Ventilation-perfusion distributions and central hemodynamics in chronic obstructive pulmonary disease. Effects of terbutaline administration.

We studied the effects of intravenous terbutaline on VA/Q distributions and central hemodynamics in 11 patients with mixed-type COPD. Terbutaline caused an increase in VA/Q inequality in patients having PaO2 values greater than 60 mm Hg which resulted in a moderate fall in the PaO2. Patients with PaO2 values less than 60 mm Hg, the highest mean PAPs and the poorest spirometric performances demonstrated no significant changes in VA/Q distributions or PaO2 after terbutaline. Cardiac output increased 40 to 60 percent in all patients after terbutaline with an increase in tissue oxygen delivery. Mean PAP did not change in any patient after terbutaline and pulmonary vasodilatation was indicated by a decrease of calculated static PVR. The decrease of PaO2 after terbutaline in COPD is related to a further deterioration of existing VA/Q relationships. The cause of these effects and lack of such responses in patients with more advanced disease are discussed.

Lowering pulmonary artery pressure in a patient with severe acute respiratory failure.

A case of pulmonary arterial hypertension on the basis of ARDS is presented. The cyclooxygenase inhibitor Ibuprofen is used to lower pulmonary arterial pressure, resulting in an improvement in the right ventricular function.

Positive correlation between 'the arterial oxygen extraction tension' and mixed venous pO2 but lack of correlation between 'the oxygen compensation factor' and cardiac output in 38 patients.

pH and blood gases were measured in simultaneous samples of arterial blood from the radial artery and mixed venous blood from the pulmonary artery using an ABL300 and OSM3 (Radiometer A/S, Denmark). Cardiac output was measured by thermodilution. The patients were suffering from chronic obstructive pulmonary disease or adult respiratory distress syndrome. The data indicate that patients respond to a decreased arterial oxygen availability by allowing the mixed venous pO2 to fall rather than by increasing the cardiac output to maintain a normal mixed venous pO2. In other words, the arterial oxygen extraction tension and the oxygen compensation factor were both highly correlated to the mixed venous pO2 but unrelated to the cardiac index. For this reason the arterial oxygen extraction tension appears to be a more relevant parameter of the overall arterial oxygen availability than the oxygen compensation factor. Comparison of the arterial and mixed venous data confirms the accuracy of the Oxygen Status Algorithm for calculating the various oxygen parameters, including the p50, the estimated 2,3-diphosphoglycerate concentration, and the estimated physiological shunt, on the basis of a single arterial blood sample.

[Prognosis for patients admitted to intensive care units with acute renal failure requiring dialysis]. / Prognosen for patienter indlagt på intensiv afdeling med dialysekraevende akut nyresvigt.

The mortality of critically ill patients who develop acute renal failure (ARF) is persistingly high. We reviewed all patients who developed ARF that required dialysis in a single intensive care unit (n = 167) during the period 1977 to 1989, in order to identify variables with possible influence on outcome. Overall mortality within hospital was 75%. Age above 60 (p < 0.02), requirement for mechanical ventilation (p < 0.0005), requirement for inotropic drugs (p < 0.0005) and increased levels of P-bilirubin (p < 0.005) had negative impacts on survival. Mortality increased significantly from 63% in the early period (1977-1985) to 84% in the late period (1986-1989) (p < 0.001), a rise that could not be explained by a single variable. The patients in the later period were, though, characterized by a higher morbidity with a higher frequency of additional organ failure.

[Preoperative or postoperative local anesthesia. Effect on postoperative pain treatment]. / Prae- eller postoperativt lokalanalgetikum. Effekt på postoperativ smertebehandling.

A randomized, double-blind trial was conducted to compare the efficacy of preincisional and postincisional wound infiltration with 1% lidocaine (40 ml) on postoperative pain. Thirty-seven patients scheduled for elective inguinal herniotomy participated. The demand for additional postoperative analgesics occurred earlier in those who received lidocaine infiltration after incision (165 min) than in those who received preincisional lidocaine (225 min), p < 0.05). The preincisional lidocaine infiltration group also had fewer patients requiring supplemental analgesics (58%) than the postincisional group (94%) (p < 0.05). We conclude that preincisional infiltration of the surgical wound with lidocaine is a more effective method for postoperative analgesia than postincisional infiltration.

A prospective study of risk factors and cardiopulmonary complications associated with anaesthesia and surgery: risk indicators of cardiopulmonary morbidity.

The aims of this study were: 1) to describe the frequency and type of cardiopulmonary complications, 2) to identify factors significantly associated with cardiovascular and pulmonary complications associated with anaesthesia and surgery, and 3) to estimate the total risk of cardiopulmonary complications for an anaesthetic when a combination of risk factors is present. Seven thousand three hundred and six anaesthetized patients undergoing gastrointestinal, urological, gynaecological, and orthopaedic surgery were included in the study; 6.3% (1:16) had one or more cardiovascular complications requiring intervention associated with anaesthesia and surgery, and 4.8% (1:21) had pulmonary complications. The total incidence of patients with one or more complications associated with anaesthesia and surgery was 9.4% (1:11). Based on logistic regression analyses, our data indicate that the following patient categories constitute high risk patients with regard to cardiovascular complications: patients aged greater than or equal to 70 years, patients with a history of ischaemic heart disease (IHD) with previous myocardial infarction less than 1 year, a history of chronic heart failure (CHF), and in patients admitted to major surgery. The extent of pulmonary complications following anaesthesia and surgery was significantly correlated to patients aged greater than or equal to 70 years, preoperative chronic obstructive lung disease (COLD), major surgery, and to general anaesthesia involving muscle relaxants. Attempts to estimate the cardiopulmonary complications which may accompany anaesthesia and surgery provided important information about the anaesthetic course and outcome. With our model it seems possible to distinguish between very different levels of cardiopulmonary risk in the anaesthetic patient.

A prospective study of mortality associated with anaesthesia and surgery: risk indicators of mortality in hospital.

The aims of this study were to: 1) determine the incidences and causes of mortality associated with anaesthesia and surgery, 2) identify important factors associated with mortality in hospital, and 3) estimate the mortality risk associated with anaesthesia and surgery when a combination of risk factors are present. A total of 7306 anaesthetized patients undergoing abdominal, urological, gynaecological, or orthopaedic surgery were included in the study. Of these, 0.05% (1:1800) died during anaesthesia, 0.1% (1:730) during the recovery period, and the overall mortality rate in hospital was 1.2% (1:81). Most deaths occurred in the elderly (greater than or equal to 70 years of age) and were unavoidable due to progression of the presenting condition, such as advanced cancer, or co-existing diseases such as cardiopulmonary or renal failure. Of the patients who developed myocardial infarction (MI) following anaesthesia, 67% (8/12) died in the postoperative period. Half of the MI patients who died received regional anaesthesia, and in addition suffered from periods of cardiovascular dysfunction intraoperatively. By utilizing logistic regression analysis, a model for prediction of mortality risk was developed. The model included five significant preoperative predictive variables: age; patients with history of chronic heart disease, and renal disease; emergency surgery; and the type of operation. With this model it is possible to distinguish between patients with very different mortality risks.

Peripheral airway pressure during high frequency ventilation.

Peripheral airway pressure (Pp) was measured during high frequency ventilation (HFV) (open system) (1-20 Hz) by retrograde catheters in eight excised dog lungs. Central airway pressure (Pc) and pleural pressure (Ppl) were measured simultaneously. We found a significant increase in peripheral end-expiratory pressure at frequencies 5 Hz and higher, when the minute ventilation was increased. Mean Pc and mean Pp remained unchanged during ventilation at different frequencies with constant minute ventilation, although tidal volume decreased. With increasing tidal volume Pc, Pp, and Ppl (mean) increased at all frequencies. The increase in end-expiratory pressure indicates an "auto-PEEP" effect, which may contribute to the better gas exchange described during HFV.

A comparison between preincisional and postincisional lidocaine infiltration and postoperative pain.

We conducted a randomized, double-blind trial to compare the efficacy of preincisional and postincisional wound infiltration with 1% lidocaine (40 mL) on the postoperative pain of 37 patients scheduled for elective inguinal herniotomy. The demand for additional postoperative analgesics occurred earlier in those who received lidocaine infiltration after incision (165 min) than in those who received preincisional lidocaine (225 min, P less than 0.05). The preincisional lidocaine infiltration group also had fewer patients requiring supplemental analgesics (58%) than the postincisional group (94%) (P less than 0.05). We conclude that preincisional infiltration of the surgical wound with lidocaine is a more effective method of providing postoperative analgesia than is postincisional infiltration.

Ventilation-perfusion inequality during endotoxin-induced pulmonary vasoconstriction in conscious sheep: mechanisms of hypoxia.

In sheep low-dose endotoxin infusion causes transient thromboxane-mediated pulmonary vaso- and bronchoconstriction. These changes are paralleled by a decrease of arterial PO2. To elucidate the mechanisms of hypoxia we analysed ventilation-perfusion (VA/Q) distributions by the multiple inert gas elimination technique before and after endotoxin infusion in six conscious sheep. We found that hypoxia after endotoxin could be explained by both a VA/Q inequality and a simultaneous decrease in the mixed venous oxygen tension. The latter was due to a decrease of cardiac output. True shunt did not contribute to hypoxia as it was unchanged.

A one-year survey of nosocomial bacteraemia at a Danish university hospital.

A 1-year prospective study of nosocomial bacteraemia was performed at Hvidovre Hospital with special reference to frequency, focus of infection and prognosis. All patients were examined clinically in order to confirm the bacteraemia. In total, 98 hospital-acquired bacteraemias were observed, giving an incidence rate of 0.28%. Bacteraemia due to Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis predominated. The overall mortality was 38%; 65% of the patients with S. aureus bacteraemia died, 25% due to the bacteraemia. The most common types of infection were urinary tract infections and intravenous catheter infections. Fifty-five of the bacteraemias were caused by foreign bodies, mostly urinary catheters and intravenous catheters, and in 14 cases the focus was unknown. The patient population was severely ill patients. We conclude that nosocomial bacteraemia occurs specially in severely ill patients often preceded by indwelling urinary or intravenous catheters. The patients seldom die due to the bacteraemia, but they die with concomitant bacteraemia.

Effects of a thromboxane antagonist (BM 13.177) during endotoxin-induced pulmonary vasoconstriction in sheep.

We investigated the effect of a thromboxane antagonist, BM 13.177, during endotoxin-induced pulmonary vasoconstriction in sheep. In control animals intravenous E-coli endotoxin (1 microgram/kg) caused a transient increase of pulmonary artery and airway pressure paralleled by large concentration increases of TXB2: in comparison peak plasma concentrations of 6-keto-PGF1 alpha (a prostacyclin metabolite) were small and delayed in time. Pre-treatment with BM 13.177 (bolus 5 mg/kg), followed by 0.75 mg/kg/min intravenously) abolished the rise of pulmonary artery and airway pressure. Plasma concentrations of TXB2 and 6-keto-PGF1 alpha were similar to controls. These and previous investigations imply that BM 13.177 specifically antagonizes TXA2 on the putative receptor in pulmonary vascular and airway smooth muscle.

Epidural clonidine enhances postoperative analgesia from a combined low-dose epidural bupivacaine and morphine regimen.

In a randomized, double-blind, placebo-controlled trial, the value of adding clonidine to a low-dose epidural regimen for postoperative pain treatment was assessed. Twenty-four patients scheduled for hysterectomy during combined thoracic epidural (bupivacaine and morphine) and general anesthesia were studied. Postoperative analgesia consisted of epidural bupivacaine (5 mg/h) and morphine (0.1 mg/h) for 12 h. In addition, the patients randomly received clonidine (75 micrograms), followed by an infusion of 18.75 micrograms/h or saline solution (placebo) epidurally. Pain was evaluated at rest, during cough, and during mobilization every hour. Sensory level of analgesia was evaluated by pinprick. We found no significant difference in pain scores at rest between the clonidine and placebo groups but an enhanced analgesic effect by clonidine during cough and mobilization (P less than 0.05). Arterial blood pressure decreased significantly during clonidine infusion and remained lower than in the control group throughout the study. We conclude that a continuous low-dose epidural clonidine infusion enhances analgesia from a combined low-dose epidural bupivacaine and morphine regimen after hysterectomy; however, the concomitant decrease in arterial blood pressure during epidural clonidine deserves further study before such a regimen can be recommended.

Pulmonary vasodilatation and augmentation of right ventricular function following terbutaline infusion in severe chronic pulmonary disease.

Twenty patients with a median age of 61 years and a median forced expired volume in 1 s (FEV1) after bronchodilating therapy of 0.55 l were studied in order to measure the effect of intravenous terbutaline on bronchial tone, cardiac function, pulmonary haemodynamics, gas exchange, and oxygen transport capacity during rest and in 10 patients during exercise. Terbutaline infusion during rest resulted in an increase in heart rate from 84 to 103 beats min-1 (P less than 0.01), a decrease in mean systemic arterial pressure from 95 to 80 mmHg (P less than 0.02), an unchanged mean pulmonary arterial pressure (18 mmHg), an increase in cardiac index from 2.89 to 3.86 l min-1 m-2 (P less than 0.01), an increase in right ventricular ejection fraction from 45 to 53% (P less than 0.01), an increase in left ventricular ejection fraction from 63 to 67% (NS), an unchanged arterial oxygen tension, and an increase in calculated oxygen delivery from 533 to 638 ml O2 min-1 m-2 (P less than 0.01). During exercise terbutaline infusion resulted in an increase in heart rate from 108 to 120 beats min-1 (P less than 0.05), a decrease in mean systemic arterial pressure from 117 to 106 mmHg (P less than 0.01), a decrease in mean pulmonary arterial pressure from 29 to 22 mmHg (P less than 0.01), an increase in cardiac index from 4.53 to 4.64 min-1 m-2 (NS), an unchanged arterial oxygen tension, and an increase in the calculated oxygen delivery from 834 to 856 ml O2 min-1 m-2 (NS). It was concluded that terbutaline augments right ventricular function: increases right ventricular ejection fraction and decreases right ventricular end-diastolic volume, and further decreases pulmonary vascular resistance without decreasing arterial oxygen tension, and increases oxygen delivery in patients with chronic pulmonary disease during rest and exercise.

Biochemical markers for brain damage after cardiac surgery -- time profile and correlation with cognitive dysfunction.

BACKGROUND: Cerebral dysfunction is common after cardiac surgery and may be reflected in increasing blood concentrations of neuron specific enolase (NSE) and S-100 beta protein. The aim of the study was to determine the optimal timing of blood sampling. METHODS: We studied 15 patients undergoing coronary artery bypass grafting. Serum concentrations of NSE and S-100 beta protein were measured before surgery and after 12, 18, 24, 30, and 36 h. Neuropsychological testing was performed before surgery, at discharge from hospital and after 3 months. RESULTS: Serum concentrations of both NSE and S-100 beta protein increased significantly. At the first postoperative test, seven patients had cognitive dysfunction and a significant correlation was found between the composite z-score and the increase in the NSE level after 36 h (R = 0.76, P=0.001). The median increase in NSE after 36 h was 4.1 microg/l in patients having cognitive dysfunction and 0.9 microg/l in the remaining patients (P<0.05). No significant correlation was found between cognitive dysfunction and the increase in S-100 beta protein. After 3 months, no statistically significant correlation was found between either NSE or S-100 beta protein and cognitive dysfunction. CONCLUSION: NSE seems to be a useful blood marker for early cognitive dysfunction after coronary artery bypass grafting, optimal timing of blood sampling being at approximately 36 h postoperatively.