Do you Snore loudly? Yes/no
Do you often feel Tired, sleepy, or fatigued during the day? Yes/no
Has anyone Observed you stop breathing? Yes/no
Have you been diagnosed with high blood Pressure? Yes/no
BMI > 35? Yes/no
Age > 50? Yes/no
Neck circumference > 17″ (male), 16″ (female)? Yes/no
Gender = male? Yes/no
Every ‘Yes’ answer is scored 1 point
Patients with scores 0–2 may be considered low risk, 3–4 intermediate risk, and 5–8 high risk of OSA
There is evidence to show that OSA increases postoperative complications, especially oxygen desaturation [36]. Also OSA patients who did not use PAP devices prior to surgery but required PAP therapy after surgery had increased complication rates [36]. Peri-operative CPAP significantly reduces postoperative AHI and improves oxygen saturation in surgical patients with moderate and severe OSA [37]. There is also evidence to show that CPAP in addition to respiratory benefits may lead to an improvement in hypertension and other related co-morbidities especially for patients with moderate to severe OSA [38].
STOP-BANG scores can be used for the eventual decision to evaluate a patient preoperatively with polysomnography. For patients with STOP-BANG score 5–8 (high risk of moderate to severe OSA) a polysomnography should be considered for diagnosis and treatment. This is especially important in patients with comorbid diseases (uncontrolled hypertension, heart failure, arrhythmias, pulmonary hypertension, cerebrovascular disease, and severe metabolic syndrome) wherein diagnosis and treatment will help for both respiratory optimization and co-morbidity stabilization. Patients with an intermediate risk of OSA based on STOP-BANG may represent false positives on screening, or may have less severe OSA and may proceed for surgery without further testing with perioperative OSA precautions. Patients deemed to be low risk on screening with score 0–2 on STOP-BANG are unlikely to have OSA. These patients may proceed for surgery with routine perioperative care.
No sufficient data exist in literature regarding the optimal time for pre-operative CPAP therapy in order to decrease the risk of perioperative complications. It has been shown that patients treated with therapeutic CPAP for 3 weeks showed significant reductions in the apnea-hypopnea index, decrease in fatigue, increase in vigor and decreased sleepiness [39]. It is reasonable to incorporate some time (~3 weeks) for adaptation to the device and benefits of CPAP in the preoperative period but whether this will translate into decreased complications postoperatively is still not known.
21.6 Perioperative Care of the Bariatric Patient with OSA
Patients with OSA who undergo bariatric surgery have an increased risk of perioperative complications [16]. The duration of this increased risk extends to around 1 week post-operatively of which the first 3 days after surgery pose the greatest risk for apnea from drug-induced sleep and the next 4 days pose a higher risk because of REM sleep rebound secondary to disturbed sleep architecture in the immediate post-operative period.
This increased risk peri-operatively mandates that certain ‘OSA risk mitigation’ strategies be followed in the preoperative, intraoperative and postoperative period [40].
OSA risk mitigation includes several steps.
Preoperatively
Sedative medications should be avoided.
Intra-operatively
Difficult mask ventilation/difficult intubation should be anticipated.
CPAP pre-oxygenation and awake intubation should be considered.
Proton pump inhibitors and rapid sequence induction should be followed as chances of as GERD (gastroesophageal reflux disease) is high.
Short acting anesthetic agents should be used.
Post-operatively
As there is an increased incidence of post-extubation obstruction it is essential that full reversal of neuromuscular blockade is verified.
Extubation should be done only when fully active and conscious.
Semi-upright position should be used for extubation and recovery.
An oral or nasal airway should be used to maintain airway.
For postoperative care
Multimodal analgesia techniques should be preferred.
Avoid opiods whenever possible and use non steroidal anti-inflammatory agents (NSAIDs).
Clonidine or Dexmedetomidine can be used as pain adjuvant or as opiod sparing agents.
If needed IV bolus narcotics can be used and basal infusion can be avoided.
For postoperative monitoring
Continuous pulse oximetry monitoring should be used with ready access to medical intervention.
Select higher risk patients such as those with severe OSA, multiple comorbidities, superobesity, or advanced age may be monitored in an ICU setting at the discretion of the surgeon/intensivist.
Monitoring can be stopped once oxygen saturation of >90 % is maintained in room air and during sleep, with no hypoxemia/airway obstruction.
21.7 Use of CPAP in the Postoperative Period
There exist no clear guidelines on the usage of CPAP in the post-operative period. Perioperative CPAP significantly reduces postoperative AHI and improves oxygen saturation in surgical patients with moderate and severe OSA [37]. However studies have also shown that postoperative CPAP and Bi-PAP can be safely omitted if patients are observed in a monitored setting and their pulmonary status is optimized by aggressive incentive spirometry and early ambulation [41, 42]. It should also be noted that there is no increase in overall or pulmonary complications despite non-routine use of CPAP [41, 42]. However it may still be required in select patients with worsening pulmonary status postoperatively. Importantly postoperative use of CPAP should not be viewed as potentially adverse to outcomes following bariatric surgery. Evidence in literature shows that the risk of anastomotic complications is not increased [43].
Thus in patients with diagnosed OSA who undergo bariatric surgery and who were using CPAP may be required to use CPAP in the post-operative period occasionally. It is often best if the patient brings their own CPAP mask, with or without their machine, with them to the hospital. This ensures the equipment fits the patient well and is readily available for use in the postoperative period.
It has been shown that >62 % of patients have significant residual disease after bariatric surgery in the long term, with an AHI of more than 15 [32]. Though there is significant subjective improvement in most patients absence of clinical symptoms does not necessarily correlate with normalization of AHI and/or severity of sleep apnea. The severity of preoperative OSA often influences the degree to which OSA improves or resolves after bariatric surgery. Many patients may still need treatment of OSA based on their AHI. Institutions differ in their practice regarding the use of CPAP in the long term post bariatric surgery. While some discontinue use others re-titrate the settings and continue to use postoperatively. However as long term effects of OSA is of concern and as continuing weight loss will have a continuing improvement of OSA, surgeons can consider repeat PSG testing after significant weight loss and restart CPAP accordingly. Currently no consensus or recommendation exists regarding indications or timing for repeat PSG either in the general population or after bariatric surgery.
Recommendations
Weight loss by any method is a well-documented treatment for OSA.
The standard method of diagnosing OSA is via polysomnography (PSG) which can be selectively used based on preoperative symptoms by clinical screening tools.
Patients with moderate to severe OSA should be optimized preoperatively with continuous positive airway pressure (CPAP) for a minimum period of 3 weeks
Postoperative CPAP and Bi-PAP can be safely omitted if patients are observed in a monitored setting and optimized by aggressive incentive spirometry and early ambulation.
Postoperative CPAP and Bi-PAP can be used in select patients with worsening pulmonary status postoperatively without the risk of anastomotic complications.
The need for continuing CPAP in the postoperative period may be based on clinical findings.
References
1.
Wilhelm CP, de Shazo RD, Tamanna S, Ullah MI, Skipworth LB. The nose, upper airway, and obstructive sleep apnea. Ann Allergy Asthma Immunol Off Publ Am Coll Allergy Asthma Immunol. 2015;115(2):96–102.CrossRef
2.
Tan H-L, Kheirandish-Gozal L, Abel F, Gozal D. Craniofacial syndromes and sleep-related breathing disorders. Sleep Med Rev. 2015;27:74–88.CrossRefPubMed
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