Endotracheal Route Research Articles

Pre-hospital cardiac arrest: room for improvement

Objective: To audit the outcome from pre-hospital cardiac arrest managed by ambulance personnel, and to assess their proficiency by analysing the time to initiate basic and advanced cardiac life support, the compliance with national guidelines, and the overall success of resuscitation. Design: A retrospective analysis of ambulance service report forms of pre-hospital cardiac arrests, where active resuscitation was attempted by ambulance personnel between October 1992 and May 1993. Setting: The City of Salford. Subjects: 100 consecutive patients who suffered cardiac arrest out-of-hospital and who were brought to the accident and emergency department of Hope Hospital alive, or with resuscitation still in progress. Results: Only 4 of 100 patients were successfully resuscitated out of hospital, of whom 2 survived to leave hospital. Detailed analysis of pre-hospital performance was performed on 89 patients only, as 11 report forms were missing (no successful pre-hospital resuscitations in this 11). Ventricular fibrillation was the first recorded rhythm in 51.7%, but 85.7% were in asystole or electromechanical dissociation on arrival at hospital. No patient who was still in cardiac arrest on arrival at hospital was successfully resuscitated. 11 patients received ‘bystander CPR’. The median time to basic life support was 6 min; the median call-to-response interval was 8 min; the median call-to-advanced cardiac life support interval was 21 min; the median on-scene time was 31 min (paramedics), or 15 min (technicians). The dose of drugs given by the intravenous route did not comply with the contemporary recommendations in 43.2%, and those doses given by the endotracheal route were inadequate in 37.9% of the cases. Endotracheal intubation was attempted in all paramedic resuscitations (91.4% success); intravenous access was attempted in 60.3% (91.7% success). Conclusions: The survival from pre-hospital cardiac arrest in this community is worse than the national average. There is no single explanation for this. Better community CPR training, greater efficiency at the scene through additional personnel, and stricter compliance with national ACLS guidelines, facilitated by extended refresher training, are all required if outcome is to be improved.

Pediatric resuscitation pharmacology

The goal of resuscitation pharmacology is to restart the heart as quickly as possible while preserving vital organ function during chest compression. Unfortunately, the application of advanced life support to pediatric cardiac arrest patients is often unsuccessful. The goal of this paper is to review the scientific rationale and educational considerations used to derive the guidelines for medication use in the pediatric patient during CPR. The first step in drug delivery during CPR is to achieve vascular access. The endotracheal route and intraosseous route may be used, although the former is not reliable. To maximize endotracheal drug effect, a larger dose should be instilled into the airway as deeply as possible. Any vascular access, including intraosseous, is preferable to endotracheal drug administration. Although other alpha-adrenergic agents are theoretically superior, epinephrine remains the drug of choice in pediatric resuscitation. The previously recommended dose, however, may be inadequate; a dose 10 to 20 times larger (100-200 micrograms/kg) should be considered, particularly if the standard dose is ineffective. Lacking convincing data, the indications and dose for calcium are unchanged. Similarly, there are no data advocating a change in the indications or dose for lidocaine, bretylium, or atropine. The treatment of arrest-induced acidosis remains controversial. The mainstay of therapy consists of efforts to maximize oxygenation and tissue perfusion. Bicarbonate is not a first-line drug; its use should be considered when the patient fails to respond to advanced life support efforts, including the administration of high-dose epinephrine. Bicarbonate may be helpful in the postresuscitation setting, but its use should not supplant efforts to maximize tissue perfusion. Adenosine is an effective and generally safe medication for the treatment of supraventricular tachycardia in infants and children. Therefore, its indications, dose, and toxicities should be included in the new guidelines. Finally, a summary of research initiatives are included, including a call for the development of a multi-institutional pediatric clinical resuscitation research group. Large numbers of patients must be enrolled in a standardized manner to better evaluate the benefits and adverse effects of various therapies. This includes the use of high-dose epinephrine, calcium, bicarbonate, and other buffer agents such as Carbicarb and THAM. Animal models simulating the etiology and pathophysiology of pediatric arrest also are needed. In both clinical and animal studies, neurologic outcome and long-term survival should be assessed rather than simply the rate of restoration of spontaneous circulation.

Epinephrine blood concentrations after peripheral bronchial versus endotracheal administration of epinephrine in dogs.

Emergency endotracheal drug administration has become an acceptable route for drug delivery during cardiopulmonary resuscitation. The purpose of the present study was to determine whether the site of endotracheal epinephrine injection is an important factor in its absorption. Epinephrine (1:1000), in a dose of 0.02 mg/kg diluted in 2 mL of saline, was given to ten anesthetized mongrel dogs. Each dog was studied twice: once when the epinephrine was injected into the endotracheal tube, and on another day, through the endotracheal tube via a flexible catheter wedged into a peripheral bronchus. Arterial blood samples for plasma epinephrine concentration determinations were collected, before and at 1, 2, 5, 10, 15, and 30 mins after each intratracheal drug administration. Both routes of epinephrine administration significantly increased plasma concentrations within 1 min of injection. Higher plasma epinephrine concentrations were achieved after peripheral bronchial epinephrine administration (maximal concentration 8.9 +/- 3.2 vs. 2.0 +/- 0.4 ng/mL), and the total dose absorbed was significantly (76.5 +/- 13.5 vs. 36.7 +/- 6.5 ng/min/mL, p < .05) higher. The time interval to reach maximal concentration was significantly shorter with the peripheral bronchial dosing than with the endotracheal route (1.3 +/- 0.2 vs. 2.7 +/- 0.5 min, p < .05). Neither group demonstrated a significant change in heart rate, and both had similar, minor decreases in BP for > 2 to 5 mins. There were no significant differences between the arterial blood gases of the two groups at various stages of the experiment. In dogs, epinephrine administered via the peripheral bronchial route has a clear pharmacologic advantage over the endotracheal route. This advantage may be more important during cardiopulmonary resuscitation conditions and other low flow states, and may account for the failure observed with the endotracheal route in recently published clinical reports.

Effects of an interferon inducer bropirimine on bleomycin-induced lung fibrosis in hamsters.

The antifibrotic effect of an interferon inducer, bropirimine (2-amino-5-bromo-6-phenyl-4(3H)-pyrimidinone, ABPP) was evaluated in bleomycin (BLM)-hamster model of lung fibrosis. ABPP is an orally active biological response modifier and has immunomodulatory, antiviral, and antineoplastic activities. The hamsters were randomized in four groups and treated with either bropirimine (100 mg/kg, intraperitoneally) suspended in carboxymethylcellulose (CMC, 10 mg/10 mg/ml) or CMC alone each day for sixteen days. After two days, the hamsters received either single bolus of BLM (7.5 U/5 ml/kg) or an equivalent volume of saline by the transoral endotracheal route. Groupings were assigned as: CMC + saline (CS), ABPP + saline (AS), CMC + BLM (CB) and ABPP + BLM (AB). Animals were sacrificed at fourteen days after intratracheal installation of either BLM or saline. Their lungs were lavaged and processed for morphometric and biochemical studies. ABPP had little effect in preventing BLM-induced weight loss and lung injury. ABPP was found to reduce the BLM-induced accumulation of collagen in the lung as measured by hydroxyproline content. The hamsters in AB group had significantly less collagen than the hamsters in CB group: 995 and 1157 micrograms hydroxyproline/lung, respectively. Administration of ABPP prevented the BLM-induced increase in the lung prolyl hydroxylase activity. The total number of monocytes and eosinophils recovered from the bronchoalveolar lavage fluid (BALF) of the AB group were significantly lower than that of the animals in CB group. However, the BALF supernatant protein content from animals in AB group (7.9 mg/lung) was significantly higher than that of CB group (4.5 mg/lung).(ABSTRACT TRUNCATED AT 250 WORDS)

Protective effect of serum antibody on respiratory infection of influenza C virus in rats

The effects of serum antibody on the replication of influenza C virus in the nose and lung were evaluated in rats challenged with the virus by the intranasal and endotracheal routes, respectively. Convalescent rat serum administered intraperitoneally prior to infection suppressed virus replication significantly in both the nasal and pulmonary tissues. Resistance achieved was however much greater in the lung than in the nose. Rats with a serum neutralizing antibody titer of 1:800 showed almost complete resistance to pulmonary virus infection, and virus yield from the lung was reduced 10- to 100-fold in animals with the antibody titer of 1:80-160 or less. In contrast, significant decrease in virus shedding from the nose was observed only in animals with a serum antibody titer of 1:800 or greater. The effect of adoptive transfer of monoclonal antibodies (MAbs) to haemagglutinin-esterase (HE) glycoprotein and matrix (M) protein on pulmonary virus replication was also examined. Anti-HE MAbs with neutralization activity prevented virus shedding from the lung almost completely whereas non-neutralizing anti-HE MAb and anti-M Mab showed no inhibitory effect.

High‐Frequency Jet Ventilation in Anesthetized, Paralyzed Dogs and Cats Via Transtracheal and and Endotracheal Tube Routes

SummaryThe ability of the SAV 6 high‐frequency jet ventilator to effectively ventilate three anesthetized, paralyzed cats (3.2–4.2 kg), two small dogs (7.2 and 10.0 kg), six medium‐sized dogs (20.5–25.0 kg), and three large dogs (36.0–43.0 kg) via a 14‐gauge (dogs) or a 16‐gauge (cats) catheter placed percutaneously into the trachea via the cricothyroid membrane or into a preplaced endotracheal tube was evaluated. The lowest driving pressure within the range of 0.25 to 2.0 kg/cm2 (1 kg/cm2= 14.2 psi) and the highest cycle rate within the range of 60 to 240 per minute that would generate a PaCO2 of 30 ± 3 mm Hg were determined.All animals could be ventilated to a PaC02 of 30 ± 3 mm Hg by the endotracheal tube and transtracheal route, except the largest dogs, which couid be ventilated to an average PaC02 of 36 mm Hg by the transtracheal route. The transtracheal route consistently required higher driving pressures and lower cycle rates than did the endotracheal tube route. Cats could be ventilated with a driving pressure of 0.25 kg/cm2; small dogs could be ventilated with 0.5 to 1.0 kg/cm2; medium‐sized dogs with 1.0 to 1.5 kg/cm2; and large dogs with 1.5 to 2.0 kg/cm2.The SAV 6 high‐frequency jet ventilator can effectively ventilate cats and dogs (7.2–43.0 kg) via a transtracheal catheter and an endotracheal tube.

A comparison of endotracheal and intravenous routes for atropine administration in anaesthetised dogs

AbstractThe endotracheal route for atropine administration was compared with the intravenous route in 50 anaesthetised dogs. The response to drug administration was recorded as the change in heart rate from a steady pretreatment value. An indication was found of a positive relationship between the dose and the response to atropine given endotracheally. The increase in heart rate following atropine administration was similar, in terms of magnitude and speed of onset, when given by the endotracheal route at 0–06 mg/kg, as compared with that obtained by the intravenous administration of atropine at 0–04 mg/kg (P&lt;0–05).

Endotracheal epinephrine is unreliable

When intravenous access cannot be obtained in an emergency, the endotracheal route of emergency drug administration can be used for epinephrine, atropine, and lidocaine. Optimal drug dosages for endotracheal administration as well as the amount and type of diluent are presently unknown. We compared central intravenous, peripheral intravenous, intraosseous, and intratracheal administration of epinephrine 1:10,000 in both normotensive and hemorrhagic shock dogs. The shock model consisted of 50% blood volume depletion over 15 min. Epinephrine was administered in a dose of 0.01 mg/kg (0.1 cc/kg) by the intraosseous route, central, and peripheral intravenous routes followed by a 5 cc normal saline flush. Intratracheal administration consisted of epinephrine 0.01 and 0.02 mg/kg diluted 1:1 and 1:2 with normal saline or sterile water and administered deep into the tracheo-bronchial tree using a 30-cm catheter. The effect of epinephrine was assessed by the response of the arterial blood pressure. Epinephrine was equally effective by the intraosseous, central intravenous, and peripheral intravenous routes in terms of time to onset of action, time to peak effect, and magnitude of effect on systolic, diastolic, and mean arterial pressures in both the shock and non-shock animals. The duration of effect was significantly longer (P less than 0.02) for the intraosseous route of administration. The endotracheal route of administration was unreliable and not reproducible in either the normotensive or shock animals. In 8/12 episodes in normotensive animals, including 5 trials with double doses of 0.02 mg/kg and dilutions of 1:1 and 1:2, and in 4/9 studies with shock animals including three with double doses, there was no discernable response of systolic or diastolic blood pressure.

Drug therapy of cardiopulmonary resuscitation in children.

In contrast to adults, cardiopulmonary arrest in infants and children is rarely an acute, primary cardiac event. Instead, it is often the terminal event in a progressive deterioration of respiratory or circulatory function. Successful resuscitation from cardiac arrest therefore is unusual in the paediatric patient and most survivors have persistent neurological impairment. Rapid vascular access and recall of drug dosages are major obstacles in treating paediatric emergencies. This paper reviews vascular access and alternative drug delivery methods. The endotracheal and intraosseous routes provide alternative sites for drug delivery, but the optimal doses and methods of drug administration via these routes are unknown. Indeed, although great progress in cardiopulmonary resuscitation (CPR) research has been made over the past 10 years, there are only limited data on paediatric arrest mechanisms and drug treatment. In this paper, recommended dosages and mechanisms of action of drugs useful during cardiopulmonary resuscitation are reviewed, highlighting recent data which suggest that changes in current drug recommendations may be needed. To avoid delays in management, precalculated tables of drugs should be readily available in emergency departments and other care areas where paediatric cases are likely to be seen. Adrenaline (epinephrine) remains the drug of choice in a cardiac arrest, but the most effective dose may be higher than currently used. Treatment of acidosis during the arrest concentrates on restoration of ventilation and blood flow and not on bicarbonate administration. In the post-arrest setting increasing data suggest bicarbonate may not be beneficial and may actually be detrimental. Calcium and atropine also have relatively minor roles in resuscitation pharmacology. Calcium is only indicated to treat hypocalcaemia, counteract the effects of hyperkalaemia or hypermagnesaemia, or reverse calcium channel blocker toxicity. Finally, the role of isoprenaline (isoproterenol), dopamine, dobutamine and adrenaline infusions to restore or maintain cardiovascular stability post-arrest is reviewed.

Emergency Drug Administration via the Endotracheal Route

Emergency Drug Administration via the Endotracheal Route

Selected Concepts and Controversies in Pediatric Cardiopulmonary Resuscitation

Although more than 80 years of research in cardiac resuscitation produced many important findings and greatly enhanced our understanding of the arrest state, outcome following pediatric cardiac arrest remains poor. Resuscitation guidelines have recently been published, but they may not reflect optimal therapy. Closed-chest compression-induced cardiac output may be higher in pediatric patients, particularly infants, than that previously reported in adults. To achieve higher cardiac outputs, direct cardiac compression is important; the recommended compression location has therefore been changed based on recent data. The optimal rate of compression, however, is uncertain, so further research is needed. Alternative vascular access sites, such as the endotracheal and intraosseous route for drug administration may permit more rapid drug delivery, but data suggest that a larger epinephrine dose than currently recommended should be used. It may also be helpful to dilute the drug in normal saline before endotracheal administration. Although experimental data suggest that a pure alpha-adrenergic agonist may be beneficial in a cardiac arrest, recent data show that epinephrine remains the drug of choice. Finally, the role of sodium bicarbonate in both the arrest and postarrest setting has become controversial. Recent data suggest that bicarbonate may be detrimental and that therapy of acidosis is best directed at improving perfusion, oxygenation, and ventilation. Alternative forms of therapy for acidosis, such as THAM and dichloroacetate may prove beneficial in the postarrest setting.

Comparison of Endotracheal and Peripheral Intravenous Adrenalin in Cardiac Arrest. Is the Endotracheal Route Reliable?

Accident and Emergency Department and University Department of Anesthesia, Leicester Royal Infirmary, Leicester, England

Comparison of endotracheal and peripheral intravenous adrenaline in cardiac arrest: Is the endotracheal route reliable?: Quinton DN, O'Byrne G, Aitkenhead AR. Lancet 1987; 1:828–829

Comparison of endotracheal and peripheral intravenous adrenaline in cardiac arrest: Is the endotracheal route reliable?: Quinton DN, O'Byrne G, Aitkenhead AR. Lancet 1987; 1:828–829

COMPARISON OF ENDOTRACHEAL AND PERIPHERAL INTRAVENOUS ADRENALINE IN CARDIAC ARREST

Twelve patients presenting to an accident and emergency department in asystolic cardiac arrest were randomly allocated to treatment with endotracheal adrenaline (five patients) or peripheral intravenous adrenaline (seven patients). Femoral-artery blood samples were taken for assay of adrenaline and noradrenaline. After intravenous adrenaline there was a good clinical and biochemical response, but after endotracheal adrenaline there was no change in serum adrenaline and no measurable clinical response. The endotracheal route of adrenaline administration is not reliable in out-of-hospital cardiac arrest.

Plasma atropine concentrations via intravenous, endotracheal, and intraosseous administration

To date, there have been limited studies on the pharmacokinetics of intravenous atropine and no pharmacokinetic studies on the endotracheal or intraosseous administration of atropine. This study examines the time to peak plasma concentration of atropine following intravenous, endotracheal, and intraosseous administration in anesthetized monkeys using a triple crossover design. Plasma atropine was assayed by a radioreceptor method. The time to peak plasma concentration of atropine was shortest with intravenous administration; and longest with endotracheal administration. The mean plasma concentration of atropine was significantly higher in intravenous administrations than in endotracheal administrations at 0.75 and 2 minutes; compared to that noted in intraosseous administrations, the concentration was significantly higher only at 0.75 minutes. The mean plasma concentration of atropine administered intraosseously was significantly higher than that of endotracheal administrations at 5 minutes and was greater than that of intravenous and endotracheal administrations for the samples collected from 5 to 30 minutes. The endotracheal and intraosseous routes provide alternatives to the intravenous administration of atropine when intravenous access is limited ornot available.

Effect of technique of administration on plasma lidocaine levels

There are many clinical situations in which IV access is unavailable, and the endotracheal route is a valuable alternative route for drug therapy. The optimal technique of endotracheal drug administration, however, has not been determined. Twenty-nine dogs were divided into five groups and given endotracheal lidocaine at two doses, 2 mg/kg and 4 mg/kg, by differing techniques: control, undiluted lidocaine in a syringe was given as a bolus; needle, the drug was given through a needle attached to the syringe; dilution, lidocaine was diluted approximately 1:1 with normal saline and the entire dilution was given as a bolus; normal saline (NS) followup, lidocaine in a syringe was given as a bolus, followed immediately by an equal bolus of normal saline; and catheter, the drug was given through a catheter that was placed inside and extended just beyond the endotracheal tube. Mean plasma lidocaine levels (microgram/mL) at five minutes were as follows (at a 2-mg/kg endotracheal lidocaine dose): control, 0.64; needle, 0.0; dilution, 3.1; and (at a 4-mg/kg endotracheal lidocaine dose) control, 1.0; needle, 0.6; dilution, 6.2; NS followup, 1.9; and catheter, 1.9. At all time periods with either dose of lidocaine (2 or 4 mg/kg), the highest plasma lidocaine levels occurred with dilution and the lowest with the needle method. These results were highly significant (P less than .001). The highest plasma lidocaine levels may be attained by diluting the drug with normal saline. Higher levels were achieved when the drug was given through a catheter or when the drug was followed with a bolus of normal saline.(ABSTRACT TRUNCATED AT 250 WORDS)

Pediatric resuscitation without an intravenous line

The case of a 3-month-old male infant who was found unresponsive and cyanotic in a crib at home is presented. On arrival in the emergency department the child was receiving basic cardiopulmonary resuscitation (CPR) by a rescue squad and was without vital signs in asystole. The patient achieved a stable rhythm and blood pressure before intravenous access was obtained. Epinephrine and atropine were given via the endotracheal route and sodium bicarbonate through intraosseous infusion.

Comparison of deep and shallow endotracheal administration of dionosil in dogs and effect of manual hyperventilation

The endotracheal route has been used as a second route of choice for administration of emergency drugs for several years; however, the optimal technique for administration of drugs by this route has not been clearly defined. One important aspect of technique involves the question of how distribution to the distal-most endobronchial tree is influenced by initial depth of endotracheally administered drug instillation and use of forced manual hyperventilation. This study demonstrates that depth of instillation of drugs administered by the endotracheal route may not be an important factor in the delivery of medications to absorptive sites in the lung. It appears, however, that forced manual hyperventilation is essential to assure bilateral and optimal distal delivery of endotracheally administered medications.

Resuscitation of the newborn. Endotracheal administration of epinephrine.

During cardiopulmonary resuscitation, when an intravenous line is not present or easily obtainable, the intracardiac injection of drugs has been a traditional route of choice. However, the intracardiac administration may be associated with serious complications. We have given epinephrine endotracheally to ten newborn infants who all had bradycardia that did not respond to ventilation with 100% oxygen, to heart compression or to bicarbonate infusion. Epinephrine, 0.1 mg/ml was injected directly into the tracheal tube, and ventilation was immediately continued. A standardized procedure has been chosen by giving 0.25 ml to the infants weighing less than 1 500 g, 0.5 ml to those weighing between 1 500 and 2 500 g, and 1.0 ml to those greater than 2 500 g. All infants had a return to normal heart rhythm within seconds after installation of the epinephrine solution. The establishment of an intravenous line in small infants can be difficult, and the infants are usually intubated before the injection of epinephrine is considered. The endotracheal route should therefore be the first route of choice in the absence of a rapidly obtainable vascular access.

Endotracheal administration of emergency medications.

When vascular access is delayed or unreliable in emergency situations, an endotracheal tube provides a rapid and reliable route for administration of medication. Epinephrine, lidocaine, and atropine have shown clinical efficacy when given by the endotracheal route. There is evidence that other medications including naloxone and diazepam may also be suitable for endotracheal use, but clear-cut recommendations await further studies of pharmacokinetics and toxicity.