Comparison of mucosal pressures induced by cuffs of different airway devices

BACKGROUND

High pressures exerted by balloons and cuffs of conventional endotracheal tubes, the Combitube (Tyco Healthcare Nellcor Mallinckrodt, Pleasanton, CA), the EasyTube (Teleflex Ruesch, Kernen, Germany), the Laryngeal Mask Airway (LMA North America, San Diego, CA), the Intubating Laryngeal Mask Airway (Fastrach; LMA North America), the ProSeal (LMA North America), and the Laryngeal Tube (LT; VBM Medizintechnik, Sulz, Germany) may traumatize the pharyngeal mucosa. The aim of this study was to compare pressures exerted on the pharyngeal, tracheal, and esophageal mucosa by different devices designed for securing the patient's airways.

METHODS

Nineteen fresh cadavers were included. To measure mucosal pressures, microchip sensors were fixed on the anterior, lateral, and posterior surfaces of the proximal balloon and the distal cuff of the investigated devices. Depending on the respective airway device, the cuff volume was increased in 10-ml increments at the proximal balloon starting from 0 to a maximum of 100 ml, and in 2-ml increments at the distal cuff starting from 0 up to 12 ml.

RESULTS

Tracheal mucosal pressures were significantly higher using the Combitube compared with the endotracheal tube and the EasyTube. Maximal esophageal pressures were significantly higher using the EasyTube compared with the Combitube. Using cuff volumes according to the manufacturers' guidelines, we found the highest pharyngeal pressures with the Intubating Laryngeal Mask Airway versus all other devices. At maximal volumes, the Laryngeal Mask Airway, the Intubating Laryngeal Mask Airway, and the ProSeal induced significantly higher pharyngeal pressures compared with all other devices. Using a pharyngeal cuff volume of 40 ml, the Intubating Laryngeal Mask Airway followed by the Laryngeal Mask Airway exerted significantly higher pressures compared with the other devices.

CONCLUSIONS

Although some devices exhibit a somewhat higher mucosal pressure when compared with others, the authors believe that the observed differences of the cuff pressures do not suggest a clinically relevant danger, because the investigated devices, except the endotracheal tubes, are not intended for prolonged use.

[The importance of the esophageal-tracheal-double lumen tube for clinical use and emergencies]

Difficult intubation can unexpectedly occur in clinical practice and emergencies. Oxygenation must be maintained with resumed artificial ventilation. Besides tracheal intubation with an ETT as the "gold standard" of airway management, the esophageal-tracheal Combitube(R) (ETC; Tyco-Healthcare, Neustadt/Donau, Germany; www.combitube.org) is another interesting device that has been used satisfactorily in a variety of circumstances, specially for management of the difficult airway. The ETC has been used during prehospital and hospital emergencies. Now, anesthesiologists have managed the ETC successfully in clinical practice also. The anesthesiological management does not differ from the management in other difficult airway situations. The use of the Combitube needs an appropriate teaching and continuous clinical practice.

Influence of prostaglandin E1 on tissue ischemia during surgical repair of the abdominal aorta

OBJECTIVE

To evaluate tissue protection by PGE1 during leg ischemia in patients undergoing aortic surgery.

DESIGN

Randomized, controlled prospective clinical trial.

SETTING

Single university hospital.

PARTICIPANTS

19 consecutive patients undergoing abdominal aortic aneurysm repair.

INTERVENTIONS

Patients received infusions of 30 ng/kg/min of PGE1 or saline.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic variables, lactate, creatine phosphokinase, and thromboxane B2 (TXB2) were measured. In the control group, the decrease in cardiac index (CI) after aortic cross-clamping (AXC) persisted until unclamping together with a decrease in femoral venous O2 content (CfvO2). In the PGE1 group, CI returned to baseline with a trend toward greater CfvO2 levels. During reperfusion in the PGE1 group, O2 consumption and lactate levels exceeded preclamp values. Pulmonary hypertension occurred equally in both groups but did not correlate with TXB2, which was not altered by surgery or by PGE1 infusion.

CONCLUSIONS

Intraoperative PGE1 treatment offers no benefit and may exacerbate tissue ischemia during AXC by redistributing microcirculatory flow or limiting cellular oxygen utilization in a manner that overwhelms any possible protective effect.

Improved cardiac performance and reduced pulmonary vascular constriction by epinephrine administration via a left atrial catheter in cardiac surgical patients

Diminished left ventricular contractility and increased right ventricular afterload are issues in cardiac surgery. The usual administration of catecholamines (epinephrine) via the central venous (CV) catheter increases cardiac output, but also may increase pulmonary vascular constriction. Epinephrine was, therefore, administered via the left atrial (LA) catheter or the CV catheter in 8 cardiac surgery patients, each serving as his or her own control. The LA administration of epinephrine has an advantage with its immediate effect on the coronary circulation, while avoiding associated pulmonary vasoconstriction by passing through the systemic capillary bed before reaching the lung. It was found in this study that administration of epinephrine via an LA catheter increased the average cardiac output by 1.05 L/min, which was significantly (P < 0.05) greater than with administration via the CV catheter. With LA administration of epinephrine, systemic arterial pressure (systolic arterial pressure and diastolic arterial pressure) (SAP, DAP) were also elevated to a greater extent than by CV administration. On the other hand, pulmonary arterial pressures (systolic pulmonary arterial pressure and diastolic pulmonary arterial pressure) (SPAP, DPAP) were less elevated than by administration via the CV catheter. This produced increased coronary perfusion and a smaller increase in pulmonary vascular tone by LA administration in contrast to CV administration of epinephrine. It is concluded that epinephrine administration via an LA catheter improved myocardial performance and pulmonary perfusion due to direct entry of the agent into the coronary circulation and partial metabolism while passing through the systemic capillary bed before reaching the lung.

[Indications for the insertion of a central venous catheter in emergency situations]

The use of a central venous catheter (CVC) is associated with numerous complications despite its usefulness. Less experienced personnel have a higher complication rate, however complications are not totally avoidable even for more experienced persons. The complication rate increases under unfavorable working conditions. Therefore, the indication for a CVC even in the emergency situation must be considered very carefully.