What is OSA? Why does OSA matter? And does STOP BANG help us truly identify OSA?

OSA is:

  • cessation of airflow >10sec, 5+x/hr + 4% desat in SaO2
  • definitions vary, but >15x /hr is diagnostistic
  • dx by polysomnography
  • Apnea/hypopnea index (AHI), which is derived from the total number of apneas and hypopneas divided by the total sleep time (mild up to 15, severe >30)


Obstructive Sleep Apnea (OSA) matters because:

  • harder to intubate, harder to ventilate
  • increased prevalance of cardiac disease: Afib, arrhythmias, stroke, CHF, cardiomyopathy, pulmonary hypertension, CAD
  • periop complications higher, including airway obstruction, hypoxemia, atelectasis, pneumonia
  • more sensitive to respiratory depressant effect of opioids and hypnotics


Is STOP BANG Helpful?

The literature shows…

“The sensitivities of the STOP questionnaire with apnea-hypopnea index greater than 5, greater than 15, and greater than 30 as cutoffs were 65.6, 74.3, and 79.5%, respectively. When incorporating body mass index, age, neck circumference, and gender into the STOP questionnaire, sensitivities were increased to 83.6, 92.9, and 100% with the same apnea-hypopnea index cutoffs.”


And what are these complications?

Mostly pulmonary, with a few possible cardiac events mixed in as noted in this study in Chest, cited in Miller’s 8th edition(


Variables ODI4% Age, yr Sex BMI, kg/m2 Type of Surgery Complication
ODI 4%< 5 0.2 27 F 46.7 Laparoscopic gastric bypass surgery Transient episodes of unspecified tachyarrhythmia during the first 3 postoperative days
3.0 52 F 59.4 Laparoscopy with conversion to open ventral herniorrhaphy and adhesiolysis Hypoxemia treated with supplemental oxygen and BPAP
ODI 4%≥ 5 5.5 49 F 26.2 Total abdominal hysterectomy and right salpingoophorectomy cystoscopy with placement of ureteral catheters Hypoxemia was observed on postoperative day 3 and treated with oxygen supplementation; atelectasis was noted
6.0 49 F 39.1 Total abdominal hysterectomy and bilateral oophorectomy Intraperitoneal bleeding was treated with embolization
6.2 39 F 44.9 Laparoscopic gastric bypass surgery Intraperitoneal bleeding which resolved without surgery
7.6 61 M 33.5 Sigmoid colon resection Hypoxemia and hypotension.
12.9 64 M 37.0 Mitral valve replacement Hypotension and junctional escape rhythm
13.0 57 M 38.9 Laparoscopic colonic polypectomy Atelectasis
14.5 58 F 41.6 Total abdominal hysterectomy and bilateral oophorectomy Atelectasis
18.6 62 M 37.3 Left inguinal herniorrhaphy Wheezing observed which required treatment with bronchodilators
24.6 49 F 28.1 Total abdominal hysterectomy and bilateral oophorectomy Pneumonia
26.3 53 F 47.9 Gastric bypass surgery GI bleeding
31.9 50 M 29.6 Radical prostatectomy Hypoxemia treated with CPAP
34.1 62 F 31.4 Total abdominal hysterectomy and bilateral oophorectomy Atelectasis
34.2 69 M 36.9 Laparoscopic right hemicolectomy Pulmonary embolism; superior mesenteric vein thrombosis
36.4 55 F 49.5 Exploratory laparotomy, adhesiolysis, small bowel resection, partial hepatic resection, gastric bypass Chest pain (MI was ruled out)
82.4 66 F 46.8 Total abdominal hysterectomy and bilateral oophorectomy Hypoxemia treated with CPAP


F = female; M = male; BPAP = bilevel positive airway pressure. See Table 1 for abbreviation not used in the text.

Midazolam for PONV

From Wick, Elizabeth, and Christopher L. Wu. “The Effect of Intravenous Midazolam on Postoperative Nausea and Vomiting: A Meta-Analysis.” (2015).

The gist: Midaz at any point reduces PONV by up to 40%!

BACKGROUND: Research has shown that high-risk surgical patients benefit from a multimodal therapeutic approach to prevent postoperative nausea and vomiting (PONV). Our group sought to investigate the effect of administering IV midazolam on PONV.
METHODS: This meta-analysis included 12 randomized controlled trials (n = 841) of adults undergoing a variety of surgical procedures that investigated the effect of both preoperative and intraoperative IV midazolam on PONV in patients undergoing general anesthesia.
RESULTS: Administration of IV midazolam was associated with significantly reduced PONV (risk ratio [RR] = 0.55; 95% confidence interval [CI], 0.43–0.70), nausea (RR = 0.62; 95% CI, 0.40–0.94), vomiting (RR = 0.61; 95% CI, 0.45–0.82), and rescue antiemetic administration (RR = 0.49; 95% CI, 0.37–0.65) within 24 hours. Individual subgroup analyses of trials excluding the use of thiopental for induction, trials of either female sex or high-risk surgery, trials involving nitrous oxide maintenance, and trials using midazolam in combination with known antiemetics all yielded similar reductions in PONV end points within 24 hours of surgery.
CONCLUSIONS: Administration of preoperative or intraoperative IV midazolam is associated with a significant decrease in overall PONV, nausea, vomiting, and rescue antiemetic use. Providers may consider the administration of IV midazolam as part of a multimodal approach in preventing PONV.