Change in P wave height during progressive exercise in patients with chronic obstructive pulmonary disease

We examined changes in P wave height in lead II of electrocardiogram during progressive exercise in patients with chronic obstructive pulmonary disease (COPD), and obtained the slope (delta P/delta VO2, %/ml/min) of the regression line calculated from the relationship between percent change of P wave height and oxygen consumption (VO2). Four COPD patients, who had a decrease over 5 mmHg in arterial oxygen tension (PaO2) at maximal exercise (group A), had significantly greater slope (0.45 +/- 0.14%/ml/min, mean +/- S.E.) than in five COPD patients (group B, 0.14 +/- 0.05), who did not have a decrease over 5 mmHg in PaO2 at maximal exercise. The increase in P wave height during exercise was inhibited by oxygen inhalation at the given VO2 in group A. These findings suggest that increase in P wave height during exercise in COPD patients may be correlated with hypoxemia during exercise.     

Influence of single low-density lipoprotein apheresis on the adhesion molecules soluble vascular cellular adhesion molecule-1, soluble intercellular adhesion molecule-1, and P-selectin.

The aim of our study was to investigate the influence of single low-density lipoprotein apheresis (heparin extracorporeal low-density lipoprotein precipitation [HELP]procedure) on plasma concentrations of soluble adhesion molecules (sAMs) such as soluble vascular cellular adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), and P-selectin in patients with familial heterozygous hypercholesterolemia and documented coronary artery disease enrolled in a chronic weekly HELP apheresis. Before HELP apheresis, the mean plasma concentration of sVCAM-1 was 515 +/- 119 ng/ml, 204 +/- 58 ng/ml for sICAM-1, and 112 +/- 45 ng/ml for P-selectin. After single HELP apheresis, plasma concentrations of sAM declined significantly by 32 +/- 7%, 18 +/- 15%, and 33 +/- 25% for sVCAM- 1,sICAM-1 and P-selectin, respectively. After a 1 week interval, sAM concentrations rose to approximately the initial values. The concentrations of all sAMs studied were significantly lower in the plasma leaving than entering the filter. Due to filtration, the decline in plasma level of sVCAM-1, sICAM-1, and P-selectin was 62 +/- 19%, 51 +/- 39%, and 67 +/- 22%, respectively. In addition to lipid reduction, single HELP apheresis significantly lowers plasma concentrations of sVCAM-1, sICAM-1, and P-selectin.     

Heparin- induced extracorporeal LDL - precipitation(HELP): Mode of action, safety and clinical experience(2)

Rheological effects of acute and chronic HELP - treatment 　　The acute reduction of rheologically relevant plasma constituents such as fibrinogen and largesized lipoproteins significantly improves whole blood and plasma viscosity by a decrease of approximately 15%, erythrocyte aggregability decreases by 53% whereas erythrocyte filtrability improves by 10% (figure 3).……     

Evidence for maximal treatment of atherosclerosis: drastic reduction of cholesterol and fibrinogen restores vascular homeostasis.

This article summarizes the clinical and biochemical evidence for maximal treatment of atherosclerosis by a simultaneous 60% to 70% reduction of plasma low-density lipoprotein cholesterol (LDL cholesterol), fibrinogen, and lipoprotein a concentrations with heparin-mediated extracorporeal LDL/fibrinogen precipitation (HELP) apheresis and statins. Apheresis has proven efficient and safe in the treatment of more than 1,000 patients since 1984 and has been applied in children and adults for the treatment of homozygous and heterozygous familial hypercholesterolemia, coronary artery disease, ischemic cardiomyopathy, generalized atherosclerosis, or transplant-associated arteriosclerosis after cardiac transplantation. Simultaneous removal of the main atherogenic plasma compounds has an immediate impact on myocardial and peripheral vasomotion by increasing myocardial blood flow, coronary flow reserve, cerebral CO2-reactivity, and muscle oxygen tension. Removal of fibrinogen and cholesterol reduces plasma viscosity by 20% and erythrocyte aggregation by 60% which gives rise to applying the HELP apheresis in various microcirculatory disorders. Pilot studies on acute retinal ischemia, critical limb ischemia, and sudden hearing loss confirm this observation.     

Oxygen desaturation in adults following inhaled metaproterenol therapy

Following bronchodilator therapy in asthmatic patients, a fall in arterial oxygen tension (PaO2) has been attributed to increased perfusion of persistently underventilated alveoli. We used continuous noninvasive pulse oximetry to evaluate the extent and timing of oxygen saturation (SaO2) decrease in adults following metaproterenol inhalation for acute bronchospasm. We also examined the effect of supplemental oxygen upon these factors. Baseline and peak drop in SaO2 after completion of the first bronchodilator therapy were measured and the percent change in SaO2 was calculated. A total of 47 patient visits were studied; 10 patients received supplemental oxygen. Mean age was 38 +/- 17.9 years. Baseline was SaO2 = 94.6 +/- 2.9%, peak drop SaO2 = 91.4 +/- 3.4%, and percent change in SaO2 = -3.4 +/- 2.5%. The mean time to peak drop was 24.4 +/- 15.4 minutes in the 40 patients, with an observed drop after initial treatment. The absolute change in SaO2 from baseline was significant both with and without oxygen (P less than .05 and less than .01, respectively). The group receiving oxygen had a significantly smaller percent drop and a larger proportion of patients showing no drop in SaO2 (P less than 0.01 and less than 0.03, respectively). Clinically significant oxygen desaturation can occur within 30 minutes of inhaled bronchodilator therapy. Supplemental oxygen (2-3 L/min) helps blunt the metaproterenol-induced drop in SaO2.     

Lung recruitment maneuver in patients with cerebral injury: effects on intracranial pressure and cerebral metabolism

OBJECTIVE: To investigate the effects of a lung recruitment maneuver on intracranial pressure (ICP) and cerebral metabolism in patients with acute cerebral injury and respiratory failure.DESIGN: Prospective investigation.SETTING: Ten-bed intensive care unit of a university hospital.PATIENTS: Eleven patients with acute traumatic or non-traumatic cerebral lesions, who were on mechanical ventilation with acute lung injury.INTERVENTIONS: Hemodynamics, ICP, cerebral perfusion pressure (CPP), jugular venous oxygen saturation (SJO(2)), and arterial minus jugular venous lactate content difference (AJDL) were measured before, during and after a volume recruitment maneuver (VRM), which included a 30-s progressive increase in peak pressure up to 60 cmH(2)O and a sustained pressure at the same level for the next 30 s.RESULTS: At the end of VRM, ICP was elevated (16+/-5 mmHg vs 13+/-5 mmHg before VRM, P<0.05) and mean arterial pressure was reduced (75+/-10 vs 86+/-9 mmHg, P<0.01), which resulted in a decrease of CPP (60+/-10 vs 72+/-8 mmHg, P<0.01). SJO(2) deteriorated at the end of the procedure (59+/-7 vs 69+/-6%, P<0.05), AJDL was not altered. In the following period all parameters returned to normal values. An improvement in arterial oxygenation was observed at the end, but not in the period after the maneuver.CONCLUSIONS: Our VRM reduced cerebral hemodynamics and metabolism. We conclude that our VRM with high peak pressure effects only a marginal improvement in oxygenation but causes deterioration of cerebral hemodynamics. We therefore cannot recommend this technique for the ventilatory management of brain-injured patients.     

Interstitial fluid volume, plasma volume and transcapillary colloid osmotic gradient in patients with hepatic cirrhosis and fluid retention

Colloid osmotic pressure in plasma (IIp) and in subcutaneous interstitial fluid (IIi) (wick technique), plasma volume (PV) and interstitial fluid volume (IFV) were measured in 12 patients with hepatic cirrhosis and fluid retention. The value of IIp (mean +/- SD) was 21.4 +/- 4.2 mmHg (28.6 +/- 3.4 mmHg in normal subjects (p less than 0.01)), mean IIi was 8.6 +/- 2.2 mmHg (15.8 +/- 2.7 mmHg in normal subjects (p less than 0.01)) and mean transcapillary colloid osmotic gradient (IIp-IIi) was 12.7 +/- 3.8 mmHg compared to 12.8 +/- 2.7 mmHg in normal subjects (p greater than 0.1). Mean PV was increased by 21% compared to normal values (p less than 0.01) and IFV increased by 43% (p less than 0.01). The study demonstrates that reduction in IIp in hepatic cirrhosis is accompanied by a decrease of IIi in subcutaneous tissue resulting in unchanged transcapillary colloid osmotic gradient. The reduction in IIi can partly be explained by simple dilution and partly by a decrease in interstitial protein mass. The wash-down of interstitial proteins in non-splanchnic tissues reduces the tendency to oedema and hypovolaemia.     

体外血脂分离术对高脂血症的疗效与护理

目的探讨采用体外血脂分离术使血脂被分离的方法以达到分离清除血脂的效果。方珐用血脂分离仪将患者静脉血液中的血浆分离、过滤、回输。结果血脂分离治疗前后血脂测定结果比较，各指标测定值显著降低（P〈0．01），血液黏稠度降低30％。结论体外血脂分离术可以达到分离清除血浆中部分血脂的目的，降低血液黏稠度，预防心脑血管病的发生。专业的护理是保证治疗顺利进行、生活质量提高的重要保证。     

Effects of AV Sequential Versus Asynchronous AV Pacing on Pulmonary Hemodynamics

We studied the effects of various pacing modes on cardiac hemodynamics and pulmonary gas alterations in chronic heart blocked dogs. Changing the pacing mode from an atrioventricular interval of 100 ms (AV100) to a ventriculo-atrial interval of 100 ms (VA100) caused a significant fall in left ventricular pressure (117.64 +/- 11.91 to 95.60 +/- 16.58 mmHg) and cardiac output from 2.18 +/- 0.24 to 1.46 +/- 0.20 L/min. Following the change in pacing mode from AV100 to VA100, there was an increase in the alveolar-arterial O2 gradient from 23.28 +/- 6.97 to 28.74 +/- 8.43 mmHg and a decrease in the arterial CO2 tension from 32.42 +/- 3.22 to 29.42 +/- 3.22 mmHg. There was also a decrease in arterial CO2 tension when the AV100 pacing mode was compared to asynchronous ventricular pacing (32.42 +/- 3.22 versus 30.56 +/- 2.82 mmHg). The minute volume of O2 also decreased when the pacing mode was changed from AV100 to asynchronous ventricular pacing (0.134 +/- 0.01 versus 0.126 +/- 0.01 L/min) and decreased further at VA100 to 0.114 +/- 0.01 L/min. Other significant changes were also observed: the percent of expired CO2 decreased when the pacing mode was changed from AV100 to VA100 (3.68 +/- 0.13 versus 3.37 +/- 0.26%) or to asynchronous ventricular pacing (3.40 +/- 0.31%). The end-expiratory O2 increased and CO2 decreased when the pacing mode was changed from AV100 to VA100. The breath-by-breath correlation of end-expiratory O2 and CO2 with left ventricular systolic pressure showed an almost immediate increase in O2 and reduction in CO2 concentration associated with decreasing systolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of inversed ratio ventilation (IRV) on arterial oxygenation during mechanical ventilation in patients with acute respiratory failure.

We investigated the effects of inversed ratio ventilation by altering the inspiratory:expiratory (I:E) ratio and assessing the time course changes in the intrapulmonary shunting (Qs/Qt) in 14 patients with acute respiratory failure. Stepwise prolongation of the I:E ratio from 1:1.9 to 2:1 and then to 2.6 or 4:1 was applied when PEEP failed to raise the PaO2 above 80 mmHg while breathing oxygen. A significant decrease in Qs/Qt was observed following prolongation of the I:E ratio from 1:1.9 (Qs/Qt = 45 +/- 9%) to 2:1 (Qs/Qt = 29 +/- 9%) but not with further prolongation of the I:E ratio (Qs/Qt = 27 +/- 7%). Improvement of the pulmonary ventilation/perfusion imbalance became more marked with continued IRV and a significant increase in PaO2 was observed at 6 h after initiating prolongation of the inspiratory time (P less than 0.05). There were no significant changes in hemodynamics, PaCO2, or peak inspiratory pressure during IRV. This ventilatory pattern may be indicated when PEEP fails to improve PaO2, but prolongation of the inspiratory time above an I:E ratio of 2:1 did not produce a greater improvement in Qs/Qt and further increases in PaO2 did not occur after more than 10 h of IRV in our 14 patients.     

Revival of an old method with new techniques: balloon aortic valvuloplasty of the calcified aortic stenosis in the elderly

Balloon aortic valvuloplasty (BAV), introduced since almost 20 years, has experienced a revival for its use in the treatment of elderly patients with severe calcified aortic stenosis that are associated with high operative risk and co-morbidities. This is due to the introduction of new balloon catheters and techniques. This study reports about 75 such cases performed within the past 28 months. The mean age of our patient group was 78 +/- 7 years (median = 80 years). Risk calculation with the EuroSCORE demonstrated an average value of 24.4 +/- 19.5%. BAV was performed along with burst pacing to reduce transvalvular blood flow for stabilization of the balloon catheter until blood pressure dropped to less than 50 mmHg. BAV was performed in 72 patients with a procedural success rate of 73%. There was a decrease of 31 mmHg peak-to-peak gradient across the aortic valve from 63 +/- 35 to 32 +/- 22 mmHg (P < 0.0001). Mean gradient was reduced from 51 +/- 24 to 27 +/- 15 mmHg (P < 0.0001). Aortic valve area increased by 49% from 0.84 +/- 0.33 to 1.25 +/- 0.45 cm(2) (P < 0.0001). Serious adverse events (SAE) occurred in 17% of the 75 BAV procedures. Follow-up revealed a significant improvement in 6-month and 1-year survival. The improved technology of BAV makes this technique attractive for elderly patients who are at high operative risk or in cases where valve replacement was refused for any reason.     

Long-term follow-up after percutaneous septal ablation in hypertrophic obstructive cardiomyopathy

OBJECTIVES: The aim of this study was to evaluate the longterm follow-up results of percutaneous transluminal septal myocardial ablation (PTSMA) in a large patient cohort. BACKGROUND: PTSMA by alcohol injection into septal branches has shown good acute and short-term results in symptomatic patients with hypertrophic obstructive cardiomyopathy. METHODS: A total of 100 consecutive symptomatic (NYHA class 2.8 +/- 0.6) patients underwent PTSMA. All patients had clinical and non-invasive follow-up at 3 months, 1 year, and annually up to 8 years. RESULTS: One patient died at day 2 after intervention due to fulminant pulmonary embolism following deep venous thrombosis, and eight patients required a permanent DDD-pacemaker due to post-interventional complete heart block. Acute reduction of the left ventricular outflow tract gradient was achieved from 76 +/- 37 to 19 +/- 21 mmHg at rest, from 104 +/- 34 to 43 +/- 31 mmHg during Valsalva maneuver, and from 146 +/- 45 to 59 +/- 42 mmHg post extrasystole (p < 0.0001, each). During follow-up (mean follow-up time: 58 +/- 14 months), three additional patients died (sudden death at 48 months, non-cardiac death at 49 months and stroke-related death at 60 months after the index procedure). All living patients showed clinical improvement to NYHA-class 1.4 +/- 0.6 (after 3 months, n = 99), 1.5 +/- 0.6 (after 1 year, n = 99), and 1.6 +/- 0.7 at final follow-up (n = 96; p < 0.0001, each). Non-invasive follow-up studies documented ongoing outflow tract gradient reduction, decrease of septal and left ventricular posterior wall thickness, and improvement of exercise capacity. CONCLUSIONS: PTSMA is an effective treatment for symptomatic patients with hypertrophic obstructive cardiomyopathy. Follow-up showed ongoing hemodynamic and clinical improvement without increased mortality and morbidity.     

Removal of low-density lipoproteins (LDL) and fibrinogen by precipitation with heparin at low pH: clinical application and experience

The clinical application of a new extracorporeal procedure (HELP) for the selective elimination of low-density lipoproteins and fibrinogen by heparin precipitation at acid pH is described. Plasma, obtained by filtration of whole blood through a 0.2 micron filter is continuously mixed with an equal volume of an acetate buffer (pH 4.85) containing heparin. After removal of the precipitated heparin complex by filtration, excess heparin is adsorbed to a specially developed filter, and the clear plasma filtrate is subject to bicarbonate dialysis/ultrafiltration to restore physiologic pH and remove excess fluid. The calculated efficiency for the elimination of low-density lipoproteins and fibrinogen from plasma by HELP is 100% and is therefore comparable to conventional plasmapheresis. However, the HELP system shows a high degree of specificity, with over 80% of total protein being returned to the patient. A total of over 350 treatment procedures have now been performed. Patient compliance and acceptance have been excellent, and no major complications have been observed. The system is therefore suitable for the treatment of severe hyper-beta-lipoproteinemia; its use for the treatment of coronary heart disease is currently under investigation in a prospective multicenter study in which treatment efficiency will be controlled by coronary angiography on 45 patients treated with HELP over a period of 2 years.     

Cardiorespiratory and conjunctival oxygen tension monitoring during resuscitation from hemorrhage

Placement of an unheated miniaturized oxygen electrode against the palpebral conjunctiva permits noninvasive measurement of tissue oxygen tension. In this study, the relationship between conjunctival oxygen tension (PcjO2) and standard cardiorespiratory variables was examined during a sequential resuscitation protocol after acute hemorrhage. Anesthetized dogs were rapidly bled to a mean arterial pressure of 40 mm Hg and then retransfused with the shed blood in a stepwise fashion. PcjO2 fell to 2% of control values after hemorrhage and did not return to prehemorrhage values until more than 90% of the shed blood had been reinfused. PcjO2 was among the last set of cardiorespiratory variables to return to control values during resuscitation and was the last noninvasive variable to normalize. The ratio of PcjO2 to arterial oxygen tension decreased from a prehemorrhage value of 0.76 +/- 0.05 (SEM) to 0.02 +/- 0.003 after hemorrhage, and did not increase to values greater than 0.50 until resuscitation was more than 90% complete. Conjunctival oxygen monitoring may play an important role in assessing the adequacy of resuscitation after acute hemorrhage.     

Early and late failure of noninvasive ventilation in chronic obstructive pulmonary disease with acute exacerbation

BACKGROUND: Despite recent encouraging results, the use of noninvasive ventilation (NIV) in the management of acute exacerbations in chronic obstructive pulmonary disease (COPD), complicated by acute respiratory failure (ARF), is not always successful. Failure of NIV may require an immediate intubation after a few hours (usually 1-3) of ventilation ('early failure') or may result in clinical deterioration (one or more days later) after an initial improvement of blood gas tension and general conditions ('late failure'). MATERIALS AND METHODS: We enrolled 122 patients affected by COPD complicated by ARF, and treated with NIV. The schedule of NIV provided sessions of 2-6 h twice daily. RESULTS: Ninety-nine (81%) patients showed a progressive improvement of the clinical parameters and were discharged. Among the remaining 23 patients, 13 had an early failure and 10 had a late failure. In the 'success' group and 'late failure' groups we found after an increase of pH 2 h of NIV (from 7.31 +/- 0.05 to 7.38 +/- 0.04 P < 0.001 and from 7.29 +/- 0.03 to 7.36 +/- 0.02 P < 0.001, respectively) and a decrease of PaCO2 (from 80.93 +/- 9.79 to 66.48 +/- 5.95 P < 0.001 and from 85.96 +/- 10.77 to 76.41 +/- 11.02 P < 0.001, respectively). After 2 h of NIV in the 'late failure' group there were no significant changes in terms of pH (from 7.20 +/- 0.10 to 7.28 +/- 0.06) nor PaCO2 (from 92.86 +/- 35.49 to 93.68 +/- 23.68). The 'early failure' group had different characteristics and, owing to more severe conditions, the value of pH, of Glasgow Coma Score, and Apache II Score were the best predictors of the failure; while, among the complications on admission, metabolic alterations were the only independently significant predictor. CONCLUSIONS: Our study confirms that NIV may be useful to avoid intubation in approximately 80% of patients with COPD complicated by moderate-severe hypercapnic respiratory failure.     

Selective management of cardiovascular dysfunction in posttraumatic SIRS and sepsis

Cardiovascular dysfunction associated with the systemic inflammatory response syndrome (SIRS) is caused by a combination of decreased myocardial contractility and low vascular resistance. The contribution of each of these components can be determined at the bedside, and directed therapy can be appropriately initiated. Over an 8-month period of time, 23 consecutive patients who experienced posttraumatic SIRS while still being monitored with a volumetric pulmonary artery catheter (PAC) were prospectively evaluated. Ventricular pressure-volume diagrams were constructed to quantify myocardial contractility and afterload. In a resuscitation protocol, dobutamine was administered to patients with an isolated decrease in contractility, and dopamine or epinephrine was instituted for the combination of reduced contractility and afterload. Variables describing cardiovascular function were measured at the time of resolution of initial shock resuscitation (BASE), at the onset of SIRS (ONSET), and after administration of inotropic or vasoactive agents (TREAT). ONSET was associated with a significant decrease in left ventricular power (LVP) (362 +/- 96 to 235 +/- 55 mmHg.L/min/m(2), P < 0.00001) and stroke work index (SWI) (4670 +/- 1213 to 3060 +/- 848 mmHg.mL/m, P < 0.00001) from BASE. Sixteen patients (70%) demonstrated predominantly decreased contractility, which returned to near BASE values after the administration of dobutamine. The remaining seven patients (30%) had both decreased contractility and afterload, which was treated with dopamine or epinephrine. LVP and SWI significantly increased (235 +/- 55 to 328 +/- 77 mmHg.L/min/m(2), P < 0.00001, and 3060 +/- 848 to 4554 +/- 1423 mmHg.mL/m(2), P < 0.00001, respectively) on the initiation of directed therapy. Specific cardiovascular abnormalities can be identified at the bedside, and this information can guide pharmacologic management. Directed therapy improves cardiovascular function.     

A five-year experience with the use of BiPAP in a pediatric intensive care unit population

The authors retrospectively reviewed their experience with bilevel positive airway pressure (BiPAP) to treat respiratory insufficiency in pediatric patients over a 5-year period. After excluding patients on chronic home BiPAP and those in whom BiPAP was used to facilitate tracheal extubation (because there were no pre-BiPAP values on which to judge its efficacy), the study cohort included 45 patients (1.5 to 22 years) in whom BiPAP was used for acute respiratory insufficiency. The primary indication for BiPAP was a primary pulmonary parenchymal process in 29 patients and postoperative atelectasis with respiratory insufficiency following cardiac or upper abdominal surgery in 16 patients. There were no differences in the pre-BiPAP values of oxygen requirement, PCO2, oxygen saturation, and respiratory rate between the 2 groups. With the application of BiPAP in patients with primary pulmonary parenchymal disease, there was a decreased oxygen requirement, PCO2, and respiratory rate. No change in oxygen saturation was noted. In patients with postoperative respiratory insufficiency, there was an improvement in all 4 parameters. There was no difference in post-BiPAP values of oxygen requirement, respiratory rate, or PCO2 between the 2 groups. The post-BiPAP oxygen saturation was greater in patients with postoperative respiratory insufficiency (96% +/- 4%) than in patients with primary pulmonary parenchymal disease (92% +/- 6%, P = .02). Endotracheal intubation was required in 11 of 29 patients with primary pulmonary parenchymal pathology versus 1 of 16 patients with postoperative atelectasis and/or respiratory insufficiency (P = .03). The chances of requiring intubation were greater in patients < or = 6 years of age (relative risk 1.9), if the oxygen requirement did not decrease to less than 60% within the first 24 hours of BiPAP use (relative risk 3.3) and if there were any PCO2 values > or = 55 mmHg during the first 24 hours of BiPAP use (relative risk 9.8). No severe complications to BiPAP were noted. BiPAP safely and effectively improves the respiratory status of and might decrease the need for endotracheal intubation in pediatric patients with acute respiratory insufficiency of various etiologies.     

Transcutaneous oxygen tension and toe blood pressure as predictors for outcome of diabetic foot ulcers.

OBJECTIVE: The present study was undertaken to compare the predictive values of transcutaneous oxygen tension (TcPO2) and toe blood pressure (TBP) measurements for ulcer healing in patients with diabetes and chronic foot ulcers. RESEARCH DESIGN AND METHODS: Investigated prospectively were 50 diabetic patients (37 men) with chronic foot ulcers. The age was 61 +/- 12 (mean +/- SD), and the diabetes duration was 26 +/- 14 years. TBP (mmHg) was measured in dig I and TcPO2 (mmHg) at the dorsum of the foot. Ulcer healing was continuously evaluated by measuring the ulcer area every 4-6 weeks. After a follow-up time of 12 months, the patients were divided into three groups according to clinical outcome: healed with intact skin, improved ulcer healing, or impaired ulcer healing. RESULTS: Of the 13 patients who deteriorated, 11 had TcPO2 < 25 mmHg, while 34 of the 37 patients who improved had TcPO2 > or = 25 mmHg. The sensitivity and specificity for TcPO2 were 85 and 92%, respectively, when a cutoff level of 25 mmHg was used for determination of outcome of ulcer healing (healing or nonhealing). The corresponding values for TBP at 30 mmHg were 15 and 97%. Measurement of TcPO2 provided a higher positive predictive value (79%) than TBP (67%). CONCLUSIONS: The results indicate that TcPO2 is a better predictor for ulcer healing than TBP in diabetic patients with chronic foot ulcers, and that the probability of ulcer healing is low when TcPO2 is < 25 mmHg.     

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

Summary. Twenty patients with a median age of 61 years and a median forced expired volume in 1 s (FEV₁) after bronchodilatating therapy of 0·55 1 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 < 0·01), a decrease in mean systemic arterial pressure from 95 to 80 mmHg (P < 0·02), an unchanged mean pulmonary arterial pressure (18 mmHg), an increase in cardiac index from 2·89 to 3·86 1 min^-1 m^-2 (P < 0·01), an increase in right ventricular ejection fraction from 45 to 53% (P < 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 < 0·01). During exercise terbutaline infusion resulted in an increase in heart rate from 108 to 120 beats min^-1 (P < 0·05), a decrease in mean systemic arterial pressure from 117 to 106 mmHg (P < 0·01), a decrease in mean pulmonary arterial pressure from 29 to 22 mmHg (P < 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.     

Blood oxygen tension-related change of theophylline clearance in experimental hypoxemia

The effects of arterial blood oxygen tension on the pharmacokinetics of theophylline were investigated using an experimental acute hypoxemia model in rats. Conscious rats were exposed to hypoxic gas composed of 8% O2-92% N2. After blood gas tensions and blood pH were stabilized, rats received 5 mg/kg i.v. theophylline, and urine and blood samples were collected. The steady-state volume of distribution, unbound free fraction and hematocrit were unaffected by hypoxemia. Total body clearance was significantly changed (P less than .01) from 0.156 +/- 0.020 l/kg/hr in control to 0.0556 +/- 0.0067 l/kg/hr in hypoxemic rats due to the reduction of both hepatic and renal clearances. In another constant rate i.v. infusion study, the plateau plasma concentration of theophylline was elevated steeply as soon as animals had inspired hypoxic gas, and the elevated concentrations went down after returning to room air. The present results suggested that the variation of arterial oxygen tension is one possible mechanism for a rapid and large intraindividual variability in theophylline clearance in acutely ill patients with chronic obstructive pulmonary disease.