Biomedical subjects
Publications and source records attributed to C Leithner.
We present the case of a patient who required immediate intubation because of increasing upper airway bleeding. Endotracheal intubation failed because the glottis could not be visualized. An airway control device designed for cases of difficult emergency intubations was used successfully. This device can be inserted without the use of a laryngoscope.
A patient presented with neck impalement after a traffic accident. Respiratory arrest demanded immediate tracheal intubation, which was impossible as a wooden splinter had partially obstructed the pharynx and prevented laryngoscopy. An oesophageal tracheal Combitube airway was inserted successfully and the patient's lungs were ventilated adequately until tracheotomy was performed.
OBJECTIVE: To assess the influence of age on the outcome of patients receiving prolonged mechanical ventilation. DESIGN: Retrospective study. SETTING: Intensive care unit. PATIENTS: A total of 1,141 patients in our ICU during a 32-month period. A total of 536 patients required mechanical ventilation. After exclusion of 171 patients ventilated for less than 24 hrs after surgery, 365 patients were investigated. MEASUREMENTS AND MAIN RESULTS: Two hundred sixty-six (73%) patients were aged less than 70 yrs; 99 (27%) patients were greater than or equal to 70 yrs. There was no significant difference in mortality rate between the younger and the older age groups. There was no significant influence of other important factors, such as severity of illness, duration of mechanical ventilation, or length of ICU stay. The only factor showing a significant influence on patient outcome was the reason for mechanical ventilation. There were more survivors in the group being ventilated because of ventilatory insufficiency than in the group with oxygenation impairment (57.8% vs. 23.9%, p less than .001). CONCLUSION: An influence of age on the outcome of mechanically ventilated patients in the ICU could not be ascertained in this study.
In a retrospective study once-daily dosage of netilmicin was compared with the thrice-daily regimen in critically ill patients. Netilmicin given once daily for 5 days appeared to be as effective as the multiple dose regimen, with no increase in the incidence of nephrotoxicity.
4 cases of inadvertent puncture of the common carotid artery following unsuccessful puncture of the internal jugular vein leading to a massive cervical hematoma are described. In all cases, acute upper airway obstruction required immediate intubation.
The esophageal tracheal combitube (ETC) is designed for emergency intubation. The ETC is inserted blindly allowing ventilation after either esophageal or endotracheal placement. A special pharyngeal balloon serves to seal the upper airways. In 10 cardiac arrest patients, emergency intubation with the ETC was performed. Blood gas analyses showed adequate ventilation. Radiography proved correct placement of the proximal and distal balloons in accordance with design theory. Hyperinflation experiments documented expansion of the proximal balloon into the oral cavity rather than towards the epiglottis.
The esophageal tracheal Combitube (ETC) is a new airway especially designed for airway maintenance and ventilation in unconscious patients such as those requiring CPR. The ETC may be used as an esophageal obturator or an endotracheal airway. Previous studies yielded a significantly higher mean arterial oxygen tension (PaO2) during ventilation using an ETC in the esophageal position compared to a conventional endotracheal airway (ETA). To investigate this phenomenon, endotracheal and airway opening pressures were examined in 12 patients in randomized order during ventilation with an ETC in the esophageal position, with an ETA, and with a mask, respectively. In this study again the PaO2 was higher with ETC compared to ETA. The following differences in intratracheal pressure and flow could be found for ETC when compared to ETA: smaller rising pressure during inspiration, prolonged expiratory flow time, and formation of a small positive end expiratory pressure (PEEP). These factors may be responsible for the improved oxygen tension with ETC. Comparing mask to ETC ventilation, PaO2 did not differ; however, mean arterial carbon dioxide tension was higher during mask ventilation.
We examined the effect of spontaneous breathing with continuous positive airway pressure (CPAP) on the plasma concentrations of immunoreactive (ir) alpha-atrial natriuretic peptide (ANP). In three experiments, each of 11 healthy male volunteers performed CPAP at 20, 10 and 0 cm H2O for 2 h during continuous volume loading. Samples were drawn from a peripheral vein. Plasma concentrations of irANP were determined by a sensitive radioimmunoassay. Significantly lower concentrations of irANP were observed during 20 cm H2O CPAP than at 10 and 0 cm H2O. The concentrations of irANP did not differ significantly when individuals breathing with CPAP at 10 and at 0 cm H2O were compared. Our data suggest that CPAP at 20 cm H2O lowers the release of ANP in volume-expanded subjects. We hypothesize that this phenomenon may contribute to the fluid retention and renal dysfunction observed frequently during high CPAP levels. The decline in plasma concentrations of irANP may be the result of atrial compression by the distended lungs and of reduced venous return to the heart during CPAP.
The influence of PEEP during controlled mechanical ventilation (CMV) on plasma levels of alpha-atrial natriuretic peptide (alpha-ANP) was examined in seven patients suffering from acute respiratory failure. The majority of patients were volume-expanded. Samples were drawn from the superior vena cava, right atrium, pulmonary artery, and radial artery. All alpha-ANP levels were significantly depressed by 15 cm H2O PEEP for one hour, when compared to CMV without PEEP. During the PEEP period, cardiac index, creatinine clearance, urinary flow and urinary sodium excretion were decreased. CMV with PEEP of 20 cm H2O depressed peripheral venous plasma levels of alpha-ANP in six volume-expanded healthy volunteers, too. The decreased release of alpha-ANP could be a consequence of atrial compression by the distended lungs and of reduced venous return. We suggest that the decline in plasma alpha-ANP levels contributes to fluid retention and renal dysfunction, which occur frequently during CMV with PEEP. More detailed studies are necessary to confirm our hypothesis.
Prompt establishment of an airway is a primary goal in CPR of nonbreathing and unconscious patients. The esophageal tracheal combitube (ETC) is a new airway, designed for emergency intubation providing sufficient ventilation whether the airway is placed into the trachea or into the esophagus. We evaluated the effectiveness of the ETC in 31 patients during CPR. Blood gas analyses obtained during esophageal placement of the ETC showed results comparable to those of ventilation with a conventional endotracheal airway (ETA). The ETC appeared to oxygenate and ventilate patients adequately without complications. The efficacy, safety, and ease of insertion ensure rapid airway control. It is concluded that the ETC provides a sufficient alternative to the ETA whenever ideal conditions or trained staff for endotracheal intubation are not immediately available.
Mechanical ventilation in critically ill patients is usually performed with the conventional endotracheal airway. The esophageal tracheal combitube (ETC) is a new device for cardiopulmonary resuscitation, conceived to bridge the gap between hospital and prehospital phases. The ETC may be used in esophageal and endotracheal positions. The authors report six patients who were ventilated with the ETC in the esophageal obturator position for 2-8 h after emergency ventilation. Blood gas data showed adequate ventilation with the ETC during the observation period. Data suggest that mechanical ventilation with the ETC is possible for several hours after cardiopulmonary resuscitation. This might be helpful during the initial post-arrest period, when replacement of the ETC by a conventional endotracheal airway might destabilize a vulnerable patient.
There is good evidence that retention products accumulating in chronic renal insufficiency influence prostaglandin (PG) synthesis, thus affecting platelet-vascular wall interaction. The vascular PGI2 synthesis is increased and prolonged in vitro, the plasma factor activity enhanced. A defective platelet function is frequently observed; it is completely restored by peritoneal dialysis, but only partially by hemodialysis. The sensitivity of platelets to PGI2 and its plasmatic degradation are unchanged. There is evidence of a shift of arachidonic acid metabolism from cyclooxygenase to lipoxygenase. These changes may be attributed to undialyzable plasma constituents, the 'middle molecules'.
The levels of alpha-atrial natriuretic peptide (ANP) in the right atrium, pulmonary artery, radial artery, and superior vena cava plasma were measured by radioimmunoassay in eight patients with volume-expansion due to different diseases. The alpha-ANP levels were significantly increased, but became decreased after fluid removal by continuous veno-venous hemofiltration. When all alpha-ANP concentrations of different anatomical locations and hemodynamic variables were grouped, pulmonary capillary wedge pressure correlated significantly with all alpha-ANP groups, whereas right atrial mean pressure correlated with alpha-ANP levels in pulmonary artery plasma only. Alpha-ANP concentrations were distinctly lower in superior vena cava plasma than in plasma from the right atrium, pulmonary artery, and radial artery. Since alpha-ANP plays an important role in the homeostasis of sodium and fluid balance, measurement of alpha-ANP concentrations, particularly in right atrium, pulmonary artery, or radial artery plasma, might provide valuable information on the status of the critically ill.
Circulating amounts of human atrial natriuretic peptide (hANP) are elevated in congestive heart failure and renal failure. Stretching of cardiac atria, due to volume expansion associated with these diseases, is widely accepted to be the predominant stimulus for release of the hormone. Measurements of hemodynamic parameters as well as plasma concentrations of ANP in the right cardiac atrium, pulmonary artery, radial artery and vena cava superior, before and after continuous veno-venous hemofiltration (CVVH) of critically ill volume expanded patients, proved that ANP might be a useful indicator of fluid balance in these patients.
Although controlled mechanical ventilation (CMV) with positive end-expiratory pressure (PEEP) has a central place in the treatment of acute respiratory failure (ARF), several side effects of this technique have to be faced. CMV with PEEP may induce pulmonary barotrauma, disturbance of cardiac performance, impairment of renal function and fluid retention. Atrial natriuretic peptides (ANP) are released from the atria upon stretching and play a major role in the control of sodium and fluid balance. Therefore it was logical to determine plasma levels of alpha-ANP in CMV. A study performed in 7 patients suffering from ARF suggested that alpha-ANP plasma levels were depressed during PEEP at 15 cm H2O in comparison with PEEP at 0 cm H2O (ZEEP). The decrease in plasma levels of alpha-ANP was evident in samples taken from superior vena cava, right atrium, pulmonary artery and radial artery as well. The decrease in alpha-ANP was associated with a decline in cardiac index, creatinine clearance, urinary output and urinary sodium excretion. Experiments in volume- expanded healthy volunteers also suggest that CMV with PEEP is able to depress plasma levels of alpha-ANP. The reasons behind the decline in release of alpha-ANP may be atrial compression by the distended lungs and the well-known reduction of venous return to the heart. Other possible factors promoting fluid retention during CMV with PEEP are the decrease in cardiac index and glomerular filtration rate, changes in intrarenal distribution of blood flow, and a stimulation of release of antidiuretic hormone via stretch receptors in the left atrium and baroreceptors in aorta and carotid arteries.
Since the differential diagnosis between cyclosporine (CyA) nephrotoxicity and acute graft rejection is still a problem in clinical routine, we studied retrospectively the value of 111-indium (In) platelet scintigraphy in 53 patients immunosuppressed with CyA and prednisolone. Autologous platelets were labeled once per week. After daily gamma camera imaging, the platelet deposition in the graft was expressed as platelet-uptake ratio (PUR). The patients were monitored during the first 4-6 weeks after surgery. PUR values measured during an episode of graft dysfunction were compared to the histological diagnosis. The PUR of well-functioning and stable grafts measured 1.07 +/- 0.11 (mean +/- SD). The 111-In platelet scintigraphy failed to register acute interstitial rejection. The PUR values in episodes of chronic vascular rejection, of acute tubular necrosis due to prolonged ischemia times, of tubular CyA nephrotoxicity and of cytomegalovirus (CMV) infection did not differ from the PUR of well-functioning and stable grafts as well. The PUR was significantly increased to 1.48 +/- 0.26 because of a marked platelet deposition in the graft in episodes of acute vascular rejection. In 4 cases of microvascular CyA nephrotoxicity the same phenomenon of significantly increased PUR (1.33 +/- 0.18), could be encountered, too. Two of these 4 cases resembled the hemolytic uremic syndrome (HUS). The value of PUR measurement for diagnosis of acute vascular rejection and microvascular CyA nephrotoxicity together, was: sensitivity 0.62, specificity 0.95, predictive value of positive result 0.64, predictive value of negative result 0.94.(ABSTRACT TRUNCATED AT 250 WORDS)
During the last four years, we have performed two studies on the clinical application of 111In-platelet scintigraphy after renal transplantation. In the first study, we collected 75 patients who were treated with prednisolone and azathioprine. The platelet deposition in the graft was expressed as a platelet-uptake index (PUI). The results suggested that the platelet scan was a valuable tool for early detection of acute graft rejection, which was indicated by an increase in PUI. Quite different results were obtained in 50 patients immunosuppressed with cyclosporin A (CSA) and prednisolone. Acute interstitial rejection escaped detection by this diagnostic procedure. Significant elevations of PUI were observed in acute vascular rejection and microvascular CSA nephrotoxicity, resembling the haemolytic uraemic syndrome (HUS) only. Therefore, platelet deposition in the graft can be regarded as a non-specific phenomenon, occurring in two entities which require completely different therapeutic approaches. In spite of the monitoring by means of the platelet scan, percutaneous biopsy is still necessary for differential diagnosis of graft dysfunction.
After inhalation of prostaglandin I2 minimal effects on lung function and the cardiovascular system could be observed in healthy volunteers. Platelet function, however, decreased significantly. In the future the application of the prostaglandin I2 may be a new approach in the treatment of thromboembolic disorders in man.