challenge is proposed with defined rules and based on the patient's response to the volumes infused. The technique allows for prompt correction of fluid deficits yet minimizes the risks of fluid overload.

LEARNING OBJECTIVES

On completion of this article, the reader should be able to: 1. Explain the signs of hypovolemia. 2. Describe how to administer a fluid challenge. 3. Use this information in a clinical setting.

[Effects of backrest position on central venous pressure and intracranial pressure in brain surgery patients]

PURPOSE

This study was done to investigate the effects of backrest elevation of 0 degree and 30 degrees that minimize the risk of increasing ICP when CVP is measured.

METHODS

Subjects were sixty-four patients who stayed in the neurosurgical intensive care unit after brain surgery at two university-based hospitals. CVP, blood pressure, heart rate and ICP were measured along with position changes in order of backrest position with primary 30 degrees backrest position, 0 degree backrest position and secondary 30 degrees backrest position. For data analysis, one-group, repeated-measures analysis of variance design was used in SAS program.

RESULTS

Backrest elevations from 0 degree to 30 degrees did not alter the CVP without increasing the ICP. Therefore, 30 degrees backrest position is a preventive position without increasing ICP.

CONCLUSION

30 degrees backrest position might be appropriate for brain injury patients when CVP is measured.

Outcome after anaesthesia and emergency surgery in patients over 100 years old

BACKGROUND

Deteriorated organ function and reduced stress response in very old patients may cause post-operative morbidity and mortality. We wanted to identify immediate and longer-term outcome after anaesthesia and surgery in the oldest of the old patients.

METHODS

We analysed retrospectively anaesthesia and hospital records of patients who were over 100 years old when undergoing major emergency surgery in our hospital during 1990-2004.

RESULTS

Altogether, 12 patients (median age 101 years) underwent 14 operations (nine for hip fracture, four for lower extremity circulatory problems and one for peritonitis). During anaesthesia, invasive arterial pressure was monitored in eight patients while central venous pressure (CVP) was monitored in only one patient. Spinal anaesthesia with bupivacaine was given as a continuous technique in six and as single-shot spinal anaesthesia in five cases. Both spinal (11) and general (3) anaesthesias were characterized by marked drops in arterial pressure. Haemodynamics was managed with intravenous (i.v.) fluids and vasopressors. Five patients had post-operative delirium. Mortality at 30 days, 6 months and 1 year was 25%, 42% and 50%, respectively. Within 15 days of the operation, three patients had died (pneumonia, cerebral infarction and myocardial infarction). Nine patients returned home and six of them lived in their pre-operative mental and physical state for at least a year.

CONCLUSION

Independently of the anaesthetic method, marked drops in blood pressure occurred, requiring pharmacological intervention. We assume that in most of the patients, hypovolaemia explains the intra-operative haemodynamic instability. A 25%, 30-day mortality may be regarded as acceptable and, overall, these very old patients tolerated emergency surgery quite well.

Spinal fluid dynamics during thoracic- and thoracoabdominal aortic surgery

AIM

The intention was to investigate cerebrospinal fluid pressure (CSFP) and volume of cerebrospinal fluid (CSF) drained during and after thoracic- and thoracoabdominal aneurysm repair. The findings were related to the occurrence of postoperative neurologic deficits.

METHODS

Twenty-nine patients (12 with thoracic and 17 with thoracoabdominal aortic aneurysm) were operated without shunting or extracorporeal circulation. For monitoring of CSFP an intrathecal catheter was placed in all patients. The volume of CSF withdrawn intraoperatively, on the day of operation as well as on the 1st and 2nd postoperative day was recorded.

RESULTS

Twenty-six patients had no postoperative neurologic sequelae. One patient had postoperative paraplegia while 2 had paraparesis. The three patients with neurologic sequelae had higher CSFP intraoperatively than those without neurologic symptoms (P=0.04). Median CSFP during aortic cross-clamping was 19 mmHg and 10 mmHg and the median volumes of CSF drained on the day of operation 210 and 85 mL in the two groups, respectively. There was a significant positive correlation between CSFP and central venous pressure.

CONCLUSIONS

A higher intraoperative CSFP was observed in patients with neurologic sequelae following thoracic- and thoracoabdominal aneurysm repair. Further, there was a tendency of higher volumes of CSF drained in this group of patients. Although, the series is too small to allow firm conclusions, it supports the view that CSFP monitoring and drainage is beneficial during thoracic- and thoracoabdominal aneurysm repair.

Translating Research to Clinical Practice

OBJECTIVE

Early goal-directed therapy (EGDT) has been shown to decrease mortality in patients with severe sepsis and septic shock. Consensus guidelines now advocate EGDT for the first 6 h of sepsis resuscitation. However, EGDT has not yet been widely adopted in practice. A need for effective collaboration between emergency medicine and critical care medicine services has been identified as an obstacle for implementation. We aimed to determine if EGDT end points could reliably be achieved in real-world clinical practice.

METHODS

EGDT was implemented as a collaborative emergency medicine/critical care quality improvement initiative. EGDT included the following: i.v. fluids (IVF) targeting central venous pressure > or = 8 mm Hg, vasopressors targeting mean arterial pressure > or = 65 mm Hg, and (if necessary) packed RBCs (PRBCs) and/or dobutamine targeting central venous oxygen saturation > or = 70%. A retrospective analysis was performed of emergency department (ED) patients with persistent sepsis-induced hypotension (systolic BP < 90 mm Hg despite 1.5 L of IVF) treated with EGDT during the first year of the initiative. Primary outcome measures included successful achievement of EGDT end points and time to achievement. A secondary analysis was performed comparing EGDT cases to historical control cases (nonprotocolized control subjects without invasive monitoring).

RESULTS

All end points were achieved in 20 of 22 cases (91%). The median time to reach each end point was < or = 6 h. In the secondary analysis, patients (n = 38; EGDT, n = 22; pre-EGDT, n = 16) had similar age, do-not-resuscitate status, severity scores, hypotension duration, and vasopressor requirement (p = not significant). In the ED, EGDT used more IVF and included PRBC/dobutamine utilization, without any impact on the overall use of these therapies through the first 24 h in the ICU. EGDT was associated with decreased ICU pulmonary artery catheter (PAC) utilization (9.1% vs 43.7%, p = 0.01).

CONCLUSIONS

With effective emergency medicine/critical care collaboration, we demonstrate that EGDT end points can reliably be achieved in real-world sepsis resuscitation. ED-based EGDT appears to decrease ICU PAC utilization.

Effect of low central venous pressure and phlebotomy on blood product transfusion requirements during liver transplantations

Correction of coagulation defects with plasma transfusion did not decrease the need for intraoperative red blood cells (RBC) transfusions during liver transplantations. On the contrary, it led to a hypervolemic state that resulted in an increase of shed blood. As well, plasma transfusion has been associated with a decreased one-year survival rate. The aim of the present prospective survey was to evaluate whether anesthesiologists could reduce intraoperative RBC transfusions during liver transplantations by changing their anesthesia practice, more specifically by maintaining a low central venous pressure (CVP), through restriction of volume replacement, elimination of all plasma transfusion and by using intraoperative phlebotomy during the transplantation. One hundred consecutive liver transplantations were prospectively studied during a two-year period and were compared to a retrospective series (1998-2002). A low CVP was maintained in all patients prior the anhepatic phase. Coagulation disorders were not corrected preoperatively, intraoperatively, or post-operatively unless uncontrollable bleeding. Phlebotomy and Cell Saver (CS) were used following pre-established criteria. Independent variables were analyzed in a univariate and multivariate fashion. The mean number of intraoperative RBC units transfused was 0.4 +/- 0.8. No plasma, platelets, albumin, or cryoprecipitate were transfused. Seventy-nine percent of the patients received no blood products during their liver transplantation. The average final hemoglobin value was 85.9 +/- 17.8 g/L. In 57 patients (58.2%), intraoperative phlebotomy and CS were used either together or separately. The one-year year survival rate was 89.1%. Logistic regression showed that avoidance of plasma transfusion, starting hemoglobin value and phlebotomy were significantly linked to liver transplantation without RBC transfusion. In conclusion, the avoidance of plasma transfusion and maintenance of a low CVP prior to the anhepatic phase were associated with a decrease in RBC transfusions during liver transplantations. Previous reports indicating that it is neither useful nor necessary to correct coagulation defects with plasma transfusion prior to liver transplantation are further corroborated by this prospective survey. We believe that this work also supports the practice of lowering CVP with phlebotomy in order to reduce blood loss, during liver dissection, without any deleterious effect.

Normovolaemia defined by central blood volume and venous oxygen saturation

1. The intravenous administration of fluid and blood has to balance the danger of unexpected death in response to a reduction of central blood volume (CBV) against that of developing pulmonary and/or peripheral oedema. 2. The initial cardiovascular response to haemorrhage is similar to that developed in response to standing. In the upright position, adults are subjected to a reduction of CBV of approximately 0.5 L and can therefore tolerate a blood loss of approximately 1 L when supine. 3. However, volume administration directed by cardiovascular variables is seldom precise, even with integration of the bradycardia and hypotension developed when CBV decreases by approximately 30%. Immediate intervention is needed because such a reduction in CBV raises the lower limit of cerebral autoregulation to approximately 80 mmHg compared with the commonly considered value of approximately 60 mmHg with an associated risk of developing brain ischaemia and irreversible shock. 4. Alternatively, the volume load can be monitored both directly and accurately by means of thoracic electrical admittance. A functional definition of normovolaemia may be the filling of the heart that ensures cardiac output and oxygen delivery. From that perspective, supine humans are normovolaemic in that a maximal venous oxygen saturation (Svo2) is established. 5. Conversely, Svo2 decreases in the upright position and, with a blood loss of approximately 100 mL, Svo2 is reduced by 1%. It is suggested that, in supine humans and guided by Svo2, normovolaemia may be established to an accuracy of approximately 100 mL and that its adequacy is controlled by recording cerebral oxygenation.

Accuracy of central venous pressure monitoring during simultaneous continuous infusion through the same catheter

Continuous central pressure monitoring and simultaneous continuous infusion via the same central venous catheter are sometimes necessary. Based on theoretical calculations and experimental measurements, we have determined that pressure monitoring is essentially unaffected if the continuous infusion rate is 50 ml.h(-1) or less for an adult and a paediatric central catheter. At rates > 200 ml.h(-1), the central venous pressure is exaggerated by up to 4 mmHg and 8 mmHg for the adult and paediatric catheters, respectively.

Intraoperative oesophageal Doppler guided fluid management shortens postoperative hospital stay after major bowel surgery

BACKGROUND

Occult hypovolaemia is a key factor in the aetiology of postoperative morbidity and may not be detected by routine heart rate and arterial pressure measurements. Intraoperative gut hypoperfusion during major surgery is associated with increased morbidity and postoperative hospital stay. We assessed whether using intraoperative oesophageal Doppler guided fluid management to minimize hypovolaemia would reduce postoperative hospital stay and the time before return of gut function after colorectal surgery.

METHODS

This single centre, blinded, prospective controlled trial randomized 128 consecutive consenting patients undergoing colorectal resection to oesophageal Doppler guided or central venous pressure (CVP)-based (conventional) intraoperative fluid management. The intervention group patients followed a dynamic oesophageal Doppler guided fluid protocol whereas control patients were managed using routine cardiovascular monitoring aiming for a CVP between 12 and 15 mm Hg.

RESULTS

The median postoperative stay in the Doppler guided fluid group was 10 vs 11.5 days in the control group P<0.05. The median time to resuming full diet in the Doppler guided fluid group was 6 vs 7 for controls P<0.001. Doppler patients achieved significantly higher cardiac output, stroke volume, and oxygen delivery. Twenty-nine (45.3%) control patients suffered gastrointestinal morbidity compared with nine (14.1%) in the Doppler guided fluid group P<0.001, overall morbidity was also significantly higher in the control group P=0.05.

CONCLUSIONS

Intraoperative oesophageal Doppler guided fluid management was associated with a 1.5-day median reduction in postoperative hospital stay. Patients recovered gut function significantly faster and suffered significantly less gastrointestinal and overall morbidity.

Effect of catheter site on the agreement of peripheral and central venous pressure measurements in neurosurgical patients

STUDY OBJECTIVE

Previous studies suggest a correlation of central venous pressure (CVP) with peripheral venous pressure (PVP) in different clinical setups. The aim of this study was to investigate the effect of measurement site on PVP and its agreement with CVP in patients undergoing general anesthesia.

DESIGN

Prospective randomized study.

SETTINGS

University hospital.

PATIENTS

Thirty patients of American Society of Anesthesiologists physical status I and II undergoing elective craniotomy.

INTERVENTIONS

Patients were randomly assigned into Group A (antecubital; n=15) and Group D (dorsum hand; n=15) for antecubital and hand dorsum catheterization sites, respectively. Central venous pressure and PVP were monitored throughout the study. A total of 1925 simultaneous measurements were recorded at 5-minute intervals. Bland-Altman assessment for agreement was used for CVP and PVP in 2 groups.

MEASUREMENTS

Peripheral venous pressure measurements were within the range of +/-2 mm Hg of CVP values, in 93.9% of the measurements in Group A, and in 91.2% of the measurements in Group D. Considering all measurements, mean bias was -0.072 mm Hg (95% CI, -0.134 to -0.010). Group A measurements showed a bias (CVP-PVP) of 0.173+/-3.557 mm Hg, whereas the bias was -0.122+/-4.322 mm Hg (mean+/-SDcorrected for repeated measurements) in Group D. All of the measurements were within mean+/-2SD of bias, which means that PVP and CVP are interchangeable in our clinical setting.

CONCLUSION

Peripheral venous pressure measurement may be a noninvasive alternative for estimating CVP in patients undergoing elective neurosurgical operations. Measuring PVP from hand dorsum does not interfere with the agreement of CVP and PVP.

Effect of autologous blood donation on the central venous pressure, blood loss and blood transfusion during living donor left hepatectomy

AIM: Autologous blood donation (ABD) is mainly used to reduce the use of banked blood. In fact, ABD can be regarded as acute blood loss. Would ABD 2-3 d before operation affect the CVP level and subsequently result in less blood loss during liver resection was to be determined.

METHODS: Eighty-four patients undergoing living donor left hepatectomy were retrospectively divided as group I (GI) and group II (GII) according to have donated 250-300 mL blood 2-3 d before living donor hepatectomy or not. The changes of the intraoperative CVP, surgical blood loss, blood products used and the changes of perioperative hemoglobin (Hb) between groups were analyzed and compared by using Mann-Whitney U test.

RESULTS: The results show that the intraoperative CVP changes between GI (n = 35) and GII (n = 49) up to graft procurement were the same, subsequently the blood loss, but ABD resulted in significantly lower perioperative Hb levels in GI.

CONCLUSION: Since none of the patients required any blood products perioperatively, all the predonated bloods were discarded after the patients were discharged from the hospital. It indicates that ABD in current series had no any beneficial effects, in term of cost, lowering the CVP, blood loss and reduce the use of banked blood products, but resulted in significant lower Hb in perioperative period.

Unusual positioning of a central venous catheter

Central venous cannulation, with or without a flow-directed pulmonary artery catheter, is commonly performed in patients undergoing cardiac surgery to measure central filling pressure and cardiac output, and to administer medications and fluids. The complications of central venous cannulation are numerous and include malposition, arterial puncture, pneumothorax, hemothorax, chylothorax, extravasation of infusate, thrombophlebitis, and infection. We describe a single-lumen catheter that was placed through the hemostatic valve of a 9F percutaneous introducer, which inadvertently entered the left internal mammary (internal thoracic) vein. The current case is unique in that it was diagnosed by visualization of the catheter during surgical dissection.

Low central venous pressure anesthesia in major hepatic resection

Blood loss and transfusion requirements are major determinants of morbidity and mortality following liver resection. This study evaluates the association of low central venous pressure [LCVP] with blood loss and blood transfusion during liver resection. Thirty consecutive hepatic resections were studied prospectively concerning CVP, volume of blood loss and volume of blood transfusion and renal outcome. Data were analyzed for those with a CVP < or = 5 mmHg, and > 5 mmHg. A multivariate analysis assessed potential confounding factors in the comparison. The mean blood loss in patients with a CVP of 5 mmHg or less was < 500 ml and that in those with a CVP > 5 mmHg was > 2000 ml. (p <0.001). Only two patients with a CVP of < or = 5 mmHg had a blood transfusion whereas 11 patients with a CVP > 5 mmHg required transfusion. No incidences of air embolism or permanent renal shutdown have been reported. It is concluded that the volume of blood loss and blood transfusion during liver resection correlates with the CVP during parenchymal transection. Lowering the CVP to less than 5 mmHg is a simple and effective technique to reduce blood loss during liver resection and delete the need for blood transfusion with its hazards.

Effects of PEEP on the intracranial system of patients with head injury and subarachnoid hemorrhage: the role of respiratory system compliance

BACKGROUND

Positive end-expiratory pressure (PEEP) can be effective in improving oxygenation, but it may worsen or induce intracranial hypertension. The authors hypothesized that the intracranial effects of PEEP could be related to the changes in respiratory system compliance (Crs).

METHODS

A prospective study investigated 21 comatose patients with severe head injury or subarachnoid hemorrhage receiving intracranial pressure (ICP) monitoring who required mechanical ventilation and PEEP. The 13 patients with normal Crs were analyzed as group A and the 8 patients with low Crs as group B. During the study, 0, 5, 8, and 12 cm H2O of PEEP were applied in a random sequence. Jugular pressure, central venous pressure (CVP), cerebral perfusion pressure (CPP), intracranial pressure (ICP), cerebral compliance, mean velocity of the middle cerebral arteries, and jugular oxygen saturation were evaluated simultaneously.

RESULTS

In the group A patients, the PEEP increase from 0 to 12 cm H2O significantly increased CVP (from 10.6 +/- 3.3 to 13.8 +/- 3.3 mm Hg; p < 0.001) and jugular pressure (from 16.6 +/- 3.1 to 18.8 +/- 3.2 mm Hg; p < 0.001), but reduced mean arterial pressure (from 96.3 +/- 6.7 to 91.3 +/- 6.5 mm Hg; p < 0.01), CPP (from 82.2 +/- 6.9 to 77.0 +/- 6.2 mm Hg; p < 0.01), and mean velocity of the middle cerebral arteries (from 73.1 +/- 27.9 to 67.4 +/- 27.1 cm/sec; F = 7.15; p < 0.001). No significant variation in these parameters was observed in group B patients. After the PEEP increase, ICP and cerebral compliance did not change in either group. Although jugular oxygen saturation decreased slightly, it in no case dropped below 50%.

CONCLUSIONS

In patients with low Crs, PEEP has no significant effect on cerebral and systemic hemodynamics. Monitoring of Crs may be useful for avoiding deleterious effects of PEEP on the intracranial system of patients with normal Crs.

Effects of volumetric vs. pressure-guided fluid therapy on postoperative inflammatory response: a prospective, randomized clinical trial

OBJECTIVE

To compare intrathoracic blood volume (ITBV) guided fluid management and central venous pressure (CVP) guided therapy in ameliorating the progression of early systemic inflammatory response in patients undergoing major surgery.

DESIGN

Prospective, randomized clinical trial.

PATIENTS

Forty patients undergoing major abdominal surgery were randomized into CVP and ITBV groups.

INTERVENTIONS

In the CVP group the target CVP was 8-12 mmHg while in the ITBV group the goal was to keep the ITBV between 850 and 950 ml/m2 during the operation.

MEASUREMENTS AND RESULTS

Hemodynamic parameters were determined by single arterial thermodilution. Measurements were repeated every 30 min intraoperatively. Serum procalcitonin (PCT) and C-reactive protein (CRP) was monitored preoperatively, on ICU admission, and then daily for 3 days. Serum TNF-alpha levels were measured intraoperatively hourly and then daily for 3 days. There was no significant difference between the two groups regarding hemodynamic parameters at any assessment point. In the overall population changes in the stroke volume index showed a significant correlation with changes in CVP and ITBV. TNF-alpha levels remained in the normal range intraoperatively and during the three postoperative days in both groups. Preoperatively normal PCT and CRP levels increased significantly postoperatively, without significant differences between the groups.

CONCLUSIONS

ITBV guided fluid therapy did not alter the magnitude of inflammatory response as monitored by serum PCT, CRP, and TNF-alpha in the early postoperative period.

Esophageal varices without portosystemic venous pressure gradient in a patient with post-pericardiotomy constrictive pericarditis: a case report

A 51-year-old woman was admitted with intractable congestive heart failure and progressive anemia. She had undergone mitral valve replacement for mitral regurgitation at age 23 years. Subsequently, her mitral prosthesis was replaced twice due to thrombotic stack and valve insufficiency. Signs of congestive heart failure became evident at age 46 years. Gastrointestinal endoscopy revealed esophageal varices, which were treated by endoscopic variceal ligation. Cardiac catheterization disclosed elevated pulmonary capillary wedge pressure (mean 16 mmHg), right atrial pressure (mean 15 mmHg), and hepatic vein wedge pressure (mean 15 mmHg). She died at age 53 years. Autopsy showed severe congestive liver but not liver cirrhosis. Esophageal varices may progress in spite of the absence of porto-systemic pressure gradient in patients with severely high venous pressure.

[Cardiovascular effects of human atrial natriuretic peptide during renal transplantation]

BACKGROUND

We evaluated the cardiovascular effects of human atrial natriuretic peptide (hANP) in the recipients of renal transplantation.

METHODS

Anesthesia was maintained by inhalation of nitrous-oxide and isoflurane in oxygen, with epidural block. The recipients were divided into three groups; one group received no hANP infusion as control and the other groups received continuous infusion of hANP at the rate of either 0.05 microg x kg(-1) x min(-1) or 0.1 microg x kg(-1) x min(-1). Intravenous infusion of hANP was started at the anastomosis of renal artery after the fresh frozen plasma was loaded to achieve PCWP over 17 mmHg. In each group, we examined cardiovascular changes by using a pulmonary artery catheter and transesophageal echocardiography. The measurements were done before and after 15 minutes of hANP infusion.

RESULTS

In comparison with control, the decreases in PCWP and CVP were significant in the 0.1 microg x kg(-1) x min(-1) group. An increase in CI and the reduction of CVP were significant in 0.05 microg x kg(-1) x min(-1) group, when compared with control group. In the 0.1 microg x kg(-1) x min(-1) group, the reductions of PCWP and CVP and MAP were significant, but the significant increase in CI was characteristic in the 0.05 microg x kg(-1) x min(-1) group.

CONCLUSIONS

We conclude that the low-dose infusion of hANP in the recipients of renal transplantation is useful for the optimal anesthetic care because of the cardiovascular improvement.

Amelioration of hemodynamics and oxygen metabolism by continuous venovenous hemofiltration in experimental porcine pancreatitis

AIM: To investigate the potential role of continuous venovenous hemofiltration (CVVH) in hemodynamics and oxygen metabolism in pigs with severe acute pancreatitis (SAP).

METHODS: SAP model was produced by intraductal injection of sodium taurocholate [4%, 1 mL/kg body weight (BW)] and trypsin (2 U/kg BW). Animals were allocated either to untreated controls as group 1 or to one of two treatment groups as group 2 receiving a low-volume CVVH [20 mL/(kg.h)], and group 3 receiving a high-volume CVVH [100 (mL/kg.h)]. Swan-Ganz catheter was inserted during the operation. Heart rate, arterial blood pressure, cardiac output, mean pulmonary arterial pressure, pulmonary arterial wedge pressure, central venous pressure, systemic vascular resistance, oxygen delivery, oxygen consumption, oxygen extraction ratio, as well as survival of pigs were evaluated in the study.

RESULTS: Survival time was significantly prolonged by low-volume and high-volume CVVHs, which was more pronounced in the latter. High-volume CVVH was significantly superior compared with less intensive treatment modalities (low-volume CVVH) in systemic inflammatory reaction protection. The major hemodynamic finding was that pancreatitis-induced hypotension was significantly attenuated by intensive CVVH (87.4±12.5 kPa vs 116.3±7.8 kPa, P<0.01). The development of hyperdynamic circulatory failure was simultaneously attenuated, as reflected by a limited increase in cardiac output, an attenuated decrease in systemic vascular resistance and an elevation in oxygen extraction ratio.

CONCLUSION: CVVH blunts the pancreatitis-induced cardiovascular response and increases tissue oxygen extraction. The high-volume CVVH is distinctly superior in preventing sepsis-related hemodynamic impairment.

Highly selective inhibition of inducible nitric oxide synthase ameliorates experimental acute pancreatitis

OBJECTIVES

Inducible nitric oxide synthase (iNOS) activity is increased in experimental acute pancreatitis. The aim of this study was to evaluate treatment with the selective iNOS inhibitors AR-C (AR-C102222AA) and L-NIL (L-N6-(1-iminoethyl)-lysine) in experimental acute pancreatitis.

METHODS

Acute pancreatitis was induced in anesthetized Australian possums by topical administration of carbachol on the sphincter of Oddi. AR-C treatment was 2 intravenous infusions (2.5 micromol/kg over 15 minutes) at 2 and 4 hours after acute pancreatitis induction. L-NIL treatment was an intraarterial infusion (1 mg/kg/h) from 2 hours after acute pancreatitis induction. At 8 hours, pancreatic tissue was harvested and inflammation assessed (histologic score). Blood samples were collected for plasma amylase, lipase, and amino acid levels. Blood pressure, central venous pressure, supplementary fluids, and urine output were monitored.

RESULTS

Treatment with AR-C or L-NIL reduced the plasma levels of amylase and the volume of supplementary fluids and improved the histological score (all P < 0.05). In animals with acute pancreatitis, plasma arginine levels were reduced (P < 0.05), while citrulline and ornithine levels increased (P < 0.05), consistent with increased nitric oxide production. Treatment with AR-C ameliorated the reduced arginine level.

CONCLUSIONS

Treatment with AR-C or L-NIL, commencing 2 hours after the induction of acute pancreatitis, has significant and beneficial effects in experimental acute pancreatitis in Australian possums.

Relationship between fluid status and its management on acute renal failure (ARF) in intensive care unit (ICU) patients with sepsis: a prospective analysis

BACKGROUND

Sepsis carries a high morbidity and mortality, further enhanced by acute renal failure (ARF). Although fluid loading can prevent ARF in dehydrated patients, this approach could be risky in septic patients, since it can deteriorate oxygenation. This study evaluates the relationship between fluid status and management and ARF development in septic patients.

METHODS AND PATIENTS

Patients admitted to the ICU between 1 January 2001 and 31 December 2001 were included if serum creatinine (Cr) was <2 mg% on admission, and if they developed sepsis. ARF was determined as a doubling of serum Cr, an increase of serum Cr >2 mg%, or oliguria <500 ml/24 hr.

RESULTS

257 out of 2442 patients, admitted to the intensive care unit (ICU), developed sepsis, 29 developed ARF, 13 needed a renal replacement. ARF vs. non-ARF patients were older (65.2 +/- 13.3 vs. 55.1 +/- 17.4, p=0.002), had a higher central venous pressure (CVP) at day 1 (9.6 +/- 4.3 vs. 5.2 +/- 3.6 mmHg, p<0.001), and at day 2 (7.1 +/- 5.1 vs. 5.1 +/- 4.0 mmHg, p=0.03), a higher colloid fluid loading for the first 3 days (2037 +/- 1681 vs. 1116 +/- 1220 mL, p<0.03), a higher serum Cr (1.25 +/- 0.39 vs. 0.96 +/- 0.33 mg/dL, p=0.009) and an increase vs. a decrease in serum Cr during the first 24 hr (+0.30 +/- 0.58 vs. -0.31 +/- 0.45 mg/dL, p=0.02), a lower diuresis (1347 +/- 649 vs. 1849 +/- 916 mL, p=0.005). There was no difference in APACHE II scores (19.2 +/- 7.2 vs. 17.2 +/- 6.6, p=0.1), or MAP (64.5 +/- 12.4 vs. 67.9 +/- 12.4, p=0.18). The fraction of inspired oxygen (FiO2) need in the ARF group increased from 40.4 +/- 11.5 to 65.6 +/- 24.2% from day 1 to day 2 (p=0.04), where it remained unchanged in the non-ARF group. The use of diuretics was higher in the ARF group (21/29 vs. 43/228, p=0.001).

CONCLUSION

Septic patients developing ARF have an elevated CVP at day 1 of sepsis, indicating cardiodepression or intrarenal causes for hypoperfusion. These patients develop ARF despite further fluid loading. Respiratory function deteriorated in patients with ARF. Persistent fluid challenges should be avoided if they do not lead to an improvement in renal function, or if oxygenation deteriorates.

Early goal-directed therapy: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for early goal-directed therapy that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

During the first 6 hrs of resuscitation of sepsis-induced hypoperfusion, specific levels of central venous pressure, mean arterial pressure, urine output, central venous (or mixed venous) oxygen saturation should be targeted. When central venous oxygen saturation remains low, despite achieving central venous pressure and mean arterial pressure targets, packed red blood cells or dobutamine should be considered. Increasing cardiac index to achieve an arbitrarily predefined elevated level is not recommended.

Hepatic response to right ventricular pressure overload

BACKGROUND & AIMS

Modifying the afferent blood supply to the liver does not change the zonal expression pattern of hepatic enzymes in the rat.

METHODS

We used pulmonary trunk banding (PTB) to study the effect of an efferent hindrance of blood flow on hepatic architecture and zonation of gene expression.

RESULTS

Most PTB rats developed right ventricular hypertrophy and congestive heart failure. The hepatic response to PTB developed concomitantly with the decline in heart function. Enzyme expression in the periportal region was not affected, but the pericentral rim of hepatocytes expressing glutamine synthetase, ornithine aminotransferase, and NADPH cytochrome P-450 reductase (CYPred) first declined in diameter, then became discontinuous, and finally disappeared. Meanwhile, ornithine aminotransferase and especially CYPred, became re-expressed in the periportal zone. These changes occurred without appreciable cell death or fibrotic changes; the expression of fibronectin and alpha-smooth muscle actin increased perisinusoidally, but that of collagen did not. Electron microscopic analysis revealed normal fenestration of the sinusoidal endothelial cells without detectable deposition of basement membrane material, but both the width of the space of Disse and the length and number of hepatic microvilli were significantly reduced, implying a decreased flow of fluid in the space of Disse.

CONCLUSIONS

The reprogramming of gene expression in livers with a postsinusoidal hindrance of blood flow results from declining access of the hepatocytes to intrasinusoidal signal-transduction molecules and suggest that the impaired biotransformation that accompanies right ventricular failure is caused by a central-to-portal shift in expression of the corresponding enzymes.

Peripheral Venous Pressure as a Measure of Venous Compliance During Pheochromocytoma Resection

Venous pressures measured from peripheral venous catheters (PVP) closely estimate the central venous pressure (CVP) in surgical and critically ill patients. CVP is often used to estimate intravascular volume; however, fluctuations of CVP may also be induced by changes in venous tone caused by alpha-adrenergic catecholamine stimulation. We simultaneously monitored PVP, CVP, and mean arterial blood pressure during resection of pheochromocytoma in a 63-yr-old woman and found excellent correlation between the three pressure variables, suggesting that fluctuations of PVP reflect overall changes in vascular tone.

Rat corin gene: molecular cloning and reduced expression in experimental heart failure

Stored cardiac pro-atrial natriuretic peptide (pro-ANP) is converted to ANP and released upon stretch from the atria into the circulation. Corin is a serin protease with pro-ANP-converting properties and may be the rate-limiting enzyme in ANP release. This study was aimed to clone and sequence corin in the rat and to analyze corin mRNA expression in heart failure when ANP release upon stretch is blunted. Full-length cDNA of rat corin was obtained from atrial RNA by RT-PCR and sequenced. Tissue distribution as well as regulation of corin mRNA expression in the atria were determined by RT-PCR and RNase protection assay. Heart failure was induced by an infrarenal aortocaval shunt. Stretch was applied to the left atrium in a working heart modus, and ANP was measured in the perfusates. The sequence of rat corin cDNA was found to be 93.6% homologous to mouse corin cDNA. Corin mRNA was expressed almost exclusively in the heart with highest concentrations in both atria. The aortocaval shunt led to cardiac hypertrophy and heart failure. Stretch-induced ANP release was blunted in shunt animals (control 1,195 ± 197 fmol·min−1·g−1; shunt: 639 ± 99 fmol·min−1·g−1, P < 0.05). Corin mRNA expression was decreased in both atria in shunt animals [right atrium: control 0.638 ± 0.004 arbitrary units (AU), shunt 0.566 ± 0.014 AU, P < 0.001; left atrium: control 0.564 ± 0.009 AU, shunt 0.464 ± 0.009 AU, P < 0.001]. Downregulation of atrial corin mRNA expression may be a novel mechanism for the blunted ANP release in heart failure.

Primary Pulmonary Sporotrichosis: A Case Report

STUDY OBJECTIVES

To review the clinical experience with high-frequency oscillatory ventilation (HFOV) in three medical-surgical ICUs in Toronto, ON, Canada, and to describe patient characteristics, HFOV strategies, and outcomes.

DESIGN AND PATIENTS

Retrospective chart review of all patients treated with HFOV at three academic university-affiliated ICUs since 1998. The data extracted included patient demographics, etiology of respiratory failure, ventilator settings, and gas exchange and cardiovascular data from baseline to 72 h of treatment, as well as at the transition from HFOV to conventional ventilation (CV). Heart rate and BP were recorded at regular intervals in all patients, and hemodynamic data were recorded in 32 patients who had pulmonary artery catheters in place. Cointerventions and ICU mortality were also recorded.

MEASUREMENTS AND RESULTS

A total of 156 adults (67 women and 89 men; mean [+/- SD] age, 48 +/- 18 years; mean acute physiology and chronic health evaluation [APACHE] II score, 23.8 +/- 7.5) with severe ARDS (ie, mean Pao(2)/fraction of inspired oxygen [Fio(2)] ratio, 91 +/- 48 mm Hg; mean oxygenation index [OI], 31 +/- 14) who had received CV for a duration of 5.6 +/- 7.6 days underwent 171 trials of HFOV. HFOV was discontinued within 4 h in 19 patients (12%) because of difficulties with oxygenation, ventilation, or hemodynamics. Pao(2)/Fio(2) ratios and OI ([Fio(2) x mean airway pressure x 100]/Pao(2)) improved significantly with the application of HFOV, and this benefit persisted for the 72-h study duration. Significant changes in hemodynamics following HFOV initiation included an increase in central venous pressure and a reduction in cardiac output (throughout the 72 h), and an increase in pulmonary artery occlusion pressure (at 3 and 6 h). Patients were treated with HFOV for 5.1 +/- 6.3 days. The 30-day mortality rate was 61.7%. Pneumothorax occurred in 21.8% of patients, 43.6% of patients were treated with inhaled nitric oxide, and 37.2% of patients were treated with steroids. Independent predictors of mortality on multivariate analysis were older age, higher APACHE II score, lower pH at the initiation of HFOV, and a greater number of days receiving CV prior to HFOV.

CONCLUSIONS

HFOV has beneficial effects on Pao(2)/Fio(2) ratios and OI, and may be an effective rescue therapy for adults with severe oxygenation failure. The early institution of HFOV may be advantageous.

Relationship between peripheral and central venous pressures in different patient positions, catheter sizes, and insertion sites

OBJECTIVE

To investigate the relationship between peripheral and central venous pressures in different patient positions (supine, prone, lithotomy, Trendelenburg, and Fowler), different catheter diameters (18 G and 20 G), and catheterization sites (dorsal hand and forearm) during surgical procedures.

DESIGN

Prospective clinical study.

SETTINGS

University hospital.

PARTICIPANTS

Five hundred adult patients.

INTERVENTIONS

Peripheral over-the-needle intravenous catheters were placed in the dorsal hand or forearm. Central venous catheters were inserted via the internal jugular or subclavian vein after induction of anesthesia.

MEASUREMENTS AND MAIN RESULTS

Simultaneous measurements of central and peripheral venous pressures were made during stable conditions at random time points in surgery; 1953 paired measurements were performed. Mean central venous pressure was 11 +/- 3.7 mmHg and peripheral venous pressure was 13 +/- 4 mmHg (p = 0.0001). The overall correlation between central venous and peripheral venous pressures was found to be statistically significant (r = 0.89, r(2) = 0.8, p = 0.0001). Mean difference between peripheral and central venous pressure was 2 +/- 1.8 mmHg. Ninety-five percent limits of agreement were 5.6 to -1.6 mmHg.

CONCLUSION

It has been assumed that replacing central venous pressure by peripheral venous pressure would cause problems in clinical interpretation. If the validity of this data is confirmed by further studies, the authors suggest that central venous pressure could be estimated by using regression equations to compare the 2 methods.

Intraoperative fluid management during orthotopic liver transplantation

OBJECTIVE

To assess clinical safety of a low central venous pressure (CVP) fluid management strategy in patients undergoing liver transplantation.

DESIGN

Retrospective record review comparing 2 transplant centers, one using the low CVP method and the other using the normal CVP method.

SETTING

University-based, academic, tertiary care centers.

PARTICIPANTS

Patients undergoing orthotopic cadaveric liver transplantation.

INTERVENTIONS

Each center practiced according to its own standard of care. Center 1 maintained an intraoperative CVP <5 mmHg using fluid restriction, nitroglycerin, forced diuresis, and morphine. If pressors were required to maintain systolic arterial pressure >90 mmHg, phenylephrine or norepinephrine was used. At center 2, CVP was kept 7 to 10 mmHg and mean arterial pressure >75 mmHg with minimal use of vasoactive drugs.

MEASUREMENTS AND MAIN RESULTS

Data collected included United Network for Organ Sharing status, surgical technique, intraoperative transfusion rate, preoperative and peak postoperative creatinine, time spent in intensive care unit and hospital, incidence of death, and postoperative need for hemodialysis. Principal findings include an increased rate of transfusion in the normal CVP group but increased rates of postoperative renal failure (elevated creatinine and more frequent need for dialysis) and 30-day mortality in the low CVP group.

CONCLUSIONS

Despite success in lowering blood transfusion requirements in liver resection patients, a low CVP should be avoided in patients undergoing liver transplantation.

Multicenter USA Amplatzer Patent Ductus Arteriosus Occlusion Device Trial

OBJECTIVES

We sought to review and report initial and one-year efficacy and safety results of the multicenter USA Amplatzer ductal occluder (ADO) device trial.

BACKGROUND

Transcatheter closure of a moderate to large patent ductus arteriosus (PDA) using conventional techniques is challenging. The ADO can close a PDA up to 12 mm in diameter.

METHODS

From September 1999 to June 2002, 484 patients were enrolled in 25 U.S. centers. Forty-five (9%) of 484 patients did not have ADO implantation, because the PDA was too small or because of elevated pulmonary resistance. The median age of the patients at catheterization was 1.8 years (range 0.2 to 70.7 years), and weight was 11 kg (range 4.5 to 164.5 kg).

RESULTS

The median PDA minimal diameter was 2.6 mm (range 0.9 to 11.2 mm); 76 (17%) of 439 were larger than 4.0 mm. Median pulmonary artery mean pressure was 20 mm Hg (range 7 to 80 mm Hg). The ADO was implanted successfully in 435 (99%) of 439 patients, with a median fluoroscopy time of 7.1 min (range 2.9 to 138.4 min). Angiographic demonstration of occlusion was seen in 329 (76%) of 435. This increased to 384 (89%) of 433 on post-catheterization day 1, with occlusion documented in 359 (99.7%) of 360 at one year. At the last evaluation in all patients at any time, PDA closure was documented in 428 (98%) of 435 patients. There have been two cases of partial left pulmonary artery occlusion after ADO implantation and no cases of significant aortic obstruction.

CONCLUSIONS

Moderate to large PDAs can be effectively and safely closed using the ADO device, with excellent initial and one-year results. This device should obviate the need for multiple coils or surgical intervention for these defects.

Relevance of type of catheters for central venous pressure measurement

OBJECTIVE

To compare simultaneous central venous pressure measurements from rigid polyurethane and soft tunneled silicone elastomere catheters.

HYPOTHESIS

There will be no significant difference in central venous pressure readings between polyurethane and silastic catheters.

SETTING

Bone Marrow Transplant Unit in a tertiary care children's hospital.

PATIENTS

Five children undergoing bone marrow transplantation with preexisting polyurethane and silastic catheters.

METHODS

Simultaneous central venous pressure readings were obtained by 2 observers blinded to the other readings and to the type of catheter. Readings were done in triplicate (total of 690 readings). Each triplicate was averaged to 1 data point yielding 115 paired central venous pressure measurements.

RESULTS

No significant difference was demonstrated between polyurethane and silicone catheters (-1 +/- 3 cm H20). Using Bland and Altman method revealed no significant bias (mean = -1 cm H2O) and acceptable agreement between catheter types.

CONCLUSION

Silicone and polyurethane catheters yield similar values of central venous pressures. Permanently implanted silicone elastomere catheters can be used to measure central venous pressure in the emergency setting.

Superior vena caval collapsibility as a gauge of volume status in ventilated septic patients

OBJECTIVE

In mechanically ventilated patients inspiratory increase in pleural pressure during lung inflation may produce complete or partial collapse of the superior vena cava. Occurrence of this collapse suggests that at this time external pressure exerted by the thoracic cavity on the superior vena cava is greater than the venous pressure required to maintain the vessel fully open. We tested the hypothesis that measurement of superior vena caval collapsibility would reveal the need for volume expansion in a given septic patient.

DESIGN AND SETTING

Prospective data collection for 66 successive patients in septic shock admitted in a medical intensive care unit and mechanically ventilated for an associated acute lung injury.

MEASUREMENTS AND RESULTS

We simultaneously measured superior vena caval collapsibility by echocardiography and cardiac index by the Doppler technique at baseline and after a 10 ml/kg volume expansion by 6% hydroxyethyl starch in 30 min. The threshold superior vena caval collapsibility of 36%, calculated as (maximum diameter on expiration-minimum diameter on inspiration)/maximum diameter on expiration, allowed discrimination between responders (defined by an increase in cardiac index of at least 11% induced by volume expansion) and nonresponders, with a sensitivity of 90% and a specificity of 100%.

CONCLUSIONS

Superior vena cava measurement should be systematically performed during routine echocardiography in septic shock as it gives an accurate index of fluid responsiveness.

Heat stress modifies human baroreflex function independently of heat-induced hypovolemia

Since human thermoregulatory heat loss responses, cutaneous vasodilation and sweating, cause hypovolemia, they should resultantly stimulate human baroreflexes. However, it is possible that the thermoregulatory system directly interacts with the baroreflex system through central neural connections independently of the heat-induced hypovolemia. We hypothesized that heat stress modifies the baroreflex control of sympathetic nerve activity independently of heat-induced hypovolemia in humans. We made whole-body heating with tube-lined suits perfused with warm water (46-47 degrees C) on 10 healthy male subjects. The heating increased skin and tympanic temperatures by 10.0 and 0.4 degrees C, respectively. It increased resting total muscle sympathetic nerve activity (MSNA, microneurography) by 94 +/- 9% and decreased central venous pressure (CVP, dependent arm technique) by 2.6 +/- 0.9 mmHg. The heating increased arterial baroreflex gain by 193%, assessed as a response of MSNA to a decrease in diastolic arterial pressure during Valsalva's maneuver, but it did not change threshold arterial pressure for MSNA activation. Although the heating did not change the cardiopulmonary baroreflex gain assessed as a response of MSNA to a change in estimated central venous pressure (CVP) during a 10 degrees head-down and -up tilt test, it upwardly shifted the stimulus-response baroreflex relationship. These changes in baroreflex functions during heating were not restored by an intravenous infusion of warmed isotonic saline (37 degrees C, 15 ml/kg) that restored the heat-induced reduction of CVP. Our results support our hypothesis that heat stress modifies the baroreflex control of MSNA independently of heat-induced hypovolemia in humans. Our results also suggest that the hyperthermal modification of baroreflex results from central neural interaction between thermoregulatory and baroreflex systems.

Right ventricular end-diastolic volume monitoring after cardiac surgery

INTRODUCTION

In the postoperative management of cardiac surgery patients, pulmonary capillary wedge pressure (PCWP) and central venous pressure (CVP) are the most commonly used parameters of preload. However, these pressure parameters are easily affected by ventricular compliance, positive end-expiratory pressure and other factors. The aim of this study was to evaluate whether right ventricular end-diastolic volume index (RVEDVI) reflects cardiac output or ventricular preload in patients after cardiac surgery during postoperative management.

METHODS

We performed measurements in 31 patients postoperatively in the intensive care unit every 1 or 2 hours using a modified thermodilution catheter.

RESULTS

There were 999 measured hemodynamic data sets and the measurement duration was 47 +/- 21 hours (mean +/- SD). RVEDVI was 119 +/- 32 ml/m(2), cardiac index (CI) was 2.7 +/- 0.7 L/min/m(2), and PCWP was 11 +/- 4 mmHg. A significant correlation was found between RVEDVI, CVP and CI in 15 of 31 patients, and between PCWP and CI in 4 of 22 patients. In 33% of cases, CVP showed a negative correlation with CI, whereas 7% showed a negative correlation between RVEDVI and CI.

CONCLUSION

RVEDVI was a significant index during the postoperative management after cardiac surgery.

Effect of human albumin administration on clinical outcome and hospital cost in patients with subarachnoid hemorrhage

OBJECT

Human albumin is used to induce hypervolemia (central venous pressure [CVP] > 8 mm Hg) after subarachnoid hemorrhage (SAH). Unfortunately, human albumin may increase the mortality rate in critically ill patients; because of this, its use became restricted in the authors' hospital in May 1999. The goal of this study was to determine the effect of human albumin on outcome and cost in patients with SAH before and after this restriction was put into place.

METHODS

All patients with aneurysmal SAH who were admitted to the authors' institution between May 1998 and May 2000 were studied. Basic demographic information, dosage of human albumin given, length of stay, and the incidence of in-hospital deaths and complications were collected. The authors obtained Glasgow Outcome Scale (GOS) scores at 3 months after SAH (good outcome, GOS > or = 4). Data were analyzed using t-test and chi-square analysis. Logistic regression was used to identify independent associations between use of human albumin and outcome. The authors studied 140 patients: 63 who were admitted between May 1998 and May 1999 (Group 1) and 77 treated between June 1999 and May 2000 (Group 2). Two subgroups of patients were further analyzed. Group 1 patients who received human albumin (albumin subgroup, 37 patients) and Group 2 patients who would have received albumin under the old protocol (that is, those who failed to achieve CVP > 8 mm Hg after normal saline administration; nonalbumin subgroup, 47 patients). Patients in the nonalbumin subgroup were more likely to be male (38% compared with 16%), to experience hypertension (55% compared with 30%), to suffer from hypomagnesemia (49% compared with 5.4%), and to have hydrocephalus (47% compared with 27%). There was a trend for these patients to have more vasospasm (28% compared with 19%, p = 0.2). Patients in the albumin subgroup were more likely to have a good outcome at 3 months.

CONCLUSIONS

Administration of human albumin after SAH may improve clinical outcome and reduce hospital cost.

Passive regulation of cardiac output during exercise by the elastic characteristics of the peripheral circulation

A change in cardiac output induced by a change in cardiac performance is accompanied by opposite changes in cardiac filling pressure owing to the resistive and capacitive properties of blood vessels. The inverse relationship between cardiac output and cardiac filling pressure provides a passive (hydraulic) regulatory mechanism that functions to keep cardiac output constant during rest and exercise.

Changes in serum albumin concentration and volume expanding effects following a bolus of albumin 20% in septic patients

BACKGROUND

Patients with systemic sepsis develop a capillary leak syndrome, and serum -albumin concentration decreases. Hyperoncotic albumin infusion can be used for volume expansion in these patients, but the degree and duration of effect are not well described. We assessed volume expansion by albumin 20% infusion and compared the retention of infused albumin in septic patients and healthy controls.

METHODS

We gave albumin 20%, 200 ml as a rapid infusion to 70 patients with septic shock and 26 controls. Blood samples were taken before and 1, 5, 15, 30, 60, 120 and 240 min after the infusion for measurement of serum albumin concentration and haematocrit. Haemodilution and the percentage of administered albumin remaining intravascularly at each time were calculated.

RESULTS

The mean proportion of the increase in albumin remaining at 4 h was 68.5 (sd 10)% in septic patients and 79 (5)% in controls (P<0.001). The albumin 20%, 200 ml caused a secondary fluid resorption and volume expansion maximal at 30 min, equivalent to a 430 ml infusion in septic patients and 500 ml in controls.

CONCLUSIONS

After giving albumin, serum albumin concentrations decrease significantly faster in septic patients than in healthy controls.

Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients

OBJECTIVE

To evaluate the extent to which respiratory changes in inferior vena cava (IVC) diameter can be used to predict fluid responsiveness.

DESIGN

Prospective clinical study.

SETTING

Hospital intensive care unit.

PATIENTS

Twenty-three patients with acute circulatory failure related to sepsis and mechanically ventilated because of an acute lung injury.

MEASUREMENTS

Inferior vena cava diameter (D) at end-expiration (Dmin) and at end-inspiration (Dmax) was measured by echocardiography using a subcostal approach. The distensibility index of the IVC (dIVC) was calculated as the ratio of Dmax - Dmin / Dmin, and expressed as a percentage. The Doppler technique was applied in the pulmonary artery trunk to determine cardiac index (CI). Measurements were performed at baseline and after a 7 ml/kg volume expansion using a plasma expander. Patients were separated into responders (increase in CI > or =15%) and non-responders (increase in CI <15%).

RESULTS

Using a threshold dIVC of 18%, responders and non-responders were discriminated with 90% sensitivity and 90% specificity. A strong relation (r = 0.9) was observed between dIVC at baseline and the CI increase following blood volume expansion. Baseline central venous pressure did not accurately predict fluid responsiveness.

CONCLUSION

Our study suggests that respiratory change in IVC diameter is an accurate predictor of fluid responsiveness in septic patients.