Christian Leithner

Evaluation of esophageal tracheal combitube in cardiopulmonary resuscitation.

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.

Influence of age on outcome of mechanically ventilated patients in an intensive care unit

ObjectiveTo assess the influence of age on the outcome of patients receiving prolonged mechanical ventilation. DesignRetrospective study. SettingIntensive care unit. PatientsA 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 <24 hrs after surgery, 365 patients were investigated. Measurements and Main ResultsTwo hundred sixty-six (73%) patients were aged <70 yrs; 99 (27%) patients were ≥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 <.001). ConclusionAn influence of age on the outcome of mechanically ventilated patients in the ICU could not be ascertained in this study.

Esophageal tracheal combitube, endotracheal airway, and mask: comparison of ventilatory pressure curves.

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.

Magnetic resonance imaging of the heart during positive end-expiratory pressure ventilation in normal subjects

ObjectivesMagnetic resonance imaging was used to assess the effects of ventilation with positive end-expiratory pressure (PEEP) on cardiac volumes, especially on atrial volumes as well as to determine semiquantitative measurements of spatial interactions between heart, lungs and chest. DesignProspective study with healthy volunteers undergoing mechanical ventilation with different levels of PEEP during magnetic resonance imaging. SettingMagnetic resonance unit, Institute of Diagnostic Imaging, Rudolfinerhaus Hospital. SubjectsTwelve healthy volunteers. InterventionsVolunteers were imaged, using a multislice-multiphase technique during spontaneous breathing and with PEEP values of O, 7, and 15 cm H2O. Measurements and Main ResultsAtrial as well as ventricular volumes, chest diameters, and midventricular contact between the heart and anterior chest wall were determined on transverse-oblique sections. Atrial volumes showed a progressive decline beginning at a PEEP of 7 cm H2O. Diastolic filling of both ventricles was reduced. A PEEP level of 15 cm H2O induced a significant increase in the sagittal-oblique but not in the transverse-oblique chest diameter. PEEP values of 7 and 15 cm H2O shortened the length of the midventricular contact between the heart and anterior chest wall. ConclusionsLeft and right ventricular enddiastolic volumes and stroke volumes decreased significantly during ventilation with PEEP at 15 cm H2O, as did end-systolic atrial volumes. Volume changes in association with changes of chest and heart configuration suggest external cardiac compression by the expanding lungs. Furthermore, this study illustrates the feasibility of magnetic resonance imaging in mechanically ventilated patients. (Crit Care Med 1994; 22:426–432)

Massive upper airway bleeding after thrombolytic therapy: Successful airway management with the combitube®

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.

Mechanical ventilation with positive end-expiratory pressure decreases release of alpha-atrial natriuretic peptide

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.

Esophageal tracheal combitube (ETC) for emergency intubation: anatomical evaluation of ETC placement by radiography.

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.

Ventilation via the esophageal tracheal combitube in a case of difficult intubation.

U NEXPECTED DIFFICULTIES or inability to intubate the trachea may arise during emergency intubation even by trained personnel. A new airway has been designed for cardiopulmonary resuscitation that can be used either as an esophageal obturator or endotracheal tube.‘g2 The Esophageal Tracheal Combitube (ETC) combines the functions of an esophageal obturator airway (EOA)3-7 and a conventional endotracheal tube (Fig 1) (Sheridan Catheter Corp, Argyle, NY). The ETC is a twin-lumen tube. One lumen acts as an EOA. It has perforations at the pharyngeal site of the ETC and a blind distal end. Therefore, esophageal contents cannot regurgitate via the perforations into the trachea. The second lumen has a distal open end. At the distal site, the ETC is surrounded by a conventional cuff. At the proximal portion, a special pharyngeal balloon is positioned. At the oral end, the two lumens are linked via short tubes with connectors. The ETC can be inserted without use of a laryngoscope. The ETC is in the correct position when the two printed rings lie between the teeth or between the alveolar ridges in toothless patients. Then, after inflation with 100 mL of air, the pharyngeal balloon occupies the space between the root of the tongue and soft palate, by pushing the latter in a dorsocranial direction, and seals the oral and nasal cavities. Subsequently, the distal cuff is inflated, sealing either the esophagus or trachea. In most cases of blind insertion the ETC goes into the esophageal position, and the patient is ventilated via the “esophageal” lumen. The gases exit via the perforations into the hypopharynx and from there into the trachea. Auscultation of breath sounds and the absence of gastric insufflation ascertain correct esophageal positioning. Absence of adequate ventilation via lumen no. 1 means that the ETC probably entered the trachea. Ventilation by lumen no. 2 should lead to adequate bilateral breath sounds. The case presented demonstrates prolonged ventilation in both the operating room and intensive care unit via the ETC after unsuccessful attempts to intubate the trachea with a conventional endotracheal tube.

Atrial natriuretic peptide release in response to different positive end-expiratory pressure levels.

ObjectiveTo assess the influence of different positive end-expiratory pressure (PEEP) levels on plasma atrial natriuretic peptide concentrations. DesignProspective, randomized study. SettingIntensive care unit of a university hospital. PatientsTwenty-seven patients who were mechanically ventilated due to acute respiratory failure. InterventionNone. Measurements and Main ResultsThe patients were randomized into three groups: in each group, a defined PEEP level (5, 10, or 15 cm H2O, respectively) was applied, alternating with zero PEEP (0 cm H2O) in consecutive order (reversal experiment). Blood samples for the determination of atrial natriuretic peptide concentrations were drawn from the pulmonary artery and the radial artery catheters. There were no decreases in atrial natriuretic peptide concentrations with a PEEP of 5 cm H2O, but significant decreases could be shown for PEEP values of 10 and 15 cm H2O. The patients of all groups were subjected to PEEP levels of 5, 10, 15, and 20 cm H2O in randomized order (step experiment). The data demonstrated a significant inverse correlation between changes in PEEP levels and changes in plasma atrial natriuretic peptide concentrations. ConclusionThe data suggest that the release of atrial natriuretic peptide is influenced by a PEEP of≥10 cm H2O, while a PEEP of ≤5 cm H2O does not disturb this cardiac endocrine function. (Crit Care Med 1993; 21:343–347)

Atrial natriuretic peptide decrease during spontaneous breathing with continuous positive airway pressure in volume-expanded healthy volunteers.

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.