Anesth Analg 2002;95:1098-1102
© 2002 International Anesthesia Research Society
GENERAL ARTICLES
Difficult Endotracheal Intubation in Patients with Sleep Apnea Syndrome
Mohammad A. Siyam, and
Dan Benhamou
Département d’Anesthésie-Réanimation, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Bicêtre Cedex, France
Address correspondence and reprint requests to Dan Benhamou, Département d’Anesthésie-Réanimation, Hôpital de Bicêtre, 94275 Le Kremlin-Bicêtre Cedex, France. Address e-mail to dan.benhamou{at}bct.ap-hop-paris.fr
 |
Abstract
|
|---|
Although sleep apnea syndrome (SAS) is common, studies assessing the anesthetic management of these patients are rare and consist mainly of case studies. We performed a retrospective case-control study to determine the incidence of difficult intubation in SAS patients and to determine the relationship between the severity of SAS and the occurrence of difficult intubation. Among 113 patients included (36 and 77 in the SAS and control groups, respectively), difficult intubation occurred more often in SAS patients than in controls (21.9% versus 2.6%, respectively; P < 0.05). No relationship was found between the severity of SAS and the occurrence of difficult intubation. Disappointingly, no single factor was associated with the occurrence of difficult intubation in SAS patients. We conclude that SAS is a risk factor for difficult intubation.
IMPLICATIONS: Because patients with sleep apnea syndrome have an increased risk of difficult endotracheal intubation and may present with cardiovascular disease, preoperative preventive measures should be undertaken to avoid untoward events.
|
Introduction
|
|---|
Two percent of women and 4% of men in the middle-aged US workforce meet the minimal diagnostic criteria for sleep apnea syndrome (SAS) (1). Because 93% of women and 82% of men with moderate to severe SAS have not been previously diagnosed (2), many patients with undiagnosed SAS undergo general or regional anesthesia. Nevertheless, SAS studies that concern anesthesia are rare (3) and consist mainly of case studies (4,5). One of the important issues of anesthesia management in patients with SAS is control of the upper airway. The concept of difficult endotracheal intubation in these patients is mostly derived from assumptions of anesthesia experts (6,7) and from case studies (8). Hiremath et al. (9) found a high prevalence of SAS in patients with difficult intubation. Gentil et al. (10) studied a small group of 18 patients undergoing ear, nose, and throat (ENT) surgery and found a (9) frequent percentage of difficult intubation (44%) in patients with SAS but also a high prevalence of difficult intubation in the control group. Moreover, the disease severity and the associated diseases were not mentioned. Although there are good theoretical grounds to suspect an association between the severity of SAS and the occurrence of difficult intubation, this remains speculative (11). Thus, we designed this retrospective case-control study to assess the incidence of difficult intubation in SAS patients, to assess the relationship between difficult intubation and the severity of SAS, and to search for any factor associated with difficult intubation in patients with SAS.
|
Methods
|
|---|
This retrospective study took place in a university teaching hospital between April 1999 and July 2001. All patients with a polysomnography-confirmed diagnosis of SAS who were undergoing surgery under general anesthesia were included in the study after approval by the Scientific Committee on Human Studies. SAS severity was measured by the apnea-hypopnea index (AHI), defined as the number of apnea and hypopnea events per hour of sleep, and the lowest oxygen saturation associated with an abnormal respiratory event during sleep (LSAT). For each SAS patient, the next two (or three when possible) control patients from the same week’s list were included in the study if they had the same sex, similar age (±10 yr), and were assigned to the same type of surgery. Patients were divided into two types of surgery: ENT and non-ENT surgery. Patients having any of following criteria were excluded: history of snoring, without a diagnostic polysomnography examination; age <16 yr; emergency surgery; and history of a predicted difficult intubation for other causes (temporomandibular joint malformation, laryngeal tumor or maxillary/mandibular injury in trauma patients). All patients who were not receiving general anesthesia with tracheal intubation were also excluded.
The two groups were compared for factors previously described as having an important relationship with SAS in the perioperative period (7). These factors included a history of smoking or excessive alcohol intake; history of previous tracheal intubation; history of arterial hypertension, right heart failure, pulmonary artery hypertension, cardiac arrhythmia, or coronary artery disease; and history of diabetes mellitus, depression, or gastroesophageal reflux. Preoperative hemoglobin (Hb) values were also compared. Difficult intubation was anticipated when the preanesthetic assessment performed by the anesthesiologist confirmed that the patient had a Grade III or IV Mallampati classification as modified by Samsoon and Young (12). Other risk factors of difficult intubation, such as neck extension, thyromental distance, and mouth opening, were also assessed. Difficult intubation was assessed by the anesthesiologist during laryngoscopy by using the Cormack and Lehane classification (13) and was defined as Grade III or IV, as well as the possibility of postextubation obstruction of the upper airway. Data pertaining to the stay in the postanesthesia care unit (PACU) were recorded: oxygen saturation on arrival, the minimal oxygen saturation, the need for morphine, the respiratory treatment applied (oxygen supplementation, nasal continuous positive airway pressure, and tracheal intubation), the length of stay in the PACU, and the occurrence of complications.
The sample size was calculated postulating that difficult intubation may occur in up to 1% of general-surgery patients (including ENT surgery) and in 20% of SAS patients. Considering a one-sided test with 
at 0.05 and ß at 0.2, 32 patients were necessary to show a significant difference between SAS and control patients (http://www.statistics.com).
Data are presented as mean ± SD or percentage when needed. Student’s t-tests, the Mann-Whitney U-test, and the 
2 test were used to compare the two groups. P < 0.05 was defined as statistically significant.
|
Results
|
|---|
Among 113 patients (12 women and 101 men) included, 36 and 77 patients were in the SAS and control groups, respectively. Three women and 33 men with SAS were included. Age varied from 16 to 82 yr. The general characteristics of the two groups are shown in Table 1. The AHI was 41.7 ± 22.1, and LSAT was 65.9% ± 18.1%. SAS surgery included bilateral turbinectomy, tonsillectomy, septoplasty, and uvulopalatopharyngoplasty. These procedures were often combined. In the preoperative period, no significant difference was found between the two groups for history of smoking, excessive alcohol intake, or previous tracheal intubation. Control group patients were more often classified as ASA status I than SAS patients. Arterial hypertension was more frequently encountered in SAS patients than in controls. Moreover, although this was not statistically significant, patients with SAS more frequently had right heart failure, coronary artery disease, and pulmonary artery hypertension and were more likely to have cardiac arrhythmias. Also, preoperative Hb values were significantly higher in SAS compared with control patients. Difficult intubation was more often anticipated and occurred more often in SAS patients compared with controls (Table 2, Figs. 1 and 2). The incidence of difficult intubation was not more frequent in patients operated on for SAS than in SAS patients undergoing surgery unrelated to SAS (18% versus 30%, respectively; not significant). For all patients, the anticipation of difficult intubation was significantly related to weight, body mass index (BMI), and difficult intubation (Table 3). This was not true in SAS patients. In SAS patients in whom difficult intubation was found, modified Mallampati class, BMI, AHI, and LSAT were not different from values obtained in SAS patients who underwent easy intubation (Table 4). This was also true for risk factors of difficult intubation (data not mentioned). In the PACU, oxygen saturation on arrival and morphine consumption were not different between the two groups (Table 2). However, in SAS patients the lowest arterial oxygen saturation was lower than in controls. SAS patients required respiratory treatment more often than control patients. SAS patients had more complications than control patients. All complications (mainly hypertension-related bleeding at the surgical site) occurred in the first hours of their PACU stay. Nevertheless, no life-threatening complication was noted.
View this table:
[in this window]
[in a new window]
|
Table 1. Preoperative and Intraoperative Characteristics of Control Patients and Patients with Sleep Apnea Syndrome (SAS)
|
|
View this table:
[in this window]
[in a new window]
|
Table 2. Characteristics of Difficult Endotracheal Intubation and Postoperative Events in Sleep Apnea Syndrome (SAS) and Control Patients
|
|
View larger version (31K):
[in this window]
[in a new window]
|
Figure 1. Distribution between sleep apnea syndrome (SAS) and control patients for modified Mallampati classification (P < 0.0001)
|
|
View larger version (31K):
[in this window]
[in a new window]
|
Figure 2. Distribution between sleep apnea syndrome (SAS) and control patients for Cormack and Lehane classification (P = 0.003)
|
|
|
Discussion
|
|---|
This study has mainly shown that, when compared with patients matched for sex, age, and surgery, patients with SAS exhibit preoperative cardiac disease more often and present with a more frequent incidence of difficult intubation and with postoperative oxygen desaturation in their PACU stay, requiring oxygen. Interpretation of these significant differences must be tempered by the retrospective nature of the analysis.
Many studies have demonstrated the relationship between arterial hypertension and the AHI (14,15). It is thus not surprising that, in our SAS patients, arterial hypertension was more prevalent than in control patients. Although the prevalence of arterial hypertension in our patients was slightly more frequent than in a standard SAS population (20%–40%) (15), this was related to a high AHI. Also, the prevalence of arterial hypertension was more frequent in the control group than in a similar population (3%–5%) (15). Many studies have also shown that patients with SAS are more likely to present with diabetes mellitus (16), depression (17), or gastroesophageal reflux (18). It is thus not surprising that only 33% of our SAS group had none of these diseases and that only 22% of patients with SAS were classified as ASA status I. Because apnea-induced hypoxemia during sleep stimulates erythropoietin production from the kidneys (7), Hb values were more than in control patients.
The prevalence of difficult intubation in our control group was more frequent than in a standard population. This is probably related to the large percentage of ENT surgery. Hiremath et al. (9) found that in 8 of their 15 patients with difficult intubation, SAS was diagnosed. The relationship between difficult intubation and SAS was strong enough to make the authors believe that "All patients who have a trachea that is difficult to intubate should be regarded as having SAS until excluded by clinical features and, where doubt exists, sleep studies." All patients with SAS should be regarded as having a high risk of difficult intubation. Several factors account for this increased risk. Obesity is significantly related to difficult intubation (19,20), and SAS patients present with a significantly greater BMI. Diabetes mellitus also increases the risk of difficult intubation (21) and is more frequently encountered in SAS patients. Finally, SAS patients frequently present with abnormal facial and upper airway morphology (retrognathia, short and thick neck, large tongue) well known to be associated with an increased risk of difficult intubation. In the letter of Gentil et al. (10), 18 patients operated for SAS were studied. The authors did not mention the associated diseases found in their patients and did not study the relationship between difficult intubation and the severity of SAS. Moreover, patients operated on for conditions unrelated to SAS were not included. Obese SAS patients often have an excess of pharyngeal tissue deposited mainly in the pharyngeal lateral walls. Theoretically, the larger the amount of pharyngeal tissue, the higher the AHI and the lesser the LSAT, and thus the greater modified Mallampati and Cormack and Lehane scores. There was, however, no clear relationship among BMI, AHI, LSAT, modified Mallampati score, or Cormack and Lehane score in this study. Moreover, we found that patients operated on for SAS did not present an increased risk of difficult intubation when compared with those with SAS operated on for unrelated indications. We also demonstrated that the severity of the underlying disease is not correlated with a proportionately increased risk of difficult intubation. SAS thus appears to be a factor for difficult intubation. It is disappointing that no preoperative factor obtained in a routine preoperative assessment was associated with difficult intubation in patients with SAS. Further studies are needed to explore this issue.
In the postoperative period, patients with SAS spent more time in the PACU than did controls. This can be explained by our hospital policy to maintain SAS patients in PACU for one night, especially if they need opioids for postoperative analgesia, although this is controversial, with several authors questioning the usefulness of systematic admission of SAS patients for the first postoperative night in the PACU (22–24). This policy is supported by the fact that oxygen desaturation occurs more frequently in the postoperative period in SAS patients, and 97% of our SAS patients required respiratory treatment in the first night after surgery. More complications occurred in our SAS group, although life-threatening complications were not seen. Several authors have mentioned that the risk of upper airway obstruction after extubation is increased in SAS patients (25), especially after uvulopalatopharyngoplasty surgery (26). However, no patient in this study experienced postextubation obstruction of upper airway. Further studies are needed to determine the postoperative management of SAS patients. Our study also emphasizes how important it is to maintain arterial blood pressure in the normal range in SAS patients (22), because a significant proportion of immediate postoperative complications were arterial hypertension-related hemorrhage.
In conclusion, our study demonstrated that SAS is a factor for difficult intubation. The associated diseases often seen in these patients require careful attention in the perioperative period.
|
References
|
|---|
- Young T, Palta M, Dempsey J, et al. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med 1993; 328: 1230–5.[Abstract/Free Full Text]
- Young T, Evans L, Finn L, Palta M. Estimation of clinically diagnosed proportion of sleep apnea syndrome in middle-aged men and women. Sleep 1997; 20: 705–6.[ISI][Medline]
- Hendolin H, Kansenen M, Koski E, Nuutinen J. Propofol-nitrous oxide versus thiopentone-isoflurane-nitrous oxide anaesthesia for uvulopalatopharyngoplasty in patients with sleep apnea. Acta Anaesthesiol Scand 1994; 38: 694–8.[ISI][Medline]
- Ostermeier AM, Roizen MF, Hautkappe M, et al. Three sudden postoperative respiratory arrests associated with epidural opioids in patients with sleep apnea. Anesth Analg 1997; 85: 452–60.[ISI][Medline]
- VanDerger DH, Martinez AP, De Lisser EA. Sleep apnea syndromes: a potential contraindication for patient-controlled analgesia. Anesthesiology 1991; 74: 623–4.[ISI][Medline]
- Connolly LA. Anesthetic management of obstructive sleep apnea patients. J Clin Anesth 1991; 3: 461–9.[Medline]
- Boushra NN. Anesthetic management of patients with sleep apnea syndrome. Can J Anaesth 1996; 43: 599–616.[Abstract/Free Full Text]
- Biro P, Kaplan V, Bloch KE. Anesthetic management of a patient with obstructive sleep apnea syndrome and difficult airway access. J Clin Anesth 1995; 7: 417–21.[ISI][Medline]
- Hiremath AS, Hillman DR, James AL, et al. Relationship between difficult tracheal intubation and obstructive sleep apnoea. Br J Anaesth 1998; 80: 606–11.[Abstract/Free Full Text]
- Gentil B, De Larminat JM, Boucherez C, Lienhart A. Difficult intubation and sleep apnoea syndrome. Br J Anaesth 1994; 72: 368.
- Loadsman JA, Hillman DR. Anaesthesia and sleep apnoea. Br J Anaesth 2001; 86: 254–66.[Abstract/Free Full Text]
- Samsoon GLT, Young JRB. Difficult tracheal intubation: a retrospective study. Anaesthesia 1987; 42: 487–90.[ISI][Medline]
- Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39: 1105–11.[ISI][Medline]
- Lavie P, Herer P, Hoffstein V. Obstructive sleep apnoea syndrome as a risk factor for hypertension: population study. BMJ 2000; 320: 479–82.[Abstract/Free Full Text]
- Peppard PE, Young T, Palta M, Skatrud J. Prospective study of association between sleep- disordered breathing and hypertension. N Engl J Med 2000; 342: 1378–84.[Abstract/Free Full Text]
- Strohl KP. Diabetes and sleep apnea. Sleep 1996; 19 (Suppl 10): S225–8.[ISI][Medline]
- Pillar G, Lavie P. Psychiatric symptoms in sleep apnea syndrome: effects of gender and respiratory disturbance index. Chest 1998; 114: 697–703.[Abstract/Free Full Text]
- Ing AJ, Ngu MC, Breslin AB. Obstructive sleep apnea and gastroesophageal reflux. Am J Med 2000; 108 (Suppl 4): 120S–5.
- Rose DK, Cohen MM. The airway: problems and prediction in 18,500 patients. Can J Anaesth 1994; 41: 372–83.[Abstract/Free Full Text]
- Wilson ME, Spiegelhalter D, Robertson JA, Lesser P. Predicting difficult intubation. Br J Anaesth 1988; 22: 969–73.
- Reissel E, Orko R, Maunuksela E-L, Lindgren L. Predictability of difficult laryngoscopy in patients with long-term diabetes mellitus. Anaesthesia 1990; 45: 1024–7.[ISI][Medline]
- Terris DJ, Fincher EF, Hanasono MM, et al. Conservation of resources: indications for intensive care monitoring after upper airway surgery on patients with obstructive sleep apnea. Laryngoscope 1998; 108: 784–8.[ISI][Medline]
- Mickelson AS, Hakim I. Is postoperative intensive care monitoring necessary after uvulopalatopharyngoplasty? Otolaryngol Head Neck Surg 1998; 119: 352–6.[ISI][Medline]
- Ulnick KM, Debo RF. Postoperative treatment of the patient with obstructive sleep apnea. Otolaryngol Head Neck Surg 2000; 122: 233–6.[ISI][Medline]
- Kadota Y, Imabayashi T, Gushiken T, et al. Pulmonary edema due to acute airway obstruction immediately after tracheal extubation [in Japanese]. Masui 1998; 47: 1333–7.[Medline]
- Gabrielczyk MR. Acute airway obstruction after uvulopalatopharyngoplasty for obstructive sleep apnea syndrome. Anesthesiology 1988; 69: 941–3.[ISI][Medline]
Accepted for publication June 14, 2002.
This article has been cited by other articles:
|
|
|
|
 
A. Milne, P. Brousseau, J. Law, D Morrison, T. Camus, and O Hung
44517 - PREVALENCE OF DIFFICULT AIRWAY IN OBSTRUCTIVE SLEEP APNEA PATIENTS
Can J Anesth,
August 1, 2007;
54(suppl_1):
44517 - 44517.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. A. Kim and J. J. Lee
Preoperative predictors of difficult intubation in patients with obstructive sleep apnea syndrome: [Predicteurs preoperatoires d'une intubation difficile chez des patients qui presentent de l'apnee obstructive du sommeil].
Can J Anesth,
April 1, 2006;
53(4):
393 - 397.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. L. Bryson, F. Chung, B. A. Finegan, Z. Friedman, D. R. Miller, J. van Vlymen, R. G. Cox, M.-J. Crowe, J. Fuller, C. Henderson, et al.
Patient selection in ambulatory anesthesia - An evidence-based review: part I: [La selection des patients en anesthesie ambulatoire - Une revue factuelle : partie I]
Can J Anesth,
October 1, 2004;
51(8):
768 - 781.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
