Article

Postoperative Hypoxemia in Morbidly Obese Patients With and Without Obstructive Sleep Apnea Undergoing Laparoscopic Bariatric Surgery

Department of Anesthesiology, Northwestern University Feinberg School of Medicine, 251 E. Huron St., F5-704 Chicago, IL 0 60611, USA.
Anesthesia and analgesia (Impact Factor: 3.42). 07/2008; 107(1):138-43. DOI: 10.1213/ane.0b013e318174df8b
Source: PubMed

ABSTRACT The increased incidence of morbid obesity has resulted in an increase of bariatric surgical procedures. Obstructive sleep apnea (OSA) is a commonly encountered comorbidity in morbidly obese patients. Sedatives, analgesics, and anesthetics alter airway tone, and airway obstruction and death have been reported in patients with OSA after minimal doses of sedatives and anesthetics, yet there is a lack of consensus regarding the care of these patients. In this study, we sought to determine whether obese patients with polysomnography-confirmed diagnosis of OSA were at significantly greater risk for postoperative hypoxemic episodes in the first 24 h after laparoscopic bariatric surgery than morbidly obese patients without a diagnosis of OSA.
Adult subjects (Body Mass Index, 35-75 kg/m(2)) scheduled to undergo laparoscopic bariatric surgery were studied. A finger pulse oximetry probe was placed preoperatively and oxygen saturation (Spo(2)) was recorded continuously. All subjects underwent preoperative polysomnography testing within 4 wk of surgery. Anesthetic management was standardized, using propofol for induction and desflurane and remifentanil for maintenance of anesthesia. Patient-controlled analgesia programmed to deliver morphine, 1 mg. every 10 minutes, was used for pain management postoperatively. Hypoxemic episodes were scored as Spo(2) >4% below the polysomnography study baseline and lasting for more than 10 s.
Eight men and 32 women were enrolled and 1 subject had incomplete data. Thirty-one of the 40 subjects had polysomnography-confirmed OSA. Eight subjects used home continuous positive airway pressure devices nightly, and six of these used their device postoperatively. Preoperatively, subjects with OSA had lower nadir Spo(2) during the polysomnography study and a larger number had an apnea/hypopnea index >10 episodes per hour compared with the non-OSA group. In the first 24 h postoperatively, there was no difference in the median Spo(2) with and without oxygen therapy, between OSA and non-OSA groups. The number of episodes of oxygen desaturation >4% below the polysomnography study baseline value and the mean number of desaturation episodes per hour did not differ between the groups.
In morbidly obese subjects, in the first 24 h after laparoscopic bariatric surgery, OSA does not seem to increase the risk of postoperative hypoxemia. Our data confirm that morbidly obese subjects, with or without OSA, experience frequent oxygen desaturation episodes postoperatively, despite supplemental oxygen therapy suggesting that perioperative management strategies in morbidly obese patients undergoing laparoscopic bariatric surgery should include measures to prevent postoperative hypoxemia.

Download full-text

Full-text

Available from: Robert J Mccarthy, Jul 06, 2015
0 Followers
 · 
156 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The effect of morphine on breathing and ventilatory chemoreflexes in obstructive sleep apnea (OSA) is unknown. It has been assumed that acute morphine use may induce deeper respiratory depression in OSA but this has not been investigated. We evaluated awake ventilatory chemoreflexes and overnight polysomnography on 10 mild-moderate OSA patients before and after giving 30mg oral controlled-release morphine. Morphine plasma concentrations were analysed. We found a 30-fold range of morphine plasma concentrations with the fixed dose of morphine, and a higher plasma morphine concentration was associated with a higher CO(2) recruitment threshold (VRT) (r=0.86, p=0.006) and an improvement in sleep time with [Formula: see text] <90% (T90) (r=-0.87, p=0.005) compared to the baseline. The improvement in T90 also significantly correlated with the increase of VRT (r=-0.79, r=0.02). In conclusion, in mild-to-moderate OSA patients, a single common dose of oral morphine may paradoxically improve OSA through modulating chemoreflexes. There is a large inter-individual variability in the responses which may relate to individual morphine metabolism.
    Respiratory Physiology & Neurobiology 11/2012; 185(3). DOI:10.1016/j.resp.2012.11.014 · 1.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND AND OBJECTIVES: Although the incidence of difficult laryngoscopy is similar in obese and non-obese patients, there are more reports of difficult intubation in obese individuals. Alternatives for the diagnosis and prediction of difficult intubation in the preoperative period may help reduce anesthetic complications in obese patients. The aim of this study was to identify predictors for the diagnosis of difficult airway in obese patients, correlating with the clinical methods of pre-anesthetic evaluation and polysomnography. We also compared the incidence of difficult facemask ventilation and difficult laryngoscopy between obese and non-obese patients, identifying the most prevalent predictors. METHODS: Observational, prospective and comparative study, with 88 adult patients undergoing general anesthesia. In the preoperative period, we evaluated a questionnaire on the clinical predictors of the obstructive sleep apnea syndrome (OSAS) and anatomical parameters. During anesthesia, we evaluated difficult facemask ventilation and laryngoscopy. Descriptive statistics and correlation test were used for analysis. RESULTS: Patients were allocated into two groups: obese group (n=43) and non-obese group (n=45). Physical status, prevalence of snoring, hypertension, diabetes mellitus, neck circumference, and Mallampati index were higher in the obese group. Obese patients had a higher incidence of difficult facemask ventilation and laryngoscopy. There was no correlation between anatomical or clinical variable and difficult facemask ventilation in both groups. In obese patients, the diagnosis of OSAS showed strong correlation with difficult laryngoscopy. CONCLUSIONS: The clinical and polysomnographic diagnosis of OSA proved useful in the preoperative diagnosis of difficult laryngoscopy. Obese patients are more prone to difficult facemask ventilation and laryngoscopy.
    Revista brasileira de anestesiologia 06/2013; 63(3):262-266. DOI:10.1016/S0034-7094(13)70228-9 · 0.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In code division multiple access (CDMA) wireless information networks, it is important to find an efficient algorithm for assigning as few codes to the stations as possible. We propose the least-conflict code grouping algorithm for selecting which stations should share the same code to reduce the number of codes needed. The simulation result shows that only a few codes are required to drive a throughput-delay performance, of the coded tone sense (CTS) protocol, very close to the case where each station has a unique code
    TENCON '93. Proceedings. Computer, Communication, Control and Power Engineering.1993 IEEE Region 10 Conference on; 11/1993