The 'TEI-index' is preload dependent and can be measured by transoesophageal echocardiography during mechanical ventilation.

BACKGROUND AND OBJECTIVE: The Doppler-derived echocardiographic TEI-index, defined as the sum of the left ventricular isovolumic contraction and isovolumic relaxation times divided by ejection time, quantifies combined systolic and diastolic ventricular functions. The index has been proposed to be independent of arterial pressure and heart rate, implying a broad clinical usefulness. However, it is unclear whether the index is preload independent. We assessed whether and to what degree the TEI-index is altered by left ventricular loading conditions, and the feasibility of measurement by transoesophageal echocardiography during anaesthesia and mechanical ventilation. METHODS: We studied 17 anaesthetized mechanically ventilated patients with coronary artery disease during variations in left ventricular preload evoked by head-up and head-down tilt, respectively. RESULTS: A head-down tilt increasing left ventricular end-diastolic area from 18.8 +/- 4 to 23.7 +/- 4 cm2 (P < 0.05) significantly decreased the TEI-index from 0.5 +/- 0.17 to 0.33 +/- 0.15 (P < 0.05). In contrast, the TEI-index remained unchanged with decreased left ventricular preload (14.4 +/- 3.7 cm2) during head-up tilt. CONCLUSIONS: An increase in preload decreases the TEI-index indicating its sensitivity to acute increases in left ventricular preload. The TEI-index can be measured perioperatively by transoesophageal echocardiography.

[Circulatory mechanics in intra- and extraperitoneal CO2 insufflation in minimally invasive procedures. The effects of a low pressure system]. / Kreislaufmechanik bei intra- und extraperitonealen minimal invasiven Eingriffen unter CO2-Insufflation. Auswirkungen im Niederdrucksystem.

Several studies have addressed the cardiovascular effects of intraperitoneal carbon dioxide insufflation and increased intraabdominal pressure. The pathophysiology of this intervention is complex. Reported results apparently differ depending on which patients are studied and are affected by blood volume and/or positioning. With the Starling resistor concept of abdominal venous return in which, analogous to pulmonary vascular zones, flow through the inferior vena cava is considered a function of the pressure difference between upstream venous and either abdominal pressure or downstream intrathoracic caval vein pressure, different results reported in literature can be reconciled.

Posterior retroperitoneoscopic adrenalectomy: lessons learned within five years.

Posterior retroperitoneoscopic adrenalectomy is one of the new endoscopic methods in endocrine surgery. In a prospective clinical study 142 posterior retroperitoneoscopic adrenalectomies (72 right, 70 left) were performed in 130 patients (52 males, 78 females, age 49.1 +/- 14.9 years). Indications were primary adrenal tumors (unilateral, n = 118; bilateral, n = 2), adrenal metastases (n = 2), and bilateral ACTH-dependent hyperplasias (n = 10). Tumor size ranged from 0.5 to 7.0 cm (mean 2.7 +/- 1.4 cm). Partial adrenalectomies were performed in 39 patients. Conversion to open posterior adrenalectomy was necessary in five patients and seven procedures (5%). Intraoperative and postoperative complications were minor and occurred in 5% and 13%, respectively. Mortality was zero. Operating time was 101 +/- 39 minutes (range 35-285 minutes) and depended on tumor type (pheochromocytoma versus others; p < 0.01), tumor size (< 3 vs. > or = 3 cm; p < 0.05), gender (p < 0.05), and extent of resection (partial versus complete, p < 0.05. Twenty-three adrenalectomies (17%) were performed within 1 hour or less. Blood loss was 54 +/- 72 ml. Consumption of analgesics was low (mean 6 mg piritramide postoperatively). Median duration of hospitalization was 3 days. Posterior retroperitoneoscopic adrenalectomy is a safe method that has become a standard procedure in endocrine surgery.

Intraperitoneal and retroperitoneal carbon dioxide insufflation evoke different effects on caval vein pressure gradients in humans: evidence for the starling resistor concept of abdominal venous return.

BACKGROUND: The authors hypothesized that intraperitoneal and retroperitoneal carbon dioxide insufflation during surgical procedures evoke markedly different effects on the venous low-pressure system, induce different inferior caval vein pressure gradients at similar insufflation pressures, and may provide evidence for the Starling resistor concept of abdominal venous return. METHODS: Intra- and extrathoracic caval vein pressures were measured using micromanometers during carbon dioxide insufflation at six cavity pressures (baseline and 10, 15, 20, and 24 mmHg and desufflation) in 20 anesthetized patients undergoing laparoscopic (supine, n = 8) or left (n = 6) or right (n = 6) retroperitoneoscopic (prone position) surgery. Intracavital, esophageal, and gastric pressures also were assessed. Data were analyzed for insufflation pressure-dependent and group effects by one-way and two-way analysis of variance for repeated measurements, respectively, followed by the Newman-Keuls post hoc test (P < 0.05). RESULTS: Intraperitoneal, unlike retroperitoneal, insufflation markedly increased, in an insufflation pressure-dependent fashion, the inferior-to-superior caval vein pressure gradient (P < 0.00001) at the level of the diaphragm. In contrast to what was observed with retroperitoneal insufflation, transmural intrathoracic caval vein pressure increased at 10 mmHg insufflation pressure, but the increase flattened with an insufflation pressure of more than 10 mmHg, and pressure decreased with an inflation pressure of 20 mmHg (P = 0.0397). These data are consistent with a zone 2 or 3 abdominal vascular condition during intraperitoneal and a zone 3 abdominal vascular condition during retroperitoneal insufflation. CONCLUSIONS: Intraperitoneal but not retroperitoneal carbon dioxide insufflation evokes a transition of the abdominal venous compartment from a zone 3 to a zone 2 condition, presumably impairing venous return, supporting the Starling resistor concept of abdominal venous return in humans.

Combined antithrombin III and C1-esterase inhibitor treatment decreases intravascular fibrin deposition and attenuates cardiorespiratory impairment in rabbits exposed to Escherichia coli endotoxin.

OBJECTIVE: To assess the effect of a combined antithrombin III and C1-esterase inhibitor treatment on intravascular organ fibrin deposition and cardiorespiratory changes following intravenous Escherichia coli endotoxin (lipopolysaccharide [LPS] 80 microg/kg i.v.) exposure. DESIGN: Prospective, randomized trial. SETTING: Research laboratory of a university medical center. SUBJECTS: Anesthetized, instrumented and mechanically ventilated rabbits ([Chbb:CH); n = 40). INTERVENTIONS: Endotoxin was given to 30 animals. Ten animals received no inhibitor (endotoxin control group). The other animals were either treated by high-dose (300 units/kg; n = 10) or low-dose (100 units/kg; n = 10) combined antithrombin III and C1-esterase inhibitor administration. Ten rabbits (time control group) were given placebo (sodium chloride 0.9%). Cardiorespiratory variables were assessed at baseline, 120 mins, and 240 mins after endotoxin or placebo administration. Four hours after endotoxin injection, liver, lung, and kidney tissue samples were examined for intravascular fibrin deposition by light microscopy. MEASUREMENTS AND MAIN RESULTS: Inhibitor treatment significantly decreased clot formation in lungs and livers without, however, demonstrating a clear dose-dependent effect. Combined antithrombin III/C1-esterase treatment attenuated the decrease of mean arterial pressure and cardiac output observed following endotoxin injection. Blood pressure improvement was significantly dependent on dosage administered. CONCLUSION: Combination of antithrombin III and C1-esterase inhibitor treatment during early endotoxin shock decreased organ fibrin deposition and improved cardiovascular stability.

Subtotal adrenalectomy by the posterior retroperitoneoscopic approach.

The retroperitoneoscopic approach offers an established operative procedure for primary adrenal gland tumors. It allows a detailed view of the adrenal gland and its surrounding region. Therefore clear differentiation between normal and neoplastic adrenal tissue is sometimes possible, permitting a planned, unilateral, subtotal resection of the gland. Between July 1994 and August 1997 primary benign adrenal gland tumors (11 Conn adenomas, 4 phenochromocytomas, 4 Cushing adenomas, 3 hormonally inactive tumors; 2.4 +/- 1.2 cm in size; 8 on the right, 14 on the left) were removed from 22 patients by the posterior retroperitoneoscopic approach maintaining tumor-free portions of the ipsilateral adrenal gland. Two patients suffered from bilateral pheochromocytomas associated with multiple endocrine neoplasia (MEN-IIa) syndrome and had previously undergone complete adrenalectomy of the contralateral gland. Following subtotal resection the operating time and blood loss did not differ significantly (p > 0.05) from that seen with complete extirpation (46 patients operated during the same period). All patients with Conn adenomas and pheochromocytomas were biochemically and clinically cured (follow-up 11 months; range 1-31 months). The four patients with Cushing adenoma currently require decreasing cortisol substitution. In the two MEN-II patients adrenal gland cortical function could be maintained; one patient is on low-dose steroid supplementation and the other on none. No local recurrence of tumors has been observed. In selected cases the retroperitoneoscopically performed subtotal adrenal gland resection is a safe procedure that can potentially maintain the function of the adrenal gland cortex.

Effect of positive end-expiratory pressure on the incidence of venous air embolism and on the cardiovascular response to the sitting position during neurosurgery.

We have studied prospectively the effect of 10 cm H2O of PEEP on the incidence of venous air embolism and on the cardiovascular response to change from the supine to the seated position in a large neurosurgical population. Patients were allocated randomly to receive either PEEP (10 cm H2O, n = 45) or conventional (control, n = 44) ventilation. Cardiovascular and respiratory variables were measured in the supine and sitting positions, and monitoring included precordial Doppler probe, pulmonary artery pressure and expiratory carbon dioxide concentration. Venous air embolism was assumed if changes in precordial Doppler sounds occurred, end-tidal carbon dioxide concentration decreased or air could be retrieved from a central venous multi-orifice catheter. The incidence of venous air embolism (26%) did not differ between patients undergoing conventional ventilation and those undergoing ventilation with 10 cm H2O of PEEP. Venous air embolism was always detected first by alterations in Doppler sounds. Cardiac output was significantly higher in patients undergoing conventional ventilation than in those undergoing ventilation with PEEP in the supine but not in the sitting position. Furthermore, pulmonary vascular resistance increased significantly only in the upright position in those undergoing ventilation with PEEP. The pulmonary artery wedge pressure to central venous pressure gradient did not attain negative values with PEEP or with upright positioning. We conclude that the use of PEEP during neurosurgical procedures performed in the sitting position should be abandoned as it does not decrease the incidence of venous air embolism but is associated with significant adverse cardiovascular effects.

Retroperitoneal and intraperitoneal CO2 insufflation have markedly different cardiovascular effects.

Both retroperitoneoscopic and laparoscopic surgical approaches to kidney and adrenal gland have been reported but their cardiopulmonary pathophysiology has been incompletely characterized. To test the hypothesis that these approaches have markedly different impact on the circulatory and respiratory systems, we assessed at similar insufflation pressures alterations in cardiovascular and respiratory variables during retroperitoneal and intraperitoneal CO2 insufflation. Eighteen healthy, anesthetized (propofol, alfentanil, vecuronium), mechanically ventilated pigs were randomly instrumented for either retroperitoneoscopic (n = 9) or laparoscopic (n = 9) surgery. After CO2 insufflation cardiovascular and respiratory variables were measured at four cavity pressures (baseline, 10, 15, and 20 mmHg), while end-expiratory CO2 tension was maintained by adjusting tidal volume. Data were analyzed for both insufflation-pressure-dependent and group effects by one-way and two-way ANOVA for repeated measurements, respectively, followed by Newman-Keuls post hoc test (P < 0.05). Cardiac output, mean arterial, pulmonary artery, central venous, and femoral venous pressures increased significantly in both groups in an insufflation-pressure-dependent fashion. However, changes in cardiac output (P < 0.001), pulmonary artery (P < 0.007), central venous (P < 0.001), and iliac venous pressures (P < 0.001) for the same insufflation pressure were markedly and significantly greater with intraperitoneal than retroperitoneal CO2 insufflation. Most important, intraperitoneal unlike retroperitoneal insufflation induced a marked inferior vena caval pressure gradient (8.9 +/- 1.1 mmHg vs 1.0 +/- 0.5 mmHg, P < 0.00001). While both retroperitoneal and intraperitoneal CO2 insufflation required increased tidal volumes to adjust endtidal CO2 tension to baseline, intraperitoneal CO2 insufflation resulted in a significantly greater increase of mixed venous and arterial carbon dioxide tensions (P < 0.007) even at similar insufflation pressures. Furthermore, significantly greater peak airway pressures (P = 0.018) were required with intraperitoneal than with retroperitoneal insufflation to administer the same tidal volume, indicating a greater decrease in quasi-static compliance with intraperitoneal insufflation (P = 0.0436). Thus, (i) cardiovascular and respiratory changes are much less during retroperitoneal than intraperitoneal CO2 insufflation, even at the same insufflation pressures, and (ii) retroperitoneal CO2 insufflation unlike intraabdominal CO2 insufflation does not induce an inferior vena caval pressure gradient and hence does not appear to impair systemic lower body venous return up to insufflation pressures of 20 mmHg.

Incidence of neurologic complications related to thoracic epidural catheterization.

BACKGROUND: Due to potential neurologic sequelae, the risk:benefit ratio of thoracic epidural analgesia is controversial. Surprisingly, however, few available data address neurologic complications. The incidence of neurologic complications occurring after thoracic epidural catheterization was studied in patients scheduled for abdominal or abdominothoracic surgery. METHODS: A total of 4,185 patients were studied, including 2,059 during the prospective phase of the study and 2,126 during the retrospective phase. After thoracic epidural catheterization, all patients received general anesthesia. Patients' neurologic status was assessed by an anesthesiologist using clinical criteria after operation and after epidural catheter removal. If neurologic complications were suspected, a neurologist was consulted. The incidence of specific complications was compared for different thoracic puncture sites: upper (T3/4-6/7), mid (T7/8-8/9), and lower (T9/10-11/12) catheter insertion levels. RESULTS: The overall incidence of complications after thoracic epidural catheterization was 3.1% (n = 128). This included dural perforation (0.7%; n = 30); unsuccessful catheter placement (1.1%; n = 45); postoperative radicular type pain (0.2%; n = 9), responsive to catheter withdrawal in all cases; and peripheral nerve lesions (0.6%; n = 24), 0.3% (n = 14) of which were peroneal nerve palsies probably related to surgical positioning or other transient peripheral nerve lesions (0.2%; n = 10). No signs suggesting epidural hematoma were recognized, and there were no permanent sensory or motor defects attributable to epidural catheterization. Unintentional dural perforation was observed significantly more often in the lower (3.4%) than in the mid (0.9%), or upper (0.4%) thoracic region. A single patient experienced severe respiratory depression after receiving epidural buprenorphine but recovered without sequelae. CONCLUSIONS: Thoracic epidural catheterization for abdominal and thoracoabdominal surgery is not associated with a high incidence of serious neurologic complications. In fact, the incidence of puncture- and catheter-related complications is less in the mid and upper than in lower thoracic region, and the predicted maximum risk for permanent neurologic complications (upper bound of the 95% confidence interval) is 0.07%.

Posterior retroperitoneoscopy as a new minimally invasive approach for adrenalectomy: results of 30 adrenalectomies in 27 patients.

Posterior retroperitoneoscopic adrenalectomy is a new minimally invasive method. It represents an alternative to conventional open procedures and laparoscopic techniques. Between July 1994 and November 1995 a total of 30 retroperitoneoscopic adrenalectomies were performed on 27 patients. In 24 patients, unilateral tumors were seen (size 1-7 cm): seven Cushing adenomas, five Conn adenomas, seven pheochromocytomas, four hormonally inactive tumors, one cyst. Three patients suffered from Cushing syndrome with bilateral adrenal gland hyperplasias (two inoperable pituitary gland tumors, one bronchial carcinoid with ACTH secretion). The operations were carried out in prone position. After balloon dilatation of the retroperitoneum and creation of a pneumoperitoneum the preparation of the adrenal gland was performed via three trocar sites positioned below the 12th rib. Twenty-five adrenalectomies were completed endoscopically, and five times (among four patients) conversion to the conventional posterior technique was necessary. The average operating time of complete endoscopic adrenalectomies was 124 minutes (45-225 minutes); blood loss was 10 to 120 ml. With minimal need for postoperative analgesia (average dosage 7.9 mg of piritramide), mobilization and adequate food uptake were possible on the day of operation. The posterior retroperitoneoscopic adrenalectomy is a relatively fast, safe method, with the advantages of the posterior open approach and minimally invasive surgery. It therefore represents an important addition to adrenal gland surgery.

Hemodynamic changes after retroperitoneal CO2 insufflation for posterior retroperitoneoscopic adrenalectomy.

Intraoperative complications and hemodynamic alterations during posterior capnoretroperitoneoscopic adrenalectomy in the prone position were investigated in 16 consecutive patients using invasive hemodynamic monitoring. Under general anesthesia with propofol and fentanyl, hemodynamic changes were made before (M1) and during retroperitoneal CO2 insufflation (15 mm Hg) [M2]; 20 mm Hg [M3]. Retroperitoneal insufflation resulted in a significant increase of cardiac output (+72%), stroke volume (+42%), mean arterial pressure (+39 %), and mean pulmonary arterial pressure (+36%). Although retroperitoneal inflation was accompanied by a significant increase of central venous pressure (+37%), an increase of preload may have lead to higher filling pressures. Heart rate, systemic vascular resistance, and pulmonary vascular resistance did not show significant changes. One pneumothorax and two cutaneous emphysemas occurred. We have demonstrated, in a small number of patients, that retroperitoneal CO2 insufflation for posterior capnoretroperitoneoscopic adrenalectomy in the prone position results in hemodynamic changes without apparent adverse effects.

The influence of C1-esterase inhibitor substitution on coagulation and cardiorespiratory parameters in an endotoxin-induced rabbit model of hypercoagulability.

In a short-time model of endotoxin-induced (lipopolysaccharide from Escherichia coli, 120 micrograms kg-1 i.v.) hypercoagulability in rabbits, the therapeutic effects of C1-esterase inhibitor (C1I) substitution (bolus 400 U kg-1 i.v. followed by continuous infusion of 400 U kg-1 4 h-1 i.v.) were studied. When compared to endotoxin-challenged untreated animals, C1I substitution significantly stabilized mean arterial pressure (p < 0.01), increased central venous oxygen saturation (p < 0.05), prevented the decrease of antithrombin III (p < 0.05), and reduced fibrin deposition in the microcirculation of the liver and the lungs to approximately 30% of that observed in the untreated animals (p < 0.01). Although C1I substitution did not reduce systemic procoagulant turnover, the improvement of blood pressure and blood flow and local inhibitory actions in the coagulation and complement cascade prevented fibrin deposition in the microcirculation of vital organs. This study supports the beneficial role of C1I substitution during early disseminated intravascular coagulation.

[Percutaneous puncture technique for portofemorosubclavicular venovenous bypass in orthotopic liver transplantation]. / Die perkutane Punktionstechnik für den portofemorosubklavikulären venovenösen Bypass bei orthotoper Lebertransplantation.

UNLABELLED: Portofemoro-axillary bypass systems are commonly used to treat adverse haemodynamic effects during the anhepatic phase of orthotopic liver transplantation (OLT). However, low shunt flows may reduce the efficacy of these bypass systems. In order to improve veno-venous bypass management, a percutaneous cannulation technique (PCT) was used to insert large-bore catheters (21 F) into the left femoral and subclavian veins. This study prospectively addresses the complications of the PCT in 195 adult patients undergoing 203 OLTs. METHODS: The left femoral and subclavian veins were cannulated preoperatively with 21 F single-lumen catheters (DLP, Grand Rapids, MN, USA) using a Seldinger technique. Intra-operatively, the centrifugal pump (Biopump, Biomedicus, Minnesota, USA) and the portal part of the bypass were connected with the femoral and subclavian catheters. Coagulation profiles, shunt flows, haemodynamic parameters, and complications during OLT associated with the bypass system were recorded. RESULTS: Percutaneous cannulation of the left subclavian and femoral veins was successful in 198 (97.6%) patients. Mean portofemoro-subclavian shuntflow was 4.3 (SD 1.3 l min-1). Although cardiac index (shunt 3.91 [SD 1.1] vs pre-shunt 4.42 [SD 1.0] l min-1 m-2, P < 0.05) and oxygen delivery (shunt 496 [SD 111] vs. pre-shunt 562 [SD 153] ml ml-1.m-2, P < 0.05) were not maintained at pre-shunt levels, renal perfusion pressure stayed above 50 mm Hg during the anhepatic phase. Two intra-operative air embolism (0.98%) and one myocardial infarction (0.49%) at the beginning of the anhepatic phase were observed. There were no bleeding complications. CONCLUSIONS: The portofemoro-subclavian bypass can be performed by percutaneous cannulation without additional complications in patients undergoing OLT. Although haemorrhagic complications following central venous catheterisation are reported to occur in patients with haemostatic defects, none of them was observed in this study. Two events of air embolism and one cardiac arrest could not be related to the PCT. In conclusion, femoro-subclavian percutaneous cannulation is a simple, rapid, and safe alternative to commonly used veno-venous bypass systems.

[Auxiliary liver transplantation in urgent and emergency indications]. / Die auxiliäre Lebertransplantation in dringlicher und notfallmässiger Indikation.

This report will focus on seven patients treated with auxiliary liver transplantation. In two cases the indication was severe metabolic disorder and in five cases a fulminant hepatic failure. The clinical course was highly complicated in both cases with metabolic disorder (the transplant was lost, one patient died), but satisfactory in the patients suffering from fulminant hepatic disease: three of five are off immunosuppression, one is under therapy and one patient died of sepsis in the early phase.

Short-time rabbit model of endotoxin-induced hypercoagulability.

We describe a short-time endotoxin-induced rabbit model of hypercoagulability for the study of the coagulation cascade and the therapeutic effects of coagulation inhibitors. Cardiorespiratory function was maintained in rabbits under general anesthesia and standardized mechanical ventilation (tidal volume, 6 ml/kg; 60 breaths/min) via tracheostomy and low-dose inotropic support. Coagulation parameters such as prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen concentration, platelet count, fibrin monomers, D-dimers, antithrombin III and factor XIII activities, thrombelastography, and platelet aggregometry were measured during a 4-h period after sequential double endotoxin administration (80 and 40 micrograms/kg of body weight, intravenously). Mean arterial pressure and arterial and central venous blood gas tensions were monitored. Global clotting, activation parameters of coagulation, and leukocyte count deteriorated significantly in the endotoxin-treated animals but was mainly unaltered in controls (P < 0.05). Tissue specimens of the lungs, liver, brain, and kidneys were examined. Endotoxin-induced, disseminated fibrin deposition was found in the lungs and liver (P < 0.01). We conclude that this short-time model of hypercoagulability in rabbits reliably induced disseminated intravascular coagulation. Tracheostomy and mechanical ventilation provided a reproducible model in which the differences between the controls and the endotoxin-treated animals were exclusively due to administration of endotoxin and not to unforeseen complications of the respiratory system. This model allows the study of therapeutic effects of coagulation inhibitors on endotoxin-induced changes.

Effects of hypertonic saline hydroxyethyl starch solution on collagen-induced platelet aggregation and ATP secretion.

OBJECTIVE: The purpose of this study was to investigate the effect of hypertonic (NaCl 7.5%) hydroxyethyl starch (HES 6%, molecular weight 200,000) (HHES) as used for small-volume resuscitation on global coagulation parameters and platelet function. DESIGN: Randomized, controlled clinical trial. SETTING: Intraoperative volume loading after induction of general anesthesia. PATIENTS: 27 consecutive patients [mean age 59 (22-76) years, mean body weight 69.8 (46-98) kg] undergoing abdominal surgery were studied. INTERVENTIONS: Global coagulation tests (aPTT: activated partial thromboplastin time; PT: prothrombin time; platelet count; thrombelastography: TEG), platelet aggregation and ATP release were measured before and 10 min after the application of 4 ml.kg-1 of HHES (study group H, n = 14) or HES (control group C, n = 13). RESULTS: The aPTT was prolonged and platelet count was significantly reduced in both study groups. In contrast to the HES group, clot formation time in the TEG was significantly prolonged and the maximum amplitude was reduced in the HHES group. Furthermore, platelet aggregation was significantly slowed down, whereas ATP release significantly increased in the HHES group. CONCLUSION: The changes in global coagulation parameters can be explained by dilutional effects of the infused solution. The hyperosmolar saline compound of the HHES solution obviously contributes to the slowing down of platelet aggregation. Osmotic stress and membrane pleating may aggravate HES-induced changes in membrane fluidity and microviscosity and thus explain this impaired interaction. The increase in ATP release suggests a change in receptor-second messenger interaction for delta granule release.