Preoperative nocturnal desaturations as a risk factor for late postoperative nocturnal desaturations

Preoperative sleep-disordered breathing and craniofacial abnormalities are risk factors for postoperative sleep-disordered breathing in patients undergoing skin-flap oropharyngeal reconstruction surgery for oral cavity cancer: a prospective case-control study

PURPOSE

After oropharyngeal reconstruction surgery, excessive flap volume within the oral cavity may increase the risk of pharyngeal obstruction during sleep. This prospective observational study aimed to test a hypothesis that the skin-flap oropharyngeal reconstructive surgery increases nocturnal apnea-hypopnea index (nAHI, primary variable) after surgery.

METHODS

Adult patients undergoing oropharyngeal reconstruction surgery participated in this study. The hypothesis was tested by comparing the results of portable type 4 sleep study and craniofacial assessments with lateral head and neck computed tomography scout image before and after surgery. Multiple linear regression analyses were performed to identify predictors for nAHI increase after the surgery.

RESULTS

In 15 patients, a postoperative sleep study was performed at 41 (27, 59) (median (IQR)) days after the surgery. nAHI did not increase after the surgery (mean (95% CI), 13.0 (7.2 to 18.7) to 18.4 (10.2 to 26.6) events.hour-1, p = 0.277), while apnea index significantly increased after the surgery (p = 0.026). Use of the pedicle flap for the oropharyngeal reconstruction (p = 0.051), small mandible (p = 0.008), longer lower face (0.005), and larger tongue size (p = 0.008) were independent predictors for worsening of nAHI after surgery. Hospital stay was significantly longer in patients with the pedicle flap (n = 8) than in those with the free flap (n = 7) (p = 0.014), and the period of hospital stay was directly associated with increase of nAHI after surgery (r = 0.788, p < 0.001, n = 15).

CONCLUSIONS

Oropharyngeal reconstruction surgery worsens sleep-disordered breathing in some patients with craniofacial and surgical risk factors.

TRIAL REGISTRATION

UMIN Clinical Trial Registry (UMIN000036260, March 22, 2019), https://rctportal.niph.go.jp/s/detail/um?trial_id=UMIN000036260.

Continuous wireless pre- and postoperative vital sign monitoring reveal new, severe desaturations after vascular surgery

OBJECTIVES

Postoperative deviating physiologic values (vital signs) may represent postoperative stress or emerging complications. But they can also reflect chronic preoperative values. Distinguishing between the two circumstances may influence the utility of using vital signs in patient monitoring. Thus, we aimed to describe the occurrence of vital sign deviations before and after major vascular surgery, hypothesising that preoperative vital sign deviations were longer in duration postoperatively.

METHODS

In this prospective observational study, arterial vascular patients were continuously monitored wirelessly - from the day before until 5 days after surgery. Recorded values were: heart rate, respiration rate, peripheral arterial oxygen saturation (SpO₂ ) and blood pressure. The outcomes were 1. cumulative duration of SpO₂  < 85% / 24 h, and 2. cumulative duration per 24 h of vital sign deviations.

RESULTS

Forty patients were included with a median monitoring time of 21 h preoperatively and 42 h postoperatively. The median duration of SpO₂  < 85% preoperatively was 14.4 min/24 h whereas it was 28.0 min/24 h during day 0 in the ward (p = .09), and 16.8 min/24 h on day 1 in the ward (p = 0.61). Cumulative duration of SpO₂  < 80% was significantly longer on day 0 in the ward 2.4 min/24 h (IQR 0.0-4.6) versus 6.7 min/24 h (IQR 1.8-16.2) p = 0.01.

CONCLUSION

Deviating physiology is common in patients before and after vascular surgery. A longer duration of severe desaturation was found on the first postoperative day in the ward compared to preoperatively, whereas moderate desaturations were reflected in postoperative desaturations. Cumulative duration outside thresholds is, in some cases, exacerbated after surgery.

Interpretation of sleep studies for patients with sleep-disordered breathing: What the anesthesiologist needs to know

There is increased interest in the perioperative management of patients with sleep-disordered breathing (SDB). Anesthesiologists must distill information from clinical reports to make key decisions for optimizing perioperative care. A patient with SDB may present with a sleep study report at the time of surgery. Knowledge of the essential components of such a report can help the anesthesiologist evaluate the patient and optimize the perioperative management. In this narrative review, we describe how level I (i.e., laboratory-based) polysomnography (PSG) data are collected and scored using the recommended scoring guidelines, as well as the basic information and salient features of a typical PSG report relevant to the anesthesiologist. In addition, we briefly review the indications for sleep studies, including the types of laboratory-based studies, as well as the role and limitations of portable monitors (level II-IV studies) and examples of PSG reports in the clinical context.

Retrospective observational evaluation of postoperative oxygen saturation levels and associated postoperative respiratory complications and hospital resource utilization

Introduction

The clinical importance of postoperative episodic hypoxemia is still unclear, and therefore largely under-studied. As a result, there is limited understanding of its relationship with early postoperative respiratory complications (PRC, defined as intubation within three days of surgery) and hospital resource utilization.

Materials and methods

This single center study was performed using a retrospective observational design. We described population based definitions of desaturation from continuous SpO₂ monitoring data captured in the post anesthesia care unit (PACU), namely median SpO₂ in PACU, duration of desaturation below median, nadir desaturation, and length of oxygen therapy relative to PACU duration. These measures were evaluated against the occurrence of early PRC in logistic regression models. Measures that were independently associated with early PRC were accepted as the primary study exposures. Stratified logistic regression models were planned if significant interaction occurred with high risk surgical procedures. Models were adjusted by including several patient conditions, procedural, and anesthesia risk factors. Propensity matching on desaturation occurrence was planned to evaluate the relationship with postoperative resource utilization.

Results

Among 125,740 patients included in the univariate analyses, 351 patients (0.3%) developed early PRC. Nadir desaturation <89% [14.3% of patients; adjusted odds ratio 2.02; 95% CI 1.52, 2.68; p<0.001] and PACU oxygen therapy requirements greater than 60 min [adjusted odds ratio 1.92 (>60 min) to 3.04 (>90 min); p<0.001] were identified as independent predictors of early PRC occurrence. A modest interaction was observed between desaturation and higher surgical risk. Propensity matching for postoperative oxygen requirement was performed in 37,354 matched patients. Matched analysis demonstrated significant increase in day of surgery charges, respiratory charges, total charges, hospital length of stay, reintubation and use of invasive or non-invasive ventilatory support.

Conclusions

In summary, we report that prolonged PACU oxygen therapy and nadir desaturation <89% in PACU as captured in a retrospective database are independently associated with early PRC. This study describes resource implications of PACU desaturation in a large academic medical center in North America.

Factors Associated with Postoperative Exacerbation of Sleep-disordered Breathing

Introduction:

The knowledge on the mechanism of the postoperative exacerbation of sleep-disordered breathing may direct the perioperative management of patients with obstructive sleep apnea. The objective of this study is to investigate the factors associated with postoperative severity of sleep-disordered breathing.

Methods:

After obtaining approvals from Institutional Review Boards, consenting patients underwent portable polysomnography preoperatively, and on postoperative nights 1 and 3 in hospital or at home. The primary outcomes were polysomnography parameters measuring the sleep-disordered breathing. They were treated as repeated measurement variables and analyzed for associated factors by mixed models.

Results:

Three hundred seventy-six patients, 168 men and 208 women, completed polysomnography on preoperative and postoperative night 1. Age was 59 ± 12 yr (mean ± SD). Preoperative apnea–hypopnea index (AHI) was 12 (4, 26) (median [25th, 75th percentile]) events per hour. Thirty-five patients had minor surgeries, 292 intermediate surgeries, and 49 major surgeries, with 210 general anesthesia and 166 regional anesthesia. The 72-h opioid dose was 55 (14, 85) mg intravenous morphine-equivalent dose. Preoperative AHI, age, and 72-h opioid dose were associated with postoperative AHI. Preoperative central apnea index, male sex, and general anesthesia were associated with postoperative central apnea index. Slow wave sleep percentage was inversely associated with postoperative AHI and central apnea index.

Conclusions:

Patients with a higher preoperative AHI were predicted to have a higher postoperative AHI. Preoperative AHI, age, and 72-h opioid dose were positively associated with postoperative AHI. Preoperative central apnea, male sex, and general anesthesia were associated with postoperative central apnea index.

Nocturnal Intermittent Hypoxia Is Independently Associated with Pain in Subjects Suffering from Sleep-disordered Breathing

Background:

On the basis of experimental and clinical evidence, the authors hypothesized that nocturnal hypoxemia would be associated with pain reports in subjects suffering from sleep-disordered breathing, independently of sleep fragmentation and inflammation.

Methods:

After obtaining institutional approval and access to the Cleveland Family Study phenotype and genotype data, the authors used proportional odds regression to examine the association between arterial desaturation and four different types of pain, as well as their composite measure, sequentially adjusted for: (1) clinical characteristics and (2) sleep fragmentation and inflammation. The authors also examined the association of selected candidate single-nucleotide polymorphisms with pain reports.

Results:

Decreased minimum nocturnal arterial saturation increased the odds for morning headache (adjusted odds ratio per SD = 1.36; 95% CI [1.08–1.71]; P = 0.009), headache disrupting sleep (1.29 [1.10–1.51]; P = 0.002), and chest pain while in bed (1.37 [1.10–1.70]; P = 0.004). A decrease in the minimum nocturnal saturation from 92 to 75% approximately doubled the odds for pain. One single-nucleotide polymorphism for the α 1 chain of collagen type XI (COL11A1–rs1676486) gene was significantly associated with headache disrupting sleep (odds ratio = 1.72 [1.01–2.94]; P = 0.038), pain disrupting sleep (odds ratio = 1.85 [1.04–3.28]; P = 0.018), and pain composite (odds ratio = 1.89 [1.14–3.14]; P = 0.001).

Conclusion:

Nocturnal arterial desaturation may be associated with an increased pain in subjects with sleep-disordered breathing, independently of sleep fragmentation and inflammation.

Quantifying respiratory complications post-adenotonsillectomy in patients with normal or inconclusive overnight oximetry

Background

Children with sleep-disordered breathing (SDB) are at risk of developing post-operative respiratory complications following adenotonsillectomy (T&A). Our goal was to describe and quantify these complications following T&A in children with clinical SDB but with a pre-operative overnight home oximetry score of “normal/inconclusive” (McGill Oximetry Score (MOS) of 1), and to determine whether these children could safely undergo surgery in peripheral hospitals or outpatient surgical centers.

Methods

We performed a retrospective chart review of patients 3 years and older who had T&A between 2003 and 2010 at 2 of our institution’s hospitals. To be included in the study, in addition to not having severe comorbidities, children had to have undergone an overnight home oximetry within 12 months of surgery that was normal or inconclusive (MOS of 1). This was defined as fewer than 3 episodes of oxygen desaturation below 90% and stable baseline saturation over 95%. Medical charts were reviewed for major and minor postoperative respiratory complications. The main outcome measure was post-T&A respiratory complications.

Results

Out of 2708 T&A patients, 231 met the inclusion criteria. No patient had a major postoperative respiratory complication requiring re-intubation or admission to the intensive care unit. Five patients (2.16%) had minor respiratory complications but only one required admission to the ward.

Conclusions

An overnight home oximetry that is “normal/inconclusive” (MOS of 1) can be used as a screening tool to identify patients with sleep-disordered breathing who can be safely sent to peripheral hospitals or outpatient surgical centers for T&A.

Preoperative screening and perioperative care of the patient with sleep-disordered breathing

PURPOSE OF REVIEW

Emerging data are raising concerns that patients with known or suspected obstructive sleep apnea (OSA) are at increased risk for a myriad of perioperative complications. Strategies to identify patients preoperatively with OSA, or at risk for OSA, are being advocated. In addition, approaches to identify patients most at risk for OSA-related postoperative complications have been described. While lacking solid evidence, a number of perioperative management strategies have been proposed for the care of these patients.

RECENT FINDINGS

Recent studies utilizing different methodologies have provided additional evidence regarding the impact that OSA can have on postoperative outcomes, including increased risk of difficult intubations, adverse pulmonary outcomes, and delirium. Tools, such as the STOP-Bang questionnaire and limited channel monitoring, have been investigated with regards to their utility to identify not only patients at risk for OSA but also those at risk for more severe OSA. Consensus-based guidelines for the perioperative care of OSA patients have recently been published.

SUMMARY

OSA is quite common in patients presenting for elective surgery and has been linked to increased perioperative complications. Attempts to identify these patients preoperatively appear prudent. Protocols on how best to manage these patients are available, although validation of their effectiveness is needed.

Perioperative care of patients with obstructive sleep apnea

OPINION STATEMENT

It has been demonstrated that patients undergoing surgical procedures are at increased risk for complications if they have obstructive sleep apnea. It is believed that this increase in risk is related to more difficult intubations, use of ventilatory depressant medications, and perhaps body positioning. Although identifying patients with a preexisting diagnosis of sleep apnea is important so they can be triaged appropriately during the perioperative period, a bigger challenge is trying to identify patients who require a surgical procedure and may have undiagnosed sleep apnea. Hospitals and surgical centers should have policies in place to assist in such identification preoperatively, with a protocol on how to manage such patients perioperatively. Such guidelines exist, but many institutions do not have such protocols in place or fail to ensure that they are consistently followed. The key to the perioperative management is close observation of these high-risk patients. In ambulatory surgery populations, these patients should be observed for an extended period before being discharged to home. In inpatient settings, the observation can be tailored to the patient's postoperative risks based on the type of surgery and the severity of his or her sleep apnea. Patients undergoing bariatric surgery are at particularly high risk. These patients have a very high prevalence of sleep apnea and comorbid conditions. Screening this population for obstructive sleep apnea is mandatory, and a plan for postoperative observation should be in place in all institutions performing such surgery.

Association of sleep-disordered breathing with postoperative complications

BACKGROUND

Obstructive sleep apnea (OSA) is associated with increased perioperative risk, but the incidence of postoperative complications and the severity of OSA associated with increased risk have not been established. We investigated the relationship between intermittent hypoxemia measured by home nocturnal oximetry with the occurrence of postoperative complications in patients with clinical signs of OSA identified during preoperative assessment for elective surgery.

METHODS

This study was performed at a tertiary care hospital. Home nocturnal oximetry was performed on elective surgical patients with clinical features of OSA. The number of episodes per hour of oxygen desaturation (or oxygen desaturation index) of > or = 4% (ODI4%) was determined. Subjects with five or more desaturations per hour (ODI4% > or = 5) were compared to those with less than five desaturations per hour (ODI4% < 5). Hospital records were reviewed to assess the incidence and type of postoperative complications.

RESULTS

A total of 172 patients were investigated as part of this study. No significant differences were observed between groups in terms of age, body mass index, number of medical comorbidities, or smoking history. Patients with an ODI4% > or = 5 had a significantly higher rate of postoperative complications than those with ODI4% < 5 (15.3% vs 2.7%, respectively [p < 0.01]; adjusted odds ratio, 7.2; 95% confidence interval, 1.5 to 33.3 [p = 0.012]). The complication rate also increased with increasing ODI severity (patients with an ODI4% of 5 to 15 events per hour, 13.8%; patients with an ODI4% of > or = 15 events per hour, 17.5%; p = 0.01) Complications were respiratory (nine patients), cardiovascular (five patients), GI (one patient), and bleeding (two patients). The hospital length of stay was similar in both groups.

CONCLUSION

An ODI4%> or = 5, determined by home nocturnal oximetry, in patients with clinical features of OSA is associated with an increased rate of postoperative complications.

[Anaesthetic management of adult patients with obstructive sleep apnea syndrome]

OBJECTIVE

The purpose of this review article is to update the anaesthetic management of adult patients with obstructive sleep apnoea syndrome (OSAS).

DATA SOURCES

All references obtained from the medical database Medline related to OSAS and anaesthesia from 1963 until May 2006 were reviewed. References included original articles, observations, clinical cases, and reviews published in English or in French.

DATA SYNTHESIS

The anaesthetic literature related to OSAS and anaesthesia is poor. Understanding anatomy and pathophysiology is important for an optimal anaesthetic management. Since the diagnosis is unknown in almost 80-90% of these patients, many undergo general or regional anaesthesia every day without recognition of the main dangers associated with the condition. Recognition of these patients, especially in the preanaesthetic assessment, is an essential step to prevent perioperative complications. Patients with OSAS are very sensitive to sedatives, hypnotics and opioids. The use of these drugs must be controlled and monitored. Anticipation of difficult intubation avoids complications during induction of general anaesthesia and the use of nasal CPAP decreases the incidence of respiratory complications in the perioperative period.

CONCLUSION

Further research is needed in this field of anesthesia. Intraoperative difficulties in the control of airway and postoperative cardiac and respiratory complications may happen. The use of nasal CPAP in the perioperative period makes the anaesthetic management easier and safer.

Nocturnal episodic hypoxemia after ambulatory breast cancer surgery: comparison of sevoflurane and propofol-fentanyl anesthesia

PURPOSE

To study the incidence and severity of nocturnal episodic hypoxemia after ambulatory breast cancer surgery and its differences with sevoflurane and propofol anesthesia.

METHODS

Sixty-one adult female patients (ASA PS I-II; age, 32-77 years) without an apparent history of sleep apnea and respiratory disease undergoing major breast cancer surgery on an outpatient basis and with planned overnight admission were randomized to one of two anesthesia maintenance groups: sevoflurane anesthesia (SEV, n = 31) or intravenous propofol, fentanyl, and vecuronium anesthesia (TIVA, n = 30). All patients were administered propofol 2 mg x kg(-1) intravenously for anesthesia induction, had a laryngeal mask airway placed, and received rectal diclofenac and local infiltration anesthesia for pain relief. No opioid analgesic or oxygen was administered after discharge from the postanesthesia care unit (PACU). Oxygen saturation (Sp(O) (2)) was recorded continuously during the first postoperative night. Sp(O) (2) <90% that lasted >10 s was regarded as hypoxemia, and the percentage of effective recording time with Sp(O) (2) <90% (%time with Sp(O) (2) <90) was evaluated.

RESULTS

Six patients (SEV3/TIVA3) had >1% of %time with Sp(O) (2) <90 (S-hypoxemia group), 17 (SEV7/TIVA10) had >0% and <or=1% (M-Hypoxemia group), and 38 (SEV21/TIVA17) had 0% (no-hypoxemia group). There were no statistical differences in age, ASA PS, anesthesia technique, and duration of anesthesia among groups. The S-hypoxemia group had higher body mass index (BMI) and incidence of oxygen supplementation in the PACU than the no-hypoxemia group. No patient had major complications.

CONCLUSION

Nocturnal episodic hypoxemia occurs frequently after ambulatory breast cancer surgery. The incidence was not different between SEV and TIVA. Hypoxic patients had a higher BMI and needed oxygen therapy in PACU more frequently.

Unrecognized sleep apnea in the surgical patient: implications for the perioperative setting

Anesthesia and surgery both affect the architecture of sleep. Aside from the postoperative effects of anesthesia and surgery, sleep deprivation and fragmentation have been shown to produce apneas or desaturations even in patients without presumed sleep apnea. Recent epidemiologic data have placed the prevalence of obstructive sleep apnea syndrome (OSAS) at about 5% among Western countries. The problem is further hindered by the difficulty in diagnosing OSAS, as patients with OSAS may present for surgery without a prior diagnosis. Clinical suspicion for OSAS may first be recognized intraoperatively. Adverse surgical outcomes appear to be more frequent in OSAS patients. Immediate postoperative complications may intuitively be attributed to the negative effects of sedative, analgesic, and anesthetic agents, which can worsen OSAS by decreasing pharyngeal tone, and the arousal responses to hypoxia, hypercarbia, and obstruction. Later events are, however, more likely to be related to postoperative rapid eye movement (REM) sleep rebound. In the severe OSAS patient, REM sleep rebound could conceivably act in conjunction with opioid administration and supine posture to aggravate sleep-disordered breathing. REM sleep rebound has also been suggested to contribute to mental confusion and postoperative delirium, myocardial ischemia/infarction, stroke, and wound breakdown. Although the data to guide the perioperative management of patients with moderate-to-severe OSAS is scarce, heightened awareness is recommended. The selected use of therapy with nasal continuous positive airway pressure before surgery and after extubation may be beneficial.

LEARNING OBJECTIVES

1. Identify common sleep architectures affected by anesthesia and surgery in the perioperative period. 2. State a perioperative complication in Obstructive Sleep Apnea Syndrome patients. 3. Identify perioperative interventions and management techniques that best facilitate improved obstructive sleep apnea syndrome patient care.

The diagnosis of obstructive sleep apnea as a risk factor for unanticipated admissions in outpatient surgery

The goal of this study was to determine whether the preoperative diagnosis of obstructive sleep apnea (OSA) is an independent risk factor for perioperative complications in patients undergoing nonotorhinolaryngologic outpatient surgical procedures. We used existing databases to identify 234 patients with polysomnography-confirmed OSA who had outpatient surgical procedures in the years 1997 through 2000. Control patients were matched for type of anesthesia, age, sex, body mass index, surgical procedure, and surgical date. Their perioperative medical records were reviewed. There was no significant difference in the intraoperative management of OSA and control patients, except that the laryngeal mask airway was less likely to be used in OSA patients. There was no significant difference in the rate of unplanned hospital admissions (23.9% versus 18.8%; odds ratio, 1.4; 95% confidence interval, 0.8-2.5) or other adverse events (2.1% versus 1.3%; odds ratio, 1.7; 95% confidence interval, 0.4-7.0) between OSA and non-OSA patients. Further, when admission did occur, it was generally unrelated to cardiac or respiratory events. In this retrospective analysis, the preoperative diagnosis of OSA was not a risk factor for either unanticipated hospital admission or for other adverse events among patients undergoing outpatient surgical procedures in a tertiary referral center.

IMPLICATIONS

In patients scheduled for outpatient surgery in a large academic practice, the diagnosis of obstructive sleep apnea confirmed by polysomnography was not an independent risk factor for unanticipated hospital admission or for other adverse perioperative events.

Overnight pulse oximetry for sleep-disordered breathing in adults: a review

Pulse oximetry is a well-established tool routinely used in many settings of modern medicine to determine a patient's arterial oxygen saturation and heart rate. The decreasing size of pulse oximeters over recent years has broadened their spectrum of use. For diagnosis and treatment of sleep-disordered breathing, overnight pulse oximetry helps determine the severity of disease and is used as an economical means to detect sleep apnea. In this article, we outline the clinical utility and economical benefit of overnight pulse oximetry in sleep and breathing disorders in adults and highlight the controversies regarding its limitations as presented in published studies.