Plasma lidocaine levels occurring with endotracheal administration during hemorrhagic shock

Plasma epinephrine levels after epinephrine administration using different tracheal administration techniques in an adult CPR porcine model

The aim of the study was to compare arterial plasma epinephrine levels after tracheal epinephrine application using three different tracheal instillation techniques at different tracheal levels in a porcine adult cardiopulmonary resuscitation model. In the prospective, randomized study, electrically-induced cardiopulmonary arrest was applied to 32 anaesthetized and paralyzed domestic pigs. After 3 min of cardiopulmonary arrest and 2 min of external chest compressions using a pneumatic compression device and mechanical ventilation, epinephrine was administered intravenously (20 microg/kg) or tracheally (50 microg/kg): using either direct injection into the upper end of the tracheal tube, via a catheter placed into the bronchial system and using a special tracheal application tube. In each group, there were eight pigs. Arterial blood samples were taken before and up to 10 min after epinephrine administration. Regression analysis was performed of the correlated data. The values of mean arterial blood pressure and end-tidal CO(2) during the time of observation did not differ between groups. Total plasma epinephrine concentrations showed a significant increase in all groups, but with no difference between the tracheal groups. However, peak epinephrine levels in the intravenous group were significantly higher than in tracheal groups. We conclude that administration using three different tracheal instillation levels result in similar onset and peak plasma epinephrine levels in this setting and therefore the preferred method of tracheal epinephrine application for cardiopulmonary resuscitation may be selected by other criteria.

The time required to perform different methods for endotracheal drug administration during CPR

We compared the times necessary to perform different endotracheal drug application techniques during CPR. In a simulated CPR situation with a mannequin 28 paramedics and seven emergency physicians performed different drug instillation techniques in a randomized manner: direct injection into the upper end of the endotracheal tube (group tube), via a suction catheter placed into the bronchial system (group suction catheter), via a flexible venous catheter placed into the bronchial system (group venous catheter), using an EDGAR tube (an endotracheal tube with an injection channel within the wall of the tube (group EDGAR). We measured the time necessary to prepare the drug solution and compared the time necessary to prepare and perform each instillation method and the time the ventilation was interrupted. Comparison between groups was performed by the Kruskal-Wallis test. It took significantly longer to perform the more complicated techniques using suction catheters (26; 18 54 s) and venous catheters (30; 22-50 s) compared to the other two groups (median; min-max) (p < 0.05). No differences concerning the application time were found between the group tube (7; 5 14 s) and group EDGAR (8; 5-13 s). The time of interruption of chest compression's and ventilation: group suction tube (11; 5-19 s) and group catheter (12; 6-18 s) was significant longer than in group tube (5; 2-9 s) (p < 0.05). In group EDGAR the connection ventilator-tube remained intact due to its concept of drug application. The use of special devices such as suction catheters or venous catheters for endotracheal instillation during CPR results in significantly longer preparation and instillation times with a longer interruption of the oxygen supply and chest compression's.

Plasma catecholamine levels following tracheal and intravenous epinephrine administration in swine

We compared plasma epinephrine levels after three different tracheal epinephrine application techniques and intravenous injection in male and female anesthetized and paralyzed domestic pigs. Epinephrine was administered intravenously (10 microg/kg) (group i.v.) or tracheally (100 microg/kg) either by direct injection into the upper end of the tracheal tube (group Tube), via a suction tube placed into the bronchial system (group Catheter) or using an EDGAR tube (group EDGAR), each group: n = 8. Arterial plasma samples were drawn before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7 and 10 min after epinephrine administration. Plasma concentrations of epinephrine were measured with high pressure liquid chromatography using electrochemical detection. Analysis was performed by regression analysis for correlated data. Total plasma epinephrine concentrations showed a significant increase within 0.5 min in all groups. However, peak plasma epinephrine levels in group i.v. were significantly higher than in tracheal groups, while no differences between tracheal groups over the time were found. We conclude that in swine with spontaneous circulation tracheal instillation techniques using special devices such as suction tubes or EDGAR tubes result in onset and peak plasma epinephrine levels equivalent to those after direct injection into the upper end of the tracheal tube.

The technique of endobronchial lidocaine administration does not influence plasma concentration profiles and pharmacokinetic parameters in humans

This study investigated plasma concentration profiles, pharmacokinetic characteristics and side-effects of lidocaine following 3 different administration techniques. Sixty ASA I/II patients undergoing elective ENT-operations were randomised into 4 groups. Lidocaine 1% (1 mg/kg) was administered 50 min before the end of the operation, via a regular endotracheal tube (group 1), a suction-catheter deep endobronchially (group 2), or an EDGAR-(Endobronchial-Drug and Gas Application during Resuscitation)-tube characterized by a separate injection channel ending at the orifice of the tube (group 3). For the control group, a regular endotracheal tube was inserted without lidocaine administration (group 4). Anesthesia was induced with propofol (2 mg/kg), sufentanil (0.5 micrograms/kg), and vecuronium (0.08 mg/kg) and continued as total intravenous anesthesia with propofol (8 mg/kg/h) and oxygen in air (FiO2 = 0.33). A control and 13 blood samples were taken up to 180 min after lidocaine administration. Lidocaine plasma concentrations were determined using a fluorescence polarization immunoassay (TDxFLx). Heart rate, blood pressure, endtidal PcO2, and oxygen saturation were similar in all groups investigated. Ventilation was interrupted for 3.6 +/- 0.5 s in group 1 and 10.2 +/- 0.8 s in group 2, to administer lidocaine. Patients from group 3 were ventilated continuously because of a separate injection channel integrated in the EDGAR-tube. Sore throat was significantly increased in group 2 as compared with groups 1, 3 and 4. Asorption of lidocaine in groups 1-3 resulted in maximal mean plasma concentrations ranging from 0.78 to 0.85 micrograms/ml after 16.9 to 22.4 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences in plasma lidocaine levels with endotracheal drug therapy secondary to total volume of diluent administered

Endotracheal drug therapy provides an effective alternative method for the administration of drugs in the numerous clinical settings in which intravenous access is difficult or impossible to obtain. However, the specific factors affecting endotracheal drug absorption and thus, the drug's plasma levels and effectiveness, has not yet been fully determined. Lidocaine alone or lidocaine mixed with normal saline was given endotracheally in four volumes (Volume I = undiluted with less than or equal to 5.5 cc total volume; Volume II = diluted to 6 cc total volume; Volume III = diluted to 12 cc total volume; Volume IV = diluted to 25 cc total volume) by the same technique of administration and in the same dosage of 4 mg/kg. Each dog served as its own control and received all four volumes of endotracheal lidocaine on different occasions. Plasma lidocaine levels at all four volumes and at all four time periods (5, 15, 30 and 60 min after giving endotracheal lidocaine) were obtained in each of the six dogs for a total of 96 plasma lidocaine levels measured in the study. Mean plasma lidocaine levels (micrograms/ml) at 5 min were: Volume I = 1.9, Volume II = 10.0, Volume III = 3.2 and Volume IV, = 4.3. These results were highly significant (P less than 0.001). The highest plasma lidocaine levels were obtained in the diluted volume, Volume II and the lowest plasma lidocaine levels in the undiluted volume, Volume I, with Volumes III and IV being intermediate.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of hypoxemia on pharmacokinetics of endotracheal lidocaine in dogs

Endotracheal administration is an effective alternative method for giving drugs in the many clinical situations in which it is difficult or impossible to quickly obtain an intravenous line. Yet whether various clinical conditions such as hypoxemia have any effect on endotracheal drug therapy is not known. Sixteen sets of plasma lidocaine levels were measured at 5, 15, 30, and 60 min after endotracheal lidocaine administration in eight dogs. Each dog was given the same dose of endotracheal lidocaine by the same technique of administration while in both a normal control state (Group I = 'Non-hypoxemia', mean Po2 = 98) and during hypoxemia (Group II = "Hypoxemia", mean Po2 = 36). Significantly higher plasma lidocaine levels occurred in the hypoxemic state (Group II) at time = 5 min while there was no significant difference in plasma lidocaine levels at time = 15, 30, and 60 min. Mean plasma lidocaine levels (micrograms/ml) at 5 min were: Group I = 1.38, Group II = 2.36 (significant at P less than 0.05). Plasma lidocaine levels were: Group I = 1.61 vs. Group II = 1.63 at time = 15 min, Group I = 1.11 vs. Group II = 1.10 at time = 30 min, and Group I = 0.54 vs. Group II = 0.51 at time = 60 min. Thus, there was a higher peak plasma lidocaine level and a shorter time to peak plasma lidocaine levels in the hypoxemic dogs.(ABSTRACT TRUNCATED AT 250 WORDS)