Bernd Schorn

Bedside Assessment of Intravascular Volume Status in Patients Undergoing Coronary Bypass Surgery

BackgroundManagement of intravascular volume is crucial in patients after cardiopulmonary bypass as myocardial dysfunction is common. The purpose of this study was to validate a novel bedside technique for real-time assessment of Intravascular volumes. MethodsEleven patients undergoing cardiopulmonary bypass were studied. In addition to standard monitors, a fiberoptic thermistor catheter was placed in the descending aorta and central venous Injections of 10 ml ice-cold indocyanine green dye were performed. Total blood volume was measured by a standard in vitro technique. Circulating and central blood volume were calculated by using cardiac output, mean transit times, and a newly developed recursive convolution algorithm that models recirculation. Measurements were performed after Induction of anesthesia and at 1, 6, and 24 h after surgery. ResultsA two-compartment model of the circulation was required for adequate fit of the data. We found a significant correlation between total and circulating blood volumes (r = 0.87). One hour after surgery, central blood volume was decreased by 10% (P < 0.05). At 6 and 24 h after surgery, circulating blood volumes were significantly increased by 29% and 20%, respectively (P < 0.01), although central blood volume was similar to control values. Before surgery stroke volume index correlated with circulating blood volume (r = 0.87) but not with pulmonary capillary wedge and central venous pressures. ConclusionsThis study shows that bedside determinations of intravascular blood volumes are feasible and that these measurements are more Indicative of Intravascular volume status than are either pulmonary capillary wedge or central venous pressures in the post-cardiopulmonary bypass period. Our data also demonstrate that despite a normal central blood volume both circulating and total blood volume are significantly Increased in the immediate post-cardiopulmonary bypass period.

Flow velocity measurements as an index of cerebral blood flow. Validity of transcranial Doppler sonographic monitoring during cardiac surgery.

Background:Transcranial Doppler sonography is increasingly used to monitor changes in cerebral perfusion intraoperatively. However, little information is available about the validity of velocity measurements as an index of cerebral blood flow (CBF). The purpose of this study was to compare invasive and Doppler-derived measurements of cerebral hemodynamic variables during coronary artery bypass graft surgery. Methods:In 15 male patients, measurements of CBF and middle cerebral artery flow velocity (VMCA) were performed before and after induction of fentanyl-midazolam anesthesia, during hypothermic cardiopulmonary bypass (CPB), and at the end of the surgical procedure. Transcranial Doppler sonography recordings of systolic, diastolic, and mean VMCA, and derived parameters such as pulsatility (PI) and resistance (RI) indexes were recorded from the proximal segment of the right middle cerebral artery. CBF was measured by the Kety-Schmidt inert gas saturation method with argon as a tracer. To facilitate comparisons of CBF and VMCA measurements, changes between consecutive measurements were expressed as percentage values. Calculations of cerebral perfusion pressure and cerebral vascular resistance (CVR) were based on jugular bulb pressure. The cerebral metabolic rate for oxygen was calculated from CBF and the arterial — cerebral venous oxygen content difference. Results:Changes In mean VMCA paralleled changes in mean CBF except for hemodynamic changes associated with hypothermic CPB. At this stage of surgery, mean VMCA increased while actual CBF decreased. Separate analysis of the periods before and after CPB revealed a poor association between percentage changes In CBF and VMCA (r=0.26, P=0.36; r=0.51, P=0.06, respectively). Mean values of CVR, PI, and RI showed consistent changes after induction of anesthesia. After termination of CPB, mean CVR significantly decreased, whereas mean PI and RI remained virtually unchanged. Neither before nor after CPB was a clinically useful correlation found between percentage changes in PI, RI, and CVR (PI r=0.28, P=0.34; r=-0.47, P=0.09, respectively; RI r=0.16, P=0.59; r=-0.53, P=0.06, respectively). Conclusions:Hypothermic CPB seems to alter the relation between global CBF and flow velocity in basal cerebral arteries. Inconsistency in directional changes in CBF and VMCA at this stage of surgery might be attributable to changes in middle cerebral artery diameter, red blood cell velocity spectra, and regional flow distribution. Although changes in mean VMCA before and after CPB appear to parallel changes In mean CBF, individual responses of VMCA cannot reliably predict percentage changes in CBF. Furthermore, Doppler sonographic PI and RI cannot provide an approximation of changes in CVR during cardiac surgery.

True aneurysm of the superior gluteal artery: Case report and review of the literature

Aneurysms of the gluteal arteries are rare and mostly are caused by pelvic fractures or penetrating injuries. As such these aneurysms are pseudoaneurysms. As an absolute rarity we report the case of a 43-year-old man with a histologically verified 5 cm-diameter, true saccular aneurysm of the left superior gluteal artery. The patient was admitted with 6-weeks ongoing sciatic pain without previous trauma. He was scheduled for surgery because an initial attempt of transcatheter embolization failed. By dividing the origin of the gluteus maximus muscle from the iliac crest, the aneurysm was exposed at the pelvic outlet by an extrapelvic approach and was excluded by endoaneurysmorrhaphy. Uncontrolled bleeding was prevented by temporary occlusion of the left iliac artery by a percutaneously inserted balloon catheter, thus avoiding an additional retroperitoneal approach. The postoperative course was uneventful, and sciatic pain had resolved completely. The chosen strategy provides safe and successful surgical management of gluteal artery aneurysms.

Effects of dexamethasone on intravascular and extravascular fluid balance in patients undergoing coronary bypass surgery with cardiopulmonary bypass.

Background Cardiac surgery with cardiopulmonary bypass is often associated with postoperative hemodynamic instability. In this regard beneficial effects of corticosteroids are known. The purpose of this study was to investigate whether these effects are due mainly to a modification of the intravascular and extravascular volume status or whether a more direct improvement of cardiovascular performance by corticosteroids is the underlying mechanism. Methods Twenty patients undergoing elective coronary bypass grafting were included in this randomized double-blind study. Patients of the treatment group received 1 mg/kg−1 dexamethasone after induction of anesthesia. In addition to the use of standard monitors and detailed fluid balance assessments, the transpulmonary double-indicator technique was used to measure extravascular lung water, total blood volume, and intrathoracic blood volume. Measurements were done after induction of anesthesia and 1 h, 6 h, and 20 h after the end of surgery. Results After cardiopulmonary bypass, no relevant increase in extravascular lung water was observed, despite highly positive fluid balances in all patients. A significantly smaller increase in extravascular fluid content was observed in the dexamethasone group. Total blood volume and intrathoracic blood volume did not differ in the two groups. Patients pretreated with dexamethasone had a decreased requirement for vasoactive substances and, in contrast with the control group, no increase in pulmonary artery pressure. Conclusions Extravascular fluid but not extravascular lung water is increased in patients after surgery with cardiopulmonary bypass. Pretreatment of adult patients with 1 mg/kg−1 dexamethasone before coronary bypass grafting decreases extravascular fluid gain and seems to improve postoperative cardiovascular performance. This effect is not caused by a better intravascular volume status.

Kidney salvage in a case of ruptured renal artery aneurysm: case report and literature review

A 79-year-old woman presented with hypovolaemic shock caused by rupture of a left renal artery aneurysm. She was successfully treated by arterial reconstruction with functional salvage of the kidney. The frequency of renal artery aneurysms, their risk of rupture and the results of urgent surgery are discussed.

Surgical treatment of abdominal aortic aneurysms of octogenarians

The purpose of this study was to determine whether elective abdominal aortic aneurysmectomy in octogenarians is justified or may even be advisable. Between January 1986 and August 1993, 30 octogenarians of mean age 83.1 (range 80-93) years underwent abdominal aortic aneurysmectomy. Patients were divided into two groups: group 1 (n = 9) underwent elective surgical repair; group 2 (n = 21) underwent emergency procedure. In 28 patients location of the abdominal aortic aneurysm was infrarenal; two patients presented with a juxtarenal aneurysm. The average aneurysm diameter was similar in both groups (group 1, 68.8 mm; group 2, 83.5 mm, P = n.s.). In group 2, two patients had free peritoneal rupture, one presented with rupture into the duodenum and one with penetration into the vena cava. Rupture was confined to the retroperitoneum in another 15 patients. Two patients had an expanding aneurysm. Hospital mortality rate was zero in group 1 and 42.8% in group 2 (P = 0.011). Most early deaths were related to cardiac disease. The overall complication rate was 22% in group 1 and 62% in group 2. Mean intensive care unit time was 1.8 (range 1-3) days in group 1 and 3.6 (range 1-8) days in group 2 (P = 0.47). The 5-year survival rate was 67% in the electively managed group and 34% in the emergency group.

Die simultane Operationsstrategie bei kardiovaskulärer Erkrankung und begleitender Karotisstenose in der Alterschirurgie

ZusammenfassungEinleitung: Die operative Strategie bei gleichzeitig vorliegender signifikanter Stenose der A. carotis interna (ACI) und operationswürdiger kardiovaskulärer Erkrankung ist immer wieder Gegenstand lebhafter Diskussionen. In vielfachen Publikationen wurde die Sicherheit und Effizienz einer simultanen Operationsstrategie dargelegt, wobei es Ziel unserer Studie war, dies auch für Patienten älter als 70 Jahre zu bestätigen. Material und Methoden: Von 1988 bis 1998 untersuchten wir retrospektiv insgesamt 205 Patienten, die sich einer simultanen Carotisendarterektomie (CEA) und einer kardiovaskulären Operation mit extrakorporaler Zirkulation (EKZ) unterzogen. Wir bildeten 2 Gruppen (Gr. A: < 70 J, n = 110; Gr. B: > 70 J, n = 95) und analysierten Risikofaktoren, neurologische und kardiologische Anamnese, angiographische Befunde, operative Daten, sowie perioperative Morbidität und Mortalität (30 Tage). Das Durchschnittsalter der Gr. A betrug 62 J, das der Gr. B 75 J. Die Indikation für eine simultane Operationsstrategie stellte sich bei Notwendigkeit für einen kardiovaskulären Eingriff unter EKZ und einer symptomatischen Carotisstenose, einer Carotisstenose von > 70% oder einer ulzerierten Carotisstenose, unabhängig vom Stenosegrad. In Allgemeinanästhesie wurde primär die CEA, anschließend die kardiovaskuläre Operation von dem gleichen Operationsteam durchgeführt. Ergebnisse: Eine signifikant höhere Rate bestehender Risikofaktoren zeigten Patienten der Gr. B hinsichtlich einer peripheren arteriellen Verschlußkrankheit, einer kompensierten Niereninsuffizienz und einer chronisch obstruktiven Lungenerkrankung. Eine dringliche Operationsindikation bezüglich der kardialen Symptomatik zeigte sich bei 19% der Gr. A und bei 37% der Gr. B. Hingegen waren 70% der Gr. A und 48% der Gr. B seitens der Carotisstenose asymptomatisch. Die meisten Patienten beider Gruppen zeigten eine 3-Gef.-KHK; 45% der Gr. A und 58% der Gr. B wiesen eine links-ventrikuläre Dysfunktion auf. Einen perioperativen Infarkt sahen wir bei 3,6% der Gr. A und bei 7,4% der Gr. B.Pathologische Veränderungen der kontralateralen ACI fanden wir bei 42% der Patienten in Gr. A und bei 57% in Gr. B. Die kardiologische bedingte Mortalität betrug 1% in Gr. A und 5% in Gr. B. Die Kombination von permanentem neurologischen Defizit und neurologisch bedingter Mortalität betrug für die Gr. A 2,7% (n = 3) und Gr. B 5,3% (n = 5). Postoperative neurologische Durchgangssyndrome, die durch den Einfluß von EKZ bedingt waren, traten bei den älteren Patienten signifikant häufiger auf (15,5% vs. 43,7%, p = 0,01). Hingegen war die gesamte stationäre Behandlungszeit der Patienten älter als 70 Jahre im Durchschnitt nicht signifikant verlängert (Gr. A: 12 Tage vs. Gr. B: 15 Tage). Zusammenfassung: Bei gleichzeitig bestehender ACI-Stenose und kardiovaskulärer Erkrankung bevorzugen wir die simultane Operationsstrategie. Obwohl es sich insgesamt um eine Hoch-Riskio-Patientengruppe handelt sehen wir eine berechtigte Indikation zur kombinierten Operationsweise auch bei Patienten mit einem höheren Lebensalter als 70 Jahre. Die kombinierte Rate von permanentem neurologischem Defizit und neurologisch bedingter Mortalität ist mit 2,7% (Gr. A) und 5,3% (Gr. B) niedrig und repräsentiert grundsätzlich die Effizienz der simultanen Operationsstrategie, vor allem aber auch bei alten Patienten.SummaryIntroduction: The best operative approach for concomitant carotid artery and cardiac disease remains controversial. Many studies proved the safety and efficiency of simultaneous surgery. We aimed to demonstrate the same benefits for patients ≥ 70 yrs. Methods: We retrospectively evaluated 205 pts simultaneously operated upon between 1988 and 1998. Group A comprised patients < 70 yrs (n = 110), group B ≥ 70 yrs (n = 95). Risk factors, neurologic and cardiac history, angiographic findings, operative data, morbidity, and mortality were examined. Mean age was 62 yrs in gr. A and 75 yrs in gr. B. All patients with symptomatic carotid artery disease, stenosis > 70%, or ulcerative carotid disease had simultaneous surgery. The carotid artery was always adressed first. Results: Patients in gr. B had a higher prevalence of peripheral vascular disease, renal insufficiency, and COPD. Urgent operation was indicated in 19% of gr. A pts. vs. 37% in gr. B. In gr. A 70% were asymptomatic regarding the carotid vs. 48% in gr. B 45% in gr. A and 58% in gr. B had LV dysfuntion. 3.6% in gr. A and 7.4% in gr. B suffered a perioperative MI. Pathologic changes of the contralateral carotid were found in 42% vs. 57% (A vs. B). Cardiac mortality was 1% and 5%, respectively. A combination of persistent neurologic deficit and neurologic death occurred in 2.7% in gr. A (n = 3) and 5.3% in gr. B (n = 5). Postoperative perturbed states were more common in gr. B (43.7% vs. 15.5%; p = 0.01). Conclusion: The incidence of persistent neurologic deficits and neurologic mortality in patients ≥ 70 yrs is low and proves the safety of simultaneous surgery for cardiac and carotid artery disease in this high-risk subgroup.

Inzidenz und Bedeutung kardiovaskulärer Therapie vor der operativen Therapie des Bauchaortenaneurysmas

ZusammenfassungEinleitung: Präoperatives Screening, interventionelle und operative Therapie kardiovaskulärer Erkrankungen sind von entscheidender Bedeutung für die Ergebnisse der peri- und postoperativen Behandlung des Bauchaortenaneurysmas (BAA). Methode: Innerhalb einer retrospektiven Untersuchung für den Zeitraum von 1980 bis 1996 haben wir alle Patienten erfaßt, die in unserer Klinik der operativen Therapie eines Bauchaortenaneurysmas zugeführt wurden. Von Interesse war die Entwicklung der präoperativen Diagnostik und Therapie kardiovaskulärer Erkrankungen. Ergebnisse: Von insgesamt 603 operierten Patienten (Elektiv: 449, Notfall: 154) behandelten wir die überwiegende Zahl elektiv (n=307) und notfallmäßig (n=95) in den Jahren 1990 bis 1996. In Betrachtung der Elektiv-Operationen fand sich der Risikofaktor KHK in 76,8% der Fälle (1980–89: 76,1%; 1990–96:77,5%). Eine invasive Koronardiagnostik war bei insgesamt 108 Patienten (29,6%) notwendig, wobei die Verteilung für beide Zeitspannen mit 31,3% gleich war. Resultierend aus der invasiven Diagnostik fand sich ein Rückgang der konservativen Therapie der KHK von 2,3%, der interventionellen Therapie durch PTCA, resp. Stentimplantation um 18,8%, jedoch ein signifikanter Anstieg der operativen Therapie im Sinne eines zweizeitigen Vorgehens um 26,6%. Bei 12 Patienten (16%) sahen wir in Verbindung beider Krankheitsbilder die dringliche Indikation für ein simultanes operatives Vorgehen. Vor elektiver Resektion eines BAA fanden sich folgende Diagnosen, die durch Operation oder interventionelle Therapie behandelt werden mußten: 3-Gef.-KHK: n=52 (PTCA/Stent: n=2), 2-Gef.-KHK: n=31 (PTCA/Stent: n=25), 1-Gef-KHK: n=2 (PTCA/Stent: n=9), Aortenvitium + KHK: n=1, Aortenvitium: n=2. Im untersuchten Zeitraum fanden wir einen Rückgang der Frühletalität bei elektiver BAA-Resektion von 4,2% auf 2,9% und einen Rückgang des Herz-Kreislaufversagens als Todesursache von 1,4% auf 0,65% , bezogen auf die Gesamtheit der Todesursachen von 33,3% auf 22,2%. Zusammenfassung: Steigende Zahlen elektiver BAA-Resektionen und höheres Alter der Patienten verbunden mit gehäuft vorhandenenen kardiovaskulären Erkrankungen, führen zu umfassender präoperativer Diagnostik. Daraus resultierend wurden seit 1990 42,6% mehr operative kardiovaskuläre Eigriffe der BAA-Resektion im Vergleich zu den Vorjahren seit 1980 vorangestellt. Dem gegenüber sank die Zahl interventioneller Behandlungsmöglichkeiten um 18,8%. Die Frületalität bei elektiver BAA-Resektion konnte durch primäre operative Beseitigung kardiovaskulärer Erkrankungen von 4,2% auf 2,9% reduziert werden.SummaryIntroduction Preoperative screening, interventional, and surgical therapy of cardiovascular diseases are of crucial importance for successful peri- and postoperative treatment of abdominal aortic aneurysms (AAA).Material and Methods: In a retrospective trial over the period from 1980 to 1996, we reassessed all cases of surgery for abdominal aortic aneurysms concentrating on the development of preoperative diagnostic and therapeutic procedures for cardiovascular diseases. Results: Of a total of 603 patients, 449 were operated electively and 154 as emergencies. Screening for coronary artery disease (CAD) as a risk factor, preoperative diagnostic was performed only in elective cases and revealed evidence of CAD in 76,8% (1980–89: 76.1%; 1990–96: 77.5%). Coronary angiography was indicated in 108 patients (29.6%). Medical treatment of CAD declined by 2.3%, interventional procedures such as PTCA or stentimplantation even by 18.8% during the observed period. Indications for step-wise surgical treatment (myocardial revascularization with subsequent resection of the aneurysm) increased by 26.6%; 12 patients (16%) required urgent simultaneous cardiac and aortic surgery. Prior to elective resection of AAA, a variety of diagnoses lead to either cardiac surgery or angioplasty: triple-vessel-disease, n=52 (PTCA/Stent: n=9); double-vessel-disease, n=31 (PTCA/Stent: n=25); single vessel-disease, n=12 (PTCA/Stent: n=9); aortic valve stenosis and CAD, n=1; aortic valve stenosis, n=2. Early mortality of AAA surgery decreased from 4.2% to 2.9% the frequency of primary cardiac failure as cause of death in our cohort dropped from 33.3% to 22.2%. Conclusions: Increasing numbers of elective AAA resections together with rising age and a higher prevalence of cardiovascular disease in surgical patients imply more extensive preoperative diagnostic procedures. Thus, 42.6% more cardiovascular procedures were performed prior to AAA resection since 1990 as compared with the years between 1980 and 1989. In contrast, the number of interventional procedures fell by 18.8%. Surgical treatment of concomitant cardiovascular disease reduced early mortality of elective AAA surgery from 4.2% to 2.9%.