Effects of beach-chair position and induced hypotension on cerebral oxygen saturation in patients undergoing arthroscopic shoulder surgery

Perioperative stroke

Ischaemic or haemorrhagic perioperative stroke (that is, stroke occurring during or within 30 days following surgery) can be a devastating complication following surgery. Incidence is reported in the 0.1-0.7% range in adults undergoing non-cardiac and non-neurological surgery, in the 1-5% range in patients undergoing cardiac surgery and in the 1-10% range following neurological surgery. However, higher rates have been reported when patients are actively assessed and in high-risk populations. Prognosis is significantly worse than stroke occurring in the community, with double the 30-day mortality, greater disability and diminished quality of life among survivors. Considering the annual volume of surgeries performed worldwide, perioperative stroke represents a substantial burden. Despite notable differences in aetiology, patient populations and clinical settings, existing clinical recommendations for perioperative stroke are extrapolated mainly from stroke in the community. Perioperative in-hospital stroke is unique with respect to the stroke occurring in other settings, and it is essential to apply evidence from other settings with caution and to identify existing knowledge gaps in order to effectively guide patient care and future research.

Cor triatriatum sinister diagnosed in a patient with postoperative cerebral infarction after beach chair position: A case report

Cor triatriatum sinister is a rare congenital heart disease in which the left atrium is divided into two compartments by a fibromuscular membrane. In most cases, its symptoms appear in childhood, and it is rarely diagnosed in adulthood. Patients with cor triatriatum sinister are more prone to neurological diseases, such as cerebral infarction. Herein, we report the case of a patient whose cor triatriatum sinister went undiagnosed in the preoperative evaluation, but was diagnosed whilst investigating a cerebral infarction that occurred following a surgery in the beach chair position. It highlights the potential complications in otherwise healthy asymptomatic patients undergoing surgery in the beach chair position. Additionally, in high-risk patients, the provision of clear communication, in advance, regarding potential complications and their management, may reduce the patient's morbidity.

Vascular Complications in Sports Surgery: Diagnosis and Management

Orthopedic sports surgery of the knee and shoulder is generally considered to be safe and effective. Vascular complications can occur during or after arthroscopy of either joint. A thorough understanding of anatomy, particularly when placing portals in non-routine locations, is extremely important. Prompt recognition of any vascular complication is of significant importance. This review will discuss the potential vascular complications for both knee and shoulder sports surgery, review the relevant anatomy, and discuss the treatment and expected outcome of each.

Point-of-Care Ultrasound (POCUS) for the assessment of volume status and fluid management in patients with severe pre-eclampsia: A systematic review and meta-analysis

BACKGROUND AND AIMS

Appropriate volume assessment and fluid management can prevent maternal deaths in the severely pre-eclamptic (SPE) parturients. We planned a systematic review and meta-analysis (MA) to evaluate the role and ability of point-of-care ultrasound (POCUS) in the assessment of volume status and early detection of lung oedema in an SPE parturient.

METHODS

An e-literature search was done from several databases. Data were extracted under five domains including POCUS-derived parameters like echo comet score (ECS), lung ultrasound (LUS) scores, B-patterns, optic nerve sheath diameter (ONSD), E/e' ratio, presence of pleural effusion, pulmonary interstitial syndrome and pulmonary congestion. The risk of bias was assessed. Extracted data were analysed using MetaXL and Revman 5.3. Heterogeneity in the studies was evaluated using the Cochrane Q test and I2 statistics. Funnel plots were used for the assessment of publication bias.

RESULTS

Seven prospective studies including 574 parturients (including 396 pre-eclamptics) were selected. POCUS included lung, optic nerve, cardiac and thoracic US. In two studies, the ECS and LUS scores pre-delivery were higher in pre-eclamptics. Two studies found a mean ONSD of 5-5.84 mm before delivery. MA revealed a significantly lower mean ECS score at post-delivery than pre-delivery, and the summary prevalence of B-pattern and pleural effusion among SPE parturients was found to be 0.28 (0.03-0.84) and 0.1 (0-0.2), respectively. A good correlation was observed between B-line patterns and diastolic dysfunction (increased E/e' ratio), LUS score and thoracic fluid content, ONSD and ECS in individual studies.

CONCLUSION

POCUS parameters can be useful as early markers of fluid status and serve as useful tools in the precise clinical management of pre-eclampsia.

Ultrasound-guided interscalene block anesthesia performed by an orthopedic surgeon: a study of 1322 cases of shoulder surgery

Background

Interscalene blocks are becoming increasingly common for shoulder surgeries. This study primarily aimed to demonstrate the efficacy and complications and the secondarily to investigate the anesthesia-related time and patient satisfaction of an ultrasound-guided interscalene block performed by an orthopedic surgeon.

Methods

We retrospectively reviewed the medical records of 1322 consecutive patients (arthroscopic, 1225 cases; open, 97 cases) with a mean age of 64.2 years, who underwent shoulder surgery (arthroscopic or opensurgery) under an ultrasound-guided interscalene block performed by an orthopedic surgeon at a single institution between December 2012 and December 2019. We investigated patient satisfaction, block success rates, and complications and also compared the anesthesia-related time of an interscalene block with that of general anesthesia (428 cases, arthroscopic, 257 cases; open, 171 cases) for shoulder surgery with patients in the beach chair position during the same period. Difference between total anesthesia time and surgical time was defined as anesthesia-related time.

Results

Approximately 98.3% of patients were satisfied with an interscalene block, and the block success rate on the first attempt was 99.9%. Total complication incidence was 2.3%, with no recorded life-threatening complications. Anesthesia-related times were significantly shorter in the interscalene block group than those in the general anesthesia group (45 ± 14 min vs. 100 ± 26 min, P < .001).

Conclusion

An ultrasound-guided interscalene block performed by an orthopedic surgeon for shoulder surgery is effective and safe, requires less time, and has a high patient acceptance rate, making it a feasible and alternative to the block performed by anesthesiologists.

Effect of Deliberate Hypotension on Regional Cerebral Oxygen Saturation During Functional Endoscopic Sinus Surgery: A Randomized Controlled Trial

Background: Deliberate hypotension can reduce bleeding and improve visualization of the surgical field during functional endoscopic sinus surgery (FESS). However, hypotension may cause brain hypoperfusion and subsequent ischemic injuries, such as delayed awakening, stroke, postoperative delirium, and postoperative cognitive dysfunction. Near-infrared spectroscopy (NIRS) can be used to monitor real-time regional cerebral oxygen saturation (rSO₂) levels to estimate brain perfusion. The present study aimed to evaluate the change in rSO₂ induced by deliberate hypotension during FESS, and assess the impact of deliberate hypotension on the surgical process.

Material and Methods: A randomized controlled trial was registered with the Chinese clinical trial registry (ChiCTR2000039846). A total of 40 patients were enrolled and randomly divided into the control and intervention groups, and finally, 39 patients were analyzed. Deliberate hypotension was induced in the intervention group using nicardipine and esmolol, whereas the control group received general anesthesia without deliberate hypotension. We recorded mean arterial pressure (MAP), saturation of pulse oximetry (SpO₂), rSO₂, and heart rate (HR) before induction of anesthesia (T0), immediately after induction of anesthesia (T1), at the beginning of the operation (corresponding with the establishment of deliberate hypotension) (T2), 10 min (T3) and 20 min (T4) after the operation began, at the end of the operation (corresponding with the end of deliberate hypotension) (T5), and 5 min (T6) and 15 min (T7) after the operation. The partial pressure of end-tidal carbon dioxide (PetCO₂) was recorded at T1, T2, T3, T4, T5, and T6. The duration of surgery, intraoperative blood loss, tracheal extubation time, and the number of patients that experienced cerebral desaturation events (CDEs) were recorded. The surgical field was estimated postoperation based on the Fromme score.

Results: A 30% decrease from the baseline MAP resulted in a decrease of intraoperative bleeding, improvement in the quality of the surgical field, and the shortening of the duration of surgery during FESS in the intervention group compared with the control group. In addition, rSO₂ was reduced and no CDEs were experienced in the intervention group. Linear regression analysis demonstrated a correlation between the decline in rSO₂ and that in MAP.

Conclusions: A decrease in MAP to a certain level will cause a decrease of rSO₂ in patients undergoing FESS under general anesthesia. Based on our findings, we recommend that the deliberate hypotensive target indicated by MAP be reduced by 30%, while PetCO₂ is maintained at 35–40 mmHg and HR is maintained at about 60 beats per minute during FESS.

Scoping review of complications associated with epinephrine use in arthroscopy fluid

Purpose: To identify if addition of epinephrine to irrigation fluid can result in any intra-operative or post-operative complications. It was hypothesized that significant adverse events would be identified with the use of epinephrine in arthroscopic fluid.Methodology: In accordance with PRISMA guidelines (Appendix 2), an electronic database search was conducted, from inception to February 2019 including MEDLINE, EMBASE, Cochrane, CENTRAL, and Scopus (MeSH search). All English-language studies that addressed complications associated with arthroscopic use of epinephrine were included. Defined outcome measures were any reported intra- or post-operative adverse events secondary to epinephrine use. Data collection included: patient demographics, comorbidities, surgical intervention, epinephrine concentration in irrigation fluid, reported complications, and details of the associated clinical prodrome.Results: Three hundred and ninety-three abstracts were screened with 22 studies identified and reviewed in detail. Of these seven case reports and four randomized trials met the inclusion criteria (1999-2017). The case reports encompassed nine patients (seven females and two males) with an average age of 38.8 years (range 19 to 52 y). Five had shoulder arthroscopies, two had knee scopes and two had hip scopes. A pattern of reported complications was noted in all reports in association with epinephrine including hypertension, tachycardia with or without evolving arrhythmia and/or pulmonary edema. One patient died. Of the four randomized trials, three did not report any adverse events in relation to epinephrine with one trial associating epinephrine to the occurrence of hypotensive bradycardic events in the setting of shoulder arthroscopy in the beach-chair position.Conclusion: While a causal association cannot be established, Anesthetists and Orthopedic Surgeons should be aware of the noted pattern of symptoms in patients undergoing epinephrine-assisted arthroscopy.Clinical relevance: While the incidence of epinephrine-related complications is rare, this review raises awareness to the pattern of reported symptoms, as it could help with identification and treatment should this rare complication be encountered.

[Significance of patient-specific risk factors for regional cerebral oxygen saturation in beach chair position]

BACKGROUND

Despite numerous studies on the regional cerebral oxygen saturation (rSO₂) measured by near infrared spectroscopy (NIRS) in orthopedic patients in the beach chair position, it is still unclear whether patient-specific factors, such as concomitant cardiovascular diseases, are more frequently associated with the occurrence of cerebral desaturation events (CDE).

OBJECTIVE

The aim of the present study was therefore to identify possible patient-specific risk factors that enable prediction of CDE.

METHODS

Data were collected on 397 orthopedic patients undergoing shoulder surgery in the beach chair position. Routine anesthesia management and standard monitoring was used in all patients. Target value for the inspiratory oxygen concentration (F_IO₂) was set to 50% and for the end-tidal carbon dioxide partial pressure to 35-45 mm Hg. RSO₂ was quantified using NIRS. The responsible anesthesiologist was blinded to the rSO₂ data. A decrease in rSO₂ > 20% or a value < 50% in the beach chair position was defined as CDE. Patients with and without CDE were analyzed with respect to different classifications, American Society of Anesthesiologists (ASA) and Revised Cardiac Risk Index (RCRI) as well as existing arterial hypertension and age. A value of p <0.05 was considered statistically significant.

RESULTS

Patients with CDE (n = 238) were significantly more often classified as ASA > 2 (p = 0.01) and RCRI > 1 (p = 0.01), suffered more often from arterial hypertension (p = 0.01) and were older (median: 60 years compared to 55 years; p = 0.01) than patients without CDE (n = 159) in the beach chair position (Wilcoxon rank sum test). Arterial hypertension remained significant after removing the effect of age (p = 0.03) and RCRI classification (p = 0.04; two-way ANOVA multivariate analysis).

CONCLUSION

On the basis of our study, patient-specific prognosis and risk factors for the occurrence of CDE, such as higher age, ASA > 2 and RCRI > 1 classification as well as pre-existing arterial hypertension could be determined. Arterial hypertension represents the main risk factor for the occurrence of CDE in the beach chair position. RCRI > 1 classification or age, however, only has an effect on the occurrence of pathological rSO₂ values due to the greater probability of simultaneous arterial hypertension.

Prophylactic measures to prevent cerebral oxygen desaturation events in elective beach-chair position shoulder surgeries; a systematic review and meta-analysis

Background

Prophylaxis for cerebral desaturation events (CDEs) during anesthesia in the beach chair position (BCP) for shoulder surgeries has not been evaluated. We systematically analyzed the effectiveness of various prophylactic measures used in this clinical setting.

Methods

We performed a meta-analysis (PROSPERO; no. CRD42020167285) of trials reporting CDEs and regional cerebral oxygen saturation (rSO₂) and jugular venous oxygen saturation (SjvO₂) values in anesthetized patients undergoing shoulder surgery in BCP. Considering the type of prophylactic measures used (pharmacological or non-pharmacological), a subgroup analysis was planned. Outcomes included (1) rSO₂ and SjvO₂ data with and without prophylactic measures for CDEs, recorded for different time intervals, and (2) the number of patients experiencing CDEs and hypotension.

Results

Twelve studies (786 patients) were included in the analysis. We observed lower absolute rSO₂ values for early and all-time periods for vasoactive agent prophylaxis. The lowest achieved rSO₂ values were also lower for vasoactive agent prophylaxis. Risk of CDEs was higher with vasoactive agent prophylaxis. Subgroup analysis identified targeted mild hypercarbia as effective in preserving cerebral oxygenation. Similarly, targeted mild hypercarbia prevented the fall in rSO₂ with position change. Meta-regressions revealed statistically significant highest estimates for vasoactive agent prophylaxis in contrast to targeted mild hypercarbia. Likelihood of not developing CDEs was higher for targeted mild hypercarbia. In contrast to rSO₂, most prophylactic methods reduced hypotensive episodes.

Conclusions

Targeted mild hypercarbia can reduce BCP-related CDEs. Evidence does not favor prophylactic use of vasoactive agents for the prevention of cerebral desaturations irrespective of whether their use interferes with cerebral oximetry readings.

The 15° reverse Trendelenburg position can improve visualization without impacting cerebral oxygenation in endoscopic sinus surgery-A prospective, randomized study

BACKGROUND

In this study we compared intraoperative bleeding and regional cerebral oxygenation in patients with different degrees of the reverse Trendelenburg position (RTP) during endoscopic sinus surgery (ESS).

METHODS

In total, 120 patients with chronic rhinosinusitis treated by ESS were randomly assigned to the following 4 groups: a horizontal position (HP) group, and 5°, 10°, and 15° RTP (5-RTP, 10-RTP, and 15-RTP, respectively) groups. The primary outcome was the Boezaart grading scale (BS). The cerebral oxygen saturation (ScO₂ ), total blood loss, numerical rating scale (NRS) scores, and complications were also recorded.

RESULTS

The median BS values in the HP, 5-RTP, 10-RTP, and 15-RTP groups were 2.0, 2.0, 2.1, and 1.7, respectively. Multiple pairwise comparisons of the BS showed significant differences between the 15-RTP group and the other 3 groups (HP, 5-RTP, and 10-RTP). Regarding the NRS and bleeding rate, significant differences were found between the HP and 15-RTP groups. No difference was found in ScO₂ among the 4 groups, and no cerebral desaturation events occurred in any group. No complications, including vital organ (heart, brain, and kidney) dysfunction problems, were reported in this study during hospitalization.

CONCLUSION

Compared with HP, 5-RTP, and 10-RTP, 15-RTP can improve visual clarity during ESS, and ScO₂ is not affected by the degree of RTP. No cerebral deoxygenation or vital organ dysfunction was observed in this study. Therefore, we recommend 15-RTP with moderate deliberate hypotension for ESS.

Improving the safety of shoulder arthroscopy in the beach chair position: a prospective randomized trial investigating the effect of compression stockings on cerebral desaturation events in obese patients

BACKGROUND

Devastating transient and permanent postoperative neurocognitive complications in previously healthy, low-risk patients have been observed after elective shoulder arthroscopy in the beach chair position (BCP). Continuous monitoring of cerebral oxygen saturation has been recommended to identify cerebral desaturation events (CDEs) and improve patient safety. However, the relatively high cost and limited availability of monitoring may not be cost-effective. More cost-effective and available measures, including the use of thigh-high compression stockings (CS), have been investigated. However, efficacy data of CS usage is limited, especially for obese patients, who have been shown to be at increased risk for CDEs. The purpose of this was study was to determine if the intraoperative addition of thigh-high compression stockings decreases the incidence, frequency, and magnitude of CDEs in obese patients undergoing shoulder arthroscopy in the BCP.

METHODS

Thirty-three patients in the treatment group wore both thigh-high compression stockings (CS) and sequential compression devices (SCDs), and the remaining 33 patients in the control group wore SCDs alone. Cerebral oximetry was monitored during surgery using near-infrared spectroscopy.

RESULTS

The incidence of CDEs was equal between groups, with 9 patients (27%) in each experiencing desaturation events. The median number of CDEs per patient was 3 for the control group and 1 for patients wearing CS (P = .29). There was no difference between groups in terms of median time from induction of anesthesia to onset of CDE (P = .79), median time from upright positioning to onset of CDE (P = .60), mean CDE duration per patient (P = .22), and median cumulative CDE duration (P = .19). The median maximal desaturation from baseline was also not different between groups: 27.6% in the control group and 24.3% in the treatment group (P = .35).

CONCLUSION

The combination of thigh-high CS and SCDs did not decrease the incidence, frequency, or magnitude of CDEs in patients undergoing shoulder arthroscopy in the BCP. Twenty-seven percent of patients undergoing shoulder arthroscopy in the BCP demonstrated CDEs with or without the use of CS. Therefore, further research is required to identify cost-effective, minimally invasive, and universally available methods of decreasing the incidence of CDEs during this common surgical procedure.

Adverse heart rate responses during beach-chair position for shoulder surgeries - A systematic review and meta-analysis of their incidence, interpretations and associations

Background and Aims

Evaluations of adverse heart rate (HR)-responses and HR-variations during anaesthesia in beach-chair-position (BCP) for shoulder surgeries have not been done earlier. We analysed the incidence, associations, and interpretations of adverse HR-responses in this clinical setting.

Methods

We performed a meta-analysis of trials that reported HR-related data in anaesthetised subjects undergoing elective shoulder surgeries in BCP. Studies included prospective, randomised, quasi-randomised and non-randomised, controlled clinical trials as well as observational cohorts. Literature search was conducted in MEDLINE, EMBASE, CINHAL and the Cochrane Central Register of Controlled Trials of the 21^st century. In the first analysis, we studied the incidence and associations of bradycardia/hypotension-bradycardia episodes (HBE) with respect to the type of anaesthesia and different pharmacological agents. In the second, we evaluated anaesthetic influences, associations and inter-relationships between monitored parameters with respect to HR-behaviours.

Results

Among the trials designed with bradycardia/HBE as a primary end point, the observed incidence of bradycardia was 9.1% and that of HBE, 14.9% and 22.7% [(for Interscalene block (ISB) ± sedation) subjects and general anaesthesia (GA) + ISB, respectively]. There was evidence of higher observed risk of developing adverse HR-responses for GA subjects over ISB (Risk Difference, P < 0.05). Concomitant use of β-agonists did not increase risk of HBEs (P = 0.29, I ²= 11.4%) or with fentanyl (P = 0.45, I ²= 0%) for ISB subjects (subgroup analysis). Fentanyl significantly influenced the HR-drop over time [meta-regression, estimates (standard error), 14.9 (5.4), 9.8 (4.3) and 17 (2.6); P = 0.007, 0.024 and <0.001; for early, mid and delayed periods, respectively] in GA subjects. With respect to number of subjects experiencing cerebral desaturation events (CDEs), total intravenous anaesthesia (TIVA)- propofol had higher risk over inhalational anaesthesia (P = 0.006, I ² = 86.7%). Meta-correlation analysis showed relationships between the HR and rSO₂(regional cerebral oxygen saturation) or SjvO₂(jugular venous oxygen saturation) values (r = 0.608, 95%CI, 0.439 to 0.735, P < 0.001, I ²= 77.4% and r = 0.397, 95%CI, 0.151 to 0.597, P < 0.001, I ²= 64.3%, respectively).

Conclusions

There is not enough evidence to claim the associations of adverse HR-responses with any specific factor. HR-fall is maximal with fentanyl and its variability is associated with changes in rSO₂. Fall in rSO₂ could be the common link triggering adverse HR-responses in BCP.

Prospective Evaluation of Cognitive Outcomes After Anesthesia for Patients in the Beach Chair Position

The beach chair position has been popularized for shoulder surgeries, particularly those involving arthroscopy. Several published case reports and studies have raised concerns for neurologic complications related to anesthesia for surgery performed with patients in the beach chair position. The question has been raised whether cerebral perfusion monitoring should be used routinely to minimize these potential complications. This prospective study evaluated cognitive outcomes in patients who underwent anesthesia in the beach chair position. Patients were randomized to 2 groups. In group 1, the anesthesiologist was blinded to the cerebral monitoring and could treat based only on mean arterial pressure (MAP). In group 2, the anesthesiologist was aware of the results of the cerebral monitoring and could treat any desaturation events. All patients were evaluated pre- and postoperatively with a cognitive assessment tool. A total of 80 patients were enrolled in the study, with 40 patients in each group. There were no significant differences regarding age, body mass index, or American Society of Anesthesiologists score. Only 3 desaturation events occurred with no significant change in cognitive function. The findings indicate no advantage to cerebral perfusion monitoring during anesthesia for surgery performed with patients in the beach chair position as long as MAP is maintained within strict limits. Although little is known about the level of cerebral desaturation that will result in cognitive dysfunction, it may likely be related to MAP and cerebral perfusion. The findings of this study reinforce the need for careful monitoring of MAP during surgery and dispute the need for additional expensive monitoring devices. [Orthopedics. 2020; 43(1):e27-e30.].

Evaluation of cerebral oxygen perfusion during shoulder arthroplasty performed in the semi-beach chair position

BACKGROUND

The beach chair position is commonly used when performing shoulder arthroplasty. However, this position has been associated with hypotension, potentially leading to cerebral hypoperfusion, which may cause neurologic injury. In addition, shoulder arthroplasty cases are associated with longer operative times, posing a potentially greater risk of cerebral hypoperfusion. We aim to evaluate the risk of cerebral desaturation events (CDEs) during the course of total shoulder arthroplasty.

METHODS

Twenty-six patients undergoing shoulder arthroplasties were monitored for changes in cerebral perfusion. Seven specific time-points during the procedure were labeled for comparison of events: baseline, beach chair, incision, humeral broaching, glenoid reaming, glenoid component implantation, and humeral component implantation. Cerebral oxygen perfusion was measured using near-infrared spectroscopy. A CDE was described as a decrease of oxygen saturation greater than 20%.

RESULTS

Nineteeen of 25 subjects experienced a CDE. 42% of these patients experienced CDEs during semi-beach chair positioning. Patients experienced the largest oxygen saturation drop during semi-beach chair positioning. Transition from baseline to semi-beach chair was the only event to have a statistically significant decrease in cerebral perfusion (8%, P < .05). There was a statistically significant percentage change in mean oxygen saturation in the semi-beach chair interval (10%, P < .01) and the semi-beach chair to incision interval (7%, P < .01).

CONCLUSIONS

Most patients experienced an intraoperative CDE, with greatest incidence during semi-beach chair positioning. The largest decline in cerebral oxygen saturation occurred during semi-beach chair positioning. Implant implantation was not associated with decrease in cerebral oximetry.

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).

Cerebral Oxygenation in the Sitting Position Is Not Compromised During Spontaneous or Positive-Pressure Ventilation

BACKGROUND

General anesthesia with neuromuscular blockade may facilitate total shoulder arthroplasty but appears to increase risk of cerebral oxygen desaturation. Cerebral desaturation is undesirable and is a proxy for risk of stroke.

PURPOSES/QUESTIONS

This study tested the hypothesis that cerebral oxygen desaturation occurs frequently during general anesthesia with neuromuscular blockade and positive-pressure ventilation but does not occur with spontaneous ventilation. Correlations were sought among cerebral oxygen saturation, blood pressure, and cardiac index.

METHODS

We designed a prospective, observational, cohort study to measure cerebral oxygenation in 25 patients during general anesthesia, both with and without positive-pressure ventilation. Patients undergoing elective shoulder arthroplasty in the sitting position received an arterial catheter, near-infrared spectroscopic measurement of cerebral oxygenation, and non-invasive cardiac output measurement. Moderate hypotension was allowed. Blood pressure was supported as needed with ephedrine or low-dose epinephrine (but avoiding phenylephrine). Hypercapnia (45 to 55 mmHg) was targeted during positive-pressure ventilation.

RESULTS

No cerebral oxygen desaturations occurred, regardless of ventilation mode. Under positive-pressure ventilation, the median (interquartile range: Q1, Q3) cerebral oxygenation was 110% of baseline (104, 113), the mean arterial pressure was 62% of baseline (59, 69), and the cardiac index was 82% of baseline (71, 104). Cerebral oxygenation did not correlate with blood pressure or cardiac index but had moderate correlation with end-tidal carbon dioxide. No strokes occurred.

CONCLUSIONS

There were no signs of inadequate brain perfusion during general anesthesia using paralytic agents. Positive-pressure ventilation with moderate hypotension in the sitting position does not endanger patients, in the context of moderate hypercapnia and hemodynamic support using ephedrine or epinephrine.

Editorial Commentary: Beach Chair Versus Lateral Decubitus for Arthroscopic Posterior Shoulder Stabilization-Here We Go Again

Recent literature has suggested that patient positioning matters when it comes to arthroscopic anterior shoulder stabilization. Although advocates of the lateral decubitus position argue that only in this position can the anteroinferior and posteroinferior aspects of the glenoid be adequately visualized and instrumented, outcomes following posterior shoulder stabilization appear independent of patient position.

Intra-operative effect of interscalene brachial plexus block to arthroscopic rotator cuff repair surgery

INTRODUCTION

To determine whether the placement of an interscalene brachial plexus block (IBPB) with general anaesthesia before shoulder arthroscopy would be effective in establishing a clear visual field and in shortening the surgical procedure.

METHOD

This prospective randomized control trial study included 152 patients who had undergone arthroscopic rotator cuff repair. Group A received IBPB and group B did not receive IBPB. A visual clarity scale (VCS) was determined by arthroscopic visualization. The systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), duration of surgical procedure, VCS, and medication that was administered for haemodynamic stability were recorded.

RESULTS

The VCS was improved in group A at stages 2 and 3 of the surgical procedures (p < 0.05), but there were no significant difference at stages 1 (p = 0.288) and 4 (p = 0.062). SBP, DBP, and HR were higher in group B during surgery (p < 0.05). The administered analgesics were higher in group B (p = 0.003), but there were no differences in hypotensive agents (p = 0.287). No significant difference was observed for the duration of surgery (p = 0.704).

CONCLUSIONS

Pre-operative IBPB with general anaesthesia for arthroscopic rotator cuff repair was beneficial in maintaining haemodynamic stability and improving the VCS during surgery.

Epinephrine in irrigation fluid for visual clarity in arthroscopic shoulder surgery: a systematic review and meta-analysis

PURPOSE

To investigate whether epinephrine in irrigation fluid improves visual clarity in arthroscopic shoulder surgery.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) that compared the surgical outcomes of patients who did and did not receive epinephrine during arthroscopic shoulder surgery. We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for relevant RCTs. We used the Cochrane Collaboration's tool to assess the risk of bias and adopted random-effects model meta-analysis to combine data. We used the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology to evaluate the overall quality of the body of the retrieved evidence. The primary outcome was visual clarity. The secondary outcomes were operative time, amount of irrigation fluid, the need for increased pump pressure, and adverse cardiovascular events.

RESULTS

This study included three RCTs with a total of 238 participants (124 in the epinephrine group and 114 in the non-epinephrine group). The use of epinephrine in irrigation fluid for shoulder arthroscopy achieved better visual clarity (standardized mean difference, 1.01; 95% confidence interval [CI] 0.63 to 1.39; p < 0.0001) and less need for increased pump pressure (risk ratio, 0.40; 95% CI 0.25 to 0.64; p = 0.0001) compared to the non-epinephrine group. No significant differences were noted in operative time (mean difference - 5.08; 95% CI - 14.46 to 4.31; p = 0.29) and amount of irrigation fluid (mean difference - 1.04; 95% CI - 2.38 to 0.39; p = 0.12) between the two groups. No adverse events were recorded in any of the included trials.

CONCLUSIONS

The current evidence shows that the use of epinephrine in arthroscopic shoulder surgery may improve visualization and does not appear to have any major disadvantages.

LEVEL OF EVIDENCE

Level I.

Compression stockings reduce the incidence of hypotension but not that of cerebral desaturation events in the beach-chair position: a randomized controlled trial

Background

The beach-chair position (BCP) results in decreases in venous return, cardiac output, and cerebral perfusion pressure. In this randomized, prospective study, we investigated whether applying thigh-high compression stockings affected the maintenance of regional cerebral tissue oxygen saturation (rSO₂) in the BCP.

Methods

Patients undergoing orthopedic surgery in the BCP under general anesthesia were included and assigned randomly to the control or the compression stocking group. Appropriately sized thigh-high compression stockings were applied to the patients in the stockings group. All patients were tilted, up to 45°, throughout the operation. Non-invasive blood pressure, invasive arterial blood pressure zeroed at the external auditory meatus, and rSO₂ were recorded.

Results

Data were analyzed from 19 patients per group. In the BCP, the values of rSO₂ and blood pressure decreased significantly compared with those at baseline, with no significant difference between the groups. The incidences of cerebral desaturation events (CDEs) were similar between the groups; however, that of hypotension was significantly lower in the compression stocking group. During 36 CDEs, the levels of rSO₂ and blood pressure decreased significantly compared with those at baseline in both groups. No significant correlation was found between rSO₂ and blood pressure.

Conclusions

Thigh-high compression stockings reduced the incidence of hypotension but not that of CDEs. Our results suggest that other factors, beyond hypotension itself, contribute to CDEs and in other words, efforts just to reduce the incidence of hypotension may not mainly contribute to a reduction of CDEs occurrence in the BCP under general anesthesia.

Effect of interscalene block on intraocular pressure and ocular perfusion pressure

BACKGROUND

Interscalene block (ISB) is commonly associated with Horner's syndrome due to spread of local anesthetic to the cervical sympathetic chain. Postganglionic neurons that originate from superior cervical ganglia form the sympathetic innervation of eye. Decrease in sympathetic tone may change intraocular pressure (IOP) and ocular perfusion pressure (OPP). The aim of the study was to investigate whether ISB affects IOP and/or OPP.

METHODS

Thirty patients scheduled for ambulatory shoulder surgery under regional anesthesia with a single-shot ISB (15 mL 0.5% bupivacaine and 15 mL 2% lidocaine) were recruited. The IOP and OPP in both eyes, mean arterial pressure (MAP), heart rate (HR) and end-tidal CO₂ (ETCO₂) were measured before ISB and 5, 10, 20, 30 and 60 min after ISB in the beach-chair position.

RESULTS

The baseline IOP and OPP were similar in the blocked and unblocked sides (IOP 17.60 ± 1.69 and 17.40 ± 1.96 respectively p = 0.432; OPP 49.80 ± 8.20 and 50 ± 8.07 respectively p = 0.432). The IOP in the blocked side significantly decreased between 10th to 60th min following ISB, compared to the baseline values (p < 0.001). The OPP in the blocked side significantly increased from 10th to 60th min (p < 0.001) whereas, there were no significant changes in IOP and OPP throughout the measurement period in the unblocked side.

CONCLUSIONS

ISB decreased IOP in the blocked side. ISB could be considered as a safe regional technique of choice in elderly patients at high risk for developing glaucoma.

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.

Range of S-100β levels during functional endoscopic sinus surgery with moderately controlled hypotension

The aim of this study is to determine the range of S-100β levels during functional endoscopic sinus surgery (FESS) when the mean arterial pressure (MAP) was controlled within 60-70 mmHg. After anesthesia induction with propofol and remifentanil, the patient was positioned in the reverse Trendelenburg position and MAP was controlled within 60-70 mmHg during surgery. For the S-100β assay, blood was taken from a radial arterial catheter before (baseline) and at 20 (T ₂₀) and 60 (T ₆₀) min after setting the reverse Trendelenburg position and controlled hypotension, and at 60 (T _post60) min after the end of the operation. In total, 34 patients completed the study. Baseline S-100β was 0.00837 ± 0.00785 ng/mL. The levels at T ₂₀ and T ₆₀ were 0.02057 ± 0.01739 and 0.01987 ± 0.01145 ng/mL, respectively. The level of T _post60 was 0.05436 ± 0.02318 ng/mL. The level at T ₂₀ increased significantly versus the baseline level (P < 0.001); there were no significant differences between T ₂₀ and T ₆₀. The level at T _post60 was significantly different versus T ₂₀ and T ₆₀ (P < 0.001). However, all S-100β levels were within the normal range. S-100β-a sensitive biomarker of cerebral ischemia-was within the normal range during FESS when moderate hypotension (MAP >60 mmHg) was provided. Thus, moderate hypotension would be seemed to be a safe and effective anesthetic technique for FESS without risk for cerebral ischemia.

Internal carotid artery blood flow in healthy awake subjects is reduced by simulated hypovolemia and noninvasive mechanical ventilation

Intact cerebral blood flow (CBF) is essential for cerebral metabolism and function, whereas hypoperfusion in relation to hypovolemia and hypocapnia can lead to severe cerebral damage. This study was designed to assess internal carotid artery blood flow (ICA-BF) during simulated hypovolemia and noninvasive positive pressure ventilation (PPV) in young healthy humans. Beat-by-beat blood velocity (ICA and aorta) were measured by Doppler ultrasound during normovolemia and simulated hypovolemia (lower body negative pressure), with or without PPV in 15 awake subjects. Heart rate, plethysmographic finger arterial pressure, respiratory frequency, and end-tidal CO2 (ETCO2) were also recorded. Cardiac index (CI) and ICA-BF were calculated beat-by-beat. Medians and 95% confidence intervals and Wilcoxon signed rank test for paired samples were used to test the difference between conditions. Effects on ICA-BF were modeled by linear mixed-effects regression analysis. During spontaneous breathing, ICA-BF was reduced from normovolemia (247, 202-284 mL/min) to hypovolemia (218, 194-271 mL/min). During combined PPV and hypovolemia, ICA-BF decreased by 15% (200, 152-231 mL/min, P = 0.001). Regression analysis attributed this fall to concurrent reductions in CI (β: 43.2, SE: 17.1, P = 0.013) and ETCO2 (β: 32.8, SE: 9.3, P = 0.001). Mean arterial pressure was maintained and did not contribute to ICA-BF variance. In healthy awake subjects, ICA-BF was significantly reduced during simulated hypovolemia combined with noninvasive PPV Reductions in CI and ETCO2 had additive effects on ICA-BF reduction. In hypovolemic patients, even low-pressure noninvasive ventilation may cause clinically relevant reductions in CBF, despite maintained arterial blood pressure.

The Effect of Compression Stockings on Cerebral Desaturation Events in Obese Patients Undergoing Shoulder Arthroscopy in the Beach-Chair Position

PURPOSE

To determine if the use of thigh-high compression stockings could decrease the incidence of cerebral desaturation events (CDEs) in patients with a body mass index (BMI) of 30 kg/m(2) or greater undergoing shoulder arthroscopy in the beach-chair position (BCP).

METHODS

Between December 2013 and May 2014, 23 patients aged 18 years or older with a BMI of 30 kg/m(2) or greater undergoing shoulder arthroscopy in the BCP were monitored intraoperatively using near-infrared spectroscopy while wearing thigh-high compression stockings. Data obtained on these patients were compared with data from a previous cohort at our institution comprising 24 patients with a BMI of 30 kg/m(2) or greater who underwent elective shoulder arthroscopy in the BCP with the same monitoring but without wearing compression stockings. The incidence of CDEs was identified in each group.

RESULTS

The incidence of CDEs in the group with compression stockings was 4% (1 of 23) compared with 18% (7 of 24) in the group without compression stockings (P = .048). There were no statistically significant differences in mean age (53.0 years v 53.3 years, P = .91), mean BMI (34.5 kg/m(2)v 36.2 kg/m(2), P = .21), or various medical comorbidities between the treatment group and control group. There was a significant difference in the operative time between the treatment group (156.6 minutes) and control group (94.1 minutes) (P < .001).

CONCLUSIONS

The use of thigh-high compression stockings may decrease the incidence of CDEs in obese patients undergoing shoulder arthroscopy in the BCP.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Cerebral tissue O2 saturation during prolonged robotic surgery in the steep Trendelenburg position: an observational case series in a diverse surgical population

Demands associated with the Trendelenburg position (TP) are well known yet there is little attention given to regional cerebral tissue O2 saturation (SctO2) in those undergoing robotic surgery in the TP with CO2 insufflation (C-INSF). This is the first study to report on SctO2 in a wide range of patients undergoing lengthy TP and robotic surgery. We measured SctO2 during robotic surgery in patients in the TP with C-INSF, as well as a control robotic thyroid surgery group who were supine with no C-INSF. We recorded relevant variables and periods of cerebral desaturation (CD). We studied 42 patients in 25°-45° of TP for ≥125 min. Management was at the providers' discretion. The INVOS(®) 5100C Cerebral Oximeter (Covidien, Boulder, CO) recorded SctO2. CD was defined as a >20 % decrease from baseline SctO2 or a value ≤55 % for ≥10 min. Patients were assessed for adverse outcome. The sample consisted of 13 males and 29 females aged 22-73, BMI 22-36 had general (N = 3), urological (N = 14) and gynecological (N = 25) surgery; two patients had CD lasting 150 and 190 min and two had episodic CD lasting 10-35 min. The four were female aged 22-60 in 38°-45° of TP. Eleven cases had multiple episodic CD for ≤15 min, 27 TP cases had no CD. Other observations included a consistent fall in SctO2 with phenylephrine; an increased SctO2 with ephedrine; and FiO2 and EtCO2 being generally strong, direct modifiers of SctO2. High MAP was inconsistently associated with high SctO2. BMI had no observed effect on SctO2. Pulse oximetry was ≥97 % in all cases. We observed no adverse cerebral events on follow-up. Additional clinical studies are warranted.

Effect of controlled hypotension on regional cerebral oxygen saturation during rhinoplasty: a prospective study

The aim of this study was to investigate the effect of controlled hypotension on cerebral oxygen saturation (rSO2) using near infrared spectroscopy (NIRS) and evaluation of postoperative cognitive function in patients undergoing rhinoplasty. Fifty adult patients who were scheduled for elective rhinoplasty surgery and required controlled hypotension were enrolled in this prospective study. Controlled hypotension was provided using a combination of propofol and remifentanil infusion supplemented with nitroglycerin infusion as necessary. rSO2 was evaluated during controlled hypotension by NIRS. Cerebral desaturation was observed in 5 out of 50 patients (10 %) during hypotensive anesthesia. The greatest decrease from baseline was 28 % when MAP was 57 mmHg. In both non-desaturated and desaturated patients, postoperative MMSE scores were significantly lower than preoperative scores. There was a 4 % decrease in the non-desaturated patients and a 7 % decrease in the desaturated patients when preoperative and postoperative MMSE scores were compared. A decline in cognitive function 1 day after surgery was observed in 23 patients (46 %) and in all patients with intraoperative cerebral desaturation. The current study showed that even if SpO2 is in the normal range, there might be a decrease of more than 20 % in cerebral oxygen saturation during controlled hypotension.

Foreseeing the danger in the beach chair position: Are standard measurement methods reliable?

PURPOSE

The aim of this study is to show whether peripheral perfusion monitoring methods reflect central perfusion during shoulder arthroscopy at beach chair position. We hypothesized that mean arterial pressure (MAP), central heart rate (CHR) and peripheral oxygenation (SaO2) measurements individually will not parallel cerebral oximetry measurements by near-infrared spectroscopy (NIRS).

METHODS

Between 2011 and 2012, 53 patients who had arthroscopic rotator cuff repair surgery in the beach chair position were enrolled prospectively. Median ages of the patients were 58 (range 42-68) years. The regional cerebral oxygen saturation value of each hemisphere was continuously monitored by the use of NIRS. MAP, CHR, SaO2 and both hemispheric cerebral oxygen saturation values were recorded at six time periods peri-operatively. Correlation and differences between parameters were evaluated.

RESULTS

Cerebral oxygen saturation of right hemisphere was dropped >20 % in 28.3 and 45.3 % of the patients. At left hemisphere, cerebral oxygen saturation was dropped >20 % in 20.8 and 43.4 % of the patients. Peripheral saturation values were statistically different from cerebral saturation values (p < 0.001). On the other hand, there was a correlation between cerebral saturation and MAP values (p < 0.05).

CONCLUSION

Cerebral oximetry by NIRS may prove useful as a monitor for cerebral ischaemia. In the absence of NIRS, CHR can partially detect abnormalities but not trustable, and MAP is the most reliable method for monitoring.

Ketamine in outpatient arthroscopic shoulder surgery: Effects on postoperative pain, hemodynamic stability and process times

Background

Pain after arthroscopic shoulder surgery is often severe, and establishing a pain treatment regimen that does not delay discharge can be challenging. The reported ability of ketamine to prevent opioid-induced hyperalgesia has not been investigated in this particular setting.

Methods

300 adult patients scheduled for shoulder arthroscopy under general anesthesia were recruited for this observational clinical trial and were allotted to either receive 1mg/kg IV bolus of ketamine before surgery (ketamine group, KG) or to a control group (CG) without ketamine. NRS pain scores were obtained on the operative day and on postoperative days 1 and 2 and compared between groups. Secondary variables were blood pressure, heart rate, process times, satisfaction with the anesthetic and unwanted effects.

Results

Pain severity did not differ significantly between the groups at any time. Propofol injection rate and cumulative dose were higher in the KG. Heart rates and blood pressures were similar. Time to emergence and time in PACU were longer and vomiting was more frequent in patients given ketamine.

Conclusion

Preoperative low-dose ketamine added to a general anesthetic does not reduce perioperative pain after outpatient shoulder arthroscopy. It increases procedural times and the incidence of PONV.

The effect of norepinephrine versus epinephrine in irrigation fluid on the incidence of hypotensive/bradycardic events during arthroscopic rotator cuff repair with interscalene block in the sitting position

PURPOSE

To compare the occurrence rate of hypotensive and bradycardic events (HBEs) during arthroscopic rotator cuff repair performed with interscalene brachial plexus block anesthesia in the sitting position in 2 groups of patients who underwent the procedure with norepinephrine or epinephrine added to the irrigation fluid. The secondary objective was to evaluate the efficacy of norepinephrine in comparison with epinephrine in controlling intraoperative bleeding and maintaining adequate visualization of the arthroscopic field of view during the procedure. We hypothesized that norepinephrine added to the irrigation fluid during shoulder arthroscopy in the sitting position would reduce the occurrence of HBEs, allowing optimal intraoperative bleeding control.

METHODS

One hundred twenty patients underwent an arthroscopic rotator cuff repair performed under peripheral anesthesia and in the beach-chair position. Patients were randomly divided into 2 groups of 60 cases each: Norepinephrine (0.66 mg/L) and epinephrine (0.33 mg/L) were added to irrigation bags in group N and group E, respectively. The primary outcome was the occurrence rate of HBEs during surgery. The secondary outcomes were timing of onset of HBEs, accompanying symptoms, and intraoperative bleeding that impaired arthroscopic visualization. The clarity of the visual field was rated postoperatively by the surgeon using a visual analog scale. Comparison between groups for all baseline variables and outcome measurements was performed with the χ(2) or Fisher exact test, as appropriate, for categorical variables and the Student t test or Mann-Whitney U test, as appropriate, for continuous variables. Significance was set at P < .05.

RESULTS

One patient was excluded from group E because of block failure; therefore 119 patients were finally included in the study. Comparison between groups showed no significant differences in baseline characteristics. The occurrence rate of HBEs was significantly greater in group E (n = 15) than in group N (n = 5) (P = .02). No differences between groups were found in the average time of onset of HBEs, accompanying symptoms, and clarity of the visual field.

CONCLUSIONS

Continuous administration of norepinephrine, 0.66 mg/L, diluted in irrigation fluid during arthroscopic rotator cuff repair with the patient in the beach-chair position reduces the incidence of HBEs and is as effective as epinephrine in controlling intraoperative bleeding and maintaining the visual clarity of the surgical field.

LEVEL OF EVIDENCE

Level I, randomized clinical study.

Surgeon-rated visualization in shoulder arthroscopy: a randomized blinded controlled trial comparing irrigation fluid with and without epinephrine

PURPOSE

The objective of the current study was to compare surgeon-rated visualization in shoulder arthroscopy using irrigation fluid with and without epinephrine.

METHODS

Eighty-three patients were randomized to receive irrigation fluid with (44 patients) or without (39 patients) epinephrine during their arthroscopic shoulder procedures. After each procedure, the blinded senior author (G.F.C.) evaluated visualization based on a visual analog scale (VAS), and all clinically important procedure variables were recorded.

RESULTS

Eighty-three arthroscopic shoulder procedures were included in the study. Fifty-four of these procedures were arthroscopic rotator cuff repairs, allowing a subset analysis of this specific procedure. There was a significant difference, with improved visualization in the epinephrine group versus the group without epinephrine when comparing all procedures (P < .0001) and when comparing only rotator cuff repairs (P < .0001). However, there was no statistical difference in other clinically important variables, including operative time and amount of irrigation fluid used.

CONCLUSIONS

The addition of epinephrine to irrigation fluid significantly improves surgeon-rated visualization in shoulder arthroscopy. Without an observed significant difference in operative time or volume of irrigation fluid used, the clinical significance of this improved visualization is unclear, and the use of irrigation fluid without epinephrine remains a viable option in the hands of an experienced surgeon.

LEVEL OF EVIDENCE

Level I, high-quality randomized controlled trial with statistically significant difference.

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

PURPOSE

To examine the risks of shoulder arthroscopy in the beach-chair position (BCP) as opposed to the lateral decubitus position. The challenge during general anesthesia, particularly with the patient in the BCP, has been to ascertain the lower limit of blood pressure autoregulation, correctly measure mean arterial pressure, and adequately adjust parameters to maintain cerebral perfusion. There is increasing concern about the BCP and its association with intraoperative cerebral desaturation events (CDEs). Assessment of CDEs intraoperatively remains difficult; the emerging technology near-infrared spectroscopy (NIRS) may provide noninvasive, inexpensive, and continuous assessment of cerebral perfusion, offering an "early warning" system before irreversible cerebral ischemia occurs.

METHODS

A systematic review was undertaken to determine the incidence of intraoperative CDEs as measured by NIRS and whether it is possible to risk stratify patients for intraoperative CDEs, specifically the degree of elevation in the BCP.

RESULTS

Searching Medline, Embase, and the Cochrane Central Register of Controlled Trials from inception until December 30, 2013, we found 9 studies (N = 339) that met our search criteria. The Level of Evidence was III or IV.

CONCLUSIONS

There remains a paucity of high-level data. The mean incidence of CDEs was 28.8%. We found a strong positive correlation between CDEs and degree of elevation in the BCP (P = .056). Emerging evidence (Level IV) suggests that we may be able to stratify patients on the basis of age, history of hypertension and stroke, body mass index, diabetes mellitus, obstructive sleep apnea, and height. The challenge remains, however, in defining the degree and duration of cerebral desaturation, as measured by NIRS, required to produce measureable neurocognitive decline postoperatively.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and IV studies.

Outcomes of arthroscopic anterior shoulder instability in the beach chair versus lateral decubitus position: a systematic review and meta-regression analysis

PURPOSE

This study aimed to systematically review the clinical outcomes and recurrence rates after arthroscopic anterior shoulder stabilization in the beach chair (BC) and lateral decubitus (LD) positions.

METHODS

The authors performed a systematic review of multiple medical databases using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All English-language literature from 1990 to 2013 reporting clinical outcomes after arthroscopic anterior shoulder stabilization with suture anchors or tacks with a minimum 2-year follow-up period were reviewed by 2 independent reviewers. Data on recurrent instability rate, return to activity/sport, range of motion, and subjective outcome measures were collected. Study methodological quality was evaluated with the Modified Coleman Methodology Score (MCMS) and the Quality Appraisal Tool (QAT). To quantify the structured review of observational data, meta-analytic statistical methods were used.

RESULTS

Sixty-four studies (38 BC position, 26 LD position) met inclusion criteria. A total of 3,668 shoulders were included, with 2,211 of patients in the BC position (average age, 26.7 ± 3.8 years; 84.5% male sex) and 1,457 patients in the LD position (average age, 26.0 ± 3.0 years; 82.7% male sex). The average follow-up was 49.8 ± 29.5 months in the BC group compared with 38.7 ± 23.3 months in the LD group. Average overall recurrent instability rates were 14.65 ± 8.4% in the BC group (range, 0% to 38%) compared with 8.5% ± 7.1% in the LD group (range, 0% to 30%; P = .002). The average postoperative loss in external rotation motion (in abduction) was reported in 19 studies in the BC group and in13 studies in the LD group, with an average loss of 2.4° ± 1.0° and 3.6° ± 2.6° in each group, respectively (P > .05).

CONCLUSIONS

Excellent clinical outcomes with low recurrence rates can be obtained after arthroscopic anterior shoulder stabilization in either the BC or the LD position; however, lower recurrence rates are noted in the LD position. Additional long-term randomized clinical trials comparing these positions are needed to better understand the potential advantages and disadvantages of each position.

LEVEL OF EVIDENCE

Level IV, systematic review of studies with Level I through Level IV evidence.

Complications of shoulder arthroscopy

Over the past 20 to 30 years, arthroscopic shoulder techniques have become increasingly popular. Although these techniques have several advantages over open surgery, surgical complications are no less prevalent or devastating than those associated with open techniques. Some of the complications associated with arthroscopic shoulder surgery include recurrent instability, soft-tissue injury, and neurapraxia. These complications can be minimized with thoughtful consideration of the surgical indications, careful patient selection and positioning, and a thorough knowledge of the shoulder anatomy. Deep infection following arthroscopic shoulder surgery is rare; however, the shoulder is particularly susceptible to Propionibacterium acnes infection, which is mildly virulent and has a benign presentation. The surgeon must maintain a high index of suspicion for this infection. Thromboemoblic complications associated with arthroscopic shoulder techniques are also rare, and studies have shown that pharmacologic prophylaxis has minimal efficacy in preventing these complications. Because high-quality studies on the subject are lacking, minimal evidence is available to suggest strategies for prevention.

Blood pressure response to combined general anaesthesia/interscalene brachial plexus block for outpatient shoulder arthroscopy

BACKGROUND

Shoulder surgery is often performed in the beach-chair position, a position associated with arterial hypotension and subsequent risk of cerebral ischaemia. It can be performed under general anaesthesia or with an interscalene brachial plexus block, each of which has specific advantages but also specific negative effects on blood pressure control. It would be worthwhile to combine the advantages of the two, but the effects of the combination on the circulation are not well investigated. We studied blood pressure, heart rate, and incidence of adverse circulatory events in patients undergoing shoulder surgery in general anaesthesia with or without an interscalene block.

METHODS

Prospective, randomised, blinded study in outpatients (age 18 to 80 years) undergoing shoulder arthroscopy. General anaesthesia was with propofol/opioid, interscalene block with 40 ml 1% mepivacaine. Hypotension requiring treatment was defined as a mean arterial pressure <60 mmHg or a systolic pressure <80% of baseline; relevant bradycardia was a heart rate <50 bpm with a decrease in blood pressure.

RESULTS

Forty-two patients had general anaesthesia alone, 41 had general anaesthesia plus interscalene block. The average systolic blood pressure under anaesthesia in the beach-chair position was 114 ± 7.3 vs. 116 ± 8.3 mmHg (p = 0.09; all comparisons General vs. General-Regional). The incidence of a mean arterial pressure under 60 mmHg or a decrease in systolic pressure of more than 20% from baseline was 64% vs. 76% (p = 0.45). The number of patients with a heart rate lower than 50 and a concomitant blood pressure decrease was 8 vs. 5 (p = 0.30).

CONCLUSION

One can safely combine interscalene block with general anaesthesia for surgery in the beach-chair position in ASA I and II patients.

CLINICAL TRIAL NUMBER

DRKS00005295.

Cardiovascular consequence of reclining vs. sitting beach-chair body position for induction of anesthesia

The sitting beach-chair position is regularly used for shoulder surgery and anesthesia may be induced in that position. We tested the hypothesis that the cardiovascular challenge induced by induction of anesthesia is attenuated if the patient is placed in a reclining beach-chair position. Anesthesia was induced with propofol in the sitting beach-chair (n = 15) or with the beach-chair tilted backwards to a reclining beach-chair position (n = 15). The last group was stepwise tilted to the sitting beach-chair position prior to surgery. Hypotension was treated with ephedrine. Continuous hemodynamic variables were recorded by photoplethysmography and frontal cerebral oxygenation (ScO₂) by near infrared spectroscopy. Significant differences were only observed immediately after the induction when patients induced in a reclining beach-chair position had higher mean arterial pressure (MAP) (35 ± 12 vs. 45 ± 15 % reduction from baseline, p = 0.04) and ScO₂ (7 ± 6 vs. 1 ± 8% increase from baseline, p = 0.02) and received less ephedrine (mean: 4 vs. 13 mg, p = 0.048). The higher blood pressure and lower need of vasopressor following induction of anesthesia in the reclining compared to the sitting beach-chair position indicate more stable hemodynamics with the clinical implication that anesthesia should not be induced with the patient in the sitting position.

Systematic review of near-infrared spectroscopy determined cerebral oxygenation during non-cardiac surgery

Near-infrared spectroscopy (NIRS) is used to monitor regional cerebral oxygenation (rScO₂) during cardiac surgery but is less established during non-cardiac surgery. This systematic review aimed (i) to determine the non-cardiac surgical procedures that provoke a reduction in rScO₂ and (ii) to evaluate whether an intraoperative reduction in rScO₂ influences postoperative outcome. The PubMed and Embase database were searched from inception until April 30, 2013 and inclusion criteria were intraoperative NIRS determined rScO₂ in adult patients undergoing non-cardiac surgery. The type of surgery and number of patients included were recorded. There was included 113 articles and evidence suggests that rScO₂ is reduced during thoracic surgery involving single lung ventilation, major abdominal surgery, hip surgery, and laparoscopic surgery with the patient placed in anti-Tredelenburg's position. Shoulder arthroscopy in the beach chair and carotid endarterectomy with clamped internal carotid artery (ICA) also cause pronounced cerebral desaturation. A >20% reduction in rScO₂ coincides with indices of regional and global cerebral ischemia during carotid endarterectomy. Following thoracic surgery, major orthopedic, and abdominal surgery the occurrence of postoperative cognitive dysfunction (POCD) might be related to intraoperative cerebral desaturation. In conclusion, certain non-cardiac surgical procedures is associated with an increased risk for the occurrence of rScO₂. Evidence for an association between cerebral desaturation and postoperative outcome parameters other than cognitive dysfunction needs to be established.

Cerebral desaturation during shoulder arthroscopy: a prospective observational study

BACKGROUND

Patients undergoing arthroscopic shoulder surgery in the beach chair position may be at increased risk for serious neurocognitive complications as a result of cerebral ischemia.

QUESTIONS/PURPOSES

We sought to define the (1) incidence; (2) timing; and (3) magnitude of intraoperative cerebral desaturation events (CDEs) in subjects undergoing arthroscopic shoulder surgery in the beach chair position, as well as whether (4) the length of surgery was an independent risk factor for intraoperative CDEs.

METHODS

Regional cerebral tissue oxygen saturation (rSO2) was monitored intraoperatively using near-infrared spectroscopy on 51 consecutive patients undergoing arthroscopic shoulder surgery in the beach chair position. Intraoperative decreases in rSO2 of 20% or greater were defined as CDEs.

RESULTS

The incidence of intraoperative CDEs in our series was 18% (nine of 51). Among the patients demonstrating CDE (n = 9), the mean time to onset of initial CDE was 18 minutes 38 seconds postinduction. Of those experiencing CDEs, the mean maximal decrease in rSO2 was 32% from preoperative baseline per patient. Additionally, the mean number of separate CDE instances was 1.89 in this patient population with an average duration of 3 minutes 3 seconds per instance. There was no statistically significant difference (p = 0.202) between patients demonstrating CDEs and those without in regard to length of surgery (95 versus 88 minutes).

CONCLUSIONS

The degree and duration of cerebral ischemia required to produce neurocognitive dysfunction in this patient population remains undefined; however, cerebral oximetry with near-infrared spectroscopy allows prompt identification and treatment of decreased cerebral perfusion. We believe protocols aimed at detecting and reversing CDE may improve patient safety.