Cerebral oxygenation using near-infrared spectroscopy in the beach-chair position during shoulder arthroscopy under general anesthesia

Physiologic Determinants of Near-Infrared Spectroscopy-Derived Cerebral and Tissue Oxygen Saturation Measurements in Critically Ill Patients

OBJECTIVES

Near-infrared spectroscopy (NIRS) is a potentially valuable modality to monitor the adequacy of oxygen delivery to the brain and other tissues in critically ill patients, but little is known about the physiologic determinants of NIRS-derived tissue oxygen saturations. The purpose of this study was to assess the contribution of routinely measured physiologic parameters to tissue oxygen saturation measured by NIRS.

DESIGN

An observational sub-study of patients enrolled in the Role of Active Deresuscitation After Resuscitation-2 (RADAR-2) randomized feasibility trial.

SETTING

Two ICUs in the United Kingdom.

PATIENTS

Patients were recruited for the RADAR-2 study, which compared a conservative approach to fluid therapy and deresuscitation with usual care. Those included in this sub-study underwent continuous NIRS monitoring of cerebral oxygen saturations (SctO2) and quadriceps muscle tissue saturations (SmtO2).

INTERVENTION

Synchronized and continuous mean arterial pressure (MAP), heart rate (HR), and pulse oximetry (oxygen saturation, Spo2) measurements were recorded alongside NIRS data. Arterial Paco2, Pao2, and hemoglobin concentration were recorded 12 hourly. Linear mixed effect models were used to investigate the association between these physiologic variables and cerebral and muscle tissue oxygen saturations.

MEASUREMENTS AND MAIN RESULTS

Sixty-six patients were included in the analysis. Linear mixed models demonstrated that Paco2, Spo2, MAP, and HR were weakly associated with SctO2 but only explained 7.1% of the total variation. Spo2 and MAP were associated with SmtO2, but together only explained 0.8% of its total variation. The remaining variability was predominantly accounted for by between-subject differences.

CONCLUSIONS

Our findings demonstrated that only a small proportion of variability in NIRS-derived cerebral and tissue oximetry measurements could be explained by routinely measured physiologic variables. We conclude that for NIRS to be a useful monitoring modality in critical care, considerable further research is required to understand physiologic determinants and prognostic significance.

Effect of pre-infusion of hypertonic saline on postoperative delirium in geriatric patients undergoing shoulder arthroscopy: a randomized controlled trial

BACKGROUND

Neuroinflammation may be a potential mechanism of postoperative delirium (POD) in geriatric patients, and hypertonic saline (HS) has immunomodulatory properties. The purpose of this study was to investigate whether HS could reduce the incidence of POD in elderly patients and its effect on neutrophil activation and inflammatory cytokine expression.

METHODS

We studied the effect of pre-infusion of 4 mL/kg 3% hypertonic saline vs. 4 mL/kg 0.9% normal saline on POD in patients undergoing shoulder arthroscopy in a prospective, randomized, double-blind, controlled trial. Neutrophil surface molecules (CD11b, CD66b and CD64) were analyzed by flow cytometry. Circulating concentrations of inflammatory factors IL-1β, IL-6, TNF-α and neurological damage factor S100β were assessed by enzyme immunoassay. The Confusion Assessment Method-Chinese Revision (CAM-CR) was applied for the assessment of POD 1-3 days after surgery.

RESULTS

The incidence of POD in group H was significantly lower than that in group N (7.14% vs 26.83%, P = 0.036). The expression levels of inflammatory cytokines ( IL-6 and TNF-α) and neutrophil surface markers (CD11b and CD66b) were significantly lower in group H than in group N at 24 h after surgery (P = 0.018, P < 0.001, P < 0.001, P = 0.024). There were no significant differences in postoperative pain, nausea and vomiting, infection, phlebitis, and patients satisfaction between the two groups.

CONCLUSION

Pre-infusion of HS can reduce the incidence of POD and the immune-inflammatory response.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (14/4/2022, registration number: ChiCTR2200058681.

Near-Infrared Spectroscopy Monitoring to Detect Changes in Cerebral and Renal Perfusion During Hypovolemic Shock, Volume Resuscitation, and Vasoconstriction

INTRODUCTION

Rapidly changing hemodynamic conditions, such as uncontrolled hemorrhage and the resulting hypovolemic shock, are a common contributor to active duty military deaths. These conditions can cause cerebral desaturation, and outcomes may improve when regional cerebral oxygen saturation (CrSO2) is monitored using near-infrared spectroscopy (NIRS) and desaturation episodes are recognized and reversed. The purpose of this porcine study was to investigate the ability of NIRS monitoring to detect changes in regional cerebral and regional renal perfusion during hypovolemia, resuscitation by volume infusion, and vasoconstriction.

MATERIALS AND METHODS

Hemorrhagic shock was induced by removing blood through a central venous catheter until mean arterial pressure (MAP) was <40 mmHg. Each blood removal step was followed by a 10-minute stabilization period, during which cardiac output, blood pressure, central venous pressure, blood oxygen saturation, and CrSO2 and regional renal oxygen saturation (RrSO2) were measured. Shock was reversed using blood infusion and vasoconstriction separately until MAP returned to normal. Statistical comparisons between groups were performed using the paired t-test or the Wilcoxon signed-rank test.

RESULTS

Using volume resuscitation, both CrSO2 and RrSO2 returned to normal levels after hypovolemia. Blood pressure management with phenylephrine returned CrSO2 levels to normal, but RrSO2 levels remained significantly lower compared to the pre-hemorrhage values (P < .0001). Comparison of the percent CrSO2 as a function of MAP showed that CrSO2 levels approach baseline when a normal MAP is reached during volume resuscitation. In contrast, a significantly higher MAP was required to return to baseline CrSO2 during blood pressure management with phenylephrine (P < .0001). Evaluation of carotid blood flow and CrSO2 indicated that during induction of hypovolemia, the two measures are strongly correlated. In contrast, there was limited correlation between carotid blood flow and CrSO2 during blood infusion.

CONCLUSIONS

This study demonstrated that it is possible to restore CrSO2 by manipulating MAP with vasoconstriction, even in profound hypotension. However, MAP manipulation may result in unintended consequences for other organs, such as the kidney, if the tissue is not reoxygenated sufficiently. The clinical implications of these results and how best to respond to hypovolemia in the pre-hospital and hospital settings should be elucidated by additional studies.

[Targeted hemodynamic monitoring in the operating theatre: what for and by what means?]

Goal directed hemodynamic monitoring and the balance in goal directed therapy between adequate fluid/volume therapy and the application of vasoactive or inotropic drugs are the basic elements of modern perioperative therapy.Surgical procedures should be accompanied by as few side effects and complications as possible. Nevertheless, the number of postoperative complications remains surprisingly high, despite of the modern surgical procedures. Anticipation of potential complications in the perioperative period and their rapid treatment build a core competence of anesthesiological action. Thus, it is clear that anesthesia plays a central role in this balancing act.This article aims to provide an overview of the application of the currently available perioperative goal directed hemodynamic monitoring. The current possibilities are discussed by using a case example and an outlook on the future of hemodynamic monitoring is given.

Neuromonitoring during general anesthesia in non-neurologic surgery

Cerebral complications are common in perioperative settings even in non-neurosurgical procedures. These include postoperative cognitive dysfunction or delirium as well as cerebrovascular accidents. During surgery, it is essential to ensure an adequate degree of sedation and analgesia, and at the same time, to provide hemodynamic and respiratory stability in order to minimize neurological complications. In this context, the role of neuromonitoring in the operating room is gaining interest, even in the non-neurolosurgical population. The use of multimodal neuromonitoring can potentially reduce the occurrence of adverse effects during and after surgery, and optimize the administration of anesthetic drugs. In addition to the traditional focus on monitoring hemodynamic and respiratory systems during general anesthesia, the ability to constantly monitor the activity and maintenance of brain homeostasis, creating evidence-based protocols, should also become part of the standard of care: in this challenge, neuromonitoring comes to our aid. In this review, we aim to describe the role of the main types of noninvasive neuromonitoring such as those based on electroencephalography (EEG) waves (EEG, Entropy module, Bispectral Index, Narcotrend Monitor), near-infrared spectroscopy (NIRS) based on noninvasive measurement of cerebral regional oxygenation, and Transcranial Doppler used in the perioperative settings in non-neurosurgical intervention. We also describe the advantages, disadvantage, and limitation of each monitoring technique.

Near-Infrared Spectroscopy Monitoring in Cardiac and Noncardiac Surgery: Pairwise and Network Meta-Analyses

Goal-directed therapy based on brain-oxygen saturation (bSo2) is controversial and hotly debated. While meta-analyses of aggregated data have shown no clinical benefit for brain near-infrared spectroscopy (NIRS)-based interventions after cardiac surgery, no network meta-analyses involving both major cardiac and noncardiac procedures have yet been undertaken. Randomized controlled trials involving NIRS monitoring in both major cardiac and noncardiac surgery were included. Aggregate-level data summary estimates of critical outcomes (postoperative cognitive decline (POCD)/postoperative delirium (POD), acute kidney injury, cardiovascular events, bleeding/need for transfusion, and postoperative mortality) were obtained. NIRS was only associated with protection against POCD/POD in cardiac surgery patients (pooled odds ratio (OR)/95% confidence interval (CI)/I2/number of studies (n): 0.34/0.14-0.85/75%/7), although a favorable effect was observed in the analysis, including both cardiac and noncardiac procedures. However, the benefit of the use of NIRS monitoring was undetectable in Bayesian network meta-analysis, although maintaining bSo2 > 80% of the baseline appeared to have the most pronounced impact. Evidence was imprecise regarding acute kidney injury, cardiovascular events, bleeding/need for transfusion, and postoperative mortality. There is evidence that brain NIRS-based algorithms are effective in preventing POCD/POD in cardiac surgery, but not in major noncardiac surgery. However, the specific target bSo2 threshold has yet to be determined.

Effects of remote ischemic preconditioning on regional cerebral oxygen saturation in patients in the beach chair position during shoulder surgery: A double-blind randomized controlled trial

STUDY OBJECTIVE

The beach chair position for shoulder surgery induces cerebral hypoperfusion. We evaluated the effects of remote ischemic preconditioning (RIPC) prior to surgery to ameliorate cerebral desaturation in a double-blind randomized fashion.

DESIGN

Blinded, prospective, randomized study.

SETTING

Operating room & postoperative recovery room, tertiary university hospital.

PATIENTS

Seventy patients scheduled for shoulder surgery were recruited. After excluding 7 patients according to the exclusion criteria, 63 patients were randomized into two groups (control and RIPC).

INTERVENTIONS

Remote ischemic preconditioning was applied by briefly inflating a tourniquet on the thigh three times just after inducing anesthesia in the RIPC group.

MEASUREMENTS

The changes in regional cerebral oxygen saturation, hemodynamic values, laboratory values, and serum levels of cytokines including interleukin (IL)-1β, IL-6, IL-10 and transforming growth factor-β were measured.

MAIN RESULTS

The remote ischemic preconditioning group had higher regional cerebral oxygen saturation just after establishment of the beach chair position (P = 0.002) and lower cerebral desaturation (P = 0.007) during operation than the control group. Hemodynamic and laboratory values did not differ between the groups. There were no significant intergroup differences in cytokine levels.

CONCLUSION

Remote ischemic preconditioning before surgery ameliorates cerebral desaturation in patients in the beach chair position during shoulder surgery. Trial Registry Number: KCT0001384 (http://cris.nih.go.kr).

Patient Positioning in Shoulder Arthroscopy: Which is Best?

When performing diagnostic and surgical arthroscopic procedures on the shoulder, the importance of patient positioning cannot be understated. The optimum patient positioning for shoulder arthroscopy should enhance intraoperative joint visualization and surgical accessibility while minimizing potential perioperative risk to the patient. Most shoulder arthroscopy procedures can be reliably performed with the patient either in the lateral decubitus (LD) or beach chair (BC) position. Although patient positioning for shoulder arthroscopy has been subject of controversy, there is no conclusive evidence to suggest superiority of one position versus another. Each position offers advantages and disadvantages and surgeon's experience and training are pivotal on selecting one position versus another. Regardless of the position, a proper positioning of the patient should provide adequate access to the joint while minimizing complications. The purpose of this review is to summarize setup and technical aspects, the advantages and disadvantages, and the possible complications of the LD and BC positions in shoulder arthroscopy.

Cerebrovascular Disease and Perioperative Neurologic Vulnerability: A Prospective Cohort Study

Background: Stroke is a devastating perioperative complication without effective methods for prevention or diagnosis. The objective of this study was to analyze evidence-based strategies for detecting cerebrovascular vulnerability and injury in a high-risk cohort of non-cardiac surgery patients.

Methods: This was a single-center, prospective cohort study. Fifty patients undergoing non-cardiac surgery were recruited −25 with known cerebrovascular disease and 25 matched controls. Neurologic vulnerability was measured with intraoperative cerebral oximetry as the primary outcome. Perioperative neurocognitive testing and serum biomarker analysis (S-100β, neuron specific enolase, glial fibrillary acid protein, and matrix metalloproteinase-9) were measured as secondary outcomes.

Results: Cerebral desaturation events (an oximetry decrease ≥20% from baseline or <50% absolute value for ≥3 min) occurred in 7/24 (29%) cerebrovascular disease patients and 2/24 (8.3%) controls (relative risk 3.5, 95% CI 0.81–15.2; P = 0.094). Cognitive function trends were similar in both groups, though overall scores (range: 1,500–7,197) were ~1 standard deviation lower in cerebrovascular patients across the entire perioperative period (−1,049 [95% CI −1,662, −436], P < 0.001). No significant serum biomarker differences were found between groups over time. One control patient experienced intraoperative hypoxic-ischemic injury, but no robust biomarker or oximetry changes were observed.

Conclusions: Cerebrovascular disease patients did not demonstrate dramatic differences in cerebral oximetry, cognitive trajectory, or molecular biomarkers compared to controls. Moreover, a catastrophic hypoxic-ischemic event was neither predicted nor detected by any strategy tested. These findings support the need for novel research into cerebrovascular risk and vulnerability.

Risk Factors for Cerebral Desaturation Events During Shoulder Surgery in the Beach Chair Position

PURPOSE

The goals of this study were 2-fold: (1) to determine the risk factors for cerebral desaturation events (CDEs) after implementation of a comprehensive surgical and anesthetic protocol consisting of patient risk stratification, maintenance of normotensive anesthesia, and patient positioning in a staged fashion, and (2) to assess for subclinical neurologic decline associated with intraoperative ischemic events through cognitive testing.

METHODS

One hundred patients undergoing shoulder surgery in the beach chair position were stratified for risk of CDE based on Framingham stroke criteria, body mass index (BMI), and history of cerebrovascular accidents. Cerebral oxygen saturation was monitored with near-infrared spectroscopy. As per a standardized protocol, mean arterial pressure was maintained between 70 and 90 mm Hg. The head was raised in 2 stages separated by 3 minutes. CDE were defined as >20% drop from baseline or <55% O₂ absolute threshold. Patients completed a Mini-Mental State Examination during preoperative examination and at the first postoperative visit.

RESULTS

The CDE rate was 4% overall and 4.3% in patients undergoing general anesthesia. Forty-five patients were in the higher risk category, and all CDEs occurred in that group. Patients with a Framingham score ≥ 10 or BMI ≥ 35 who underwent general anesthesia had an increased risk of CDE (P = .04). No significant change was noted in Mini-Mental State Examination scores between pre- and postoperative visits. No correlation was shown between CDE and history of diabetes, smoking, cardiovascular disease, or left ventricular hypertrophy.

CONCLUSIONS

Our observed CDE rate was lower than previously reported rates, likely because of risk stratification, staged positioning, and normotensive anesthesia. Framingham score ≥ 10 and BMI ≥ 35 are risk factors for CDE in the beach chair position.

LEVEL OF EVIDENCE

Level II, prospective observational study with >80% follow-up.

Preemptive volume therapy to prevent hemodynamic changes caused by the beach chair position: hydroxyethyl starch 130/0.4 versus Ringer's acetate-a controlled randomized trial

BACKGROUND

Hemodynamic instability frequently occurs in beach chair positioning for surgery, putting patients at risk for cerebral adverse events. This study examined whether preoperative volume loading with crystalloids alone or with a crystalloid-colloid combination can prevent hemodynamic changes that may be causative for unfavorable neurologic outcomes.

METHODS

The study randomly assigned 43 adult patients undergoing shoulder surgery to 3 study groups. Each group received an infusion of 500 mL of Ringer's acetate between induction of anesthesia and being placed in the beach chair position. The crystalloid group received an additional bolus of 1000 mL Ringer's acetate. The hydroxyethyl starch group was administered an additional bolus of 500 mL of 6% hydroxyethyl starch 130/0.4. Hemodynamic monitoring was accomplished via an esophageal Doppler probe. Cerebral oxygen saturation was examined with near-infrared spectroscopy. Changes in stroke volume variation between the prone and beach chair positions were defined as the primary outcome parameter. Secondary outcomes were changes in cardiac output and cerebral oxygen saturation.

RESULTS

The control group was prematurely stopped after enrollment of 4 patients because of adverse events. In the hydroxyethyl starch group, stroke volume variation remained constant during positioning maneuvers (P = .35), whereas a significant increase was observed in the Ringer's acetate group (P < .01; P = .014 for intergroup comparison). This was also valid for changes in cardiac output. Cerebral oxygen saturation significantly decreased in both groups.

CONCLUSIONS

Preprocedural boluses of 500 mL of 6% hydroxyethyl starch 130/0.4 as well as 1000 mL of Ringer's acetate were efficient in preserving hemodynamic conditions during beach chair position.

The effectiveness of cerebral oxygenation monitoring during arthroscopic shoulder surgery in the beach chair position: a randomized blinded study

BACKGROUND

Beach chair positioning for shoulder surgery is associated with measurable cerebral desaturation events (CDEs) in up to 80% of patients. Near-infrared spectroscopy (NIRS) technology allows real-time measurement of cerebral oxygenation and may minimize the frequency of CDEs. The purpose of this study was to investigate the incidence of CDEs when anesthetists were aware of and blinded to NIRS monitoring and to determine the short-term cognitive effects of surgery in the beach chair position.

METHODS

NIRS was used to monitor cerebral oxygenation saturation in 41 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. Patients were randomized to 2 groups, anesthetists aware of or blinded to NIRS data. The Montreal Cognitive Assessment (MoCA) was used to assess cognitive function preoperatively, immediately postoperatively, and at 2 and 6 weeks postoperatively.

RESULTS

Overall, 7 (17.5%) patients experienced a CDE, 5 (25%) in the aware group and 2 (10%) in the blinded group. There was no significant difference in MoCA scores between the aware and blinded groups preoperatively (27.9.1 vs. 28.2; P = .436), immediately postoperatively (26.1 vs. 26.2; P = .778), 2 weeks postoperatively (28.0 vs. 28.1; P = .737), or 6 weeks postoperatively (28.5 vs. 28.4; P = .779). There was a correlation of NIRS with systolic blood pressure (r = 0.448), diastolic blood pressure (r = 0.708), and mean arterial pressure (r = 0.608).

CONCLUSION

In our series, the incidence of CDEs was much lower than previously reported and was not lowered by use of NIRS. Patients did not have significant cognitive deficits after arthroscopic surgery in the beach chair position, and there was a correlation between NIRS and intraoperative brachial blood pressure.

Factors impacting arthroscopic rotator cuff repair operational throughput time at an ambulatory care center

Identifying patient factors influencing operational throughput time is becoming more imperative due to an increasing focus on value and cost savings in healthcare. The primary objective of this study was to determine patient factors influencing throughput time for primary rotator cuff repairs. Demographic information, medical history and operative reports of 318 patients from one ambulatory care center were retrospectively reviewed. Operating room set up, incision to closure and recovery room time were collected from anesthesia records. Univariate analysis was performed for both continuous and categorical variables. A stepwise, multivariable regression analysis was performed to determine factors associated with operating room time (incision to closure) and recovery room time. Of the 318 patients, the mean age was 54.4±10.0 and 197 (61%) were male. Male patients had a significantly longer OR time than females (115.5 vs. 100.8 minutes; P<0.001) Furthermore, patients set up in the beach chair position had a significantly longer OR time than patients positioned lateral decubitus (115.8 vs. 89.6 mins, P<0.0001). Number of tendons involved, and inclusion of distal clavicle excision, biceps tenodesis and labral debridement also added significant OR time. Type and number of support staff present also significantly affected OR time. Recovery room time was significantly longer patients who had surgery in the beach chair position (+9.61 minutes) and for those who had a cardiac-related medical comorbidity (+11.7 minutes). Our study found that patients positioned in a beach chair spent significantly more time in the operating and recovery rooms. While ease of set up has been a stated advantage of beach chair position, we found the perceived ease of set up does not result in more efficient OR throughput.

The effect of the beach-chair position angle on cerebral oxygenation during shoulder surgery

BACKGROUND

Although the safety of the beach-chair position (BCP) is widely accepted, rare devastating neurologic complications have been reported and attributed to cerebral hypoperfusion. Cerebral oxygenation (regional oxygen saturation [rSO₂]) can be monitored noninvasively using near-infrared spectroscopy. The purpose of this study was to determine the effect of BCP angle on cerebral oxygenation in patients undergoing shoulder surgery in the BCP.

METHODS

Fifty patients undergoing shoulder arthroscopy were prospectively enrolled to participate. Following induction of general anesthesia, each patient's rSO₂ was recorded at 0° of elevation and again at 30°, 45°, 60°, and 80° of elevation. Mean rSO₂ values and mean differences in rSO₂ were reported.

RESULTS

An average total decrease of 5% in rSO₂ was seen when comparing 0° with 80° (P < .001). There were statistically significant differences in rSO₂ values at beach-chair angles of 0° versus 30° (P <.001), 30° versus 45° (P = .007), and 45° versus 60° (P <.001) but not between 60° and 80° (P = .12). The decrease in rSO₂ was similar between each progressive increase in the beach-chair angle, leading to a linear decline in rSO₂ as the BCP increased (regression slope of -0.060%/°, P <.001). No patient's cerebral oxygenation dropped greater than 20% from baseline. Neither body mass index nor American Society of Anesthesiologists score had a significant impact on the relation of rSO₂ to BCP angle.

CONCLUSIONS

The average drop in rSO₂ is significantly less than the threshold of 20% used as an identifier for a cerebral deoxygenation event. This study illustrates the direct effect the BCP angle has on cerebral oxygenation.

Detection of critical cerebral desaturation thresholds by three regional oximeters during hypoxia: a pilot study in healthy volunteers

Background

Regional oximetry is increasingly used to monitor post-extraction oxygen status of the brain during surgical procedures where hemodynamic fluctuations are expected. Particularly in cardiac surgery, clinicians employ an interventional algorithm to restore baseline regional oxygen saturation (rSO₂) when a patient reaches a critical desaturation threshold. Evidence suggests that monitoring cardiac surgery patients and intervening to maintain rSO₂ can improve postoperative outcomes; however, evidence generated with one manufacturer’s device may not be applicable to others. We hypothesized that regional oximeters from different manufacturers respond uniquely to changes in oxygen saturation in healthy volunteers.

Methods

Three devices were tested: INVOS™ 5100C (Medtronic), EQUANOX™ 7600 (Nonin), and FORE-SIGHT™ (CASMED) monitors. We divided ten healthy subjects into two cohorts wearing a single sensor each from INVOS and EQUANOX (n = 6), or INVOS and FORE-SIGHT (n = 4). We induced and reversed hypoxia by adjusting the fraction of inspired oxygen. We calculated the magnitude of absolute rSO₂ change and rate of rSO₂ change during desaturation and resaturation, and determined if and when each device reached a critical interventional rSO₂ threshold during hypoxia.

Results

All devices responded to changes in oxygen directionally as expected. The median absolute rSO₂ change and the rate of rSO₂ change was significantly greater during desaturation and resaturation for INVOS compared with EQUANOX (P = 0.04). A similar but nonsignificant trend was observed for INVOS compared with FORE-SIGHT; our study was underpowered to definitively conclude there was no difference. A 10% relative decrease in rSO₂ during desaturation was detected by all three devices across the ten subjects. INVOS met a 20% relative decrease threshold in all subjects of both cohorts, compared to 1 with EQUANOX and 2 with FORE-SIGHT. Neither EQUANOX nor FORE-SIGHT reached a 50% absolute rSO₂ threshold compared with 4 and 3 subjects in each cohort with INVOS, respectively.

Conclusions

Significant differences exist between the devices in how they respond to changes in oxygen saturation in healthy volunteers. We suggest caution when applying evidence generated with one manufacturer’s device to all devices.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-016-0298-7) contains supplementary material, which is available to authorized users.

Total shoulder arthroplasty in patients with HIV infection: complications, comorbidities, and trends

BACKGROUND

Patients with human immunodeficiency virus (HIV) infection were previously at substantial risk for immunosuppression-related complications. As a result of highly active antiretroviral therapy, HIV-infected patients are living longer and are presenting for elective surgery. Outcomes in HIV-infected patients are well described for hip and knee arthroplasty but not for total shoulder arthroplasty (TSA). The purpose of this study was to examine postoperative complications of TSA in HIV-positive patients.

METHODS

We queried the entire 2005 to 2012 Medicare database. Current Procedural Terminology and International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify the procedure, demographics, comorbidities, and postoperative complications. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

The query returned 2528 HIV-positive patients who underwent TSA or reverse TSA (RTSA). There was increased utilization of TSA and RTSA in this population from 2005 to 2012; 1353 patients had 2-year follow-up. These patients were slightly older and had higher prevalence of comorbidities, suggesting a sicker cohort. HIV-positive patients had alarmingly higher rates of 90-day cerebrovascular accident (OR, 35.98; CI, 30.34-42.67). HIV-positive patients had higher overall rates of broken prosthetic joints (OR, 1.72; CI, 1.20-2.47), periprosthetic infection (OR, 1.36; CI, 1.01-1.82), and TSA revision or repair (OR, 2.44; CI, 1.81-3.28).

CONCLUSIONS

To our knowledge, this is the first study that directly examines the postoperative outcomes of HIV-positive patients after TSA or RTSA. As more of these patients present for surgery, surgeons should be aware that these patients might be at increased risk for certain postoperative surgical and medical complications.

Patterns of intra-arterial blood pressure monitoring for patients undergoing total shoulder arthroplasty under general anesthesia: a retrospective analysis of 23,073 patients

Total shoulder arthroplasty (TSA) is typically performed in the beach-chair position. Maintenance of adequate mean arterial pressure is required to provide appropriate cerebral perfusion pressure and prevent cerebral ischemia. Placement of an arterial line to facilitate invasive monitoring is discretionary, based on clinical judgment. We aimed to describe patient, surgical and institutional factors associated with the current use of blood pressure monitoring via an arterial line for TSA. We used de-identified patient data from the National Anesthesia Clinical Outcomes Registry between 2010 and 2015 to identify patients undergoing TSA under general anesthesia. We conducted a multivariable logistic regression model to demonstrate factors significantly associated with arterial line placement. We report results as odds ratios (OR) with their associated 95 % confidence intervals (CI). Of 23,073 patients undergoing TSA under general anesthesia, 443 (1.92 %) had intra-arterial blood pressure monitoring. Patient age over 65 years old (OR 1.74, CI 1.37-2.21), congestive heart failure (OR 7.09, CI 2.63-19.14) and surgery lasting at least 180 min (OR 4.10, CI 3.33-5.05) were all associated with increased odds for arterial line placement. Compared to university hospitals, arterial line placement was more likely in attached or freestanding surgical centers (OR 2.01, CI 1.37-2.96) and less likely in medium sized community hospitals (OR 0.62, CI 0.42-0.93), small community hospitals (OR 0.11, CI 0.03-0.34) and facilities performing less than 100 TSAs per year (OR 0.19, CI 0.12-0.31). Utilization of arterial line monitoring for TSA has associations with both institutional and patient factors. This study demonstrates the national patterns for the use of arterial lines for TSA and may serve as a resource to aid in clinical judgment.

Basic Shoulder Arthroscopy: Beach Chair Patient Positioning

Shoulder arthroscopy is an orthopaedic procedure that has grown significantly in popularity over the last 40 years. The 2 principle patient positions during shoulder arthroscopy include the beach chair position and lateral decubitus position. This Technical Note details the operating room setup for shoulder arthroscopy in the beach chair position. Proper positioning for this procedure will minimize potential complications and facilitate ease of surgical intervention.

Prediction of fluid responsiveness in the beach chair position using dynamic preload indices

Hemodynamic instability in the beach chair position (BCP) may lead to adverse outcomes. Cardiac preload optimization is a prerequisite to improve hemodynamics. We evaluated the clinical usefulness of dynamic indices for the prediction of fluid responsiveness in BCP patients under general anesthesia. Forty-two patients in the BCP under mechanical ventilation received colloids at 6 ml/kg for 10 min. Stroke volume variation (SVV), pulse pressure variation (PPV), pleth variability index (PVI), and hemodynamic data were measured before and after the fluid challenge. Patients were considered responders to volume expansion if the stroke volume index increased by ≥15 %. The areas under receiver operating characteristic curves for SVV, PPV and PVI were 0.83, 0.81 and 0.74, respectively (p < 0.05), with the corresponding optimal cut-off values of 12, 15 and 10 %. SVV, PPV and PVI can be used to predict fluid responsiveness in the BCP under mechanical ventilation.