Cardiovascular effects of fibrescope‐guided nasotracheal intubation

Abstract

SummaryThe cardiovascular efects ojjibrescope-guided nasotracheal intubation were compared to those o f a control group of patients who w'ere intubated using the Macintosh laryngoscope. The 60 Stimulation of the upper respiratory tract by laryngoscopy and tracheal intubation induces sympathetically-mediated tachycardia and hypertension.',? This pressor response can cause significant morbidity and mortality, and may be hazardous particularly for patients with cerebral or cardiovascular disease.'." It has been reported recently that fibreoptic orotracheal intubation under general anaesthesia produces a more severe pressor response than conventional intubation using the Macintosh Iaryngo~cope.~ Nasotracheal rather than orotracheal intubation is indicated in anaesthesia for intra-oral operations, when the presence of a transoral tube may obstruct surgical access. The cardiovascular changes appear to be minimal when fibreoptic nasal intubation is performed under local anaesthesia in awake but sedated patients.6 However, the responses to fibreoptic nasal intubation under general anaesthesia have not been investigated.There is evidence that the magnitude of the pressor response varies with the intubation technique;>' consequently, it is important to establish the cardiovascular effects of fibreoptic-assisted nasal intubation in anaesthetised patients. This study was designed to identify the heart rate and arterial pressure changes during nasal intubation effected with the fibreoptic laryngoscope and to compare them with those of nasal intubation effected with the Macintosh laryngoscope during general anaesthesia. Patients and methodsThe investigation was approved by the ethics committee of the South Birmingham Health Authority and informed written consent was obtained from each patient. Sixty fit (ASA class 1) patients aged between 16 and 48 years who required elective nasotracheal intubation for oral surgery under general anaesthesia were studied. Patients taking vasoactive drugs and those expected to present difficulty at intubation were excluded from the trial. The majority were scheduled for either the excision of impacted third molar teeth or the enucleation of maxillary cysts.Patients were premedicated orally with temazepam 20 mg, one hour before the operation. An intravenous cannula was sited and continuous ECG monitoring established in the anaesthetic room. Arterial pressure and heart rate were recorded at one-minute intervals with a Dinamap 1846 monitor and TR2000 printer. A 5-minute stabilisation period was allowed before baseline measurements were made. Anaesthesia was induced with a dose of thiopentone sufficient to obtund the eyelash reflex (usually 4-5 mg/kg over 30 seconds); then vecuronium was administered in a dose of 0.125 mg/kg. The patient's lungs were ventilated for 4 minutes with oxygen 50%, nitrous oxide 50% and isoflurane 1 % by means of a Guedel airway and a facemask attached to a Bain system with an initial fresh gas flow rate

Cardiovasular changes after placement of a classic endotracheal tube, double-lumen tube, and Laryngeal Mask Airway

“…2, respectively). Heart rate and MAP at baseline were significantly higher than values recorded at one, 3,5,10,15,20,25, and 30 minutes in Groups T and D (P b 0.01).…”

“…The usual hemodynamic responses to laryngoscopy and intubation in an anesthetized patient are hypertension, tachycardia [4], and arrhythmia [5]. The cardiovascular response to tracheal intubation, although transient, may be harmful to some patients, mainly those with myocardial or cerebrovascular disease.…”

Comparison of Hemodynamic Response and Complications in Patients with Difficult Airway Using Two Techniques-Retrograde and Fibreoptic Intubation

“…However, this was in contrast to study done by Sun et al [7], Smith et al [8] which showed no significant difference in blood pressure and heart rate between the two groups (p=0.13). This inter study difference may be related to their use of intravenous sedation prior to intubation which causes decrease in rise of mean arterial pressure and heart rate.…”

Haemodynamic Changes During Nasotracheal Intubation: A Comparision Between Direct Laryngoscopic and Fibreoptic Technique

“…The differences between our findings and those of Smith et al [5] may be due to differences in anaesthetic technique. Smith et al used vecuronium in the dose of 0.125 mg/kg.…”