17.4.1 Management of Patient During Pregnancy
Multidisciplinary approach involving the obstetrician, anesthesiologist, neonatologist, and sleep physician is recommended to decrease OSA-related problems during peri- partum period. Pregnancy-specific management of OSA is lacking because of the insufficient evidence in terms of reducing maternal and fetal morbidity. In patients with severe OSA, upper airway surgery and significant weight loss may be good ther- apy alternatives in indicated patients and have to be done before a planned pregnancy.
However, during pregnancy a well-controlled weight gain can be beneficial.
Options, including continuous positive airway pressure (CPAP) and positional therapy, used in general OSA population can be adapted and safely applied along the pregnancy. In preeclamptic patients, OSA causes decrease in heart rate, stroke volume, and cardiac output during sleep, which has been shown to be minimized with the use of nocturnal nasal CPAP [16]. Readjustment of CPAP pressure may be necessary according to the patients’ requirements over the course of pregnancy.
Although early application of CPAP may relieve sleep-related breathing distur- bances, it cannot prevent negative pregnancy outcomes but may aid to reduce their severity [17, 18].
Table 17.3 Epworth Sleepiness Scale
From https://www.sleepapnea.org/assets/files/pdf/ESS%20PDF%201990-97.pdf Score:
0–5 lower normal daytime sleepiness 6–10 higher normal daytime sleepiness 11–12 mild excessive daytime sleepiness 13–15 moderate excessive daytime sleepiness 16–24 severe excessive daytime sleepiness
Lateral recumbent or head-elevated positions should be encouraged to avoid the aggravating effect of supine position on OSA as known from general population [19]. Furthermore in postpartum patients with OSA, 45° upper body elevation has to be demonstrated to increase upper airway cross-sectional area and reduce apnea- hypopnea index [19].
17.4.2 Anesthetic Management 17.4.2.1 Preoperative Assessment
Pregnant OSA patients should be counseled by the anesthesiologist during the early phases of pregnancy. Patient’s history should be evaluated for difficult or failed intubations and postoperative course of previous operations. Routine preoperative evaluation is sufficient in asymptomatic or mild OSA patients. Patients with moder- ate or severe OSA need optimization of comorbid conditions prior to labor or a planned cesarean delivery. Patients, who are on CPAP, should be informed to bring their devices while coming for delivery.
17.4.2.2 Labor Analgesia
Neuraxial analgesia is the technique of choice during labor. Most of the OSA patients are obese, which is related to increased risk of fetal macrosomia, dysfunctional or prolonged labor, instrumental delivery, or even emergency cesarean delivery. The pain intensity is also positively correlated with body mass index [20]. Therefore, the insertion of a functioning epidural catheter during the early phase of labor is manda- tory. Combined techniques like combined spinal epidural (CSE) or dural puncture epidural (DPE) can also be chosen as they offer a faster onset of analgesia [18]. An untested epidural catheter in CSE was a subject of discussion for many years and was assumed to be a risk factor for epidural catheter failure. But a recent retrospective cohort study revealed a significantly lower incident of catheter failure with a CSE compared to straight epidural (6.6% vs. 11.6%) without a significant delay in recog- nition of it [21]. In DPE, dura is punctured with a spinal needle similar to CSE tech- nique without injecting drugs into subarachnoid space while epidural catheter can be tested as well. Beside faster analgesia onset by intrathecal spread of epidural drug, DPE also offers a better sacral analgesia than a straight epidural technique. The iden- tification of bony landmarks and midline may be facilitated by ultrasound imaging.
To avoid the catheter dislodgement in obese patients, catheters should be fixed at the skin after changing the posture given during epidural puncture [22].
In case of contraindication of neuraxial techniques, opioid-based systemic anal- gesia may be used under closed control with monitoring of oxygen saturation and respiratory rate.
17.4.2.3 Anesthesia for Cesarean Section
Neuraxial anesthesia should be preferred also for cesarean delivery while avoiding high doses of long-acting neuraxial opioids. Spinal anesthesia may be an inappro- priate choice in obese patients with previous abdominal operations as operation
times may be prolonged. Epidural or CSE technique allows titrating the drugs according to the patient’s needs [18].
When general anesthesia is justified, short-acting anesthetics and analgesics with careful titration are recommended. Patients with OSA are sensitive to sedatives, opioids, and inhaled anesthetics. Head-up position and CPAP are helpful for pre- oxygenation prior to anesthetic induction in obese parturient. Anesthetic team should be prepared for difficult intubation. Oxygen insufflation during apnea may avoid hypoxia during airway management. The trachea should be extubated after full reversal of neuromuscular blockade while the patient is awake and positioned semi-upright or lateral. In addition to standard monitoring, an arterial line is advis- able for accurate blood pressure monitoring as well as frequent blood sampling in patients with severe OSA or OSA-related comorbidities. Pulmonary hypertension or conditions with decreased cardiac output may necessitate more sophisticated noninvasive or invasive monitoring [18, 23].
17.4.3 Postpartum Care
Postpartum care of a patient with moderate to severe OSA requires high dependency care unit with monitoring and cardiorespiratory support facilities. Labor and delivery cause narrowing of the airway resulting in a decrease of oral and pharyngeal volume, which can objectively be observed as an increase of Mallampati class [24]. This change in airway diameter is reported both in normal and preeclamptic parturient, which may persist for 48 h postpartum in both groups of patients. Therefore, careful monitoring, including respiratory rate, pulse oximetry, and capnography, is essential in the postpartum period especially in cases with moderate to severe OSA or suspi- cious for undiagnosed OSA, in the postpartum period [23, 25]. CPAP reduce airway obstruction, but evidence is lacking for its use to decrease major postoperative com- plications [23]. Patients could be discharged to an unmonitored position when they are able to maintain oxygen saturation on room air especially during sleep.
Following operative delivery, analgesia without interfering the respiration is very important. Epidural technique allows excellent postoperative analgesia via epidural catheter utilizing local anesthetics and lipophilic opioid combinations. Local anes- thetics are effective against both visceral and somatic pain. They should be used in low concentrations to avoid muscle weakness resulting from neuraxial analgesia.
The more hydrophilic morphine has to be applied with care as it may result in a biphasic respiratory depression: Intravascular absorption may lead to an early depression after 30–90 min, whereas a late one may appear due to its rostral migra- tion into the respiratory center, which necessitates monitoring for 24 h following intrathecal morphine injection [26]. Intrathecal morphine up to 0.15 mg offers a relatively safe alternative for postoperative analgesia following single-shot spinal anesthesia [27]. But data for its use in parturients with OSA is lacking.
Following general anesthesia, multimodal analgesia, utilizing non-opioid anal- gesics like paracetamol and nonsteroidal anti-inflammatory drugs supported with peripheral nerve blocks, is challenging because of the opioid-induced respiratory
depression risk following opioid analgesics [28–30]. Bilateral transversus abdomi- nis plane (TAP) block may reduce opioid consumption and opioid-related side effects by providing pain control and improving patient satisfaction [31]. However, TAP blocks do offer any additional benefit if patients have received intrathecal mor- phine [32]. Local anesthetic wound infiltration in the form of an infusion or single- injection technique is used also for postoperative analgesia [33]. But despite reduction in opioid requirements, no clear benefits can be shown in terms of reduc- ing opioid-related side effects following cesarean delivery.
A reevaluation of patients for OSA 2–3 months postpartum is suggested, because after this period of time most of the gestational weight gain would have been lost.
There is not sufficient data about the risk of developing OSA in subsequent preg- nancies with previously diagnosed pregnancy-related OSA. It is advisable to follow up the patient for possible OSA development.
In conclusion, OSA during pregnancy is related to higher maternal and fetal morbidity. Therefore special attention should be paid for the detection of pregnant patients with OSA. Validated diagnostic tools and specific management options for pregnant population are still lacking. The adaptation of current knowledge to the dynamic process and progressive change of pregnancy and postpartum period is a challenge for anesthesiologist in this particular group of patients.
Key Learning Points
• Pregnancy-related physiological changes make pregnant patients prone to OSA or increase the severity of previously existing OSA.
• Maternal OSA is associated with increased rates of systemic and pulmo- nary hypertension, preeclampsia, gestational diabetes, depression, asthma, fetal growth retardation, preterm birth, fetal distress, and lower Apgar scores at delivery.
• Currently there are no screening tools for accurate diagnosis of OSA dur- ing pregnancy. However STOP-BANG Questionnaire had the highest specificity with a high negative predictive value. Portable home polysom- nography may also be used, but the data supporting its application for pregnant women is currently inadequate.
• Pregnancy-specific management of OSA is lacking. A well-controlled weight gain, continuous positive airway pressure, and positional therapy may be beneficial.
• Neuraxial blocks are the technique of choice for labor and cesarean deliv- ery. Short-acting anesthetics and analgesics with careful titration are rec- ommended for general anesthesia.
• Postpartum care of a patient with moderate to severe OSA requires high dependency care unit with monitoring and cardiorespiratory support facili- ties. Multimodal analgesia including neuraxial or regional local anesthet- ics is challenging to avoid respiratory depression risk following opioid analgesics.
References
1. Abdullah HR, Nagappa M, Siddiqui N, Chung F. Diagnosis and treatment of obstructive sleep apnea during pregnancy. Curr Opin Anaesthesiol. 2016;29:317–24.
2. Louis JM, Mogos MF, Salemi JL, Redline S, Salihu HM. Obstructive sleep apnea and severe maternal-infant morbidity/mortality in the United States, 1998-2009. Sleep. 2014;37:843–9.
3. Contreras G, Gutiérrez M, Beroíza T, Fantín A, Oddó H, Villarroel L, et al. Ventilatory drive and respiratory muscle function in pregnancy. Am Rev Respir Dis. 1991;144:837–41.
4. Louis JM, Auckley D, Sokol RJ, Mercer BM. Maternal and neonatal morbidities associated with obstructive sleep apnea complicating pregnancy. Am J Obstet Gynecol. 2010;202:261.
e1–5.
5. Campos-Rodriguez F, Martinez-Garcia MA, de la Cruz-Moron I, Almeida-Gonzalez C, Catalan-Serra P, Montserrat JM. Cardiovascular mortality in women with obstructive sleep apnea with or without continuous positive airway pressure treatment: a cohort study. Ann Intern Med. 2012;156:115–22.
6. Louis J, Auckley D, Bolden N. Management of Obstructive Sleep Apnea in pregnant women.
Obstet Gynecol. 2012;119:864–8.
7. Sahin FK, Koken G, Cosar E, Saylan F, Fidan F, Yilmazer M, et al. Obstructive sleep apnea in pregnancy and fetal outcome. Int J Gynaecol Obstet. 2008;100:141–6.
8. Chen YH, Kang JH, Lin CC, Wang IT, Keller JJ, Lin HC. Obstructive sleep apnea and the risk of adverse pregnancy outcomes. Am J Obstet Gynecol. 2012;206:136.e1–5.
9. Lockhart EM, Ben Abdallah A, Tuuli MG, Leighton BL. Obstructive sleep Apnea in preg- nancy: assessment of current screening tools. Obstet Gynecol. 2015;126:93–102.
10. Ding X-X, Wu Y-L, Xu S-J, Zhang SF, Jia XM, Zhu RP, et al. A systematic review and quan- titative assessment of sleep-disordered breathing during pregnancy and perinatal outcomes.
Sleep Breath. 2014;18:703–13.
11. Xu T, Feng Y, Peng H, Guo D, Li T. Obstructive sleep apnea and the risk of perinatal outcomes:
a meta-analysis of cohort studies. Sci Rep. 2014;4:6982.
12. Health Quality Ontario. Polysomnography in patients with obstructive sleep apnea: an evi- dence-based analysis. Ont Heal Technol Assess Ser. 2006;6:1–38.
13. Nagappa M, Liao P, Wong J, Auckley D, Ramachandran SK, Memtsoudis S, et al. Validation of the STOP-Bang questionnaire as a screening tool for obstructive sleep Apnea among different populations: a systematic review and meta-analysis. PLoS One. 2015;10:e0143697.
14. Facco FL, Ouyang DW, Zee PC, Grobman WA. Development of a pregnancy-specific screen- ing tool for sleep apnea. J Clin Sleep Med. 2012;8:389–94.
15. Pien GW, Pack AI, Jackson N, Maislin G, Macones GA, Schwab RJ. Risk factors for sleep- disordered breathing in pregnancy. Thorax. 2014;69:371–7.
16. Blyton DM, Sullivan CE, Edwards N. Reduced nocturnal cardiac output associated with pre- eclampsia is minimized with the use of nocturnal nasal CPAP. Sleep. 2004;27:79–84.
17. Guilleminault C, Palombini L, Poyares D, Takaoka S, Huynh NT-L, El-Sayed Y. Pre-eclampsia and nasal CPAP: part 1. Early intervention with nasal CPAP in pregnant women with risk- factors for pre-eclampsia: preliminary findings. Sleep Med. 2007;9:9–14.
18. Booth JM, Tonidandel AM. Peripartum management of obstructive sleep Apnea. Clin Obstet Gynecol. 2017;60:405–17.
19. Zaremba S, Mueller N, Heisig AM, Shin CH, Jung S, Leffert LR, et al. Elevated upper body position improves pregnancy-related OSA without impairing sleep quality or sleep architec- ture early after delivery. Chest. 2015;148:936–44.
20. Melzack R, Kinch R, Dobkin P, Lebrun M, Taenzer P. Severity of labour pain: influence of physical as well as psychologic variables. Can Med Assoc J. 1984;130:579–84.
21. Booth JM, Pan JC, Ross VH, Russell GB, Harris LC, Pan PH. Combined spinal epidural tech- nique for labor analgesia does not delay recognition of epidural catheter failures: a single- center retrospective cohort survival analysis. Anesthesiology. 2016;125:516–24.
22. Hamilton CL, Riley ET, Cohen SE. Changes in the position of epidural catheters associated with patient movement. Anesthesiology. 1997;86:778–84. discussion 29A.