Predicting Hospital Survival in Patients Admitted to ICU with Pulmonary Embolism.

OBJECTIVE: The Pulmonary Embolism Severity Index (PESI) and simplified PESI (sPESI) predict mortality for patients with PE. We compared PESI/sPESI to the Acute Physiology and Chronic Health Evaluation IV (APACHE-IV) in predicting mortality in patients with PE admitted to the intensive care unit (ICU). Additionally, we assessed the performance of a novel ICU-sPESI score created by adding three clinical variables associated with acuity of PE presentation (intubation, confusion [altered mental status], use of vasoactive infusions) to sPESI. MATERIALS AND METHODS: Using the eICU Collaborative Research Database from 2014 to 2015, we conducted a large retrospective cohort study of adult patients admitted to the ICU with a primary diagnosis of PE. We calculated APACHE-IV, PESI, sPESI, and ICU-sPESI scores and compared their performance for predicting in-hospital mortality using area under the receiver operating characteristic (AUROC) curve. Score thresholds for >99% negative predictive values (NPV) were calculated for each score. Survival was estimated using the Kaplan-Meier method. RESULTS: We included 1424 PE cases. In-hospital mortality was 6.3% [95% CI: 5.1%-7.6%]. AUROC for APACHE-IV, PESI, and sPESI were 0.870, 0.848, and 0.777, respectively. APACHE-IV and PESI outperformed sPESI (P < 0.01 for both comparisons), while APACHE-IV and PESI demonstrated similar performance (P = 0.322). The ICU-sPESI performance was similar to APACHE-IV and PESI (AUROC = 0.847; AUROC comparison: APACHE-IV vs ICU-sPESI: P = 0.396; PESI vs ICU-sPESI: P = 0.945). Hospital mortality for ICU-sPESI scores 0-2 was 1.1%, and for scores 3, 4, 5, 6, and ≥7 was 8.6%, 11.7%, 29.2%, 37.5%, and 76.9%, respectively. Score thresholds for >99% NPV were ≤48 for APACHE-IV, ≤115 for PESI, and 0 points for sPESI and ICU-sPESI. CONCLUSIONS: By accounting for severity of PE presentation, our newly proposed ICU-sPESI score provided improved PE mortality prediction compared to the original sPESI score and offered excellent discrimination of mortality risk.

Effect of Propofol Infusion on Need for Rescue Antiemetics in Postanesthesia Care Unit After Volatile Anesthesia: A Retrospective Cohort Study.

BACKGROUND: Postoperative nausea and vomiting (PONV) are frequent after volatile anesthesia. We hypothesized that coadministration of propofol with volatile anesthetic compared to pure volatile anesthetics would decrease the need for postoperative antiemetic treatments and shorten recovery time in the postanesthesia care unit (PACU). METHODS: We retrospectively identified adult patients who underwent procedures using general anesthesia with volatile agents, with or without propofol infusion, from May 2018 through December 2020, and who were admitted to the PACU. Inverse probability of treatment weighting (IPTW) analysis was performed using generalized estimating equations with robust variance estimates to assess whether propofol was associated with decreased need for rescue antiemetics. RESULTS: Among 47,847 patients, overall IPTW rescue antiemetic use was 4.7% for 17,573 patients who received propofol and 8.2% for 30,274 who did not (odds ratio [OR], 0.55; 95% confidence interval [CI], 0.49-0.61; P <.001). This effect associated with propofol was present regardless of the intensity of antiemetic prophylaxis (OR, 0.59, 0.51, and 0.58 for 0-1, 2, and ≥3 antiemetics used, respectively), procedural duration (OR, 0.54, 0.62, and 0.47 for ≤2.50, 2.51-4.00, ≥4.01 hours), and type of volatile agent (OR, 0.51, 0.52, and 0.57 for desflurane, isoflurane, and sevoflurane) (all P <.001). This effect was dose dependent, with little additional benefit for the reduction in the use of PACU antiemetics when propofol rate exceeded 100 µg/kg/min. Patients who received rescue antiemetics required longer PACU recovery time than those who did not receive antiemetics (ratio of the geometric mean, 1.31; 95% CI, 1.28-1.33; P <.001), but use of propofol did not affect PACU recovery time (ratio of the geometric mean, 1.00; 95% CI, 0.98-1.01; P =.56). CONCLUSIONS: The addition of propofol infusions to volatile-based anesthesia is associated with a dose-dependent reduction in the need for rescue antiemetics in the PACU regardless of the number of prophylactic antiemetics, duration of procedure, and type of volatile agent used, without affecting PACU recovery time.

Postanesthesia Care Unit Recovery Time According to Volatile Anesthetic Used in Clinical Practice.

BACKGROUND: Whether volatile anesthetic solubility affects postanesthesia recovery time in clinical practice is unclear. We investigated the association among 3 volatile agents and 2 clinically relevant outcomes-postanesthesia care unit (PACU) recovery time (time from PACU admission to fulfillment of discharge criteria) and oversedation (Richmond Agitation-Sedation Scale score ≤-3)-as a potential contributor to delaying PACU discharge. The volatile agents studied were isoflurane, desflurane, and sevoflurane. We hypothesized that increased solubility of the volatile agent (isoflurane versus desflurane or sevoflurane) would be associated with longer PACU recovery time and higher rates of oversedation. METHODS: This retrospective observational study included adults (≥18 years) who underwent surgical procedures under general anesthesia with a volatile agent and were admitted to the PACU from May 5, 2018, to December 31, 2020. The primary outcome was PACU recovery time, and the secondary outcome was oversedation. PACU recovery time was log-transformed and analyzed with linear regression. Oversedation was analyzed by using logistic regression. To account for potential confounding, inverse probability of treatment weighting (IPTW) was used. Pairwise comparisons of the 3 agents were performed, with P < .017 (Bonferroni-adjusted) considered significant. RESULTS: Of 47,847 patients included, 11,817 (24.7%) received isoflurane, 11,286 (23.6%) received desflurane, and 24,744 (51.7%) received sevoflurane. Sevoflurane had an estimated 4% shorter PACU recovery time (IPTW-adjusted median [interquartile range {IQR}], 61 [42-89] minutes) than isoflurane (64 [44-92] minutes) (ratio of geometric means [98.3% confidence interval {CI}], 0.96 [0.95-0.98]; P < .001). Differences in PACU recovery time between desflurane and the other agents were not significant. The IPTW-adjusted frequency of oversedation was 8.8% for desflurane, 12.2% for sevoflurane, and 16.7% for isoflurane; all pairwise comparisons were observed to be significant (odds ratio [98.3% CI], 0.70 [0.62-0.79] for desflurane versus sevoflurane, 0.48 [0.42-0.55] for desflurane vs isoflurane, and 0.69 [0.63-0.76] for sevoflurane versus isoflurane; all P < .001). Although oversedated patients had longer PACU recovery time, differences in the oversedation rate across agents did not result in meaningful differences in time to PACU recovery. CONCLUSIONS: In clinical practice, only small, clinically unimportant differences in PACU recovery time were observed between the volatile anesthetics. Although oversedation was associated with increased PACU recovery time, differences in the rate of oversedation among agents were insufficient to produce meaningful differences in overall PACU recovery time across the 3 volatile agents. Practical attempts to decrease PACU recovery time should address factors other than volatile agent selection.

Anesthetic Management and Deep Sedation After Emergence From General Anesthesia: A Retrospective Cohort Study.

BACKGROUND: Residual deep sedation during anesthesia recovery may predict postoperative complications. We examined the incidence and risk factors for deep sedation after general anesthesia. METHODS: We retrospectively reviewed health records of adults who underwent procedures with general anesthesia and were admitted to the postanesthesia care unit from May 2018 to December 2020. Patients were dichotomized by Richmond Agitation-Sedation Scale (RASS) score: ≤-4 (deeply sedated/unarousable) or ≥-3 (not deeply sedated). Anesthesia risk factors for deep sedation were assessed with multivariable logistic regression. RESULTS: Of the 56,275 patients included, 2003 had a RASS ≤-4 (35.6 [95% CI, 34.1-37.2] cases per 1000 anesthetics administered). On adjusted analyses, the likelihood of a RASS ≤-4 increased when more soluble halogenated anesthetics were used. Compared with desflurane without propofol, the odds ratio (OR [95% CI]) for a RASS ≤-4 was higher with sevoflurane (1.85 [1.45-2.37]) and isoflurane (4.21 [3.29-5.38]) without propofol. Compared with desflurane without propofol, the odds of a RASS ≤-4 further increased with use of desflurane-propofol (2.61 [1.99-3.42]), sevoflurane-propofol (4.20 [3.28-5.39]), isoflurane-propofol (6.39 [4.90-8.34]), and total intravenous anesthesia (2.98 [2.22-3.98]). A RASS ≤-4 was also more likely with the use of dexmedetomidine (2.47 [2.10-2.89]), gabapentinoids (2.17 [1.90-2.48]), and midazolam (1.34 [1.21-1.49]). Deeply sedated patients discharged to general care wards had higher odds of opioid-induced respiratory complications (2.59 [1.32-5.10]) and higher odds of naloxone administration (2.93 [1.42-6.03]). CONCLUSIONS: Likelihood of deep sedation after recovery increased with intraoperative use of halogenated agents with higher solubility and increased further when propofol was concomitantly used. Patients who experience deep sedation during anesthesia recovery have an increased risk of opioid-induced respiratory complications on general care wards. These findings may be useful for tailoring anesthetic management to reduce postoperative oversedation.

Incidence of postoperative opioid-induced respiratory depression episodes in patients on room air or supplemental oxygen: a post-hoc analysis of the PRODIGY trial.

BACKGROUND: Supplemental oxygen (SO) potentiates opioid-induced respiratory depression (OIRD) in experiments on healthy volunteers. Our objective was to examine the relationship between SO and OIRD in patients on surgical units. METHODS: This post-hoc analysis utilized a portion of the observational PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) trial dataset (202 patients, two trial sites), which involved blinded continuous pulse oximetry and capnography monitoring of postsurgical patients on surgical units. OIRD incidence was determined for patients receiving room air (RA), intermittent SO, or continuous SO. Generalized estimating equation (GEE) models, with a Poisson distribution, a log-link function and time of exposure as offset, were used to compare the incidence of OIRD when patients were receiving SO vs RA. RESULTS: Within the analysis cohort, 74 patients were always on RA, 88 on intermittent and 40 on continuous SO. Compared with when on RA, when receiving SO patients had a higher risk for all OIRD episodes (incidence rate ratio [IRR] 2.7, 95% confidence interval [CI] 1.4-5.1), apnea episodes (IRR 2.8, 95% CI 1.5-5.2), and bradypnea episodes (IRR 3.0, 95% CI 1.2-7.9). Patients with high or intermediate PRODIGY scores had higher IRRs of OIRD episodes when receiving SO, compared with RA (IRR 4.5, 95% CI 2.2-9.6 and IRR 2.3, 95% CI 1.1-4.9, for high and intermediate scores, respectively). CONCLUSIONS: Despite oxygen desaturation events not differing between SO and RA, SO may clinically promote OIRD. Clinicians should be aware that postoperative patients receiving SO therapy remain at increased risk for apnea and bradypnea. TRIAL REGISTRATION: Clinicaltrials.gov: NCT02811302, registered June 23, 2016.

Association of Blood Pressure Variability with Delirium in Patients with Critical Illness.

BACKGROUND: The objective was to examine the association of blood pressure variability (BPV) during the first 24 h after intensive care unit admission with the likelihood of delirium and depressed alertness without delirium ("depressed alertness"). METHODS: This retrospective, observational, cohort study included all consecutive adult patients admitted to an intensive care unit at Mayo Clinic, Rochester, Minnesota, from July 1, 2004, through October 31, 2015. The primary outcomes were delirium and delirium-free days, and the secondary outcomes included depressed alertness and depressed alertness-free days. Logistic regression was performed to determine the association of BPV with delirium and depressed alertness. Proportional odds regression was used to assess the association of BPV with delirium-free days and depressed alertness-free days. RESULTS: Among 66,549 intensive care unit admissions, delirium was documented in 20.2% and depressed alertness was documented in 24.4%. Preserved cognition was documented in 55.4% of intensive care unit admissions. Increased systolic and diastolic BPV was associated with an increased odds of delirium and depressed alertness. The magnitude of the association per 5-mm Hg increase in systolic average real variability (the average of absolute value of changes between consecutive systolic blood pressure readings) was greater for delirium (odds ratio 1.34; 95% confidence interval 1.29-1.40; P < 0.001) than for depressed alertness (odds ratio 1.06; 95% confidence interval 1.02-1.10; P = 0.004). Increased systolic and diastolic BPV was associated with fewer delirium-free days but not with depressed alertness-free days. CONCLUSIONS: BPV in the first 24 h after intensive care unit admission is associated with an increased likelihood of delirium and fewer delirium-free days.

Perioperative management of mastocytosis.

PURPOSE: Patients with mastocytosis have an increased risk of anaphylaxis during surgical procedures with general anesthesia. Therefore, we reviewed the anesthesia course of a large cohort of patients with mastocytosis. METHODS: We retrospectively reviewed adult and pediatric patients with mastocytosis who underwent surgical procedures with general anesthesia at Mayo Clinic from January 1, 2000, through June 30, 2021. We also included any procedures with general anesthesia that occurred during the 3-year period preceding mastocytosis diagnosis and designated the patients who underwent these procedures as having an unknown diagnosis at the time of their surgical procedure. We analyzed whether patients received chronic antimediator treatment for mastocytosis and/or prophylactic medications before the procedures. We also determined whether medications indicative of mastocytosis-related adverse events were intraoperatively administered. RESULTS: We identified 113 patients who underwent 219 procedures during the study period; 25 procedures were performed before mastocytosis diagnosis. Of 194 procedures in patients with known mastocytosis, patients received chronic antimediator therapy and/or perioperative prophylactic medications for 178 (91.8%) procedures. Among these procedures, 10 were potentially complicated by mast cell activation, which was inferred from administration of inhaled albuterol (n = 3) or intravenous diphenhydramine (n = 8). In addition, there was only one case of intraoperative anaphylaxis which occurred in a patient who underwent anesthesia before mastocytosis diagnosis and therefore did not receive prophylaxis. CONCLUSION: Intraoperative anaphylaxis can be the first presenting sign of mastocytosis. Patients with mastocytosis who received chronic antimediator therapy and/or preoperative prophylactic medications had an uneventful surgical course.

Hemodynamics in Patients With Pheochromocytoma or Paraganglioma Undergoing Non-neuroendocrine Operations.

INTRODUCTION: Surgical resection of pheochromocytoma and paraganglioma (PPGL) may be associated with excessive hemodynamic variability. Whether hemodynamic variability occurs in patients with undiagnosed PPGL undergoing unrelated, non-neuroendocrine, operations is unknown. METHODS: We identified patients who underwent non-neuroendocrine surgical procedures up to 5 y before pathologic diagnosis of PPGL. For each PPGL, two non-PPGL patients were matched based on sex, age, type, and year of operation. Electronic medical records were reviewed for intraoperative blood pressures, heart rates, and hemodynamic variability was assessed with range (maximum-minimum), standard deviation, coefficient of variation, and average real variability. RESULTS: Thirty-seven PPGL patients underwent operations preceding the diagnosis of PPGL: 25 pheochromocytomas, 11 paragangliomas, and one metastatic pheochromocytoma. Median interquartile range tumor size at diagnosis was 35 mm (23 to 60). The time from index operation to PPGL diagnosis was ≤12 mo in 21 (56.8%) patients. In 23 (62.2%) patients, the subsequently diagnosed PPGL was functional. Fifteen (40.5%) PPGL and 20 (27.0%) control patients were preoperatively treated for hypertension (P = 0.149). Maximum intraoperative systolic BP was >180 mmHg for 4 (10.8%) PPGL patients and 3 (4.1%) controls (P = 0.219). Two PPGL patients had intraoperative systolic BP >230 mmHg. No significant differences were found with all other measures of intraoperative hemodynamic variability. Similarly, in secondary analysis there was no significant difference in intraoperative hemodynamic variability between biochemically active PPGL and their respective controls. CONCLUSIONS: Patients with undiagnosed PPGL undergoing a wide variety of non-neuroendocrine operations had intraoperative hemodynamic variability comparable to non-PPGL patients undergoing the same type of procedures.

Incidence and Outcomes of Life-Threatening Events During Hospitalization: A Retrospective Study of Patients Treated with Naloxone.

BACKGROUND: We describe the clinical course of medical and surgical patients who received naloxone on general hospital wards for suspected opioid-induced respiratory depression (OIRD). METHODS: From May 2018 through October 2020, patients who received naloxone on hospital wards were identified and their records reviewed for incidence and clinical course. RESULTS: There were 86,030 medical and 106,807 surgical admissions. Naloxone was administered to 99 (incidence 11.5 [95% confidence interval 9.4-14.0] per 10,000 admissions) medical and 63 (5.9 [95% confidence interval 4.5-7.5]) surgical patients (P < 0.001). Median oral morphine equivalents administered within 24 hours before naloxone were 32 [15, 64] and 60 [32, 88] mg for medical and surgical patients, respectively (P = 0.002). The rapid response team was activated in 69 (69.7%) vs 42 (66.7%) and critical care transfers in 51 (51.5%) vs 30 (47.6%) medical and surgical patients respectively. The number of in-hospital deaths was 21 (21.2%) vs two (3.2%) and the number of discharges to hospice 12 (12.1%) vs one (1.6%) for medical and surgical patients, respectively (P = 0.001). Naloxone did not reverse OIRD in 38 (23%) patients, and these patients had more transfers to the intensive care unit and a higher 30-day mortality rate. CONCLUSION: Medical inpatients are more likely to suffer OIRD than are surgical inpatients despite lower opioid doses. Definitive OIRD was confirmed in 77% of patients because of immediate naloxone response, whereas 23% of patients did not respond, and this subset was more likely to need a higher level of care and had a higher 30-day mortality rate. Careful monitoring of mental and respiratory variables is necessary when opiates are used in hospital.

Association Between Race and Opioid-Induced Respiratory Depression: An International Post Hoc Analysis of the Prediction of Opioid-induced Respiratory Depression In Patients Monitored by Capnography Trial.

BACKGROUND: Opioid-induced respiratory depression (OIRD) is common on the medical and surgical wards and is associated with increased morbidity and health care costs. While previous studies have investigated risk factors for OIRD, the role of race remains unclear. We aim to investigate the association between race and OIRD occurrence on the medical/surgical ward. METHODS: This is a post hoc analysis of the PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) trial; a prospective multinational observational blinded study of 1335 general ward patients who received parenteral opioids and underwent blinded capnography and oximetry monitoring to identify OIRD episodes. For this study, demographic and perioperative data, including race and comorbidities, were analyzed and assessed for potential associations with OIRD. Univariable χ 2 and Mann-Whitney U tests were used. Stepwise selection of all baseline and demographic characteristics was used in the multivariable logistic regression analysis. RESULTS: A total of 1253 patients had sufficient racial data (317 Asian, 158 Black, 736 White, and 42 other races) for inclusion. The incidence of OIRD was 60% in Asians (N = 190/317), 25% in Blacks (N = 40/158), 43% in Whites (N = 316/736), and 45% (N = 19/42) in other races. Baseline characteristics varied significantly: Asians were older, more opioid naïve, and had higher opioid requirements, while Blacks had higher incidences of heart failure, obesity, and smoking. Stepwise multivariable logistic regression revealed that Asians had increased risk of OIRD compared to Blacks (odds ratio [OR], 2.49; 95% confidence interval [CI], 1.54-4.04; P = .0002) and Whites (OR, 1.38; 95% CI, 1.01-1.87; P = .0432). Whites had a higher risk of OIRD compared to Blacks (OR, 1.81; 95% CI, 1.18-2.78; P = .0067). The model's area under the curve was 0.760 (95% CI, 0.733-0.787), with a Hosmer-Lemeshow goodness-of-fit test P value of .23. CONCLUSIONS: This post hoc analysis of PRODIGY found a novel association between Asian race and increased OIRD incidence. Further study is required to elucidate its underlying mechanisms and develop targeted care pathways to reduce OIRD in susceptible populations.

Postoperative pulmonary complications with adjuvant regional anesthesia versus general anesthesia alone: a sub-analysis of the Perioperative Research Network study.

BACKGROUND: Adjuvant regional anesthesia is often selected for patients or procedures with high risk of pulmonary complications after general anesthesia. The benefit of adjuvant regional anesthesia to reduce postoperative pulmonary complications remains uncertain. In a prospective observational multicenter study, patients scheduled for non-cardiothoracic surgery with at least one postoperative pulmonary complication surprisingly received adjuvant regional anesthesia more frequently than those with no complications. We hypothesized that, after adjusting for surgical and patient complexity variables, the incidence of postoperative pulmonary complications would not be associated with adjuvant regional anesthesia. METHODS: We performed a secondary analysis of a prospective observational multicenter study including 1202 American Society of Anesthesiologists physical status 3 patients undergoing non-cardiothoracic surgery. Patients were classified as receiving either adjuvant regional anesthesia or general anesthesia alone. Predefined pulmonary complications within the first seven postoperative days were prospectively identified. Groups were compared using bivariable and multivariable hierarchical logistic regression analyses for the outcome of at least one postoperative pulmonary complication. RESULTS: Adjuvant regional anesthesia was performed in 266 (22.1%) patients and not performed in 936 (77.9%). The incidence of postoperative pulmonary complications was greater in patients receiving adjuvant regional anesthesia (42.1%) than in patients without it (30.9%) (site adjusted p = 0.007), but this association was not confirmed after adjusting for covariates (adjusted OR 1.37; 95% CI, 0.83-2.25; p = 0.165). CONCLUSION: After adjusting for surgical and patient complexity, adjuvant regional anesthesia versus general anesthesia alone was not associated with a greater incidence of postoperative pulmonary complications in this multicenter cohort of non-cardiothoracic surgery patients.

Bladder spasms following ambulatory urologic procedures.

INTRODUCTION: Bladder spasm are common complications following cystoscopic urologic procedures. This study aims to determine the incidence and risk factors for bladder spasm after ambulatory cystoscopic urologic procedures. MATERIALS AND METHODS: Medical records of adult patients who underwent urologic procedures in our ambulatory center from May 1st, 2018 through December 30th, 2020, were reviewed. Bladder spasm was identified from the administration of antispasmodic therapy (e.g. oxybutynin) during anesthesia recovery. Multivariable analyses were performed to assess the association between bladder spasm and clinical factors. RESULTS: Included were 2,671 patients, of which 917 (34.3%) developed postoperative bladder spasm, yielding an incidence of 343 (95%CI 325-361) per 1,000 procedures. Risk factors associated with bladder spasm were younger adult age (< 60 years), longer (> 45 minutes) and more complex procedures. Compared to cystoscopy the risk of spasm following transurethral resection of the bladder tumor was OR 4.35 (95%CI 3.22, 5.87) and for transurethral resection of the prostate OR 3.25 (95% CI 2.24, 4.71). Spasm prophylaxis with belladonna and opium suppositories (B&O) was used in 1,158 patients and 384 (33.2%) developed spasms. The use of B&O was not associated with reduction of bladder spasm, OR 0.91 (95%CI 0.75, 1.1, p = 0.318). Postoperative outcomes did not differ between patients who did or did not develop spasms. CONCLUSION: Bladder spasms are common following ambulatory urologic procedures, more so with more extensive procedures. Prophylaxis with B&O was not significantly associated with a lower rate of bladder spasms.

Myocardial Infarction and Cardiac Arrest in a Patient With Severe Undiagnosed Hypothyroidism During Bronchoscopy.

Thyroid hormones have an integral role in cardiac homeostasis, and hypothyroidism may be associated with impaired myocardial contractility, altered endothelial function, and blunted response to catecholamines. Herein, the case of a patient with undiagnosed severe hypothyroidism, who developed an acute myocardial infarction and cardiac arrest during sedation for bronchoscopy, is described. He required prolonged resuscitation, which included coronary catheterization and placement of an intra-aortic balloon pump. The resuscitation was noteworthy for blunted physiologic responses to large doses of epinephrine; in particular, persistent bradycardia without evidence of conduction abnormalities. On admission to the intensive care unit, he was hypothermic (31.4°C), bradycardic, and hypotensive. Laboratory investigations revealed profound hypothyroidism, and thyroid hormone replacement was initiated. Within hours of initiation of thyroid hormone replacement, the need for vasopressor support was reduced. He had a complete recovery and was discharged home neurologically intact. The authors of the present report believe that this favorable neurologic outcome could be attributed to efficient resuscitation, prompt coronary revascularization, and profound hypothermia likely related to a hypothyroidism-associated hypometabolic state.

Perioperative considerations for adult patients with obstructive sleep apnea.

PURPOSE OF REVIEW: Obstructive sleep apnea (OSA) is a common, but often undiagnosed, sleep breathing disorder affecting approximately a third of adult surgical patients. OSA patients have increased sensitivity to anesthetic agents, sedatives, and opioid analgesics. RECENT FINDINGS: Newer technologies (e.g., bedside capnography) have demonstrated that OSA patients have repetitive apneic spells, beginning in the immediate postoperative period and peaking in frequency during the first postoperative night. Compared to patients without OSA, OSA patients have double the risk for postoperative pulmonary as well as other complications, and OSA has been linked to critical postoperative respiratory events leading to anoxic brain injury or death. Patients with OSA who have respiratory depression during anesthesia recovery have been found to be high-risk for subsequent pulmonary complications. Gabapentinoids have been linked to respiratory depression in these patients. SUMMARY: Surgical patients should be screened for OSA and patients with OSA should continue using positive airway pressure devices postoperatively. Use of shorter acting and less sedating agents and opioid sparing anesthetic techniques should be encouraged. In particular, OSA patients exhibiting signs of respiratory depression in postanesthesia recovery unit should receive enhancer respiratory monitoring following discharge to wards.

Urine output and acute kidney injury following laparoscopic pancreas operations.

BACKGROUND: This study aims to assess if intraoperative urine output is associated with acute kidney injury (AKI) during laparoscopic pancreas surgery. METHODS: Medical records of adult patients who underwent laparoscopic pancreas surgery from 2010 to 2020 were reviewed to identify patients who experienced AKI (creatinine increase of 0.3 mg/dL within 72 h). Surgeries were classified as with 'vascular reconstruction' (e.g. Whipple, total pancreatectomy) versus 'without reconstruction' (e.g., distal pancreatectomy). RESULTS: Included were 365 patients (221 with and 114 without reconstruction), and 42 (11.4%) developed AKI (32 [14.5%] reconstruction and 10 [6.9%] without reconstruction (P = 0.164)). The median urine output for AKI group was 0.79 [0.43, 1.15] mL/kg/h and 0.88 [0.55, 1.53] mL/kg/h for non-AKI group, P = 0.121. Urine output between AKI and non-AKI did not vary among reconstruction cases (P = 0.383), but was lower in AKI patients without reconstruction (P = 0.047). Older age, preexisting kidney disease, higher disease burden, and intraoperative hypotension were associated with AKI. Postoperative course was more complicated for AKI patients including rates of pancreatic fistulas and mortality. CONCLUSION: Incidence of AKI increases with more extensive surgery, but is not associated with low urine output. However, low urine output was associated with AKI in patients undergoing operation without reconstruction.

Pharmacologically Induced Ventilatory Depression in the Postoperative Patient: A Sleep-Wake State-Dependent Perspective.

Pharmacologically induced ventilatory depression (PIVD) is a common postoperative complication with a spectrum of severity ranging from mild hypoventilation to severe ventilatory depression, potentially leading to anoxic brain injury and death. Recent studies, using continuous monitoring technologies, have revealed alarming rates of previously undetected severe episodes of postoperative ventilatory depression, rendering the recognition of such episodes by the standard intermittent assessment practice, quite problematic. This imprecise description of the epidemiologic landscape of PIVD has thus stymied efforts to understand better its pathophysiology and quantify relevant risk factors for this postoperative complication. The residual effects of various perianesthetic agents on ventilatory control, as well as the multiple interactions of these drugs with patient-related factors and phenotypes, make postoperative recovery of ventilation after surgery and anesthesia a highly complex physiological event. The sleep-wake, state-dependent variation in the control of ventilation seems to play a central role in the mechanisms potentially enhancing the risk for PIVD. Herein, we discuss emerging evidence regarding the epidemiology, risk factors, and potential mechanisms of PIVD.

Frequency and Temporal Distribution of Postoperative Respiratory Depressive Events.

BACKGROUND: The frequency and temporal distribution of postoperative respiratory depression (RD) events are not completely understood. This study determined the temporal distribution and frequency of RD episodes in postsurgical patients continuously monitored by bedside capnography and pulse oximetry. METHODS: This was a post hoc study of a subset of postsurgical patients enrolled in The PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) trial from 2 sites in the United States. These patients had undergone continuous bedside monitoring on general care wards. These data were adjudicated for potential RD episodes. The number of RD episodes per patient and the time of each RD episode were determined. The first RD episode experienced by a patient was classified as an "initial" episode, and the initial and all subsequent RD episodes experienced by a patient were classified as "all" episodes. A PRODIGY risk score was calculated. RESULTS: Data analyzed from 250 patients contained 2539 RD episodes in 155 (62.0%, 95% confidence interval, 55.7-68.0) patients with median 2 [0-8], range of 0-545 RD episodes per patient, with a PRODIGY risk score distribution of 100 (40.0%) low, 79 (31.6%) intermediate, 70 (28.0%) high (missing data from 1 patient). Median time to the initial RD episode was 8.8 [5.1-18.0] hours postoperatively. There was a peak occurrence of initial RD events between 14:00 and 20:00 on the day of surgery, and these were associated with a large number of subsequent events in the same timeframe. The peak time of all RD episodes occurred from 02:00 to 06:00. Patients with high PRODIGY risk scores had higher incidence and greater number of RD episodes per patient (P < .001, overall comparisons between groups for both incidence [χ2] and number of episodes [Kruskal-Wallis test]). CONCLUSIONS: Continuous monitoring of surgical patients demonstrates that RD episodes are common, and risk increases with higher PRODIGY scores. In this patient cohort, the rate of initial RD episodes peaked in the afternoon to early evening, while peak rate of all RD episodes occurred in early morning. Further, among patients with RD episodes, the number of episodes increased with higher PRODIGY scores.

Identification of Sleep Medicine and Anesthesia Core Topics for Anesthesia Residency: A Modified Delphi Technique Survey.

BACKGROUND: Sleep disorders affect up to 25% of the general population and are associated with increased risk of adverse perioperative events. The key sleep medicine topics that are most important for the practice of anesthesiology have not been well-defined. The objective of this study was to determine the high-priority sleep medicine topics that should be included in the education of anesthesia residents based on the insight of experts in the fields of anesthesia and sleep medicine. METHODS: We conducted a prospective cross-sectional survey of experts in the fields of sleep medicine and anesthesia based on the Delphi technique to establish consensus on the sleep medicine topics that should be incorporated into anesthesia residency curricula. Consensus for inclusion of a topic was defined as >80% of all experts selecting "agree" or "strongly agree" on a 5-point Likert scale. Responses to the survey questions were analyzed with descriptive statistical methods and presented as percentages or weighted mean values with standard deviations (SD) for Likert scale data. RESULTS: The topics that were found to have 100% agreement among experts were the influence of opioids and anesthetics on control of breathing and upper airway obstruction; potential interactions of wake-promoting/hypnotic medications with anesthetic agents; effects of sleep and anesthesia on upper airway patency; and anesthetic management of sleep apnea. Less than 80% agreement was found for topics on the anesthetic implications of other sleep disorders and future pathways in sleep medicine and anesthesia. CONCLUSIONS: We identify key topics of sleep medicine that can be included in the future design of anesthesia residency training curricula.

Individualized PEEP to optimise respiratory mechanics during abdominal surgery: a pilot randomised controlled trial.

BACKGROUND: Higher intraoperative driving pressures (ΔP) are associated with increased postoperative pulmonary complications (PPC). We hypothesised that dynamic adjustment of PEEP throughout abdominal surgery reduces ΔP, maintains positive end-expiratory transpulmonary pressures (Ptp_ee) and increases respiratory system static compliance (Crs) with PEEP levels that are variable between and within patients. METHODS: In a prospective multicentre pilot study, adults at moderate/high risk for PPC undergoing elective abdominal surgery were randomised to one of three ventilation protocols: (1) PEEP≤2 cm H2O, compared with periodic recruitment manoeuvres followed by individualised PEEP to either optimise respiratory system compliance (PEEPmaxCrs) or maintain positive end-expiratory transpulmonary pressure (PEEPPtp_ee). The composite primary outcome included intraoperative ΔP, Ptp_ee, Crs, and PEEP values (median (interquartile range) and coefficients of variation [CVPEEP]). RESULTS: Thirty-seven patients (48.6% female; age range: 47-73 yr) were assigned to control (PEEP≤2 cm H2O; n=13), PEEPmaxCrs (n=16), or PEEPPtp_ee (n=8) groups. The PEEPPtp_ee intervention could not be delivered in two patients. Subjects assigned to PEEPmaxCrs had lower ΔP (median8 cm H2O [7-10]), compared with the control group (12 cm H2O [10-15]; P=0.006). PEEPmaxCrs was also associated with higher Ptp_ee (2.0 cm H2O [-0.7 to 4.5] vs controls: -8.3 cm H2O [-13.0 to -4.0]; P≤0.001) and higher Crs (47.7 ml cm H2O [43.2-68.8] vs controls: 39.0 ml cm H2O [32.9-43.4]; P=0.009). Individualised PEEP (PEEPmaxCrs and PEEPPtp_ee combined) varied widely (median: 10 cm H2O [8-15]; CVPEEP=0.24 [0.14-0.35]), both between, and within, subjects throughout surgery. CONCLUSIONS: This pilot study suggests that individualised PEEP management strategies applied during abdominal surgery reduce driving pressure, maintain positive Ptp_ee and increase static compliance. The wide range of PEEP observed suggests that an individualised approach is required to optimise respiratory mechanics during abdominal surgery. CLINICAL TRIAL REGISTRATION: NCT02671721.

Exposure to surgery with general anaesthesia during adult life is not associated with increased brain amyloid deposition in older adults.

BACKGROUND: Exposure to surgery with general anaesthesia (surgery/GA) is associated with cortical atrophy, but the aetiology remains unknown. Amyloid-ß (Aß) deposition is one of the hallmark pathological characteristics of Alzheimer's disease (AD). We examined brain Aß burden in study participants exposed to surgery/GA. METHODS: We performed a cross-sectional analysis of residents of Olmsted County, MN, USA, in the Mayo Clinic Study of Aging who were aged 70-97 yr and underwent measurement of (i) brain Aß with Pittsburgh compound B positron emission tomography (PiB PET), (ii) brain glucose metabolism with 18-fluorodeoxyglucose (FDG) PET, and (iii) temporal cortical thickness with MRI. Separate analyses were performed with exposure to surgery/GA, defined as occurring after age 40 yr, and with exposure to surgery/GA, defined as occurring within 20 yr before neuroimaging. Imaging measurements were compared between participants who were exposed to surgery/GA vs not exposed. RESULTS: Of the 2563 participants, 585 had PET scans. Regardless of the definition used to quantify exposure, no significant associations were detected between exposure and either global PiB PET or FDG PET. In contrast, exposure to surgery/GA was associated with an increased likelihood of abnormal cortical thinning: odds ratio (OR)=1.98 (95% confidence interval [CI]: 1.19-3.31); P=0.010 in those exposed after age 40 yr, and OR=1.64 (95% CI: 1.05-2.55); P=0.029 in those exposed in the prior 20 yr. CONCLUSIONS: Exposure to surgery/GA is not associated with increases in cortical amyloid deposition. This finding suggests that the modest cortical thinning associated with surgery/GA is not related to AD pathology, but rather is caused by other processes.