H. T. Sun

The clinical observation of difficult laryngoscopy and difficult intubation in infants with cleft lip and palate

Background:  The aims of this study were to evaluate the incidence of difficult laryngoscopy in infants with cleft lip and palate and to observe its relationships with age, sites, and degrees of deformities.

Cricoid Pressure Impedes Insertion of, and Ventilation Through, the ProSeal Laryngeal Mask Airway in Anesthetized, Paralyzed Patients

BACKGROUND: We designed this prospective self-controlled study to assess whether cricoid pressure hampers placement of and ventilation through the ProSeal laryngeal mask airway (ProSeal LMA) in anesthetized, paralyzed adult patients. METHODS: After induction of anesthesia, the ProSeal LMA was inserted using the introducer tool with cricoid pressure advanced as far as possible, and the cuff pressure was set at 60 cm H2O. Ventilation adequacy and anatomic position were scored using measures previously described for ProSeal LMA assessment. Airway seal pressure was recorded. Cricoid pressure was then released, the ProSeal LMA further advanced and reseated, and the assessment repeated. RESULTS: Lung ventilation scores, anatomic position scores, and airway seal pressure were significantly better after release of cricoid pressure and reseating of the ProSeal LMA than in the first position, where the ProSeal LMA was seated with cricoid pressure (P < 0.05). Expiratory tidal volume during intermittent positive pressure ventilation was similar with and without cricoid pressure, but peak inspiratory pressure decreased from 28 cm H2O with cricoid pressure to 14 cm H2O without cricoid pressure (P < 0.05). CONCLUSIONS: Cricoid pressure applied before insertion hampered proper placement of the ProSeal LMA. Temporary cricoid pressure release during insertion allowed the device to be advanced to the proper position. After correct placement of the ProSeal LMA, application of cricoid pressure did not change tidal volume, but produced a significant increase in peak inspiratory pressure.

Comparison of haemodynamic responses to orotracheal intubation with GlideScope ® videolaryngoscope and fibreoptic bronchoscope

Background and objective: The GlideScope® videolaryngoscope is a newly developed laryngoscope for tracheal intubation recently introduced into clinical anaesthesia. In this randomised clinical study, we compared the haemodynamic responses to orotracheal intubation using a GlideScope® videolaryngoscope and a fibreoptic bronchoscope. Methods: Fifty‐six adult patients, ASA I–II scheduled for elective plastic surgery under general anaesthesia requiring orotracheal intubation were randomly allocated to either the GlideScope® videolaryngoscope group or the fibreoptic bronchoscope group. After a standard intravenous anaesthetic induction, orotracheal intubation was performed. Noninvasive blood pressure and heart rate were recorded before and after induction, at intubation and for 5 min after intubation at 1 min intervals. Results: As compared with the post‐induction values the orotracheal intubations using a fibreoptic bronchoscope and a GlideScope® videolaryngoscope resulted in the significant increases in blood pressures which did not exceed their baseline values. In the two groups, heart rates at intubation and within 2 min after intubation were significantly higher than their baseline values. However, there were no significant differences in blood pressures and heart rates at all time points, their maximal values and maximal percent changes during the observation and the times required to reach their maximal values between the two groups. Conclusions: The orotracheal intubations using a fibreoptic bronchoscope and a GlideScope® videolaryngoscope produce similar haemodynamic responses.

Glidescope®-assisted awake fibreoptic intubation : initial experience in 13 patients

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The circulatory responses to fibreoptic intubation: a comparison of oral and nasal routes

The circulatory responses to fibreoptic intubation under general anaesthesia were studied in 60 adult female patients who were randomly assigned to receive either the oral or nasal route for insertion. Non‐invasive blood pressure and heart rate were recorded before anaesthesia induction (baseline values), immediately after anaesthesia induction (post‐induction values), at intubation and every minute for a further 5 min. The product of heart rate and systolic blood pressure (rate pressure product) at every time point was also calculated. The results showed that both fibreoptic orotracheal intubation and fibreoptic nasotracheal intubation resulted in significant increases in blood pressure, heart rate and rate pressure product compared to baseline and post‐induction values. The times required to reach the maximum values of systolic blood pressure and heart rate were significantly longer in the fibreoptic nasotracheal intubation group than in the fibreoptic orotracheal intubation group. There were no significant differences between the two groups in blood pressure, heart rate and rate pressure product at any measuring point, or in the maximum values during observation. The time required for recovery of systolic blood pressure to the post‐induction value was not significantly different between the two groups, but the time required for recovery of heart rate to post‐induction value was significantly longer in the fibreoptic orotracheal intubation group than in the fibreoptic nasotracheal intubation group. It was concluded that both fibreoptic orotracheal and fibreoptic nasotracheal intubations could cause a similar magnitude of circulatory responses in general anaesthetised, female adults, but the tachycardic response to fibreoptic orotracheal intubation lasted longer than that to fibreoptic nasotracheal intubation.

Blood pressure and heart rate changes during intubation: a comparison of direct laryngoscopy and a fibreoptic method.

Blood pressure and heart rate changes during nasotracheal intubation under general anaesthesia were studied in 100 patients who were randomly allocated to fibreoptic bronchoscope or direct laryngoscopy intubation. Noninvasive blood pressure and heart rate were recorded before and immediately after anaesthesia induction, at anaesthesia intubation and every minute thereafter for 5 min. Nasotracheal intubation was accompanied by significant increases in blood pressure and heart rate compared to baseline values in both groups. Blood pressure and heart rate at intubation, and the maximum values of blood pressure during the observation were significantly higher in the fibreoptic bronchoscope group. However, the maximum values of heart rate were not significantly different between the two groups. Fibreoptic nasotracheal intubation may result in more severe pressor and tachycardiac responses than direct laryngoscopic nasotracheal intubation.

Different small-dose remifentanil blunting the cardiovascular response to laryngoscopy and intubation in children: a randomized double-blind comparison.

Background: The available data provide inconsistent results on the efficacy of small‐dose remifentanil attenuating the cardiovascular response to intubation in children. Therefore, this randomized double‐blind study was designed to assess the ability of different small doses of remifentanil on the cardiovascular intubation response in children, with the aim of determining the optimal dose of remifentanil for this purpose. Methods: One hundred and twenty‐four children aged 3‐9 yr were randomized to one of four groups to receive the following in a double‐blind manner: normal saline (Group 1), remifentanil 0.75 &mgr;g kg−1 (Group 2), remifentanil 1 &mgr;g kg−1 (Group 3) and remifentanil 1.25 &mgr;g kg−1 (Group 4). Non‐invasive blood pressure and heart rate were recorded before anaesthesia induction (baseline value), immediately before intubation (postinduction values), at intubation and at 1 min intervals for 5 min after intubation. Results: Tracheal intubation caused significant increases in systolic blood pressure and heart rate in Groups 1‐3 compared with the baseline values. The maximum percent increases of systolic blood pressure and heart rate were 10% and 26% of the baseline values, respectively, in Group 2; 5% and 14% in Group 3; and 1% and 8% in Group 4 compared with 27% and 37% in Group 1. Except for the Group 3 vs. Group 4 comparison, there were significant differences among the four groups in the maximum percent increases of systolic blood pressure and heart rate. Conclusions: When used as part of anaesthesia induction with propofol and vecuronium in children, bolus administration of remifentanil resulted in a dose‐related attenuation of the cardiovascular intubation response.

Circulatory responses to fiberoptic intubation in anesthetized children : A comparison of oral and nasal routes

BACKGROUND: Previous studies have demonstrated a significant difference in the circulatory responses in adults to fiberoptic nasotracheal intubation (FNI) and fiberoptic orotracheal intubation (FOI). But, it is unknown whether there is a clinically relevant difference in the circulatory responses in children to these two intubation methods. METHODS: In this randomized clinical study, we compared the arterial blood pressure and heart rate changes during FNI and FOI in 66 children, ASA physical status I-II, aged 3–9 yr scheduled for elective plastic surgery. After anesthesia induction with fentanyl-propofol and vecuronium, fiberoptic intubation was performed. Noninvasive arterial blood pressure and heart rate were recorded before (baseline values) and after anesthesia induction (postinduction values), at intubation, and every minute for the first 5 min after intubation. The maximum values of arterial blood pressure and heart rate during the observation were also recorded. RESULTS: The total intubation time was significantly longer in the FNI group than in the FOI group. Both FOI and FNI caused significant increases in arterial blood pressure and heart rate compared with the baseline and postinduction values. Arterial blood pressure and heart rate at intubation and after intubation, and their maximum values during the observed periods were significantly lower in the FNI group compared with the FOI group. The times required to reach the maximum values of systolic blood pressure and heart rate were significantly longer in the FNI group than in the FOI group, but the times required for recovery of systolic blood pressure and heart rate to postinduction values were significantly shorter in the FNI group than in the FOI group. After the intubation, the times required to reach the peak levels of systolic blood pressure and heart rate were not significantly different between the two groups. CONCLUSIONS: Both FOI and FNI can cause significant circulatory responses in healthy anesthetized children, and the circulatory responses to FNI are fewer and of a shorter duration than those to FOI.

The circulatory responses to tracheal intubation in children: a comparison of the oral and nasal routes

The circulatory responses to laryngoscopic tracheal intubation in 62 healthy children undergoing surgery requiring tracheal intubation were studied. They were randomly assigned to receive either the oral or nasal route for intubation. Baseline non‐invasive blood pressure and heart rate were recorded following induction of anaesthesia, at intubation and then every minute for 5 min. The percentage changes of systolic blood pressure and heart rate during the measurement period were calculated. The results demonstrated that intubation time was significantly longer in the nasal group. Both oral and nasal intubation caused significant increases in blood pressure and heart rate compared to baseline and postinduction values. However, there were no significant differences found between the two groups in relation to blood pressure and heart rate. The two groups were similar with respect to the percentage changes of systolic blood pressure and heart rate during the observation period. It is concluded that oral and nasal intubation using a direct laryngoscopy can result in a similar circulatory response in anaesthetised children.

A comparative study of hemodynamic responses to orotracheal intubation with fiberoptic bronchoscope and laryngoscope in children

Background : The purposes of this study were to further identify the hemodynamic responses to orotracheal intubation in children, using a fiberoptic bronchoscope (FOB) and a direct laryngoscope (DLS), and to validate whether the FOB can attenuate the hemodynamic response to orotracheal intubation compared with the DLS.