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.

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 H(2)O with cricoid pressure to 14 cm H(2)O 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 hemodynamic responses to orotracheal intubation with the GlideScope videolaryngoscope and the Macintosh direct laryngoscope.

STUDY OBJECTIVES: To identify the hemodynamic responses to orotracheal intubation using a GlideScope videolaryngoscope (GSVL) in healthy adults, and to determine whether the GSVL could attenuate the hemodynamic response to orotracheal intubation compared with the Macintosh direct laryngoscope (MDLS). DESIGN: Randomized study. SETTING: Operating room, Plastic Surgery Hospital of the Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China. PATIENTS: 57 adult, ASA physical status I patients, scheduled for elective plastic surgery during general anesthesia requiring orotracheal intubation. INTERVENTIONS: Patients were randomly allocated to either the GSVL group (n = 30) or the MDLS group (n = 27). Anesthesia was induced with intravenous injection of fentanyl 2 microg/kg, propofol 2 mg/kg, and vecuronium 0.1 mg/kg. Orotracheal intubation was started two minutes after vecuronium injection. All intubation procedures were performed by a single anesthesiologist experienced in using an MDLS and a GSVL. After intubation, anesthesia was maintained with 1% isoflurane and 60% nitrous oxide in oxygen. MEASUREMENTS AND MAIN RESULTS: Noninvasive blood pressure (BP) and heart rate (HR) were recorded before (baseline values) and immediately after induction (postinduction values), at intubation, and for 5 minutes at one-minute intervals. Maximal BP and HR values during the observation and intubation times were also noted. The product of HR and systolic BP (ie, the rate-pressure product [RPP]) was calculated. Intubation time was significantly longer in the GSVL group than in the MDLS group (P < 0.01). Except for maximal value of diastolic BP in the GSVL group, increases in BPs during the observation in the two groups did not significantly exceed baseline values (P > 0.05). In the GSVL group, HR and RPP at intubation were significantly higher than their baseline values, and HR increases lasted for 4 minutes. In the MDLS group, HR at intubation was also significantly higher than its baseline value, but the tachycardic response lasted only for 1 minute. During the observation, there were no significant differences between the two groups in BPs, HRs, or RPPs at any time points or in their maximal values. CONCLUSIONS: The hemodynamic responses to orotracheal intubation using a GSVL and an MDLS were similar. The GSVL had no any special advantage over the MDLS in attenuating the hemodynamic responses to orotracheal intubation.