Printer Friendly

Intraoperative awake tracheal intubation using the Airway Scope[TM] in caesarean section.

SUMMARY

The Airway Scope[TM], a novel videolaryngoscope used for tracheal intubation, is minimally invasive and can be used in conscious patients. The parturient with a potentially difficult airway should sometimes be intubated while awake, without anaesthesia or neuromuscular block. Two pregnant women who experienced massive postpartum haemorrhage during caesarean section underwent unscheduled intraoperative tracheal intubation using the Airway Scope. They were conscious and were intubated with minimal local anaesthesia so as to prevent cardiovascular compromise. We believe the Airway Scope is useful for anaesthetic procedures in the parturient who has haemodynamic instability.

Key Words: caesarean section, awake tracheal intubation, Airway Scope[TM]

**********

Unscheduled tracheal intubation is sometimes required as part of the induction of general anaesthesia during caesarean section. Tracheal intubation after a rapid sequence induction remains the first choice for airway management, but failed intubation can lead to life-threatening complications. The Airway Scope[TM] (AWS, Pentax, Tokyo, Japan; Figure 1) is a novel videolaryngoscope for tracheal intubation that provides a non-sightline view of the airway (1). This report describes the use of the AWS for intubation during caesarean section, performed under regional anaesthesia, when patients had massive intraoperative postpartum haemorrhage. Both patients provided permission for this report.

CASE 1

A 43-year-old, 162 cm, 61 kg, gravid 8 para 5 woman at 38 gestational weeks was scheduled for elective caesarean section due to placenta praevia. Her Mallampati classification was II and she wished to be conscious. Following epidural cathcterisation, spinal anaesthesia was performed using 0.5% hyperbaric bupivacaine 2.4 ml with fentanyl 10 [micro]g and morphine 150 [micro]g. Seventeen minutes after skin incision, an infant with good Apgar scores was delivered and the placenta removed. Postpartum haemorrhage followed and at 56 minutes into the operation, the parturient complained of abdominal discomfort. She was given epidural 2% lignocaine 6 ml. Porro's operation, a utero-ovarian amputation, was performed to control bleeding and complete the surgery. The estimated blood loss was 4740 ml and the patient's systolic blood pressure had decreased to 60 mmHg. It was decided to convert to general anaesthesia and in view of the severe hypotension, to perform tracheal intubation with the AWS while the parturient remained awake. The AWS was inserted using topical lignocaine jelly as far as the pharynx, where the Intlock blade[R] made mucosal contact. The AWS with its preloaded tracheal tube was then advanced so that the tip of the Nade was positioned below the epiglottis and the AWS adjusted to show the glottis, centred in the cross mark of the scope's monitor. A size 6.5 mm tracheal tube was passed smoothly into the trachea, the AWS detached and removed. Adequate ventilation was confirmed with capnography, after which midazolam 3 mg and fentanyl 90 [micro]g were administered intravenously.

In spite of rapid transfusion, the patient remained hypotensive (systolic blood pressure 80 mmHg), so a central venous catheter was placed in the right internal jugular vein and a dopamine infusion commenced. Anaesthesia was maintained initially using midazolam, guided by bispectral index monitoring and, after stabilisation of haemodynamic status, with a propofol infusion at 2-4 mg/kg/hour. Total blood loss was 7430 ml and operation time was 311 minutes. Transfusion included 1960 mi of red blood cells and 1350 ml of fresh frozen plasma. The patient was extubated in the operating room and experienced temporary hoarseness on the first postoperative day.

[FIGURE 1 OMITTED]

CASE 2

A 33-year-old, 151 cm, 64 kg, gravid 1 para 0 woman at 38 weeks of gestation was scheduled for elective caesarean section due to uterine fibroids. Her Mallampati classification was II. Spinal anaesthesia was performed using 0.5% hyperbaric bupivacaine 2.4 ml with fentanyl 10 [micro]g and morphine 150 [micro]g. The infant was delivered 13 minutes after skin incision and the placenta delivered after 17 minutes, but massive bleeding occurred (the estimated initial blood loss being 3465 ml). At 93 minutes after the spinal anaesthetic commenced, her systolic blood pressure had decreased to 70 mmHg. Tracheal intubation of the awake parturient, using the AWS with lignocaine jelly to anaesthetise the pharynx, was performed smoothly at the first attempt. Following intubation, general anaesthesia was induced using intravenous midazolam 2 mg and fentanyl 190 [micro]g. The caesarean section lasted 182 minutes and total blood loss was 5055 ml. The patient was extubated in the operating theatre, although she subsequently required transluminal uterine arterial embolisation for continued bleeding.

DISCUSSION

The AWS is a novel instrument for tracheal intubation (1). It has an in-built liquid crystal display on which a camera attached to the tip of the instrument displays a laryngeal view. A single-use blade (Intlock blade) covers the camera and a tracheal tube is attached to the outside. For tracheal intubation, the blade is positioned under the epiglottis and elevates it, such that the glottic opening can be viewed with the camera. Tracheal intubation is considered easier with the AWS than with a Macintosh laryngoscope and the time to intubation is reduced compared with a fibrescope (2). However, practice is needed with new devices for tracheal intubation and anaesthetists should become familiar with the AWS in scheduled elective non-obstetric surgery before considering its use in emergency cases.

[FIGURE 2 OMITTED]

Indications for general anaesthesia in the parturient include the need for rapid delivery of the foetus, failed regional block, supplemental surgical procedures such as emergency obstetric hysterectomy and maternal resuscitation. When converting to general anaesthesia intraoperatively because of massive haemorrhage during caesarean section, unstable maternal haemodynamics may be worsened by anaesthetic drugs used to facilitate tracheal intubation. Fibreoptic intubation is considered a method of choice for awake intubation in this situation because it is less invasive than direct laryngoscopy with a Macintosh laryngoscope. However, fibreoptic intubation takes several minutes, may not always be readily available and is difficult for inexperienced anaesthetists. Few obstetric anaesthetists report experience with fibreoptic intubation of conscious parturients (3). Intubation with the AWS under topical local anaesthesia, with or without sedation, may be less invasive in awake patients (4). Local anaesthetic can be delivered onto the larynx by means of the Intlock blade (Figure 2).

The patients we have described did not appear likely to be difficult to intubate using a Macintosh laryngoscope, but the severity of their hypotension was such that we wished to perform awake intubation to avoid worsening haemodynamic instability from anaesthetic drugs. Experience and training in tracheal intubation of pregnant women has decreased (3,5). During training for AWS, the laryngeal view is seen on a monitor and the view can be shared with other anaesthetists and recorded. The AWS appears to require less procedural experience than the Macintosh laryngoscope, because non-anaesthetic residents required fewer attempts and less time to intubate than when using a Macintosh laryngoscope (3).

In summary, we have described two women who underwent unscheduled intraoperative awake tracheal intubation during caesarean section. The AWS appears useful for the parturient with haemodynamic instability due to massive haemorrhage.

Caption: Figure 1: Airway Scope[TM]. The in-built display monitor shows a non-sightline laryngeal view provided by a camera attached to the tip of the scope. A single-use blade, with the tracheal tube attached to its side, covers the camera.

Caption: Figure 2: Injection port through the Intlock blade[R] of the Airway Scope[TM]. A coloured injection catheter (black triangle) passes through the Intlock blade (solid arrow). Local anaesthetic can be administered onto the larynx. Dotted arrow: camera covered with the Intlock blade. White triangle: tracheal tube attached to the outside of the Intlock blade.

REFERENCES

(1.) Koyama J, Aoyama T, Kusano Y, Seguchi T, Kawagishi K, Iwashita Tet al. Description and first clinical application of AirWay Scope for tracheal intubation. J Neurosurg Anesthesiol 2006; 18:247-250.

(2.) Hirabayashi Y, Seo N. Tracheal intubation by non-anesthesia residents using the Pentax-AWS airway scope and Macintosh laryngoscope. J Clin Anesth 2009; 21:268-271.

(3.) Collis R, Evans M, Farley C, Chethan D. Anaesthesia for caesarean section: general anaesthesia. In: Clyburn R Collis R, Harries S, Davies S (eds). Obstetric Anaesthesia. New York: Oxford University Press 2008; p. 311-366.

(4.) Jarvi K, Hillermann C, Danha R, Mendonca C. Awake intubation with the Pentax Airway Scope. Anaesthesia 2011; 66:314.

(5.) Hawkins JL. Anesthesia-related maternal mortality. Clin Obstet Gynecol 2003; 46:679-687.

N. KARIYA *, K. KIMURA ([dagger]), R. IWASAKI ([double dagger]), R. UEKI ([section]), T. TATARA **, C. TASHIRO ([dagger][dagger])

Department of Anesthesiology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan

* MD, Associate Professor.

([dagger]) MD, Resident.

([double dagger]) MD, Assistant Professor.

([section]) MD, Lecturer.

** MD, PhD, Professor.

([dagger][dagger]) MD, PhD, Hospital Director.

Address for correspondence: Dr N. Kariya. Department of Anesthesiology, Hyogo College of Medicine, Mukogawa-cho 1-1, Nishinomiya, Hyogo 663-8501, Japan. Email: nkariya@gmail.com

Accepted for publication on February 22, 2013.
COPYRIGHT 2013 Australian Society of Anaesthetists
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2013 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Case Reports
Author:Kariya, N.; Kimura, K.; Iwasaki, R.; Ueki, R.; Tatara, T.; Tashiro, C.
Publication:Anaesthesia and Intensive Care
Article Type:Clinical report
Date:May 1, 2013
Words:1454
Previous Article:Post-cardiac surgery thrombotic thrombocytopenic purpura with digital ischaemia.
Next Article:Spontaneous intracranial hypotension and epidural blood patch: a report involving seven cases.
Topics:

Terms of use | Copyright © 2017 Farlex, Inc. | Feedback | For webmasters