Tracheal intubation conditions at 60 seconds in children, adults and elderly patients

Abstracts

JUSTIFICATIVA E OBJETIVOS: O rocurônio apresenta um início de ação mais rápido do que todos os outros bloqueadores neuromusculares adespolarizantes disponíveis comercialmente, permitindo a intubação traqueal em tempo similar ao da succinilcolina. Além do relaxamento das cordas vocais, também é importante para uma intubação rápida e segura, em que não haja reação ao tubo traqueal ou tosse após a sua colocação. Esse trabalho tem por objetivo comparar as condições de intubação traqueal com rocurônio (0,6 mg.kg-1) com escala clínica em crianças, adultos e idosos. MÉTODO: Após medicação pré-anestésica com midazolam, monitorização de rotina e indução da anestesia com propofol e fentanil, foram avaliadas, por escala clínica, as condições de intubação traqueal após 60 segundos, em 60 pacientes com idades entre 1 e 88 anos, estado físico ASA I a III, que receberam rocurônio (0,6 mg.kg-1) em 5 segundos. Os pacientes foram divididos em três grupos de acordo com a faixa etária: Grupo 1 (G1) crianças de até 12 anos, Grupo 2 (G2), adultos de 18 a 65 anos e Grupo 3 (G3), pacientes acima de 65 anos. Foram analisados os seguintes parâmetros: as condições de intubação traqueal por escala clínica, a pressão arterial e o pulso, aferidos antes (controle),após a indução, após a injeção de rocurônio, 3 e 5 minutos após a intubação traqueal. RESULTADOS: Todos os pacientes foram intubados com sucesso em 60 segundos, mas as condições clinicamente aceitáveis em 100% dos casos só foram obtidas nos adultos e idosos. Três crianças foram classificadas como em condições ruins devido à presença de tosse sustentada por mais de 10 segundos. Não houve alterações significativas da pressão arterial nem da freqüência do pulso durante o estudo. CONCLUSÕES: Nas condições desse estudo, a dose de 0,6 mg.kg-1 foi suficiente para intubação traqueal em 60 segundos em adultos e idosos. No entanto, foi insuficiente para obtenção de condições de intubação traqueal clinicamente aceitáveis em 60 segundos em 100% das crianças.

BLOQUEADORES NEUROMUSCULARES; BLOQUEADORES NEUROMUSCULARES; INTUBAÇÃO TRAQUEAL

SCIENTIFIC ARTICLE

Tracheal intubation conditions at 60 seconds in children, adults and elderly patients^*

Evaluación de las condiciones de intubación traqueal con rocuronio a los 60 segundos en niños, adultos y ancianos

Maria Cristina Simões de Almeida, TSA, M.D.^I; Rogério Silveira Martins, TSA, M.D.^II; Ana Lúcia Costa Martins, M.D.^II

^IDoutora em Medicina pela Universidade Johannes Gutenberg-Alemanha, Professora Adjunta da UFSC

^IIAnestesiologista do Hospital de Clínicas de Porto Alegre

^{Correspondence}

SUMMARY

BACKGROUND AND OBJECTIVES: Rocuronium has the fastest onset as compared to all other available nondepolarizing neuromuscular blockers, allowing tracheal intubation time similar to succinylcholine's. In addition to vocal cords relaxation, it is also important that there is no tube reactions (bucking) or coughing after its placement, in order to achieve fast and safe tracheal intubation. This study aimed at comparing intubation conditions after 0.6 mg.kg^-1 rocuronium at 60 seconds in children, adults and elderly patients.

METHODS: Following premedication with midazolam, routine monitoring and induction with fentanyl and propofol, intubation conditions at 60s were evaluated according to clinical criteria in 60 ASA I-III patients aged 1 to 88 years who received 0.6 mg.kg^-1 rocuronium in 5 seconds. Patients were divided in three groups according to age: Group 1 (G1) children up to 12 years of age; Group 2 (G2), adults aged 18 to 65 years; Group 3 (G3) patients above 65 years of age. The following parameters were evaluated: tracheal intubation conditions by clinical criteria, blood pressure and pulse measured before induction (control), after induction, after rocuronium injection, 3 and 5 minutes after tracheal intubation.

RESULTS: All patients were successfully intubated in 60s, but clinically acceptable conditions in 100% of cases were only achieved in adults and elderly patients. Three children were classified as having unacceptable conditions due to sustained cough for more than 10 seconds. There were no significant changes in blood pressure or pulse during the study.

CONCLUSIONS: In the conditions of our study, 0.6 mg.kg^-1 rocuronium was sufficient for tracheal intubation in 60 seconds in adult and elderly patients. It was, however, insufficient for clinically acceptable tracheal intubation conditions in 60 seconds in 100% of children.

Key Words: NEUROMUSCULAR BLOCKERS, Nondepolarizing: rocuronium; TRACHEAL INTUBATION

RESUMEN

JUSTIFICATIVA Y OBJETIVOS: El rocuronio presenta un inicio de acción mas rápido que todos los otros bloqueadores neuromusculares adespolarizantes disponibles comercialmente, permitiendo la intubación traqueal en tiempo similar al de la succinilcolina. Además del relajamiento de las cuerdas vocales, también es importante, para una intubación rápida y segura, que no haya reacción al tubo traqueal o tos después de su colocación. Ese trabajo tiene por objetivo comparar las condiciones de intubación traqueal con rocuronio (0,6 mg.kg^-1) con escala clínica en niños, adultos y ancianos.

MÉTODO: Después de pre-medicación con midazolam, monitorización de rutina e inducción de la anestesia con propofol y fentanil, fueron evaluadas, por escala clínica, las condiciones de intubación traqueal después de 60 segundos, en 60 pacientes con edades entre 1 y 88 años, estado físico ASA I a III, que recibieron rocuronio (0,6 mg.kg^-1) en 5 segundos. Los pacientes fueron divididos en tres grupos de acuerdo con la faja de edad: Grupo 1 (G1) niños de hasta 12 años, Grupo 2 (G2), adultos de 18 a 65 años y Grupo 3 (G3), pacientes mayores de 65 años. Fueron analizados los siguientes parámetros: las condiciones de intubación traqueal por escala clínica , y la presión arterial y el pulso, aferidos antes (control), después de la inducción, después de la inyección de rocuronio, 3 y 5 minutos después de la intubación traqueal.

RESULTADOS: Todos los pacientes fueron intubados con suceso en 60 segundos, más las condiciones clínicamente aceptables en 100% de los casos solo fueron obtenidas en los adultos y ancianos. Tres niños fueron clasificados con malas condiciones debido a la presencia de tos sustentada por más de 10 segundos. No hubo alteraciones significativas de la presión arterial ni de la frecuencia del pulso durante el estudio.

CONCLUSIONES: En las condiciones de ese estudio, la dosis de 0,6 mg.kg^-1 fue suficiente para intubación traqueal en 60 segundos en adultos y ancianos. No obstante, fue insuficiente para obtención de condiciones de intubación traqueal clínicamente aceptables en 60 segundos en 100% de los niños.

INTRODUCTION

Rocuronium (ORG 9426) is a steroid nondepolarizing neuromuscular blocker with 1/5 the potency of its analog vecuronium ¹. Its major characteristic is faster onset as compared to all other commercially available relaxants ², allowing tracheal intubation time similar to succinylcholine's ^3-5.

There are several studies in the literature on rocuronium for fast tracheal intubation and, in general, they have shown that children, adults and elderly patients may be easily intubated in 60 seconds or less ^4,6-9. However, it is difficult to compare tracheal intubation conditions with 0.6 mg.kg^-1 rocuronium among different age brackets since studies involved different methods.

Our study aimed at comparing tracheal intubation conditions with rocuronium at 60 seconds in children, adults and elderly patients using the scale recommended for pharmacokinetic studies with neuromuscular blockers ¹⁰.

METHODS

After the protocol approval by the Ethics Committees of Hospitals involved in the study and the informed consent of patients or tutors, participated in this study 60 patients aged 1 to 88 years submitted to elective surgeries under general anesthesia. Patients were divided in three groups according to age: Group 1 (G1) children up to 12 years of age; Group 2 (G2), adults aged 18 to 65 years; Group 3 (G3) patients above 65 years of age. Exclusion criteria were: pregnant or breastfeeding patients, neuromuscular, liver or renal diseases, patients under medication knowingly interfering with neuromuscular transmission and those with history suggesting hypersensitivity reactions to agents scheduled for the protocol.

Patients were premedicated with oral 7.5 to 15 mg midazolam (adults and elderly), or 0.5 to 1 mg.kg^-1 for children (maximum 15 mg orally). At operating room patients were monitored with ECG at D_II lead, pulse oximetry and noninvasive blood pressure. After oxygen under facial mask for 3 minutes, anesthesia was induced with fentanyl (3 to 5 µg.kg^-1) and 3 to 4 mg.kg^-1 (children) or 2 to 3 mg (adults and elderly) propofol. All patients received rocuronium in the fixed dose of 0.6 mg.kg^-1 in 5 seconds and tracheal intubation was performed in 60 seconds after rocuronium injection.

The following parameters were evaluated: tracheal intubation conditions by clinical criteria ¹⁰ and blood pressure and pulse measured before induction (control), after induction, after rocuronium injection, 3 and 5 minutes after tracheal intubation.

Descriptive measures and multiple correspondence analysis were used for statistical analysis and MANOVA was used for circulatory parameters. Significance level was p < 0.05.

RESULTS

Demographics data and physical status (ASA) are shown in table I. There has been a predominance of males in G1 and of ASA II and III in G2 and G3, respectively.

Brazilian Journal of Anesthesiology, 2004; 54: 2: 204 - 211

Tracheal intubation conditions at 60 seconds in children, adults and elderly patients

Maria Cristina Simões de Almeida; Rogério Silveira Martins; Ana Lúcia Costa Martins

Laryngoscopy conditions according to age are shown in table II. There have been excellent or good laryngoscopy conditions with vocal cords abducted or in intermediary position in all cases. The highest reaction rate was in item "cuff". Children have reacted more vigorously than adults and elderly, with limbs movement and even sustained cough.

Brazilian Journal of Anesthesiology, 2004; 54: 2: 204 - 211

Tracheal intubation conditions at 60 seconds in children, adults and elderly patients

Maria Cristina Simões de Almeida; Rogério Silveira Martins; Ana Lúcia Costa Martins

Figure 1 shows results according to multiple correspondence analysis. It is observed that less satisfactory intubation conditions are associated to tracheal tube reaction with limbs movement and/or cough. As to age, children had less favorable tracheal intubation conditions.

Brazilian Journal of Anesthesiology, 2004; 54: 2: 204 - 211

Tracheal intubation conditions at 60 seconds in children, adults and elderly patients

Maria Cristina Simões de Almeida; Rogério Silveira Martins; Ana Lúcia Costa Martins

Systolic blood pressure and pulse in different moments are shown in figure 2 and figure 3. In general, there have been no significant changes during the observation period.

Brazilian Journal of Anesthesiology, 2004; 54: 2: 204 - 211

Tracheal intubation conditions at 60 seconds in children, adults and elderly patients

Maria Cristina Simões de Almeida; Rogério Silveira Martins; Ana Lúcia Costa Martins

Brazilian Journal of Anesthesiology, 2004; 54: 2: 204 - 211

Tracheal intubation conditions at 60 seconds in children, adults and elderly patients

Maria Cristina Simões de Almeida; Rogério Silveira Martins; Ana Lúcia Costa Martins

DISCUSSION

Results have shown that all patients were intubated in 60 seconds with the conventional 0.6 mg.kg^-1 rocuronium dose, but tracheal intubation conditions were better in adult and elderly patients.

Clinical criteria, and not neuromuscular transmission monitors, have been indicated to evaluate tracheal intubation since masseter and diaphragm relaxation and anesthetic depth are better determinants of tracheal intubation conditions than adductor policis muscle relaxation ^11,12.

Tracheal intubation conditions depend on several factors, among them the induction agent, the use of opioids and neuromuscular blocker dose ^13-15.

In experimental animals, induction agents do not interfere with rocuronium potency ¹⁶. In humans, although being mild with intravenous anesthetics ¹⁷, there have been better conditions when rocuronium was associated to propofol ⁹, which per se suppresses laryngeal muscles electromyographic effect ¹⁸. It is used for tracheal intubation even without neuromuscular blockers, although some authors do not indicate its single use for this objective ^19,20. The simultaneous use of opioids, in addition to being associated to easier tracheal intubation, attenuates cardiovascular effects of laryngoscopy and tracheal intubation maneuvers ¹⁹.

The fact that all patients were successfully intubated in 60 seconds after 0.6 mg.kg^-1 rocuronium confirms previous observations of safe relaxation in situations when airway has to be rapidly sealed ^8,13,14. Major difference among groups was reaction to cuffs. Situations here defined as "clinically poor" in 3 pediatric patients suggest inadequate dose or time for diaphragm relaxation. Children with adequate mandible relaxation and open vocal cords, or with reactions, cough and diaphragmatic movements have already been observed by other authors ²¹, suggesting diaphragm relaxation time different than that observed for muscles implied in tracheal intubation.

The calculation of doses in mg.kg^-1 for pediatric patients, although easy, may lead to prescription errors. It is not uncommon that subdoses are administered based on this calculation, varying minus 45% to minus 25% as compared to those calculated as from body surface. In order to correct this deviation, it has been suggested that in children with up to 30 kg, dose should be (weight x 2)% of adult doses, and that for children above 30 kg, this calculation should be (weight + 30)% of adult doses ²². In the three cases with sustained cough optimal doses then should have been approximately 14, 7.2 and 15 mg, instead of 10, 6 and 10 mg. So, although not being a consensus ²³, it seems that the major advantage of doses above 2 times DE₉₅ is early relaxation, which is even more evident in children ²⁴.

A different explanation for poor conditions could have been insufficient time for relaxation. Hopkins et al. ²⁵ have indicated that for 0.6 mg.kg^-1 rocuronium, optimal time to obtain best conditions is approximately 70 seconds.

Differences in relaxation behavior in children and adults have already been identified ²⁶, among them potency. It is higher in neonates and infants as compared to adults or older children ²⁷.

Some cases were described in the literature of children with unexplained blockade installation delay with alcuronium ²⁸. This seems to be related to decreased cardiac output, with consequent decrease in the balance rate of the relaxant between blood and muscle tissue ²⁹. Invasive hemodynamic measurements were not used in this study, but studied children had no diseases followed by cardiac output decrease and, although not being able to state that this has not occurred, it seems unlikely that relaxation delay could have been caused by such clinical condition.

Fast tracheal intubation in all adults and elderly confirms data of pharmacodynamic studies that onset does not change with aging ^30,31.

The lower incidence of tube reactions with diaphragm movements or cough in adult patients is in line with the literature, which has shown by electromyography similar relaxation installation rate in laryngeal muscles and diaphragm ³². Other authors, however, have emphasized that tracheal intubation conditions with 0.6 mg.kg^-1 rocuronium are poorer than those obtained with 1 mg.kg^-1 succinylcholine ³³. So, there is a current trend to indicate 0.9 to 1.2 mg.kg^-1 rocuronium when the aim is to replace succinylcholine ^8,14,34-36.

Blood pressure and pulse changes, in general, had no clinical significance confirming previous circulatory stability observed with hypnotics and this neuromuscular blocker ³⁵.

Rocuronium dose used in our study has allowed for tracheal intubation in 60 seconds in all patients. However, for a fast and safe induction, it is important that in addition to laryngeal muscles, diaphragm and intercostal muscles are also blocked to prevent tracheal tube or cuff reactions. So, our data suggest that 0.6 mg.kg^-1 is insufficient to obtain clinically accepted conditions in children.

REFERENCES

Apresentado (Submitted) em 05 de maio de 2003

Aceito (Accepted) para publicação em 05 de agosto de 2003

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Correspondence to

Dra. Maria Cristina Simões de Almeida

Rua Renato Barbosa, 227 Jurerê Tradicional

88053-640 Florianópolis, SC

*

Recebido do (

Received from) do Hospital Universitário de Florianópolis e Hospital de Clínicas de Porto Alegre, RS

Publication Dates

• Publication in this collection
  29 June 2004
• Date of issue
  Apr 2004

History

• Received
  05 May 2003
• Accepted
  05 Aug 2003