Anaesthesia and systemic oxygenation.

BACKGROUND: Anaesthesia induction and deep anaesthesia may be accompanied by a considerable haemodynamic depression, especially in patients suffering from cardiovascular diseases. A decrease in cardiac index (CI) leads to a concomitant decrease in oxygen transport (DO2I). We examined whether these changes in haemodynamic performance and oxygenation can cause an oxygen debt and anaerobic metabolism. METHODS: DO2I, oxygen uptake (VO2I), oxygen extraction ratio (O2ER) and plasma lactate were analysed at 9 pre-defined study stages during anesthesia induction, deep anaesthesia prior to surgery and during surgery in 65 patients (ASA 3) undergoing elective vascular surgery. Polynomials of increasing order were fitted to the data for the determination of the critical value of oxygen transport from the inflection point of the regression curve. RESULTS: CI, heart rate, mean arterial pressure and DO2I decreased significantly after anaesthesia induction and during deep anaesthesia. VO2I showed an almost parallel change during the study period so that O2ER remained nearly constant. Plasma lactate did not exceed the physiological range in any patient and a critical value of DO2I could not be detected because a linear regression always provided the best fit for the data. CONCLUSIONS: We conclude that in patients suffering from a substantial cardiovascular disease systemic oxygenation is not impaired by considerable haemodynamic changes induced by general anaesthesia. This fact can be explained by the parallel decrease in oxygen demand, expressed by the decrease in VO2I.

[Laparoscopic cholecystectomy as a suitable procedure for patients with cardiopulmonary risk factors?]. / Ist die laparoskopische Cholezystektomie das geeignete Verfahren für kardiopulmonale Risikopatienten?

There is considerable debate whether or not the laparoscopic technique for cholecystectomy supersedes conventional procedures in patients with pre-existing cardiopulmonary disease. Hemodynamic stress and CO2 absorption from the peritoneum can have a negative effect on intraoperative safety. On the other hand, a more rapid recovery of lung function and a shorter stay in hospital are the obvious advantages. 74 patients were investigated in our study: 54 with a low cardiopulmonary risk (group 1, ASA classes I or II) and 20 high risk patients belonging to ASA class III (group 2). Series of blood-gas samples were drawn from an arterial catheter and the respiratory parameters and blood gas values measured before and at the end of the CO2-insufflation period were compared. No dangerous rise in paCO2 or decrease in pH occurred with the ventilation method used in this study (Ti:Te = 1:1, PEEP = 5 mbar, Rf = 10/min modification of the tidal-volume according to the measured paCO2 and ventilation with an O2/air mixture). No significant changes in arterial O2 saturation compared with baseline values occurred and values remained within the physiological range. We conclude that excessive intraoperative paCO2 increase can be avoided by modification of the ventilation procedure and that laparoscopic cholecystectomy is an advantageous technique in the patient with cardiopulmonary disease.

Perioperative TNF alpha and IL-6 concentrations correlate with septic state, organ function, and APACHE II scores in intra-abdominal infection.

OBJECTIVE: To find out if concentrations of tumour necrosis factor a (TNF alpha) and interleukin-6 (IL-6) play a part in the pathophysiology of intra-abdominal infection, and try to identify patients who would benefit from immunotherapy against TNF alpha. DESIGN: Prospective open study. SETTING: University hospital. SUBJECTS: 19 consecutive patients (septic shock, n = 4; sepsis syndrome, n = 6; and no sepsis syndrome, n = 9, classified by the APACHE II score and the criteria of the Methyl-prednisolone Severe Sepsis Study Group) who were to undergo their first operation for intra-abdominal infection. MAIN OUTCOME MEASURES: Correlation between median (interquartile) concentrations of TNF alpha and IL-6 (pg/ml), and APACHE II score, plasma lactate concentration, and organ function. RESULTS: Perioperative concentrations of both TNF alpha (p = 0.001) and IL-6 (p = 0.006) were significantly higher in patients with septic shock. Preoperative cardiovascular and respiratory failure were associated with significantly raised TNF alpha (p < 0.001 in both cases) and IL-6 concentrations (p = 0.02 and p < 0.001, respectively). The preoperative APACHE II score correlated with the increased TNF alpha concentration (r = 0.5, p < 0.001) and plasma lactate concentration with that of IL-6 (r = 0.7, p = 0.003). CONCLUSION: Perioperative TNF alpha and IL-6 concentrations correlated with the severity of intra-abdominal infection, so it is possible that patients who present with either septic shock or the sepsis syndrome may benefit from immunotherapy against TNF alpha.

[The clinical picture and therapy of septic shock]. / Klink und Therapie des septischen Schocks.

This special article for continued education begins with a broad definition of septic shock. The following section describes the fundamental organ dysfunctions and pathomechanisms. The different pattern of septic shock and a clearly defined therapeutic concept are also offered. The specific therapeutic interventions (only those which have been proven effective and recommendable for routine clinical use) will be presented. Monitoring of infection and organ function are discussed briefly.

[Preoperative plasma exchange in treatment of plasma-related coagulation disorders before liver transplantation]. / Präoperativer Plasmaaustausch zur Therapie plasmatischer Gerinnungsstörungen vor Lebertransplantation.

PATIENTS AND METHODS: Seventy-two consecutive patients undergoing orthotopic liver transplantation at the Department of Surgery I, University of Vienna Medical School (OLT nos. 1 to 72), were evaluated. Their mean age was 47 years (range: 18-63 years). The indications for liver transplantation are listed in Table 1. All transplant procedures were performed without using a bypass technique. The intraoperative management and surgical procedure have been described elsewhere [7]. Patients were categorized in two groups, each of which was divided in two subgroups. Group I consisted of 18 patients transplanted before the introduction of preoperative plasma exchange. These were retrospectively allocated to two subgroups on basis of their preoperative prothrombin times (PT): A (n = 9): preoperative PT less than 40%; B (n = 9): preoperative PT greater than 40%. The two subgroups of group 2, which contained 54 patients, were compared on a prospective basis: C (n = 32): preoperative PT above 40%; D (n = 22): PT on admission below 40%, preoperative plasma exchange. Comparison of the two subgroups was based on the following parameters: (1) pre-exchange PT (subgroup D); (2) preoperative PT (= PT post-plasma exchange in subgroup D; (3) intraoperative infusion volumes (balanced electrolyte solutions and human albumin to maintain an intravascular colloid osmotic pressure greater than 16 mm Hg); (4) transfusion volumes (whole blood stored for no more than 72 h or packed red cells and fresh plasma, as available; and (5) intraoperative sodium bicarbonate requirements to maintain an arterial pH greater than 7.20. RESULTS: (Table 2) . Prothrombin time (PT): Group 1: Patients in subgroup A had a mean preoperative PT of 34% (range: 15%-40%). This was significantly lower than in subgroup B (74%; 52%-100%; P less than 0.001). Group 2: The pre-exchange mean PT in subgroup D was 27% (12%-39%) vs. 68% in subgroup C (45%-104%), the difference being highly significant (P less than 0.0001). In patients in subgroup D a mean plasma volume of 3638 ml was exchanged by plasmapheresis. This resulted in a significant increase in PT to 55% (Table 3). As a result, the preoperative post-exchange PT in subgroup D was slightly but significantly (P less than 0.005) less than in subgroup C. Transfusion volumes: Group 1: Patients in subgroup A needed significantly more blood units than those in subgroup B (55.3 units [19-110] vs. 18.7 [3-33]).(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of large volume replacement with balanced electrolyte solutions on extravascular lung water in surgical patients with sepsis syndrome.

We investigated the effect of large volume replacement with balanced electrolyte solutions on extravascular lung water (EVLW) in 16 adult surgical patients with sepsis syndrome. Patients entered the study within the 24 h period following surgical interventions for acute necrotizing pancreatitis, intra-abdominal abscesses, and/or peritonitis. Sequential measurements (n = 108) were made at intervals of 6-12 h over a 48 h period. There were no significant differences between initial and final values of thermal-dye EVLW (5.0 +/- 1.1 vs. 5.7 +/- 1.1 ml/kg), plasma colloid osmotic pressure (COP, 13.3 +/- 2.5 vs. 13.2 +/- 2.9 mmHg), pulmonary artery wedge pressure (PAWP, 9.2 +/- 3.0 vs. 10.8 +/- 3.0 mmHg), and COP-PAWP gradient (4.0 +/- 3.5 vs. 2.4 +/- 3.9 mmHg). All results expressed as (mean +/- SD). The EVLW did not correlate with plasma COP, PAWP, or COP-PAWP gradient. We conclude that large volume replacement with balanced electrolyte solutions with the secondary decrease in plasma COP and COP-PAWP gradient do not necessarily contribute to a substantial increase in EVLW. This study fails to show any causal relationship between decrease in plasma COP or COP-PAWP gradient and oedema formation in the lung.

[Evoked potentials in the follow-up and prognosis of patients with craniocerebral trauma]. / Evozierte Potentiale zur Verlaufs- und Prognosebeurteilung von Schädel-Hirn-Trauma-Patienten.

The aims of this study were to find a reliable way of establishing the prognosis for the final outcome in the first week after head injury, to show the correlation between abnormalities in evoked potentials (EP) and clinical coma score, and finally, to document EP results in patients with the clinical diagnosis of brain death. We examined 46 patients, 23 in different states of coma and 23 with bulbar syndrome (complete absence of cortical and brain stem function). In the group of comatose patients brain stem auditory EP (BAEP) and somatosensory EP (SEP) were recorded in the first 48 h, 3-5 days, 1 week and 4 weeks after the head injury. The depth of coma was scaled with a scoring system devised by the authors and with the Innsbruck coma scale. Outcome was evaluated with the Glasgow outcome scale after 3, 6, and 9 months. BAEP were recorded bilaterally after stimulation with clicks; SEP were recorded from the neck (C2) and the contralateral cortex (C3', C4') after electrical stimulation of the median nerve. Evoked potentials were scored according to a four-point scale from grade 1 (normal) to grade 4 (only component I present in BAEP or absence of cortical responses on both sides in SEP). We found a significant correlation between the mean SEP score of the first week and the Glasgow outcome of the 3rd month, but no significant correlation between the BAEP score of the first week and the Glasgow outcome. There was a significant correlation between SEP (BAEP) scores and the corresponding clinical score.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemodynamic and metabolic changes during orthotopic liver transplantation]. / Hämodynamische und metabolische Anderungen während orthotoper Lebertransplantation.

Hemodynamic and metabolic profiles were obtained on 48 adult patients (mean age 46 years) undergoing orthotopic liver transplantation without using a bypass technique during the anhepatic period. Baseline measurements after induction of anesthesia (A) revealed a high-output circulatory state. During hepatic dissection (B, preclamping control), mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), and elevated cardiac index (CI) were well maintained. Preoperative plasma exchange with fresh frozen plasma in the presence of severe coagulation defects and liberal use of platelet concentrates limited the need for massive blood transfusion, and thus contributed to stable hemodynamics during this stage. Significant cardiovascular changes occurred immediately after clamping of the inferior vena cava and the portal vein (C): there was a marked fall in MAP (-30%), MPAP (-45%), PCWP (-48%), RAP (-40%), and CI (-60%) reflecting the hemodynamic adaptation to the impeded venous return. At the end of the anhepatic period (D), MAP (-21%), MPAP (-38%), PCWP (-39%), RAP (-24%), and CI (-56%) were persistently lowered because no attempts were made to attenuate the clamping response by vigorous volume expansion or infusion of inotropic drugs. The reduction in oxygen availability index (O2AVI) was compensated by enhanced oxygen extraction. Oxygen consumption index (VO2I) fell secondary to the removal of the liver and the decrease in body temperature (BT). Potassium levels and acid-base balance were well controlled; no hypoglycemic episode was observed during the anhepatic period.(ABSTRACT TRUNCATED AT 250 WORDS)

[Glucose-potassium-insulin in hypodynamic septic shock]. / Glucose-Kalium-Insulin im hypodynamen septischen Schock.

Haemodynamic and metabolic effects of glucose-potassium-insulin (GKI) were studied in 14 patients with peritonitis. Study entry criteria were: hypodynamic septic shock (mean arterial pressure less than 50 mmHg and cardiac index less than 3.5 l/min) despite a highly positive fluid balance (greater than +2,000 ml during the last 12 h) and use of catecholamines (greater than 15 mcg/kg/min Dobutamine). GKI (glucose 70% 1 g/kg + potassium 10 mval + insulin 1.5 U/kg) was infused within 15 min via a central venous catheter. Before and 10 min after GKI haemodynamic and metabolic measurements were performed. GKI led to significant increases in systolic (+53%) and mean (+61%) arterial pressures, cardiac index (+50%), right (+60%) and left (+109%) ventricular stroke work indices, and oxygen consumption index (+18%). Heart rate remained unchanged, pulmonary shunt fraction increased slightly, systemic and pulmonary vascular resistances showed an insignificant decline. Serum glucose (p less than 0.01) and pCO2 (p less than 0.1) increased. The haemodynamic improvement lasted from 30 min or less (n = 3; 21%) to several hours. Nine patients (64%) survived more than 2 days, and two patients (14%) were eventually discharged from the hospital. We conclude, that in hypodynamic septic shock refractory to volume loading and catecholamine treatment GKI may be beneficial, although the mechanism of action remains unclear.

[Acute renal failure in abdominal infection. Comparison of hemodialysis and continuous arteriovenous hemofiltration]. / Akutes Nierenversagen bei abdomineller Sepsis. Vergleich von Hämodialyse und kontinuierlicher arteriovenöser Hämofiltration.

58 patients with peritonitis and acute renal failure (ARF) were treated either by haemodialysis (HD, n = 22), continuous arteriovenous haemofiltration (CAVH, n = 9), or continuous pump-driven haemofiltration (CPDHF, n = 27). In contrast to HD, which led to severe hypotension in 31.9% of procedures and to cardiac arrest in 3 cases, CPDHF caused neither haemodynamic nor metabolic alterations. Control of uraemia was most effective in the CPDHF group, too. Mean daily BUN and creatinine values fell significantly (p less than 0.005) and remained at 60 mg % and 2.0 mg %, respectively, whereas during HD no significant changes were found. During CAVH serum creatinine showed an insignificant decline, whereas BUN even increased. Despite higher costs CPDHF seems to be a promising alternative to HD or CAVH for treatment of ARF in septic patients, as mortality was lower in the CPDHF group and recovery of renal function occurred in 48.2%, whereas during HD only 27.3% recovered from ARF.

[Evaluation of the thermal technic for the quantitative measurement of extravascular lung water]. / Die Bewertung der thermalen Messtechnik zur quantitativen Bestimmung des extravaskulären Lungenwassers.

To evaluate the accuracy of the method, sequential measurements (n = 159) of extravascular lung water (EVLW) using the thermo-dye double-indicator dilution technique were performed in 22 critically surgical ill patients. Radiographic grading of lung water content served as clinical standard. Normal mean EVLW defined radiographically without evidence of pulmonary edema was 4.8 +/- 1.1 ml/kg. Early interstitial fluid accumulation was quite accurately detected with 6.9 +/- 2.1 ml/kg EVLW (p less than 0.001 vs normal lung water content). The mean EVLW present with definitive interstitial and alveolar edema was 11.5 +/- 3.8 ml/kg and 19.1 +/- 4.5 ml/kg, respectively. Despite some objections to the method (diffusion limitation of the thermal indicator, uneven regional lung perfusion), this technique for measuring EVLW reliably assesses the degree of pulmonary edema. Even when properly performed, chest roentgenograms only confirm gross changes in the lung water content.

[Monitoring kidney function in abdominal infection]. / Uberwachung der Nierenfunktion bei abdomineller Sepsis.

In ICU patients suffering from abdominal sepsis acute renal failure (ARF) is a common (50% incidence) and often lethal (more than 80% mortality) complication. Continuous monitoring of renal function is necessary for both adequate fluid replacement and early detection of ARF. Using a programmable handheld computer the following parameters are calculated at least daily: creatinine, osmolal and free water clearance, fractional excretion of sodium and potassium and non-saline loss. The clearance values are corrected to 1.73 m2 body surface area. Free water clearance proved to be a particularly valuable guide for fluid therapy as well as for early diagnosis of ARF. In all septic patients renal function is impaired to some degree, since despite increased cardiac output creatinine clearance is only normal or even decreased. More than 50% of our patients with abdominal sepsis develop ARF, resulting in a dramatic increase in mortality. Goal of renal monitoring in sepsis is to detect ARF as early as possible and to differentiate between extrarenal and septic origin to enable immediate surgical treatment.