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Biomedical subjects

K J Falke

Publications and source records attributed to K J Falke.

At least 19 recordsLinked to original sources
PubMed1995

Extracorporeal membrane oxygenation with heparin-coated systems in a 13-month-old infant with acute hypoxic respiratory failure after correction of tetralogy of Fallot.

Hemorrhagic disorders due to systemic heparinization are frequent during extracorporeal lung support (veno-venous extracorporeal membrane oxygenation: vv-ECMO). The development of heparin-coated systems has reduced the need for high-dose heparinization. Whereas the use of these heparin-coated membrane lungs and tubings has been described in former studies in adults, only few reports exist in children. This case report describes the application of a heparin-coated extracorporeal system for long-term vv-ECMO in a 13-month-old infant suffering from acute hypoxic respiratory failure after correction of tetralogy of Fallot. Only moderately elevated levels of activated clotting time (ACT, 120-160 s) and activated partial thromboplastin time (aPTT, 40-60 s) were necessary to avoid thrombotic events in the extracorporeal system. Thoracotomies were performed twice without bleeding complications by discontinuation of the systemic heparinization. We conclude that the use of heparin-coated membrane lungs in infants may improve the safety of extracorporeal lung support and permits surgical intervention without major risk of bleeding.

Acute Disease↗
PubMed1995

Influence of mixed venous PO2 and inspired O2 fraction on intrapulmonary shunt in patients with severe ARDS.

In 12 patients undergoing extracorporeal membrane oxygenation for treatment of severe acute respiratory distress syndrome (ARDS), we examined the effects of independent variations in mixed venous oxygen tension (PvO2) and inspired oxygen fraction (FIO2) on the distribution of ventilation and perfusion as assessed by the multiple inert gas elimination technique. Reducing the oxygen concentration of the constant gas stream through the membrane lungs allowed us to decrease the PvO2 by approximately 20 Torr independently of variations in cardiac output and FIO2 as well as to augment FIO2 without influencing PvO2. The interventions did not induce any change in heart rate or systemic or pulmonary hemodynamics. In general, neither during mechanical ventilation at FIO2 of 0.6 nor during mechanical ventilation at FIO2 of 1.0 did the reduced PvO2 cause variations in the distribution of pulmonary blood flow in our patients with severe ARDS. Nevertheless, in individual patients, decreasing PvO2 or ventilation at FIO2 of 1.0 was associated with changes in intrapulmonary shunt. Therefore, we conclude that it is not possible to predict the influence of such interventions in pulmonary gas exchange in the individual patient suffering from ARDS. Differences in the regulation of the local distribution of blood flow caused by the disease itself might explain this phenomenon.

Acute Disease↗
PubMed1995

Incidence, severity, and mortality of acute respiratory failure in Berlin, Germany.

A prospective multicenter study was carried out from October 1 to November 30, 1991, to determine the incidence, severity, and mortality of acute respiratory failure (ARF) in Berlin, Germany, a metropolis with a population of 3.44 million. Adult patients from 72 intensive care units (ICUs) were evaluated. ARF was defined as: (1) intubation and mechanical ventilation (I+MV) > or = 24 h; age > or = 14 yr. Incidence of ARF was assessed as the number of patients fulfilling ARF criteria within the 2-mo study period. Severity of ARF was defined as "no lung injury" (NLI), "mild-to-moderate lung injury" (MMLI), and "severe lung injury" (SLI) according to Murray and coworkers' proposals. Mortality was assessed as number of patients with ARF dying during ICU stay. During the study period, 508 patients were diagnosed as having ARF, representing an incidence of ARF of 88.6 per 100,000/yr. Twenty-four h after I+MV, MMLI occurred in 94% and SLI in 3.6% of the ARF patients. Overall mortality rate was 42.7%. Mortality rate in the NLI group was 36.4%; in patients with MMLI, 40.8%; and in patients with SLI, 58.8%. Our data offer novel information on incidence, severity, and mortality of ARF in a major urban population.

Adult↗
PubMed1994

Autoinhalation of nitric oxide after endogenous synthesis in nasopharynx.

Exogenous nitric oxide (NO) reduces pulmonary vascular resistance after low-dose inhalation in patients. To estimate endogenous NO synthesis in the upper respiratory tract, we measured inhaled and exhaled NO in volunteers and patients during spontaneous or controlled ventilation, respectively. 20.3 nmol per min NO was synthesised in the nasopharynx of non-smoking volunteers, leading to autoinhalation of 0.07-0.13 NO parts per million during inspiration; smokers had reduced NO synthesis. In volunteers, 50-70% of the NO was resorbed by the lungs; ventilated patients were deprived of NO autoinhalation. Bacteria in the nose may take part in endogenous NO synthesis.

Adolescent↗
PubMed1994

[The relevance of perioperative coagulation parameters to indications for blood transfusion. A retrospective analysis of 300 liver transplantations].

In the present study, a retrospective statistical analysis of laboratory data, clinical data, and perioperative blood requirements from 300 primary orthotopic liver transplantations (OLT) is described. METHODS. OLT was performed using established surgical techniques and total IV anaesthesia. Volume was substituted with red blood cells (RBC) and fresh frozen plasma (FFP) according to haemodynamic data, haemoglobin, and diuresis. Platelet counts, prothrombin time, activated partial thromboplastin time (aPTT), thrombin time, fibrinogen, and antithrombin III were registered but not used as indications for transfusions. Statistics were performed using regression analysis and analysis of variance. RESULTS. The mean intraoperative fluid requirement was 793 ml balanced salt solution, 7.1 units RBC, and 8.4 units FFP; pooled random donor platelets were given only once. During 24 h postoperatively, an average of 1.8 units RBC and 4.6 units FFP had to be transfused. Currently, 278 of the 300 patients (92.7%) are alive. There was no significant correlation between clotting data and intraoperative blood use; for postoperative transfusion rates, the preoperative aPTT and postoperative platelet counts had a significant correlation. Reviewing the basic diseases of the patients, there were significant differences in coagulation status, but no differences in transfusion rates. CONCLUSION. According to the data presented, indications for transfusions in OLT according to clotting data are not valid, since these data do not correlate with the blood requirement. In addition, strategies for pretreatment of patients such as preoperative plasmapheresis are no longer justified with respect to possible side effects.

Adult↗
PubMed1994

Influence of positioning on ventilation-perfusion relationships in severe adult respiratory distress syndrome.

In 12 patients with severe adult respiratory distress syndrome (ARDS), pulmonary gas exchange and hemodynamics were evaluated before, during, and after a 2-h period of pressure-controlled mechanical ventilation with the patient in the prone position. Ventilation-perfusion relationships (VA/Q) were assessed by a multiple inert gas elimination technique. Pressure-controlled mechanical ventilation in the prone position resulted in an overall increase (p < or = 0.05) of arterial oxygenation after 120 min (98.4 +/- 50.3 to 146.2 +/- 94.9 mm Hg). Whereas eight patients revealed an improvement of PaO2 of more than 10 mm Hg after 30 min in the prone position (responders), four patients reacted to positional changes with a deterioration of arterial oxygenation (nonresponders). Data about the continuous distribution of ventilation-perfusion ratios revealed that in the responder group positioning caused a decrease of shunt perfusion of 11 +/- 5% and a concomitant increase of normal VA/Q by 12 +/- 4% after 30 min. There was no change demonstrable within low VA/Q areas. Returning the patient to the supine position reversed the improvement in gas exchange. The nonresponder group did not show any significant alteration in the distribution of VA/Q during the study. We concluded that improvement of oxygenation during pressure-controlled mechanical ventilation in the prone position is due to a shift of blood flow away from shunt regions, thus increasing areas with normal VA/Q. This redistribution of blood flow is most likely caused by a recruitment of previously ateletatic but nondiseased areas induced by altered gravitational forces.

Adolescent↗
PubMed1994

Inhalation of nitric oxide--a new approach in severe ARDS.

Pulmonary hypertension due to increased pulmonary vascular resistance, and hypoxaemia based on an elevated intrapulmonary shunt are important pathophysiological features of the adult respiratory distress syndrome (ARDS). Systemically infused vasodilators reduce pulmonary hypertension but also decrease mean systemic arterial pressure and impair pulmonary gas exchange because of their global vasodilatory effects on the systemic and pulmonary circulation. Recently, inhaling low concentrations of the gas nitric oxide (NO), an important endothelium-derived relaxing factor which is rapidly inactivated by binding to haemoglobin, has been shown to induce selective vasodilation of ventilated lung regions. Thus, inhaled NO reduces pulmonary hypertension in severe ARDS and improves arterial oxygenation by redistributing blood flow away from areas with intrapulmonary shunt to areas with a normal ventilation/perfusion ratio.

Administration, Inhalation↗
PubMed1993

Inhaled nitric oxide for the adult respiratory distress syndrome.

BACKGROUND: The adult respiratory distress syndrome is characterized by pulmonary hypertension and right-to-left shunting of venous blood. We investigated whether inhaling nitric oxide gas would cause selective vasodilation of ventilated lung regions, thereby reducing pulmonary hypertension and improving gas exchange. METHODS: Nine of 10 consecutive patients with severe adult respiratory distress syndrome inhaled nitric oxide in two concentrations for 40 minutes each. Hemodynamic variables, gas exchange, and ventilation-perfusion distributions were measured by means of multiple inert-gas-elimination techniques during nitric oxide inhalation; the results were compared with those obtained during intravenous infusion of prostacyclin. Seven patients were treated with continuous inhalation of nitric oxide in a concentration of 5 to 20 parts per million (ppm) for 3 to 53 days. RESULTS: Inhalation of nitric oxide in a concentration of 18 ppm reduced the mean (+/- SE) pulmonary-artery pressure from 37 +/- 3 mm Hg to 30 +/- 2 mm Hg (P = 0.008) and decreased intrapulmonary shunting from 36 +/- 5 percent to 31 +/- 5 percent (P = 0.028). The ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2), an index of the efficiency of arterial oxygenation, increased during nitric oxide administration from 152 +/- 15 mm Hg to 199 +/- 23 mm Hg (P = 0.008), although the mean arterial pressure and cardiac output were unchanged. Infusion of prostacyclin reduced pulmonary-artery pressure but increased intrapulmonary shunting and reduced the PaO2/FiO2 and systemic arterial pressure. Continuous nitric oxide inhalation consistently lowered the pulmonary-artery pressure and augmented the PaO2/FiO2 for 3 to 53 days. CONCLUSIONS: Inhalation of nitric oxide by patients with severe adult respiratory distress syndrome reduces the pulmonary-artery pressure and increases arterial oxygenation by improving the matching of ventilation with perfusion, without producing systemic vasodilation. Randomized, blinded trials will be required to determine whether inhaled nitric oxide will improve outcome.

Adolescent↗
PubMed1993

Long-term inhalation with evaluated low doses of nitric oxide for selective improvement of oxygenation in patients with adult respiratory distress syndrome.

OBJECTIVE: To evaluate the lowest dose of inhaled nitric oxide (NO) in patients with adult respiratory distress syndrome (ARDS), which is able to improve arterial oxygenation more than 30% compared to baseline data. DESIGN: Prospective, clinical study. SETTING: Anesthesiological ICU in a university hospital. PATIENTS: 3 consecutive patients with severe ARDS according to clinical and radiological signs. INTERVENTIONS: Pressure-controlled ventilation with positive end-expiratory pressure of 8-12 cm H2O. Inhalation of NO was performed with a blender system and a Servo 300 ventilator. The lowest effective NO dose was defined by titrating the inspiratory NO dose until reaching a 30% improvement of PaO2/FiO2. This dose was used for the following continuous long-term NO inhalation; controls of efficacy by investigation of hemodynamics and blood gas exchange were performed initially and 2 times per patient after intervals of 3-5 days. MEASUREMENTS AND RESULTS: Initial NO concentrations were found to be effective at 60, 100, and 230 parts per billion (ppb). In all measurements, arterial oxygenation was found to be elevated by NO inhalation with the initially evaluated dose compared to baseline data; in parallel, the venous admixture (Qva/Qt) was reduced. The O2 delivery increased, although O2 consumption and hemodynamics did not change. In 1 patient, interruption of NO inhalation caused remarkable increase of pulmonary resistance. CONCLUSIONS: The improvement of oxygenation by NO inhalation in ARDS does not require reduction of pulmonary resistance and can be performed using low doses in the ppb range, which has to be considered as probably non-toxic.

Administration, Inhalation↗
PubMed1993

Time-course and dose-response of nitric oxide inhalation for systemic oxygenation and pulmonary hypertension in patients with adult respiratory distress syndrome.

Inhalation of nitric oxide (NO), an endogenous vasodilator, was recently described to reduce pulmonary vascular resistance, and to improve arterial oxygenation by selective vasodilation of ventilated areas in patients with adult respiratory distress syndrome (ARDS). We describe the time-course and dose-response of initial short-term NO inhalation in 12 patients with ARDS. Enhanced oxygenation was achieved within 1-2 min after starting NO inhalation; after inhalation, baseline conditions were re-achieved within 5-8 min. Effective doses for improvement of oxygenation [baseline: PaO2 = 10.2 +/- 2.5 KPa (76.4 +/- 18.7 mmHg)] were low: ED50 was about 100 ppb--a concentration similar to the atmosphere. NO doses of more than 10 ppm [10 ppm NO: PaO2 = 17.3 +/- 3.3 KPa (129.4 +/- 25.1 mmHg)] re-worsen the arterial oxygenation. The ED50 for reduction of mean pulmonary artery pressure was 2-3 ppm. This indicates that inhalation of NO for improvement of oxygenation in severe ARDS should be performed using lower doses, with lower risk of toxic side effects.

Administration, Inhalation↗
PubMed1993

Arterial blood gas tensions during breath-hold diving in the Korean ama.

Korean female unassisted divers (cachido ama) breath-hold dive > 100 times to depths of 3-7 m during a work day. We sought to determine the extent of arterial hypoxemia during normal working dives and reasonable time limits for breath-hold diving by measuring radial artery blood gas tensions and pH in five cachido ama who dove to a fixed depth of 4-5 m and then continued to breath hold for various times after their return to the surface. Eighty-two blood samples were withdrawn from indwelling radial artery catheters during 37 ocean dives. We measured compression hyperoxia [arterial PO2 = 141 +/- 24 (SD) Torr] and hypercapnia (arterial PCO2 = 46.6 +/- 2.4 Torr) at depth. Mean arterial PO2 near the end of breath-hold dives lasting 32-95 s (62 +/- 14 s) was decreased (62.6 +/- 13.5 Torr). Mean arterial PCO2 reached 49.9 +/- 5.4 Torr. Complete return of these values to their baseline did not occur until 15-20 s after breathing was resumed. In dives of usual working duration (< 30 s), blood gas tensions remained within normal ranges. Detailed analysis of hemoglobin components and intrinsic oxygenation properties revealed no evidence for adaptive changes that could increase the tolerance of the ama to hypoxic or hypothermic conditions associated with repetitive diving.

2,3-Diphosphoglycerate↗
PubMed1993

Continuous pulse oximetry in the breath-hold diving women of Korea and Japan.

Arterial oxygen saturation during breath-hold diving has not previously been measured continuously. We devised a submersible, waterproof, backpack computer to continuously record heart rate, depth, and arterial oxygen saturation (SPO2) as determined by earlobe pulse oximetry. Our measurements showed that one assisted (Funado) diver had reduced SPO2 values immediately after surfacing from 22 dives which lasted 23-76 s, from a mean of 99 +/- 1% SPO2 to 96 +/- 3% SPO2. SPO2 returned to 97 +/- 2% within 15 s after surfacing (P < 0.05 surface value differs from predive base line). Four unassisted (Cachido) divers showed no significant reduction of mean predive SPO2 below 98 +/- 2% at any time during the dive or recovery period in 92 routine dives lasting from 15 to 44 s. Upon surfacing from diving, mean SPO2 was 98 +/- 2% and the mean SPO2 15 s after surfacing was 97 +/- 3% for the unassisted divers. Three Cachido divers were asked to dive and breath hold for as long as possible. Mean SPO2 at the conclusion of breath holding was 73% after an average dive and breath hold lasting 69 s.

Adult↗
PubMed1993

Inhaled nitric oxide: its effects on pulmonary circulation and airway smooth muscle cells.

Nitric oxide (NO), an endothelium-derived relaxing factor synthesized from L-arginine by the enzyme NO synthase, has been identified as an important, short-acting, endogenous vasodilator. In patients with pulmonary hypertension, inhaling a low dose of NO as a gaseous vasodilator has been shown to induce selective vasodilation in ventilated lung areas. It achieves this without the disadvantages attributed to systemically infused vasodilators e.g. systemic vasodilation and an increase in pulmonary right-to-left shunt with a consecutive fall in PaO2. Thus, inhaled NO reduces pulmonary hypertension in the severe adult respiratory distress syndrome and in persistent pulmonary hypertension of the newborn, and improves arterial oxygenation by redistributing pulmonary blood flow away from the shunt and towards areas with almost normal ventilation/perfusion ratios. The bronchodilatory effect of NO may be an alternative therapy for treating asthma and bronchospasm.

Administration, Inhalation↗
PubMed1992

Nitrogen tensions in brachial vein blood of Korean ama divers.

Intravascular bubble formation and symptoms of decompression sickness have been reported during repetitive deep breath-hold diving. Therefore we examined the pattern of blood N2 kinetics during and after repetitive breath-hold diving. To study muscle N2 uptake and release, we measured brachial venous N2 partial pressure (PN2) in nine professional Korean breath-hold divers (ama) during a 3-h diving shift at approximately 4 m seawater depth and up to 4 h after diving. PN2 was determined with the manometric Van Slyke method. Diving time and depth were recorded using a backpack computer-assisted dive longer that allowed calculating the surface-to-depth time ratio to derive the effective depth. With the assumption that forearm muscle N2 kinetics follow the general Haldanian principles of compression and decompression, i.e., forearm muscle is a single compartment with a uniform tissue PN2 equal to venous PN2, PN2 data were fitted to monoexponential functions of time. In the early phase of the diving shift, PN2 rapidly increased to 640 Torr (half time = 6 min) and then slowly declined to baseline levels (half time = 36 min) after the work shift. Peak PN2 levels approximated the alveolar PN2 derived from the effective depth. We conclude that forearm muscle N2 kinetics are well described by a Haldanian single-compartment model. Decompression sickness is theoretically possible in the ama; it did not occur because the absolute PN2 remained low due to the shallow working depth of the ama we studied.

Diving↗
PubMed1991

Influence of SIMV plus inspiratory pressure support on VA/Q distributions during postoperative weaning.

Since the introduction of synchronized intermittent mandatory ventilation (SIMV) several advantages have been attributed to this ventilatory mode, one of them being a more homogeneous distribution of ventilation and perfusion than during controlled mechanical ventilation (CMV). Up to now no data are available to confirm whether this is true when SIMV is used in combination with inspiratory pressure support (IPS). Therefore, we compared the influence of CMV and SIMV + IPS on the distributions of ventilation and perfusion in 9 patients undergoing weaning from postoperative mechanical ventilation. Continuous distributions of ventilation and perfusion were assessed using the multiple inert gas elimination technique (MIGET). SIMV + IPS did not induce any change in the hemodynamic or oxygenation parameters, in particular CI and PaO2 remained constant. Physiological dead space (VD/VT) increased, but PaCO2 remained unchanged due to increased minute ventilation (from 9.5 +/- 0.9 l.min-1 to 11.3 #/- 1.2 l.min-1). The perfusion distributions remained unaltered; there was no change in QS/QT nor in the perfusion of the low VA/Q lung regions. This result was underscored by the unchanged dispersion of the perfusion distribution (log SDQ). The increased VD/VT was caused by increased inert gas dead space (from 22.0 +/- 9.6 to 26.8 +/- 8.7%) which was accompanied by increased ventilation of lung regions with high VA/Q ratios (10 less than VA/Q less than 100) in 3 patients. These results show that in our group of patients partial removal of CMV together with pressure support assistance of spontaneous ventilation did not induce a clinically significant loss of the efficiency of the breathing pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗