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Biomedical subjects

M Specht

Publications and source records attributed to M Specht.

At least 37 records · Page 2Linked to original sources
PubMed1996

Intercurrent complications in chronic alcoholic men admitted to the intensive care unit following trauma.

OBJECTIVE: A chronic alcoholic group following trauma was investigated to determine whether their ICU stay was longer than that of a non-alcoholic group and whether their intercurrent complication rate was increased. DESIGN: Prospective study. SETTING: An intensive care unit. PATIENTS: A total of 102 polytraumatized patients were transferred to the ICU after admission to the emergency room and after surgical treatment. Of these patients 69 were chronic alcoholics and 33 were allocated to the non-alcoholic group. The chronic-alcoholic group. met the DSM-III-R and ICD-10 criteria for alcohol dependence or chronic alcohol abuse/harmful use. The daily ethanol intake in these patients was > or = 60 g. Diagnostic indicators included an alcoholism-related questionnaire (CAGE), conventional laboratory markers and carbohydrate-deficient transferrin. MEASUREMENT AND RESULTS: Major intercurrent complications such as alcohol withdrawal syndrome (AWS), pneumonia, cardiac complications and bleeding disorders were documented and defined according to internationally accepted criteria. Patients did not differ significantly between groups regarding age, TRISS and APACHE score on admission. The rate of major intercurrent complications was 196% in the chronic alcoholic vs 70% in the non-alcoholic group (p = 0.0001). Because of the increased intercurrent complication rate, the ICU stay was significantly prolonged in the chronic-alcoholic group by a median period of 9 days. CONCLUSIONS: Chronic alcoholics are reported to have an increased risk of morbidity and mortality. However, to our knowledge, nothing is known about the morbidity and mortality of chronic alcoholics in intensive care units following trauma. Since chronic alcoholics in the ICU develop more major complications with a significantly prolonged ICU stay following trauma than non-alcoholics, it seems reasonable to intensify research to identify chronic alcoholics and to prevent alcohol-related complications.

Adolescent↗
PubMed1996

Splanchnic blood flow is greater in septic shock treated with norepinephrine than in severe sepsis.

OBJECTIVE: To assess global and splanchnic blood flow and oxygen transport in patients with sepsis with and without norepinephrine treatment. DESIGN: Prospective, clinical study. SETTING: University hospital intensive care unit. PATIENTS: A convenience sample of 15 septic shock patients treated with norepinephrine and 13 patients with severe sepsis who did not receive norepinephrine. MEASUREMENTS AND MAIN RESULTS: There were no differences between the two groups in global haemodynamics and oxygen transport. Splanchnic blood flow and oxygen delivery (splanchnic DO2 303 +/- 43 ml/min per m2) and consumption (splanchnic VO2 100 +/- 13 ml/min per m2) were much higher in the septic shock group compared with the severe sepsis group (splanchnic DO2 175 +/- 19 ml/min per m2, splanchnic VO2 61 +/- 6 ml/min per m2). Gastric mucosal pH was subnormal in both groups (septic shock 7.29 +/- 0.02, severe sepsis 7.25 +/- 0.02) with no significant difference. No significant differences between groups were detected in lactate values. CONCLUSION: These data confirm a redistribution of blood flow to the splanchnic region in sepsis that is even more pronounced in patients with septic shock requiring norepinephrine. However, subnormal gastric mucosal pH suggested inadequate oxygenation in parts of the splanchnic region due to factors other than splanchnic hypoperfusion. Progress in this area will depend on techniques that address not only total splanchnic blood flow, but also inter-organ flow distribution, intra-organ distribution, and other microcirculatory or metabolic malfunctions.

APACHE↗
PubMed1996

[The effect of prophylactically administered n-acetylcysteine on clinical indicators for tissue oxygenation during hyperoxic ventilation in cardiac risk patients].

UNLABELLED: Hyperoxic ventilation, used to prevent hypoxia during potential periods of hypoventilation, has been reported to paradoxically decrease whole-body oxygen consumption (VO2). Reduction in nutritive blood flow due to oxygen radical production is one possible mechanism. We investigated whether pretreatment with the sulfhydryl group donor and O2 radical scavenger N-acetylcysteine (NAC) would preserve VO2 and other clinical indicators of tissue oxygenation in cardiac risk patients. METHODS: Thirty patients, requiring hemodynamic monitoring (radial and pulmonary artery catheters) because of cardiac risk factors, were included in this randomized investigation. All patients exhibited stable clinical conditions (hemodynamics, body temperature, hemoglobin, F1O2 < 0.5). Cardiac output was determined by thermodilution and VO2 by cardiovascular Fick. After baseline measurements, patients randomly received either 150 mg kg-1 NAC (n = 15) or placebo (n = 15) in 250 ml 5% dextrose i.v. over a period of 30 min. Measurements were repeated 30 min after starting NAC or placebo infusion, 30 min after starting hyperoxia (F1O2 = 1.0), and 30 min after resetting the original F1O2. RESULTS: There were no significant differences between groups in any of the measurements before treatment and after the return to baseline F1O2 at the end of the study, respectively. NAC, but not placebo infusion, caused a slight but not significant increase in cardiac index (CI), left ventricular stroke work index (LVSWI) and a decrease in systemic vascular resistance. Significant differences between groups during hyperoxia were: VO2 (NAC: 108 +/- 38 ml min-1m-2 vs placebo: 79 +/- 22 ml min-1m-2; P < or = 0.05), CI (NAC: 4.6 +/- 1.0 vs placebo: 3.7 +/- 1.11 min-1m-2; P < or = 0.05) and LVSWI (NAC: 47 +/- 12 vs placebo: 38 +/- 9; P < or = 0.05). The mean decrease of VO2 was 22% in the NAC group vs 47% in the placebo group (P < or = 0.05) and the mean difference between groups in venoarterial carbon dioxide gradient (PvaCO2) was 14% (P < or = 0.05). ST segment depression ( > 0.2 mV) was significantly less marked in the NAC group (NAC: -0.02 +/- 0.17 vs placebo: -0.23 +/- 0.15; P < or = 0.05). CONCLUSIONS: NAC helped preserve VO2, oxygen delivery, CI, LVSWI and PvaCO2 during brief hyperoxia in cardiac risk patients. Clinical signs of myocardial ischemia did not occur such as ST-depression if patients were prophylactically treated with NAC. This suggests that pretreatment with NAC could be considered to attenuate impaired tissue oxygenation and to preserve myocardial performance better in cardiac risk patients during hyperoxia.

Acetylcysteine↗
PubMed1996

Monitoring of flaps by measurement of intracapillary haemoglobin oxygenation with EMPHO II: experimental and clinical study.

OBJECTIVE: To find out whether measurements of intracapillary haemoglobin oxygenation made with the non-invasive Erlangen microlightguide spectrophotometer (EMPHO II) provided accurate data about the oxygen supply as well as the blood flow to free flaps in rats and humans. DESIGN: Experimental, and prospective open clinical study. SETTING: University hospital, Germany. ANIMALS and SUBJECTS: Thirty male Wistar rats and 20 patients who underwent microsurgical transplant of free flaps (radial forearm, n = 8; osteocutaneous fibula, n = 7; and myocutaneous from the lateral thigh, n = 5). INTERVENTIONS: Measurement of the haemoglobin oxygenation of the skin before, during, and after transfer of the flap. MAIN OUTCOME MEASURES: Reproducibility and mean curves for haemoglobin oxygenation and haemoglobin concentration. RESULTS: All values were reproducible, and there were only slight fluctuations. Uninjured skin in rats (baseline value) oxygenation of the total haemoglobin concentration ranged from 15% to 45% (mean 23%). After the flaps were raised there was a slight increase (to a mean of 37%), probably as a result of reactive hyperaemia. There was a rapid decrease within a few minutes of arterial occlusion, and residual oxygenation of up to 20% after perfusion stopped. The flap was totally deoxygenated after 1 h. Venous occlusion caused a similar pattern and all flaps were deoxygenated by 30 min. In the clinical study ligation of the vascular pedicle caused a massive reduction in values but after anastomosis there was significantly higher haemoglobin oxygenation (P = 0.05) and this continued to increase postoperatively. There were no complications and oxygenation gradually and continuously decreased from the base of the flap to the periphery. CONCLUSION: The non-invasive EMPHO II provides reliable and easily assessable data about the circulation and supply of oxygen to a transplanted free flap.

Anastomosis, Surgical↗
PubMed1996

Beta-carbolines in chronic alcoholics following trauma.

In our society every second polytraumatized patient is a chronic alcoholic. A patient's alcohol-related history is often unavailable and laboratory markers are not sensitive or specific enough to detect alcohol-dependent patients who are at risk of developing alcohol withdrawal syndrome (AWS) during their post-traumatic intensive care unit (ICU) stay. Previously, it has been found that plasma levels of norharman are elevated in chronic alcoholics. We investigated whether beta-carbolines, i.e. harman and norharman levels, could identify chronic alcoholics following trauma and whether possible changes during ICU stay could serve as a predictor of deterioration of clinical status. Sixty polytraumatized patients were transferred to the ICU following admission to the emergency room and subsequent surgery. Chronic alcoholics were included only if they met the DSM-III-R and ICD-10 criteria for alcohol dependence or chronic alcohol abuse/harmful use and their daily ethanol intake was > or =60 g. Harman and norharman levels were assayed on admission and on days 2, 4, 7 and 14 in the ICU. Harman and norharman levels were determined by high pressure liquid chromatography. Elevated norharman levels were found in chronic alcoholics (n = 35) on admission to the hospital and remained significantly elevated during their ICU stay. The area under the curves (AUC) showed that norharman was comparable to carbohydrate-deficient transferrin (CDT) and superior to conventional laboratory markers in detecting chronic alcoholics. Seventeen chronic alcoholics developed AWS; 16 of these patients experienced hallucinations or delirium. Norharman levels were significantly increased on days 2 and 4 in the ICU in patients who developed AWS compared with those who did not. An increase in norharman levels preceded hallucinations or delirium with a median period of approximately 3 days. The findings that elevated norharman levels are found in chronic alcoholics, that the AUC was in the range of CDT on admission and that norharman levels remained elevated during the ICU stay, support the view that norharman is a specific marker for alcoholism in traumatized patients. Since norharman levels increased prior to the onset of hallucinations and delirium it seems reasonable to investigate further the potential role of norharman as a possible substance which triggers AWS.

Journal Article↗
PubMed1996

Therapy of alcohol withdrawal syndrome in intensive care unit patients following trauma: results of a prospective, randomized trial.

OBJECTIVES: To assess the effect of three different alcohol withdrawal therapy regimens in traumatized chronic alcoholic patients with respect to the duration of mechanical ventilation and the frequency of pneumonia and cardiac disorders during their intensive care unit (ICU) stay. DESIGN: A prospective, randomized, blinded, controlled clinical trial. SETTING: A university hospital ICU. PATIENTS: Multiple-injured alcohol-dependent patients (n=180) transferred to the ICU after admission to the emergency room and operative management. A total of 180 patients were included in the study; however, 21 patients were excluded from the study after assignment. INTERVENTIONS: Patients who developed actual alcohol withdrawal syndrome were randomized to one of the following treatment regimens: flunitrazepam/clonidine (n=54); chlormethiazole/haloperidol (n=50); or flunitrazepam/haloperidol (n=55). The need for administration of medication was determined, using a validated measure of the severity of alcohol withdrawal (Revised Clinical Institute Withdrawal Assessment for Alcohol Scale). MEASUREMENTS AND MAIN RESULTS: The duration of mechanical ventilation and major intercurrent complications, such as pneumonia, sepsis, cardiac disorders, bleeding disorders, and death, were documented. Patients did not differ significantly between groups regarding age, Revised Trauma and Injury Severity Score and Acute Physiology and Chronic Health Evaluation II score on admission. In all except four patients in the flunitrazepam/clonidine group, who continued to hallucinate, the Revised Clinical Institute Withdrawal Assessment for Alcohol Scale decreased to <20 after initiation of therapy. ICU stay did not significantly differ between groups (p=.1669). However, mechanical ventilation was significantly prolonged in the chlormethiazole/haloperidol group (p=.0315) due to an increased frequency of pneumonia (p=.0414). Cardiac complications were significantly (p=.0047) increased in the flunitrazepam/clonidine group. CONCLUSIONS: There was some advantage in the flunitrazepam/clonidine regimen with respect to pneumonia and the necessity for mechanical ventilation. However, four (7%) patients had to be excluded from the study due to ongoing hallucinations during therapy. Also, cardiac complications were increased in this group. Thus, flunitrazepam/haloperidol should be preferred in patients with cardiac or pulmonary risk. Further studies are required to determine which therapy should be considered.

Adult↗
PubMed1996

Intensive care unit stay is prolonged in chronic alcoholic men following tumor resection of the upper digestive tract.

BACKGROUND: The prevalence of chronic alcohol misuse in patients with oral, pharyngeal, laryngeal or esophageal carcinomas exceeds 60%. No data is available, to our knowledge, on the morbidity and mortality of chronic alcoholics in surgical intensive care units (ICU) following tumor resection. We investigated whether the subsequent ICU stay in chronic alcoholics following tumor resection was prolonged and whether the incidence of pneumonia and sepsis was increased. METHODS: 213 patients with carcinomas of the upper digestive tract were evaluated regarding their drinking habits. Chronic alcoholics met either the DSM-III-R criteria for alcohol abuse or dependence. Conventional laboratory markers and serum carbohydrate-deficient transferrin were determined preoperatively. Major intercurrent complications during ICU stay such as an alcohol withdrawal syndrome, pneumonia and sepsis as well as the frequency of death were documented. RESULTS: Patients did not differ significantly between groups regarding age or APACHE score on admission to the ICU.121 patients were diagnosed as being chronic alcoholics, 39 as being social drinkers and 61 as being non-alcoholics. In chronic alcoholics the frequency of death was significantly increased. Due to the increased incidence of pneumonia and sepsis the ICU stay was significantly prolonged in chronic alcoholics by approximately 8 days. CONCLUSIONS: The increased mortality and morbidity rate demonstrates that chronic alcoholics undergoing major tumor surgery have to be considered as high-risk patients during their postoperative ICU stay. Further studies are required with respect to the immuno-competence of chronic alcoholics and the prevention of alcohol withdrawal syndrome, pneumonia and sepsis in these patients.

APACHE↗
PubMed1995

[Cerebral vasospasm following aneurysmal subarachnoid hemorrhage. Therapeutic value of treatment with calcium antagonists, hypervolemic hemodilution and induced arterial hypertension].

Only 53%-58% of patients with a subarachnoid haemorrhage (SAB) following the rupture of a cerebral aneurysm survive without neurological damage. Morbidity and mortality are closely related to the delayed ischaemic neurological deficit due to cerebral vasospasm. The following review gives an account of pathophysiological mechanisms; the importance of treatment with calcium antagonists, hypervolaemic haemodilution, and induced arterial hypertension is discussed in light of the current literature. PATHOPHYSIOLOGY. In addition to other vasoactive substances in the blood, haemoglobin, which is released from lysed erythrocytes on the 2nd to 4th day after the haemorrhage, plays an important role in inducing vasospasm. An inflammatory angiopathy ensues, with complete resolution after 6-12 weeks. The cerebral blood flow (CBF) is reduced depending on the extent of vasospasm. Irreversible infarction may follow the decrease of CBF below a critical value. Severe vasospasm causes autoregulatory disturbances and reduced responsiveness of cerebral vessels to CO2. CALCIUM ANTAGONISTS. The calcium blocker nimodipine causes dilatation of small pial vessels with increased CBF. However, systemic vasodilation with the subsequent fall in blood pressure may limit the increase in CBF. Furthermore, it is known that nimodipine decreases intracellular calcium concentrations resulting in some protection against ischaemic cellular injury. Seven placebo-controlled clinical studies have shown that nimodipine improves the outcome of patients with severe neurological damage due to cerebral vasospasm. HYPERVOLAEMIC HAEMODILUTION. Volume expansion and haemodilution to a hematocrit of 30%-33% is suggested to improve cerebral perfusion during vasospasm. The central venous and pulmonary capillary wedge pressures should be 10-12 mm Hg and 15-18 mm Hg, respectively. But there is no evidence of improved outcome with this measure, and pulmonary edema is a frequent side effect. However, impairment of cerebral perfusion and increased neurological damage can be demonstrated with hypovolaemia and haemoconcentration. INDUCED ARTERIAL HYPERTENSION. In the presence of cerebral vasospasm and resulting autoregulatory disturbances, cerebral perfusion can be increased by raising systemic arterial pressure. This measure, too, fails to improve neurological outcome. CONCLUSION. Treatment of cerebral vasospasm following a SAB aims to avoid any impairment of cerebral perfusion. Hypovolaemia and haemoconcentration have to be corrected. Normoventilation should be established to avoid hypocapnic vasoconstriction. Nimodipine should be administered continuously after a SAB. In view of the autoregulatory disturbances, systemic hypotension with its danger of decreased CBF must be prevented. The importance of hypervolaemic haemodilution and/or induced arterial hypertension is not clear. Despite therapeutic efforts, the number of patients who have survived a SAB without a substantial neurological deficit has not increased.

Aneurysm, Ruptured↗
PubMed1995

Prophylaxis of alcohol withdrawal syndrome in alcohol-dependent patients admitted to the intensive care unit after tumour resection.

Prophylaxis of alcohol withdrawal syndrome (AWS) in alcohol-dependent patients shortens the duration of stay in the intensive care unit (ICU). The objective of this study was to assess the effect of four different prophylactic regimens on the duration of ICU stay, prevention of AWS and rate of major intercurrent complications in alcohol-dependent patients admitted to the ICU after tumour resection. A total of 197 alcohol-dependent patients, diagnosed by the Diagnostic and Statistical Manual of Mental Disorders (third revised edition) with a daily ethanol intake of 60 g, were allocated randomly to one of the following regimens which were commenced on admission to the ICU: flunitrazepam-clonidine, chlormethiazole-haloperidol, flunitrazepam-haloperidol or ethanol. The duration of ICU stay, prevention of AWS, incidence of tracheobronchitis and major intercurrent complications such as pneumonia, sepsis, cardiac disorders, bleeding disorders and death were documented. On admission, patients did not differ significantly in age, APACHE II and multiple organ failure scores. ICU stay, incidence of AWS, severity of AWS (revised clinical institute withdrawal assessment for alcohol scale > 20) and major intercurrent complication rate did not differ significantly between groups. Although there was no advantage in any of the four regimens with respect to the primary outcome measures, pulmonary and cardiac patients were not included in the study. Patients in the chlormethiazole-haloperidol group had a significantly increased incidence of tracheobronchitis (P = 0.0023), probably because of an increased incidence of hypersecretion.

Adrenergic alpha-Agonists↗
PubMed1995

Beta-carbolines in chronic alcoholics undergoing elective tumor resection.

The prevalence of chronic alcoholism in patients with carcinomas of the upper digestive tract exceeds 60%. The patient's history and laboratory markers, preoperatively, are often not sensitive or specific enough to detect alcohol-dependent patients, preoperatively, who are at risk of developing alcohol withdrawal syndrome (AWS) during their postoperative intensive care unit (ICU) stay. Previously, it was found that plasma norharman was elevated in chronic alcoholics, suggesting marker characteristics for chronic ethanol misuse and possibly alcohol dependence. We investigated whether beta-carbolines (i.e., harman and norharman) were different between chronic alcoholics and nonalcoholics with carcinoma, and how the levels change in alcohol-dependent patients during their hospital stay. Ninety-seven patients with oral, pharyngeal, laryngeal, or esophageal carcinomas were evaluated regarding their drinking habits. Sixty patients were transferred to the ICU following tumor resection. Chronic alcoholics met the DSM-III-R and ICD-10 criteria for alcohol dependence or chronic alcohol abuse/harmful use. The daily ethanol intake in chronic alcoholics was > or = 60 g. Blood samples were collected on admission to the hospital, preoperatively, on admission to the ICU and on days 2, 4, and 7 in the ICU. Harman and norharman were determined by HPLC. Elevated norharman was found in chronic alcoholics on admission to the hospital, whereas harman did not differ between groups. On admission, the area under the receiver operating characteristics curve was significantly larger for carbohydrate-deficient transferrin and preoperatively for norharman. The preoperative norharman levels were significantly correlated with the period of mechanical ventilation and the length of ICU stay. Postoperatively, norharman decreased in all patients, except a group of 11 alcohol-dependent patients who developed AWS during their ICU stay. The finding that elevated norharman levels were found in chronic alcoholics on admission to the hospital and preoperatively supports the view of a specific marker for alcoholism. Preoperative norharman was superior to carbohydrate-deficient transferrin and was associated with a prolonged ICU stay and a prolonged period of mechanical ventilation. Further studies are required to determine whether norharman aids in the preoperative diagnosis of chronic alcohol misuse with respect to the prevention of postoperative complications.

Adult↗
PubMed1995

N-acetylcysteine preserves oxygen consumption and gastric mucosal pH during hyperoxic ventilation.

Hyperoxic ventilation, used to prevent hypoxemia during potential periods of hypoventilation, has been reported to paradoxically decrease whole body oxygen consumption (VO2). Reduction in nutritive blood flow due to oxygen radical production is one possible mechanism. We investigated whether pretreatment with the sulfhydryl group donor and O2 radical scavenger N-acetylcysteine (NAC) would preserve whole body VO2 and prevent deterioration of oxygenation in gastric mucosal tissue during hyperoxia. Thirty-eight patients, requiring hemodynamic monitoring (radial and pulmonary artery catheters) due to sepsis syndrome, were included in this randomized experiment. All patients exhibited stable clinical conditions (hemodynamics, body temperature, hemoglobin, FIO2 < 0.5). A gastric tonometer was placed to measure the gastric intramucosal pH (pHi), which indirectly assesses nutritive blood flow to the mucosa. Cardiac output was determined by thermodilution and VO2 by cardiovascular Fick. After baseline measurements, patients randomly received either 150 mg.kg-1 NAC (n = 19) or placebo (n = 19) in 250 ml 5% dextrose intravenously over a period of 15 min. Measurements were repeated 30 min after starting NAC or placebo infusion, 30 min after starting hyperoxia (FIO2 = 1.0), and 60 min after resetting the original FIO2. There were no significant differences between groups in any of the measurements before treatment and after the return to baseline FIO2 at the end of the study. NAC, but not placebo infusion, caused a slight but significant increase in cardiac output and decrease in systemic vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcysteine↗
PubMed1994

The relationship between mixed venous and hepatic venous O2 saturation in patients with septic shock.

It was the purpose of this study to measure the relationship between hepatic venous O2 saturation (ShvO2) and mixed venous O2 saturation (SvO2) in septic patients (n = 21) following treatment with various catecholamines (epinephrine, norepinephrine, dopamine, dopexamine). At baseline mean SvO2 was 74 +/- 5% while mean ShvO2 was 59 +/- 12%. Alpha-mimetic substances such as epinephrine and norepinephrine reduced ShvO2 and increased the difference between SvO2 and ShvO2.Beta2-mimetic and dopaminergic substances (dopexamine, dopamine) did not change the difference between SvO2 and ShvO2. These results show that SvO2 does not necessarily reflect all changes of ShvO2. Monitoring ShvO2 may be helpful in managing septic shock by adding information on adequacy of O2 supply/consumption ratio in the crucial splanchnic region.

Dobutamine↗
PubMed1994

The relevance of measuring O2 supply and O2 consumption for assessment of regional tissue oxygenation.

Septic shock and ARDS are associated with disturbed tissue oxygenation. It has been suggested to increase O2 supply (DO2) above the normal level (> 600 ml/min/m2) to compensate for the tissue hypoxia. The lack of a rise in O2 consumption (VO2) after increases of DO2 has been presumed to indicate adequate tissue oxygenation (negative O2 flux test). We were interested in whether a negative O2 flux test precludes an improvement of regional tissue oxygenation. The pH value of the gastric mucosa (pHi) is considered to be a sensitive marker for hypoxia in the splanchnic region. We measured pHi as well as DO2 and VO2 in 10 patients with hyperdynamic septic shock to assess the effect of volume substitution on tissue oxygenation. The initial therapeutic approach (volume substitution and catecholamines) led to a DO2 of 717 +/- 187 ml/min/m2. However, all patients had pHi values < 7.35 indicating regional tissue hypoxia. An additional increase of DO2 by colloidal volume substitution caused a significant rise of pHi from 7.20 +/- 0.05 to 7.25 +/- 0.05 but did not change VO2. We conclude that a negative O2 flux test does not rule out regional tissue hypoxia, and second, an increase in DO2 may improve tissue oxygenation without measurable changes in VO2. Furthermore, adequate volume substitution is an important step in the treatment of septic shock to increase total body blood flow and more specifically regional blood flow.

Biological Transport, Active↗
PubMed1993

[O2 supply, O2 consumption and the pH value of the gastric mucosa. Indicators of tissue oxygenation].

The lack of a rise in global O2 consumption (VO2) after increased O2 supply (DO2) (negative O2-flux test) is an indication of adequate tissue oxygenation. We were interested in whether a negative O2-flux test precludes an improvement in regional tissue oxygenation. The pH of the gastric mucosa (pHi) is considered a sensitive marker for tissue hypoxia. Method. The study was approved by the ethics committee of our hospital. In 12 intensive-care patients with septic shock, gastric pHi was determined (Trip'TGS catheter, Tonometrics) in addition to measuring O2-transport-related parameters via invasive haemodynamic monitoring. Following the initial measurement, a further increase in the O2 supply via volume substitution was attempted in all already hyperdynamic patients with DO2 in the upper-normal range. Results. Volume substitution with 1.246 +/- 594 ml colloid resulted in an increase in pulmonary capillary wedge pressure from 14 +/- 2 mm Hg to 17 +/- 1 mm Hg (P < 0.01). All patients had an increase in DO2 from 755 +/- 192 ml/min.m2 to 846 +/- 236 ml/min.m2 (P < 0.05). There was no significant change in VO2, at 153 +/- 28 ml/min.m2 before and 156 +/- 35 ml/min.m2 after volume administration. However, pHi increased from 7.19 +/- 0.08 to 7.24 +/- 0.08 (P < 0.01). DISCUSSION AND CONCLUSION. The low pHi at the time of the initial measurement shows that regional tissue hypoxia may be present even in patients with an above-normal O2 supply > 600 ml/min.m2. Apparently, the lack of rise in global O2 consumption after increased O2 supply does not exclude a regional improvement in tissue oxygenation. The less invasive pHi measurement is an additional useful monitoring procedure for the optimisation of regional tissue oxygenation in critically ill patients.

Cell Hypoxia↗
PubMed1993

[Hepatic venous and mixed venous O2 saturation during catecholamine therapy in patients with septic shock].

Mixed venous O2-saturation (SvO2) reflects the ratio of global O2 supply to O2 consumption. However, in septic shock, there may be alterations in the ratio of regional O2 supply to O2 consumption, particularly in the splanchnic region. The aim of the study was therefore to investigate the relation between SvO2 and hepaticovenous O2-saturation (ShvO2) in septic shock with different catecholamine regimens. METHOD. Following approval of the ethics commission at our hospital, SvO2 and ShvO2 were measured simultaneously in 29 patients (7.5-F pulmonary arterial catheter). RESULTS. SvO2 and ShvO2 showed a considerable inter-individual difference with values between 1.3 and 36.9% and a mean of 14.7 +/- 9.3%. Alterations of ShvO2 were only tendentially reflected in alterations of the SvO2. Under different catecholamines SvO2 and ShvO2 showed the same changes but varying in extent (Table 1; Fig. 2). After switching the catecholamine therapy from dobutamine to epinephrine, SvO2 decreased only from 76.7 +/- 3.6 to 76.1 +/- 2.3 but ShvO2 from 61.4 +/- 8.1 to 54.2 +/- 10.3%. When the therapy was switched from dobutamine to norepinephrine, SvO2 decreased from 74.8 +/- 4.9% to 68.5 +/- 4.8%, ShvO2 decreased from 61.9 +/- 12.9% to 49.2 +/- 12.8%. When dopamine was added to norepinephrine, SvO2 increased from 68.6 +/- 4.3% to 73.6 +/- 4.4%, ShvO2 increased from 52.6 +/- 12.7% to 63.7 +/- 9.8%. When dopexamine was added to dobutamine, SvO2 increased from 74.6 +/- 4.5% to 76.9 +/- 2.5%, while ShvO2 increased from 57.6 +/- 11.5% to 58.8 +/- 13.4%. DISCUSSION AND CONCLUSION. The results presented show that SvO2 does not provide sufficient information about the venous O2 saturation of the splanchnic region. The intraindividually variable differences between SvO2 and ShvO2 during therapeutic interventions demonstrate that a selective alteration of blood supply to or O2 consumption of the splanchnic region has taken place, which is insufficiently reflected by the SvO2.

Dobutamine↗
PubMed1989

[The effect of pre-oxygenation on hemodynamics and oxygen consumption].

Pre-oxygenation is routinely used prior to anesthesia and intubation. In awake, premedicated patients scheduled for major aortic surgery we assessed the effects of breathing oxygen for 10 min via a loosely fitting face mask on hemodynamics and oxygen consumption (VO2). RESULTS. O2-breathing increased arterial PO2 to 51 +/- 13 kPa and decreased VO2 from 109 +/- 18 to 92 +/- 24 ml.min-1.m-2 (P less than 0.001 for both variables). This reduction of VO2 resulted from both a fall in cardiac index from 3.22 +/- 0.67 to 3.04 +/- 0.75 1.min-1/m-2 (P less than 0.05) and a decrease in arterio-venous oxygen content difference from 3.45 +/- 0.60 to 3.03 +/- 0.57 ml/dl (P less than 0.001). Systemic peripheral vascular resistance increased slightly from 1453 +/- 359 to 1538 +/- 383 dyne.s.cm-5.m-2 (P less than 0.05). CONCLUSIONS. These results indicate that an increase in F1O2 in patients without severe limitations of oxygen uptake by the lungs or oxygen transport to the tissues does not improve tissue oxygenation. We speculate that increased peripheral shunting acts to protect tissue PO2 during high arterial PO2 levels.

Aorta, Abdominal↗