Perioperative Hypoxemia Research Articles

Anesthetic Management of Pediatric Ingestion of Multiple Magnetic Beads: A Case Report

The incidence of magnet ingestion among children is increasing, though it remains rare. This case describes a 3-year-old child who ingested multiple magnetic beads and was planned to have the foreign bodies removed by endoscopy under sedation. However, perioperative hypoxemia occurred because gastric perforation had not been detected beforehand. An exploratory laparotomy was performed immediately, all magnetic beads were extracted, and the stomach perforation was closed. This report emphasizes the importance of anesthesia evaluation, anesthesia preparation, airway management, and intraoperative circulation maintenance.

Single-centre observational study of the safety and efficacy of thoracoscopy under local anaesthesia for the management of thoracic infections

ObjectivesThoracoscopy under local anaesthesia is widely performed to diagnose malignancies and infectious diseases. However, few reports have described the use of this procedure for diagnosing and treating intrathoracic infections. This study aimed to evaluate the safety and efficacy of thoracoscopy under local anaesthesia for the management of intrathoracic infections.ResultsData from patients who underwent thoracoscopy procedures performed by chest physicians under local anaesthesia at our hospital between January 2018 and December 2023 were retrospectively reviewed. We analysed their demographic factors, reasons for the examinations, diseases targeted, examination lengths, anaesthetic methods used, diagnostic and treatment success rates, as well as any adverse events. Thirty patients were included. Of these, 12 (40%) had thoracoscopies to diagnose infections, and 18 (60%) had them to treat pyothorax. In terms of diagnosing pleurisy, the causative microorganism of origin was identified via thoracoscopy in only three of 12 (25.0%) patients. For diagnosing pyothorax, the causative microorganism was identified in 7 of 18 (38.9%) patients. Methicillin-resistant Staphylococcus aureus was the most common causative microorganism identified. The treatment success rates were very high, ranging between 94.4 and 100%, whereas the identification rate of the causative microorganisms behind infections was low, ranging between 25.0 and 38.9%. The most frequent adverse events included perioperative hypoxaemia and pain. There were two (6.7%) serious adverse events of grade ≥ 3, but none resulted in death.ConclusionsThe efficacy of managing intrathoracic infections through thoracoscopy under local anaesthesia is commendable. Nonetheless, the diagnostic accuracy of the procedure, regarding the precise identification of the causative microorganisms responsible for intrathoracic infections, persists at a notably low level, presenting a substantial clinical hurdle.

Lung ultrasound imaging and clinical consequences of intraoperative high inspired oxygen fraction in healthy mechanically ventilated children

Study objectiveHigh inspired oxygen concentrations (FiO2) are claimed to cause resorption atelectasis increasing the risk for perioperative hypoxemia and postoperative pulmonary complications. Pediatric physicians are still reluctant to accomplish low FiO2 strategies in children. We investigated the association between lung ultrasound score (LUS) and arterial oxygenation (PaO2/FiO2 ratio)in anesthetized mechanically ventilated children undergoing non-abdominal surgery using different FiO2 fractions. Study designObservational cohort. Study settingsOperative rooms and post-anesthesia care unit. PatientsThirty-three patients aged (3–12 years) of both sexes. InterventionPatients were anesthetized while receiving high FIO2 protocol (preoxygenation 1.0, induction and recovery 0.8, maintenance 0.6, post-extubation 1.0 and 0.21 for 2h postoperative). Measurements: LUS was performed after intubation and initiation of mechanical ventilation, after the end of surgery, and 2h postoperatively. Arterial blood gas analysis was performed at the same time points and respiratory mechanics were recorded intraoperatively. LUS scores were tested for probability of bivariate correlation with PaO2/FiO2 ratio (primary endpoint), age, weight, operation time, PaO2, and dynamic compliance. Main resultsAfter intubation, the median LUS score was 2 (Range: 0–14) which significantly decreased after surgery to 1 (0–8), (P = 0.010). At 2- hours postoperatively, it was 0 (0–6) which was significantly lower than both after intubation (P = 0.001) and after surgery (P = 0.007). No significant Correlation was found between the LUS score and any investigated parameters. ConclusionsEven though we found no significant correlation between LUS and PaO2, or PaO2/FiO2 ratio, the high values of LUS after intubation necessitate caution when administering high FiO2 levels in pediatrics. Trial registrationClinicalTrials.gov ID: NCT04581226.

Serum tau protein and myelin basic protein in pediatric patients with congenital heart defects undergoing cardiac surgery: preliminary assessment as novel neuromarkers of brain injury.

Neurological impairment is a big concern in the development of patients with congenital heart defects (CHD). A number of neuromarkers have been studied in search of a diagnostic or prognostic marker for brain injury during the vulnerable perioperative period. Our aim was to assess two novel neuromarkers, myelin basic protein (MBP) and protein Tau (pTau), as diagnostic markers for brain injury in perioperative period in children with CHD. Forty patients were enrolled and dichotomized based on peripheric oxygen saturation in cyanotic and non-cyanotic group. Blood samples were collected preoperative, after the induction of anesthesia, and in postoperative day 1. Neuromarker concentrations were measured using commercially available ELISA kits. Neuromarkers' values were increased postoperative, with statistical significance reached only in non-cyanotic group (p < 0.0001). A significant positive correlation was observed between preoperatory MBP and albumin level, hemoglobin level, height, and weight of patients. Association with cerebral saturations were analyzed by a coefficient defined as ≥ 20% reduction in cerebral saturation measured by near-infrared spectroscopy during perioperative period. An acceptable predicting model was observed with pTau in cyanotic group (AUC = 0.7). We evaluated MBP and pTau as potential biomarkers of brain injury in children with CHD undergoing cardiac surgery. Elevated postoperative pTau and MBP concentrations were observed in both groups. Elevated pTau values were associated with perioperative hypoxemia.

Catecholamine-Refractory Anaphylactic Shock to Vecuronium in a Patient with Tetralogy of Fallot: A Case Report

Serious anaphylactic reactions to anesthetics can be life-threatening events. Vecuronium is promoted as a neuromuscular blocking drug that is least likely to cause anaphylaxis due to its low histamine-releasing potential. Perioperative hypoxemia in patients with tetralogy of Fallot (TOF) due to anaphylactic reactions can be easily misdiagnosed as anoxic spells. We report a patient with TOF who suffered from symmetrical peripheral gangrene after undergoing catecholamine-refractory anaphylactic shock to vecuronium perioperatively. CPB (cardiopulmonary bypass) is the most effective support for severe anaphylactic shock during the perioperative period. Intradermal test screening for anaphylaxis to anesthetics is an effective method for prevention and diagnosis.

Effect of the VivaSight double-lumen tube on the incidence of hypoxaemia during one-lung ventilation in patients undergoing thoracoscopic surgery: a study protocol for a prospective randomised controlled trial

IntroductionA double-lumen tube (DLT) is a traditional one-lung ventilation tool that needs to be positioned under the guidance of a fibreoptic bronchoscope or auscultation. The placement is complex, and poor...

Perioperative Hypoxemia and Postoperative Respiratory Events in Infants with Hypertrophic Pyloric Stenosis.

Normalization of metabolic alkalosis is an important pillar in the treatment of infantile hypertrophic pyloric stenosis (IHPS) because uncorrected metabolic alkalosis may lead to perioperative respiratory events. However, the evidence on the incidence of respiratory events is limited. We aimed to study the incidence of peroperative hypoxemia and postoperative respiratory events in infants undergoing pyloromyotomy and the potential role of metabolic alkalosis. We retrospectively reviewed all patients undergoing pyloromyotomy between 2007 and 2017. All infants received intravenous fluids preoperatively to correct metabolic abnormalities close to normal. We assessed the incidence of perioperative hypoxemia (defined as oxygen saturation [SpO2] < 90% for > 1min) and postoperative respiratory events. Additionally, the incidence of difficult intubations was evaluated. We performed a multivariate logistic regression analysis to evaluate the association between admission or preoperative serum pH values, bicarbonate or chloride, and peri- and postoperative hypoxemia or respiratory events. Of 406 included infants, 208 (51%) developed 1 or more episodes of hypoxemia during the perioperative period, of whom 130 (32%) experienced it during induction, 43 (11%) intraoperatively, and 112 (28%) during emergence. About 7.5% of the infants had a difficult intubation and 17 required more than 3 attempts by a pediatric anesthesiologist. Three patients developed respiratory insufficiency and 95 postoperative respiratory events were noticed. We did not find a clinically meaningful association between laboratory values reflecting metabolic alkalosis and respiratory events. IHPS frequently leads to peri- and postoperative hypoxemia or respiratory events and high incidence of difficult tracheal intubations. Preoperative pH, bicarbonate, and chloride were bad predictors of respiratory events.

Clinical effects of remimazolam alone or in combination with dexmedetomidine in patients receiving bronchoscopy and influences on postoperative cognitive function: a randomized-controlled trial.

Remimazolam and dexmedetomidine are commonly used as sedatives. However, the effects and safety of remimazolam alone or in combination with dexmedetomidine have not been investigated. We sought to investigate the clinical effects of remimazolam alone or in combination with dexmedetomidine in bronchoscopy, and their influence on cognitive function. Ninety eligible patients who underwent bronchoscopy under intravenous anesthesia were randomly divided into three groups: propofol control, remimazolam, and remimazolam plus dexmedetomidine. The primary outcome was the incidence of perioperative hypoxemia. Secondary outcomes included induction and maintenance doses of remimazolam, hemodynamic variables, scores for modified Observer's Assessment of Alertness/Sedation (MOAA/S), coughing, limb movement, incidence of adverse events, patient satisfaction, bronchoscopist satisfaction, incidence of post-operative cognitive dysfunction (POCD), time to loss of consciousness (LoC), and time to awake. The incidence of hypoxemia, hypotension, and bronchoscopist satisfaction score were significantly decreased, and time to LoC and time to awake were markedly longer in the remimazolam and remimazolam plus dexmedetomidine groups than in the propofol control group (p < 0.05). The remimazolam group had significantly decreased induction and maintenance doses of remimazolam and a shorter time to LoC than the remimazolam plus dexmedetomidine group (p < 0.05). Scores for coughing, limb movement, MOAA/S, and post-operative patient satisfaction were comparable among the three groups. POCD was not induced in any of the groups. Remimazolam is safe and effective for painless bronchoscopy, with a low incidence of adverse reactions, and exhibits a good synergistic effect with dexmedetomidine. This trial protocol had been registered on Chinese Clinical Trial Registry (ChiCTR2000041435, date: 2020 12 26.

Pneumothorax Following Breast Surgery at an Ambulatory Surgery Center

Pneumothorax is a known complication following breast surgery but is likely underappreciated by anesthesiologists. Iatrogenic pneumothorax can be caused by needle injury during local anesthetic injection, surgical damage to the intercostal fascia or pleura, or pulmonary injury from mechanical ventilation. We present two cases of pneumothorax following bilateral mastectomy with bilateral pectoral blocks and immediate breast reconstruction. Both cases occurred at a freestanding ambulatory surgery center in patients with no history of lung disease. One patient was found to have bilateral pneumothoraxes after complaining of shortness of breath and chest pain in the post-operative care unit. The second patient was asymptomatic but found to have a right-sided pneumothorax on a chest X-ray (CXR) that was ordered to rule-out left-sided pneumothorax due to concern of intraoperative breach of the left chest wall. Both patients were treated with chest tubes, transferred to a nearby hospital, and discharged several days later. Anesthesiologists must be aware of this potentially life-threatening complication and consider pneumothorax in the differential diagnosis of perioperative hypoxemia, shortness of breath, chest pain, and hemodynamic collapse in patients undergoing breast surgery. Though traditionally diagnosed via radiograph, pneumothorax can be rapidly diagnosed with ultrasound. Tension pneumothorax should be decompressed immediately with a needle. A clinically significant, non-tension pneumothorax is treated with chest tube placement. Equipment necessary to treat pneumothorax should be available for emergency treatment in facilities wherever breast surgery is performed.

Point of Care Ultrasound Assessment of Hypoxemia

Point of care ultrasound has the advantages of rapid, real-time and radiation-free, and has been widely used in clinical practice. The combination of Bedside Lung Ultrasound in Emergency Protocol (BLUE) and Focus Assessed Transthoracic Echocardiography Protocol (FATE) has good application value in the etiological diagnosis of perioperative hypoxemia. The author combined BLUE protocol and FATE protocol to diagnose perioperative hypoxemia.

Revisited Hyperoxia Pathophysiology in the Perioperative Setting: A Narrative Review.

The widespread use of high-dose oxygen, to avoid perioperative hypoxemia along with WHO-recommended intraoperative hyperoxia to reduce surgical site infections, is an established clinical practice. However, growing pathophysiological evidence has demonstrated that hyperoxia exerts deleterious effects on many organs, mainly mediated by reactive oxygen species. The purpose of this narrative review was to present the pathophysiology of perioperative hyperoxia on surgical wound healing, on systemic macro and microcirculation, on the lungs, heart, brain, kidneys, gut, coagulation, and infections. We reported here that a high systemic oxygen supply could induce oxidative stress with inflammation, vasoconstriction, impaired microcirculation, activation of hemostasis, acute and chronic lung injury, coronary blood flow disturbances, cerebral ischemia, surgical anastomosis impairment, gut dysbiosis, and altered antibiotics susceptibility. Clinical studies have provided rather conflicting results on the definitions and outcomes of hyperoxic patients, often not speculating on the biological basis of their results, while this review highlighted what happens when supranormal PaO2 values are reached in the surgical setting. Based on the assumptions analyzed in this study, we may suggest that the maintenance of PaO2 within physiological ranges, avoiding unnecessary oxygen administration, may be the basis for good clinical practice.

Tracheotomy in COVID-19 patients: A retrospective study on complications and timing.

ObjectivesThe aim of this study was to analyze the timing of tracheotomy and the duration of mechanical ventilation and stay in the intensive care unit (ICU) in patients with COVID‐19 infection. Furthermore, we aimed to investigate tracheotomy complications and mortality.MethodsConsecutive patients with COVID‐19 infection admitted to the Department of Infectious Diseases in Gothenburg, Sweden were identified. Medical records were retrieved and retrospectively assessed.ResultsOne hundred eighty‐eight patients with COVID‐19 infection requiring hospital care were identified. Of these, 116 patients were critically ill and intubated, and 55 patients underwent tracheotomy. The mean time from endotracheal intubation to tracheotomy was 12 days (range 5‐28 days). There was a correlation between the timing of tracheotomy and the duration of mechanical ventilation, where a shorter time between intubation and tracheotomy was correlated with a shorter duration of mechanical ventilation (r .58, P < .001), and a correlation was identified between the timing of tracheotomy and the duration of ICU stay (r .52, P < .001). Perioperative hypoxemia was registered in 9% of tracheotomies performed, whereas postoperative bleeding was observed in 27% of cases, the majority of which were minor.ConclusionsThis retrospective cohort study indicates that early tracheotomy is related to a reduced need for mechanical ventilation and a shorter duration of stay in the ICU in severe cases of COVID‐19 disease. Complications during and after tracheotomy in this specific cohort included risk perioperative hypoxia and postoperative bleeding. Prospective randomized controlled trials would be of value to confirm these findings.Level of Evidence4, Case series.

Randomised Study Comparing the use of Propofol Versus Dexmedetomidine as a Sedative Agent for Patients Presenting for Lower Gastrointestinal Endoscopy

Objectives:: Dexmedetomidine, the alpha 2 agonist sedative and an analgesic agent may be beneficial in sedation for endoscopic intervention. Our aim was to compare the use of dexmedetomidine versus the traditional use of propofol as a sedative agent for colonoscopies. Methods:: This study included 100 patients presenting for elective colonoscopy under sedation with random and equal allocation of patients into two groups; group P, in which patients received propofol in a loading dose of 1.5 mg/kg and maintenance dose of 0.5 mg/kg/hr, and group D, in which patients received dexmedetomidine at a loading dose of 1ug/kg and maintenance dose of 0.5 ug/kg/hr. In addition to the demographic data, time to recovery, time of discharge, and endoscopist rating were measured. Also, the hemodynamic parameters were recorded, and also the incidence of postoperative complications. Results:: The basic patients' characteristics, time to recovery, and time of discharge were comparable between the two groups. Moreover, the endoscopist did not significantly report more convenient procedure with one group over the other. Also, there was no significant difference in hemodynamic parameters or in the incidence of complications between the two studied groups. However the use of dexmedetomidine decreased the incidence of hypoxemia. Conclusion:: The use of dexmedetomidine seems to have a similar effect to the use of propofol as a sedative agent for lower GIT endoscopy with the positive effect of dexmedetomidine in decreasing the incidence of perioperative hypoxemia.

Perioperative continuous positive airway pressure compliance and postoperative nocturnal hypoxemia in obstructive sleep apnea patients: a prospective cohort study

Perioperative continuous positive airway pressure compliance and postoperative nocturnal hypoxemia in obstructive sleep apnea patients: a prospective cohort study

Positive end-expiratory pressure increases arterial oxygenation in elderly patients undergoing urological surgery using laryngeal mask airway in lithotomy position.

Elderly patients undergoing urological surgery in the lithotomy position may be vulnerable to perioperative hypoxemia. Positive end-expiratory pressure (PEEP) can improve arterial oxygenation. Although laryngeal mask airway (LMA) is widely utilized in urological surgery, it is not known how PEEP affects arterial oxygenation in these patients. We, therefore, evaluated the effect of PEEP on arterial oxygen partial pressure (PaO2) in elderly patients using LMA during urological surgery in the lithotomy position. Patients randomly received zero end-expiratory pressure (group Z, n = 34) or PEEP of 7 cmH2O (group P, n = 33). Ventilatory, respiratory, and haemodynamic variables were measured at 5min (T0), 30min (T1), and 60min (T2) after LMA Supreme™ (sLMA) insertion. The primary outcome was the difference of PaO2 at T2 between the two groups. Atelectasis score, the incidence of a significant leak, and complications associated with sLMA insertion were also evaluated. PaO2 at T2 was significantly higher in group P than in group Z (20.0 ± 4.9 vs. 14.7 ± 3.7kPa, P < 0.001). Atelectasis score at T2 was lower in group P than in group Z (5.3 ± 1.7 vs. 8.4 ± 2.3, P < 0.001). However, the incidence of a significant leak and complications associated with LMA insertion did not significantly differ between the two groups. PEEP can improve arterial oxygenation and reduce atelectasis in elderly patients using sLMA during urological surgery in the lithotomy position, suggesting that PEEP may be useful for elderly patients with an increased risk of perioperative hypoxemia when using sLMA.

Vascular Graft Infection: Incidence and Potential Risk Factors.

The purpose of this study was to identify factors that increase the risk of vascular graft infections (VGI) in patients following abdominal or lower extremity revascularization surgery. Retrospective, descriptive study. We reviewed the electronic health records of 223 patients who had undergone abdominal or lower extremity revascularization procedures from July 2012 to November 2014, looking for factors associated with VGI. We reviewed 28 preoperative, intraoperative, and post-operative factors. Descriptive statistics (mean, range, and standard deviation) were used to describe the sample; χ was used to determine correlations between the risk factors and subsequent VGIs. The level of significance was determined at P = .05, with a confidence level of 95%. We identified 33 cases of VGIs for the 223 charts reviewed, yielding an incidence rate of 15%. Seventeen of the 33 patients with VGI (51.5%) were male. The average age of patients who experienced VGI was 60.9 years (standard deviation, 12.2 years, range, 29-81 years). Preoperative factors that were shown to show statistical significance for the development of VGI were sequential procedures (P = .003), diabetes mellitus (P = .002), hemoglobin A1c more than 7.0 (P = .0002), blood glucose more than 180 mg/dL (P = .0006), and lack of mobility (0.0097). Intraoperative factors associated with VGI were hemostatic agents applied to the surgical field intraoperatively (P = .003) and perioperative hypoxemia (P = .027). Postoperative factors associated with VGI were discharge from the hospital to skilled nursing facility or acute rehabilitation facility (P = .005) and unscheduled clinic visits (P = .008). We measured a 15% incidence of VGI and identified multiple pre-, intra-, and postoperative associated factors. Vigilance is required to prevent VGI and knowledge of specific risk factors is important.

Successful administration of venovenous extracorporeal membrane oxygenation through the modified Blalock-Taussig operation in an infant with graft dysfunction after the Norwood procedure.

Dear editor Insufficient pulmonary blood flow through a right ventricle-to-pulmonary artery conduit following the Norwood procedure is remediable by adding a modified Blalock–Taussig shunt (MBTS).1 First, however, perioperative hypoxemia must be managed. Venovenous extracorporeal membrane oxygenation (VV-ECMO) is likely to be a useful method for respiratory support in such cases.2,3 We present the case of a 2-month-old patient with graft dysfunction after the Norwood procedure who underwent MBTS with VV-ECMO support.

Step-by-step clinical management of one-lung ventilation: continuing professional development.

The purpose of this Continuing Professional Development Module is to review the issues pertinent to one-lung ventilation (OLV) and to propose a management strategy for ventilation before, during, and after lung isolation. The need for optimal lung isolation has increased with the advent of video-assisted thoracoscopic surgery, as surgical exposure is critical for successful surgery. Continuous positive airway pressure applied to the operative lung or intermittent two-lung ventilation should therefore be avoided if possible. Optimal management of OLV should provide adequate oxygenation and also prevent acute lung injury (ALI), the leading cause of death following lung resection. Research conducted in the last decade suggests implementing a protective ventilation strategy during OLV that consists of small tidal volumes based on ideal body weight, routine use of positive end-expiratory pressure, low inspired oxygen fraction, with low peak and plateau airway pressures. High respiratory rates to compensate for low tidal volumes may predispose to significant air trapping during OLV, so permissive hypercapnea is routinely employed. The management of OLV extends into the period of two-lung ventilation, as the period prior to OLV impacts lung collapse, and both the time before and after OLV influence the extent of ALI. Lung re-expansion at the conclusion of OLV is an important component of ensuring adequate ventilation and oxygenation postoperatively but may be harmful to the lung. Optimal perioperative care of the thoracic patient includes a protective ventilation strategy from intubation to extubation and into the immediate postoperative period. Anesthetic goals include the prevention of perioperative hypoxemia and postoperative ALI.

Perioperative hypoxemia is common with horizontal positioning during general anesthesia and is associated with major adverse outcomes: a retrospective study of consecutive patients.

BackgroundReported perioperative pulmonary aspiration (POPA) rates have substantial variation. Perioperative hypoxemia (POH), a manifestation of POPA, has been infrequently studied beyond the PACU, for patients undergoing a diverse array of surgical procedures.MethodsConsecutive adult patients with ASA I-IV and pre-operative pulmonary stability who underwent a surgical procedure requiring general anesthesia were investigated. Using pulse oximetry, POH was documented in the operating room and during the 48 hours following PACU discharge. POPA was the presence of an acute pulmonary infiltrate with POH.ResultsThe 500 consecutive, eligible patients had operative body-positions of prone 13%, decubitus 8%, sitting 1%, and supine/lithotomy 78%, with standard practice of horizontal recumbency. POH was found in 150 (30%) patients. Post-operative stay with POH was 3.7 ± 4.7 days and without POH was 1.7 ± 2.3 days (p < 0.0001). POH rate varied from 14% to 58% among 11 of 12 operative procedure-categories. Conditions independently associated with POH (p < 0.05) were acute trauma, BMI, ASA level, glycopyrrolate administration, and duration of surgery. POPA occurred in 24 (4.8%) patients with higher mortality (8.3%), when compared to no POPA (0.2%; p = 0.0065). Post-operative stay was greater with POPA (7.7 ± 5.7 days), when compared to no POPA (2.0 ± 2.9 days; p = 0.0001). Conditions independently associated with POPA (p < 0.05) were cranial procedure, ASA level, and duration of surgery. POPA, acute trauma, duration of surgery, and inability to extubate in the OR were independently associated with post-operative stay (p < 0.05). POH, gastric dysmotility, acute trauma, cranial procedure, emergency procedure, and duration of surgery had independent correlations with post-operative length of stay (p < 0.05).ConclusionsAdult surgical patients undergoing general anesthesia with horizontal recumbency have substantial POH and POPA rates. Hospital mortality was greater with POPA and post-operative stay was increased for POH and POPA. POH rates were noteworthy for virtually all categories of operative procedures and POH and POPA were independent predictors of post-operative length of stay. A study is needed to determine if modest reverse-Trendelenburg positioning during general anesthesia has a relationship with reduced POH and POPA rates.

Cerebral oximetry and thoracic surgery

Cerebral oximetry, though first described for clinical use in cardiac surgery, has been increasingly used in the setting of thoracic surgery. Research focusing on the use of cerebral oximetry in this setting is relatively sparse. This review outlines our current understanding of the use of cerebral oximetry for thoracic surgery. Cerebral desaturation, though variably defined, is a relatively common occurrence during thoracic surgery. The reasons for this desaturation largely relate to perioperative hypoxemia, but may also be related to other physiologic disturbances such as lateral decubitus positioning, one-lung ventilation, as well as other nonhypoxemia-related mechanisms. It is unlikely to result from specific reductions in cardiac output. There is some preliminary data suggesting a relationship between cerebral desaturation and various adverse postoperative outcomes. Although it is clear that cerebral desaturation can commonly occur during thoracic surgery, it is partly dependent upon how desaturation is defined. The relationship between cerebral desaturation and adverse outcomes after thoracic surgery, as well as the potential ability for cerebral oximetry to guide therapeutic modalities, awaits much needed additional research before being more widely accepted.