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 Table of Contents  
ORIGINAL RESEARCH REPORT
Year : 2016  |  Volume : 13  |  Issue : 1  |  Page : 6-11

An audit of airway management in critically ill patients in a sub-Saharan tertiary hospital


1 Department of Anaesthesia and Intensive Care Unit, College of Medicine University of Lagos, Lagos, Nigeria
2 Department of Surgery, Cardiothoracic Unit, Lagos University Teaching Hospital, Lagos, Nigeria

Date of Web Publication2-Feb-2016

Correspondence Address:
Oyebola Olubodun Adekola
Department of Anaesthesia and Intensive Care Unit, College of Medicine University of Lagos, Lagos University Teaching Hospital, Lagos
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1595-9587.175480

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  Abstract 

Critically ill patients have poor physiological reserves, and are at increased risk of cardiopulmonary complications such as hypoxia, hypotension, arrhythmias and cardiac arrest when undergoing airway management. This study audited airway management in critically ill patients. Patients Method: A Prospective observational study in 120 critically ill adult patients who required endotracheal intubation over a one year period. Induction was with IV midazolam (0.15mg/kg), and suxamethonium (1.5mg/kg). Data collected included immediate complications (complications during intubation), and early complications (complications on days one to seven of tube insertion). Results: The median age was 32 years, males constituted 68 (56.6%) and female 52 (43.4%). One hundred and fifty-eight intubation attempts were recorded, one attempt to success in 93 (77.5%), and 2 attempts in 22 (18.33%). Difficult intubation occurred in 17 (10.49%), of whom 5 subjects had more than 3 intubation attempts, and 2 had surgical tracheostomy performed. The intubation aids used included stylet in 86.67%, bougie (3.33%), and laryngeal mask airway (1.67%). There was a significant association between the number of attempts at intubation, and trauma, bleeding, oesophageal intubation, aspiration or cardiac arrest, P<0.05. Tubal blockade occurred in 65 (36.31%) subjects after a median duration of 38.5 hours. Conclusion: This study elicited the need to review the airway management of critically ill patients in our institution, provide different airway and intubating devices during difficult intubation, and ensure appropriate training in airway skills.

Keywords: Airway management, complications, critically ill


How to cite this article:
Adekola OO, Kushimo OT, Ohuoba EI, Asiyanbi GK, Olusoji OO, Rotimi MK. An audit of airway management in critically ill patients in a sub-Saharan tertiary hospital. J Clin Sci 2016;13:6-11

How to cite this URL:
Adekola OO, Kushimo OT, Ohuoba EI, Asiyanbi GK, Olusoji OO, Rotimi MK. An audit of airway management in critically ill patients in a sub-Saharan tertiary hospital. J Clin Sci [serial online] 2016 [cited 2019 Oct 15];13:6-11. Available from: http://www.jcsjournal.org/text.asp?2016/13/1/6/175480


  Introduction Top


A critically ill patient often requires airway management for airway patency and/or mechanical ventilation.[1],[2] Airway management in the critically ill is, however, not without adverse effects, which can be as grave as cardiac arrest and death.[1],[2] The overall incidence of complications range between 28-54%.[1],[2] The reported complications include hypoxaemia (19.1-25%),[1] hypotension (9.6-20%),[1],[2] difficult intubation (8-22%),[1],[2] esophageal intubation (2-7.4%),[1],[2] and pulmonary aspiration (2-5.9%), especially after two or three attempts at intubation.[2],[4]

The risk of complication during endotracheal intubation in the critically ill is heightened by their poor cardiopulmonary reserve and the presence of coexisting medical conditions, which limit the choice of induction agents.[4],[5] Other risk factors include poor monitoring facilities, lack of specific guidelines for airway management in the critically ill, high risk of difficult intubation, and the level of competence in airway skills of the attending intensivists or anesthetist.[1],[2],[4]

This study investigated the complications that follow airway management in critically ill patients induced with intravenous midazolam and suxamethonium.


  Patients and Methods Top


The study was a prospective observational review of tracheal intubations in a sub-Saharan Teaching Hospital, with 6 beds in its general intensive care unit (ICU), which admits medical, surgical, paediatrics, and obstetric subjects, from April 2012 to April 2013. Approval from the Institution Human and Research Ethics Committee was obtained. 120 adult critically ill subjects requiring endotracheal intubation were recruited. Exclusion criteria include age younger than 18 years old, Mallampati III or IV, known sensitivity to suxamethonium, neuromuscular disorders such as Gullain-Barrie Syndrome and Myasthenia gravis, and obesity. In addition, refusal to participate in the study, potassium abnormalities, and cervical spine fracture were exempted.

Baseline vital signs were measured in all subjects; hypnosis was facilitated with intravenous (IV) midazolam 0.15 mg/kg and muscle relaxation with IV suxamethonium 1.5 mg/kg. An appropriate-sized endotracheal tube was inserted, bilateral air entry was confirmed and the endotracheal tube was secured. Following intubation the blood pressure, pulse rate and oxygen saturation were monitored for 10 min at 2 min interval.

Statistical analysis

Data collected included demographic indices, immediate and early complications following airway management, and the effect of the number of attempts at intubation on airway complications. This included complications during endotracheal intubation and the first seven days after intubation. Data were expressed as median, interquartile range, or absolute numbers, while the Chi-square was used to determine the association between attempts at intubation, airway skill experience of attending anesthetist, and complications. A P value of < 0.05 was considered significant for all tests. All analyses were performed using the Statistical Package for Social Sciences for Windows version 20 (SPSS, Chicago, IL).

The primary outcome included immediate complications arising during endotracheal intubation such as hemodynamic changes, oropharyngeal injury, and aspiration of gastric content, oesophageal intubation, difficult airway, and surgical tracheostomy.

The secondary outcome determined were the early complications of airway management occurring from 1-7 days following endotracheal intubation such as hypoxia, hypercapnia, mucous plugged of endotracheal tube, and accidental extubation, as well as the relationship between the duration of experience of anaesthetist and immediate complications, and the relationship between the number of attempts at intubation and immediate complications.

For the purpose of this study, the following definitions were used

Duration of intubation: Time from the introduction of laryngoscopy into the mouth until clinical confirmation of endotracheal tube placement and detection of end-tidal CO2 (if available).

Bradycardia: HR < 60 bpm or 20% decrease from baseline[5]

Tachycardia: HR > 100 or 20% increase from baseline[5]

Hypotension: SBP ≤ 90 mmHg (MAP ≤ 50 mm Hg) or 20% decrease from baseline

Severe hypotension: Systolic arterial pressure<80 mm Hg[5]

Hypertension: SBP > 160 or 20% increase from baseline

Hypoxemia: SPO2<90% during the intubation attempt[5]

Severe hypoxemia: SPO2<80%[5]

Regurgitation: Gastric contents, which required suction removal during laryngoscopy in a previously clear airway

Aspiration: Visualization of newly regurgitated gastric contents below glottis or suction removal of contents via the endotracheal tube.

Oropharyngeal injury: Trauma to any structure in the oropharynx such as gum, lip, mucosa of the mouth, or evidence of bleeding after insertion of laryngoscopy into the mouth or intubation.

Difficult airway: Clinical situation in which a conventionally trained Anesthesiologist experiences difficulty with mask ventilation, difficulty with tracheal intubation, or both.”[6]

Difficult intubation: Occurring when “proper insertion of the tracheal tube with conventional laryngoscopy requires more than three attempts or more than 10 minutes.”[6]

Cardiac arrest related to intubation: Asystole, bradycardia, or dysrhythmia with non-measurable mean arterial blood pressure requiring cardiopulmonary resuscitation during or within 5 min of intubation.


  Results Top


A total of 120 critically ill subjects were studied with a median age of 32 years (25th-75th quartile range, 25-45), including 68 males (56.7%) and 52 females (43.3%). The median duration of ICU admission was 4 days (25th-75th quartile range, 2.5-8) [Table 1]. A greater proportion of subjects who required endotracheal intubation had severe traumatic brain injury (38, 31.7%) followed by stroke (15, 12.5%), and severe eclampsia/HELLP syndrome (13, 10.8%), while the least number had severe burns (2, 1.67%) and severe tetanus (2, 1.67%), [Figure 1].
Table 1: Demographic and clinical characteristic of patients requiring airway management

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Figure 1: Patients diagnosis on admission to intensive care unit

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The median years of airway skill experience of the attending anaesthetist was 3 years (25th-75th quartile range, 2-4.5). The majority of intubations (79.2%) were performed by an anaesthetist with more than 2 years of airway skill experience, while in 3 anaesthetist with less than 6 months exposure, intubation was done under supervision by a senior registrar or consultant [Table 2].
Table 2: The Characteristic of attending anesthetists

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120 subjects were studied with 158 intubation attempts: 93 (77.5%) intubations were successful at the first attempt, 22 (18.33%) at the second attempt, and 5 (4.17%) required more than 3 attempts, including 2 patients whom had surgical tracheostomy. The risk of trauma to the oropharynx, including bleeding, oesophageal intubation, and cardiac arrest increased with the number of attempts at intubation, P < 0.05 [Table 3]. The intubation aids used included stylet in 86.67%, Eschermann bougie introducer (3.33%), and laryngeal mask airway (1.67%).
Table 3: The association between number of intubation attempts and early complications

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There were 162 immediate complications in 120 subjects; some subjects had more than one complication. The most common immediate complication was tachycardia in 43 (26.54%) followed by hypertension in 41 (25.31%), and difficult intubation in 17 (10.49%), and cardiac arrest in 5 (3.09%). Oropharyngeal injuries were observed in 10 (6.17%) subjects, involving abrasion of the mucosa, bleeding in the mouth after laryngoscopy, and/or intubation [Table 4]. There was a significant association between years of airway skill experience and cardiac arrest, or regurgitation, P < 0.05. A significant association existed between cardiac arrest and hypotension (P < 0.001).
Table 4: The immediate complications during endotracheal intubation

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There were 179 early complications reported; some subjects had more than one complication. One patient developed bilateral pneumothorax two days after surgical tracheostomy necessitating chest tube drainage and mechanical ventilation. The most frequent tube-related complications included tubal blockade after a median time of 38.5 hours (65, 36.31%), hypoxia (29, 16.2%), and hypercapnea (28, 15.64%), as well as cardiac arrest arising from mucous plugging of endotracheal tube (20, 11.17%). In addition, we observed tube kink (17, 9.50%) and unplanned extubation (19, 10.62%), [Table 5].
Table 5: Early complications of airway management

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  Discussion Top


The critically ill patient is prone to avoidable risk and complications such as hypoxia, arrhythmia and cardiac arrest during periods of apnea, as seen when undergoing endotracheal intubation. This may be attributed to their poor physiological reserve, as the majority of the patients require one form of organ support or another.[1],[2] Other factors implicated include the urgency of airway management, inadequate preparation, inadequate personnel, and equipment. However, adequate planning and preparation have been shown to minimize such complications.[2] In a sub-Saharan setting, the ICU condition, and preparation may be sub-optimal due to confounding variables, therefore avoidable risk and complications are not uncommon.

This study has demonstrated that airway complications in the critically ill are not uncommon in our ICU. The first attempt intubation success rate is lower (77.5%) and a higher number of our subjects' required surgical airway (2) than values reported by Simpson et al., a success rate of 91%, with one required surgical airway [1] In their review, Simpson et al.[1] attributed the high first attempt at intubation success rate of (91%) to the presence of highly skilled airway operators. Surprisingly, we also had highly skilled airway operator as 79.17% of our operators had more than two years' experience in airway skills. The intubation aid frequently used during first attempt intubation in our center is the stylet, while bougie and laryngeal mask airway are used after two or more intubation attempts.

We observed that the incidence of trauma to the oropharynx, bleeding, aspiration, and cardiac arrest increased with increasing number of attempts at intubation. However, none of our patients had damage to their teeth. Mort [3] during emergency intubation reported that the frequency of regurgitation and cardiac arrest increased by sevenfold, while that of hypoxaemia increased by 14 times after two attempts at intubation. There is, therefore, a need for specific guidelines on airway management in the critically ill with the intent of limiting the number of attempts at intubation. This will be in line with the Difficult Airway Society recommendations that during elective surgical procedure, intubation should not be attempted more than 3 times, after which further attempts at intubation should be suspended and the surgical procedure postponed.[8] However, suspending intubation in the critically ill may be an impossible mission, as often it is a lifesaving procedure, hence there is a need for modification in the guideline to suit the critically ill patient.

The incidence of difficult intubation (10.49%) in our study is higher than the values reported by Griesdale (4.8-9.6%).[2] The differences are probably due to variation in the definition of difficult intubation: Griesdale defined difficult intubation using laryngoscopic grade than three,[2] while we defined difficult intubation as occurring when “proper insertion of the tracheal tube with conventional laryngoscopy requires more than three attempts or more than 10 minutes.”[6]

The incidence of oesophageal intubation was within values of 1.3-9.7% reported in critical illness,[1],[2] and was associated with increasing number of attempts at intubation. Other factors which might have contributed to oesophageal intubation in our study included suboptimal positioning as a result of malfunction remote control position system and poor lightning during intubation due to the use of generator supply secondary to frequent power outages in the country, which may result in a poor laryngeal view. This is in agreement with observation in previous studies that proper preparation such as appropriate instruments, optimal intubating conditions, adequate personnel, optimal patient positioning and lighting before endotracheal intubation is paramount in the critically ill, as it influences success at intubation.[1]

The incidence of regurgitation and aspiration of gastric contents was higher than that reported by Simpson.[1] This may be based on our criteria for the diagnosis of aspiration, as we defined aspiration as the visualization of newly-regurgitated gastric contents below glottis or suction removal of contents via the endotracheal tube,[5] which is less rigid than the criterion used by Jaber et al.[4] who defined aspiration as the presence of a new, unexpected infiltrate on post-endotracheal intubation chest radiograph. Though a portable X-ray facility is available in our institution, post-intubation chest radiography is not a routine investigation in our institution, as this increases the financial burden on the patient in a poor resource economy.

The cardiovascular complications reported by us included tachycardia, hypertension, hypotension, bradycardia, and cardiac arrest. The incidence of severe hypotension was within values documented in previous reports.[1] This was contrary to our expectation because we believed that midazolam has a less depressant effect on the myocardium and is relatively cardiostable, therefore, should have minimal effect on the blood pressure, which was the basis of our choice of induction agent. However, the risk of developing hypotension has been reported to depend on the dose of the induction agent.[10] Simpson et al.[1] reported that the risk of developing hypotension was greater after midazolam or propofol than after etomidate, ketamine, or thiopental. In another study, the factors which increased the incidence of hypotension after propofol induction included patients 50 years and older, and those with American Society of Anaesthesiologists (ASA) class III or IV physical status.[11] Therefore, the choice of induction agent alone may not be the major determinant of hypotension, but confounding variables in the patients such as age (≥50 years), ASA status, and hemodynamic instability may contribute. We hope in future studies, to be able to investigate the effect of different doses of midazolam on hypotension. We observed a significant association between hypotension and cardiac arrest, which is similar to observations made in previous studies.[1],[7]

The overall rate of life-threatening complications (58.10%) in our study was higher than values of (40.35%) reported in previous studies.[2] This may be due to the high incidence of endotracheal tube blockade observed in the course of critical care in our review. The tube blockade was secondary to mucous plugging of the endotracheal tube, and resulted in hypoxia and hypercapnea. It was diagnosed during tube exchange as evidence by inspissated mucous plug in the endotracheal tube. The delay in diagnosis was because a greater proportion of the subjects lack a multiparameter monitor, which can measure the end-tidal carbon dioxide. The need for adequate and proper monitoring in critically ill patients, whose clinical conditions change drastically within few seconds, was brought to the limelight. The Association of Anaesthetist of Great Britain and Ireland recommended capnography to confirm correct placement of the endotracheal tube in all intubations.[12] The capnogram tracing can also be used in the diagnosis of tube blockade, rebreathing of carbon dioxide and increase carbon dioxide production.

In subjects with tube blockade, 30.77% had cardiac arrest, which we believed were preventable, hence endotracheal tube exchange is now routinely performed after 48 hours of endotracheal intubation in our institution. Other researchers however, did not report on tube blockade in their reviews.[1],[3],[4] There were episodes of unplanned extubation (accidental or self-extubation), and frequent tube exchange during the first seven days of ICU admission, which were related to longer duration of endotracheal intubation. This is not surprising as prolonged endotracheal intubation has been associated with multiple episodes of unplanned endotracheal intubation.[13] The practise in our institution in patients with prolonged period of unconsciousness is to perform a surgical tracheostomy after seven days of endotracheal intubation, while endotracheal tubes are changed at the intensivists' discretion. We, however suggest that the need for a surgical tracheostomy should be individualised, and tracheostomy should be performed as soon as possible especially in subjects who show evidence of possible prolong duration of unconsciousness or those requiring endobronchial toileting from copious secretions such as those with stroke, severe traumatic brain injury and severe tetanus.

The overall ICU mortality (65%) in this report is higher than in ICU located in developed nations (15.4-25%);[1],[2] multiple confounding factors may be responsible. Our admission consists of subjects with very poor clinical conditions, who present late either due to delayed referral from peripheral hospital or lack of bed space in the ICU. They usually arrive with clinical evidence of aspiration of gastric content, sepsis, cardiovascular instability and organ failure.

The limitations to this study include the fact that this is a single center observational study, in an ICU without specific airway guidelines. Despite, these limitations, this study has highlighted the need to review the airway management of critically ill patients in our institution with the intent to provide different airway and intubating devices during intubation, ensure appropriate training in airway skills, and provide adequate monitoring in all critically ill patients. Walz et al.[12] had earlier recommended that the implementation of training programs for ICU staff, immediate access to advanced airway devices, and the knowledge and incorporation of the ASA, difficult airway algorithm (DAA) may decrease the incidence of serious complications related to airway instrumentation. We suggest these recommendations be adopted by critical care managers in the sub-Saharan region.

 
  References Top

1.
Simpson GD, Ross MJ, McKeown DW, Ray DC. Tracheal intubation in the critically ill: A multi-centre national study of practice and complications. Br J Anaesth 2012;108:792-9.  Back to cited text no. 1
    
2.
Griesdale DE, Bosma TL, Kurth T, Isac G, Chittock DR. Complications of endotracheal intubation in the critically ill. Intensive Care Med 2008;34:1835-42.  Back to cited text no. 2
    
3.
Mort TC. Emergency tracheal intubation: Complications associated with repeated laryngoscopic attempts. Anesth Analg 2004;99:607-13, table of contents.  Back to cited text no. 3
    
4.
Jaber S, Amraoui J, Lefrant JY, Arich C, Cohendy R, Landreau L, et al. Clinical practice and risk factors for immediate complications of endotracheal intubation in the intensive care unit: A prospective, multiple-center study. Crit Care Med 2006;34:2355-61.  Back to cited text no. 4
    
5.
Martin LD, Mtyre JM, Shanks AM, Tremper KK, Kheterpal S. 3,423 emergency tracheal intubtaions at a University hospital: Airway outcomes and complications. Anesthesiology 2011;114:42-8.  Back to cited text no. 5
    
6.
Practice guidelines for management of the difficult airway. A report by the American Society of Anesthesiologists Task Force on management of the difficult airway. Anesthesiology 1993;78:597-602.  Back to cited text no. 6
    
7.
Difficult Airway Society. Rapid sequence induction guidelines: Rapid sequence induction, non-pregnant, no predicted difficulty. Available from: . [Last accessed on 2013 Apr 12].  Back to cited text no. 7
    
8.
Jaber S, Jung B, Corne P, Sebbane M, Muller L, Chanques G, et al. An intervention to decrease complications related to endotracheal intubation in the intensive care unit: A prospective, multiple-center study. Intensive Care Med 2010;36:248-55.  Back to cited text no. 8
    
9.
Practice guidelines for management of the difficult airway. A report by the American Society of Anesthesiologists Task Force on management of the difficult airway. Anesthesiology 1993;78:597-602.  Back to cited text no. 9
    
10.
Reich DL, Hossain S, Krol M, Baez B, Patel P, Bernstein A, et al. Predictors of hypotension after induction of general anesthesia. Anesth Analg 2005;101:622-8, table of contents.  Back to cited text no. 10
    
11.
AAGBI safety statement capnography outside the operating theatre. Available from: . [Last accessed on 2013 Apr 12].  Back to cited text no. 11
    
12.
Christie JM, Dethlefsen M, Cane RD. Unplanned endotracheal extubation in the intensive care unit. J Clin Anesth 1996;8:289-93.  Back to cited text no. 12
    
13.
Walz JM, Zayaruzny M, Heard SO. Airway management in critical illness. Chest 2007;131:608-20.  Back to cited text no. 13
    


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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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