Chemical Paralysis Research Articles

Relationship Between Muscle Strength Pattern, Facial Wrinkles Classification and Dose of Botulinum Toxin Serotype-A

Background: Botulinum toxin type A (BoNT-A) primarily acts by inhibiting the release of acetylcholine from the presynaptic terminal, resulting in reversible chemical paralysis of muscles. It is a widely accepted treatment for improving the appearance of glabellar expression lines that develop due to muscle contraction. Method: The glabellar force patterns, facial wrinkle classification, and a number of BoNT-A units used in the corrugator and procerus muscles were evaluated. Results: The mean total units of BoNT-A used were 7.2U in the corrugator muscle (7.1U in women and 7.4U in men) and 3.9U in the procerus muscle (3.9U in women and 4.1U in men), with a positive correlation between the number of units used and the age of the 58 participants. Regarding muscle strength pattern, more units were used in the corrugator muscle with a strong pattern and facial wrinkle classification of 3-4 and moderate with the same wrinkle classification (8U and 8.5U, respectively). In the procerus muscle, more units were used in the strong force pattern with wrinkles classified as 3-4 (5U). Wrinkles classified as 3-5 required the highest number of BoNT-A units. Conclusion: The quantity of BoNT-A units used is directly proportional to the strength pattern and classification of facial wrinkles, with more units required when a strong force pattern and deep wrinkle classification are observed.

The impact of the COVID-19 pandemic on ICU clinical trials: a description of one research team’s experience

BackgroundDisruptions to clinical trials conducted in the intensive care unit (ICU) due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2; coronavirus disease 2019 [COVID-19]) pandemic included fewer new trials activated and more trials stopped. While a number of ongoing, non-COVID-19 clinical trials remained open to enrollment, the direct impact of the pandemic on ICUs instilled chaos in this already challenging environment. The numerous challenges need to be reported so investigators can proactively plan and manage these myriad challenges. Thus, the purpose of this study was to describe the impact of the COVID-19 pandemic on screening and accrual for a non-COVID-19 parent clinical trial enrolling critically ill ICU patients receiving mechanical ventilatory support.MethodsA descriptive, retrospective design using quantitative data from detailed screening logs and qualitative observations with field notes from a parent clinical trial were used to address the objectives. The primary aims of the two-site parent clinical trial (n = 190) are to test the efficacy of self-administration of sedative therapy by mechanically ventilated ICU patients on anxiety and delirium occurrence. ICUs from two academic medical centers [names removed for blinding] plus a community hospital in Minnesota were screened daily for alert patients (Richmond Agitation Sedation Scale [RASS] − 2 to + 1), following commands, hemodynamically stable with sufficient hand grip strength to depress a push-button device. Screening data were summarized based on the primary reason patients were not enrolled (screen failures, declinations of consent). Descriptive statistics (frequencies, percentages), chi-square, and Fisher’s Exact test were used to describe the data and to determine any differences among distributions of screening failures and recruitment declinations during the defined pre-pandemic (August 27, 2018–March 15, 2020, 2976 screened patients) and pandemic timeframes (March 16, 2020–February 28, 2022, 3912 screened patients). Qualitative data from varied sources such as screening logs, institutional email communications, staff field notes, and research team meeting minutes were summarized into themes.ResultsDespite significantly fewer screen failures due to hypotension, cognitive impairment/dementia, coma, or chemical paralysis with 938 additional patients on the screening log, more were accrued pre-pandemic (n = 55) than during the pandemic period (n = 45); declination reasons were non-significant. Pandemic burdens experienced by study personnel, ICU care providers, and patients/families were revealed that attributed to decreased accrual.ConclusionsWhile the parent clinical trial remained opened, cumulative factors adversely impacted the trial during the pandemic period with fewer patients accrued. The human toll of the pandemic on research staff, clinicians, and patients/family members demands that investigators be proactive in managing these challenges to conduct ICU clinical trials successfully, including careful oversight of human and financial resources.Trial registrationClinicalTrials.gov NCT#02,819,141 Registered 29 June 2016.

Robotic-assisted Bronchoscopy and Cone-beam CT: A Retrospective Series.

Robotic-assisted Bronchoscopy and Cone-beam CT: A Retrospective Series.

Physical Therapy and Sedation While on Extracorporeal Membrane Oxygenation for COVID-19–Associated Acute Respiratory Distress Syndrome

ObjectivesThis study aimed to determine whether patients on extracorporeal membrane oxygenation (ECMO) with coronavirus disease 2019 (COVID-19) achieved lower rates of physical therapy participation and required more sedation than those on ECMO without COVID-19.DesignRetrospective, observational, matched-cohort study.SettingBicenter academic quaternary medical centers.ParticipantsAll adults on ECMO for severe COVID-19-associated acute respiratory distress syndrome (ARDS) during 2020 and matched (matched 1:1 based on age ± 15 years and medical center) adults on ECMO for ARDS not associated with COVID-19.InterventionsObservational only.Measurements and Main ResultsMeasurements were collected retrospectively during the first 20 days of ECMO support and included daily levels of physical therapy activity, number of daily sedation infusions and doses, and level of sedation and agitation (Richmond Agitation and Sedation Score). During the first 20 days of ECMO support, the 22 patients who were on ECMO for COVID-19–associated ARDS achieved a similar proportion of days with active physical therapy participation while on ECMO compared to matched patients on ECMO for non-COVID-19 ARDS (22.5% v 7.5%, respectively; p value 0.43), a similar proportion of days with Richmond Agitation and Sedation Score ≥-2 while on ECMO (47.5% v 27.5%, respectively; p value 0.065), and a similar proportion of days with chemical paralysis while on ECMO (8.4% v 18.0%, respectively; p value 0.35).ConclusionsThe results of this matched cohort study supported that sedation requirements were not dramatically greater and did not significantly limit early physical therapy for patients who had COVID-19–associated ARDS and were on venovenous extracorporeal membrane oxygenation (VV-ECMO) versus those without COVID-19–associated ARDS who were on VV-ECMO.

Right heart failure with left ventricular assist device implantation in children: An analysis of the Pedimacs registry database

The use of ventricular assist device (VAD) in children has increased, but the decision of left VAD (LVAD) vs biventricular support remains a challenge. Children who undergo LVAD placement are at risk for right ventricular failure (RHF), but the incidence has not been described. Analysis was performed for patients <18 years old who underwent durable LVAD placement within the Pedimacs registry (September 19, 2012-February 28, 2017), excluding single ventricle morphology and temporary devices. RHF was defined as the need for right ventriculalr assist device (RVAD) or prolonged inotrope use between 1 week to 1 month and 1 to 3 months. End-points included death, heart transplant (HT), and recovery. A total of 272 durable LVAD were placed of which 37 died on device over 24 month follow-up, primarily from multiorgan failure and neurologic dysfunction. RVAD occurred in 12 children at median 8.5 days, with 9 undergoing HT and 3 dying on device. In patients with only LVAD, RHF was present in 111/207 (55%) between 1 week to 1 month and 28/116 (25%) between 1 and 3 months. Younger age, smaller weight, Intermacs profile 1, chemical paralysis, and pulsatile flow VAD were associated with RHF. RHF was associated with increased risk of death on device at both >1 month (hazard ratio 3.2, 95% CI 1.4-7.7, p = 0.007) and >3 month (hazard ratio 6.9, 95% CI 2-23.1, p = 0.002). In children, RHF is common after durable LVAD implantation, but subsequent RVAD is relatively rare. RHF in children, as indicated by prolonged inotrope support, was associated with an increased risk of death on the device. Whether early RVAD support and higher waitlist status may improve the outcome remains unknown.

Sedation and paralytic use in open abdomen patients—results from the EAST SLEEP Survey

BackgroundPatients with an open abdomen after trauma or emergency surgery may benefit from reduced sedation and chemical paralysis. We studied the effect of attending surgeon experience on sedation depth and paralytic use, as well as enteral nutrition and time between laparotomies. MethodsWe performed an institutional review board-approved survey (Sedation Level after Emergent ExLap without Primary Fascial Closure) of the senior and active Eastern Association for the Surgery of Trauma membership using Qualtrics (Qualtrics, Inc, Provo, UT). We obtained 393/1,655 responses (23.7%). Spearman’s rho was used for ordinal data, and multivariate logistic regression was used to adjust for trauma center level and presence of trainees in the relationship between surgeon experience and use of deep sedation. ResultsSurgeon experience was associated with deep sedation (Richmond Agitation and Sedation Score ≤–3, P = .001) and chemical paralysis (P = .001). Surgeon experience was associated with less concern about delirium and more concern for evisceration as the reason for sedation depth (P = .001) and for paralysis (P = .001). Using multivariate logistic regression, surgeon experience was associated with deep sedation (odds ratio 3.6 [95% confidence interval 1.3, 10.4], P = .017 for ≥20 years; odds ratio 3.5 [95% confidence interval 1.1, 10.4], P = .025 for 15–20 years). Trauma center level was also significant (odds ratio 7.2 for Richmond Agitation and Sedation Score ≤–3 [95% confidence interval 1.7, 31.0], P = .008 for level III/IV versus level I/II). Increased surgeon experience was associated with delay of commencement of enteral feeds until return of bowel function (P = .013). Few respondents indicated willingness to extubate or mobilize open abdomen patients. Experienced surgeons were likely to wait for a defined time rather than for normalization of resuscitation markers to perform the first takeback laparotomy (P = .047) and waited longer between subsequent laparotomies (P = .004). ConclusionThere were significant variations in practice among respondents based on the length of time since their last residency or fellowship, including variations that deviate from current best practice for management of patients with an open abdomen.

Effect of Neuromuscular Blocking Agents on Sedation Requirements in Trauma Patients with an Open Abdomen.

The appropriate level of sedation in patients with an open abdomen following damage control laparotomy (DCL) is debated. Chemical paralysis with neuromuscular blocking agents (NMBAs) has been used to decrease time to abdominal closure. We sought to evaluate the effect of NMBA use on sedation requirements in patients with an open abdomen and to determine the effect of sedation on patient outcomes. A retrospective cohort study was conducted at an American College of Surgeons' verified level 1 trauma center. Adult trauma patients who underwent DCL between 2009 and 2015 were included. Patients with an intensive care unit length of stay of less than 48hours and those who died before abdominal closure were excluded. The NMBA+ group received continuous NMBA within 24hours of DCL; the NMBA- group did not. The primary outcome was cumulative sedation dose during the 7days following DCL. Secondary outcomes included Richmond Agitation-Sedation Scale (RASS) score, mechanical ventilation-free days, and delirium-coma-free days. Delirium-coma-free days were analyzed with linear regression. A total of 222 patients were included (NMBA+ 125; NMBA- 97). Demographics were similar between groups including age, Injury Severity Score, and mechanism of injury. The median time to closure in the overall cohort was 2days (interquartile range [IQR] 1-2days). Propofol and fentanyl were the primary sedatives used. The NMBA+ group received higher cumulative doses of propofol (NMBA+ 5405mg, IQR 3103-10,573mg; NMBA- 3601mg, IQR 1605-6887mg; p=0.007), but not of fentanyl. Time to abdominal closure, but not NMBA use, was associated with a higher cumulative propofol dose on multivariate analysis. The NMBA+ group had significantly lower RASS scores on the first 3days following DCL. Mechanical ventilation-free days (NMBA+ 20days vs NMBA- 18days, p=0.960) and delirium-coma-free days (NMBA+ 18days vs NMBA- 18days, p=0.610) were similar between the groups. On linear regression, cumulative propofol dose was associated with fewer delirium-coma-free days (β-coefficient -0.007, 95% confidence interval -0.015 to -0.003). In trauma patients managed with DCL, higher cumulative sedative doses were administered in patients who received adjunctive NMBA, although NMBA therapy was not associated with a higher cumulative propofol dose on multivariate analysis. Consideration must be given to the potential effect of sedation on delirium and awakening following DCL.

Respiratory failure requiring mechanical ventilation in critically ill adults in Ghana: A prospective observational study.

IntroductionRespiratory failure is commonly seen in African emergency centres and intensive care units, but little is known about the need for intubation and mechanical ventilation.MethodsFrom April to October 2017, we recorded the number of patients intubated and ventilated in the emergency centre and intensive care unit at Komfo Anokye Teaching Hospital in Kumasi, Ghana on a daily basis. We assessed patients for presence of acute respiratory distress syndrome (ARDS) using the Kigali Modification of the Berlin ARDS criteria. ARDS patients were re-assessed daily.ResultsDuring the study period, 102 patients were intubated, of which 82 were assessed by the study team. The remaining 20 patients died before they could be assessed. Two (2.4%) patients were identified as having ARDS, and both died. Neither was treated with prone positioning or chemical paralysis. It is possible that many of the patients who died before an assessment suffered from ARDS, considering its associated high mortality, and thus the true incidence of ARDS may have been higher.ConclusionRespiratory failure requiring intubation and mechanical ventilation is common in patients presenting to the emergency centre or intensive care unit at an academic tertiary care centre in Ghana. The true incidence of ARDS was likely underestimated by our study.

PS01.092: FOKER GROWTH INDUCTION FOR LONG GAP ESOPHAGEAL ATRESIA: WHAT WE HAVE LEARNED

Abstract Background The Foker process is used in patients with long-gap esophageal atresia (LGEA) to maintain the native esophagus; however, chemical paralysis, used to ‘protect’ the esophagus, is associated with complications and longer hospital stays. The purpose of this study was to identify changes in practice patterns with increased Foker experience, and to review the relationship of paralysis time with the incidence of esophageal leaks and need for stricture resections. Methods A retrospective review of LGEA patients from January 2006 to December 2016 was performed. Patients were excluded if they had previous attempts elsewhere. Patients were initially divided into two groups: early group (surgery before 2013) and late group (2013–2016) to assess outcomes. All patients, irrespective of surgery date, were then divided into three subgroups based on esophageal anastomotic tension. Logistic regression with odds ratio (OR) and 95% confidence interval (CI) was used to assess risk of leaks and need for stricture resection. Results Fifty-eight patients met criteria, and demographics were similar between groups. The late group required significantly fewer surgeries between Foker I and Foker II and had shorter ICU length of stay (LOS). Variables that trended towards statistical significance included total length of paralysis, time between Foker I and Foker II, and total hospital LOS. Overall, 18 patients developed a leak, and 13 required stricture resections. There was no correlation between paralysis time or anastomotic tension with incidence of leak or stricture resection. Multivariable analysis indicated that the occurrence of a leak (OR 5.7, 95% CI: 1.4–27.3, P = 0.025) and need for &gt; 8 dilations (OR 11.0, 95% CI: 2.3–53.4, P = 0.002) were significant predictors of need for stricture resection. Conclusion As our experience has grown, the need for multiple procedures between Foker I and Foker II has decreased, leading to less paralytic exposure, shorter ICU LOS, and trending toward decreased hospital LOS. By verifying that specified paralysis times are not required, we can continue to mitigate complications associated with lengthy paralysis times and longer hospital admissions without risking esophageal health. Disclosure All authors have declared no conflicts of interest.

The Effect of Adipose-derived Mesenchymal Stem Cells on Healing of Massive Chronic Rotator Cuff Tear in Rodent Model

Objectives:Mesenchymal stem cells (MSCs) may promote restoration of the structure and function of the injured tendon-bone interface of the healing rotator cuff following repair. As compared to acute tears, chronic massive rotator cuff tears are a challenging healing microenvironment, with degenerative changes present in the muscle, tendon, and bone. Therefore, the purpose of this study was to explore the efficacy of MSCs in restoring the tendon-bone interface following repair of massive chronic rotator cuff tears in a rodent model.Methods:Adipose-derived mesenchymal stem cells (ADSCs) were isolated from inguinal fat of adult Lewis rats (n= 8) and expanded to passage 2 (P2). To induce degenerative changes in a rat modeling a massive chronic rotator cuff tear, the supraspinatus and infraspinatus tendons were transected bilaterally near their bony insertion and the corresponding muscle bellies were injected with 2.5 U botulinum toxin A (botox). Eight weeks later, tendons were repaired with or without augmentation at the tendon-bone interface. In particular, there were 5 groups ; (1) no repair (defect), (2) repair, (3) repair + fibrin, (4) repair + fibrin + ADSCs, (5) repair + fibrin + ADSCs + TGF-β3 (n=12 shoulders per condition). An equivalent cohort of animals received acute tendon transection (without botox injection) and immediate repair with or without augmentation. At 4 weeks following repair, animals were euthanized and the shoulders were harvested for analysis of bone morphometry, histology, and mechanical properties. Bone morphometry of the humeral head including; bone mineral density, bone volume percentage, and trabeculae number, thickness, and spacing was determined using micro-computed tomography. Statistical analyses included 2-way ANOVA with Tukey post-hoc tests. Analyses of histology and mechanical properties are ongoing.Results:ADSCs at P2 demonstrated a spindle-shaped morphology and were capable of forming colonies (Fig. 1A) and undergoing trilineage differentiation (Fig. 1B). Compared to healthy and acutely injured shoulders, muscles in the chronic condition exhibited atrophy, fibrosis, and fatty infiltration, with corresponding reductions in wet weights (Fig. 1C). All groups in the acute and chronic conditions possessed significantly reduced bone mineral density and bone volume percentage compared to healthy controls (p < 0.05), while only groups in the chronic condition exhibited compromised trabecular number and spacing. (p < 0.05). Augmentation of repairs with ADSCs (with or without TGF-β3) in the chronic condition significantly increased bone mineral density over defect controls (p < 0.05).Conclusion:Two-tendon transection and chemical paralysis of rotator cuff muscles in a rodent model mimics the degenerative changes seen in human shoulders, including decrements in bone quality. The efficacy of ADSCs in restoring structure and function of the tendon-bone interface likely depends on tear chronicity and size and may have greater benefit in chronic tears, as suggested by improvements in parameters of bone morphometry. This study will help further clarify the involvement of adult stem cell therapy in enhancing healing of the rotator cuff enthesis in the setting of degenerative tissue. Future studies would investigate the potential of adult stem cells to promote muscle regeneration in chronic rotator cuff tears and augment structural healing at the enthesis.

Architectural and biochemical adaptations in skeletal muscle and bone following rotator cuff injury in a rat model.

Injury to the rotator cuff can cause irreversible changes to the structure and function of the associated muscles and bones. The temporal progression and pathomechanisms associated with these adaptations are unclear. The purpose of this study was to investigate the time course of structural muscle and osseous changes in a rat model of a massive rotator cuff tear. Supraspinatus and infraspinatus muscle architecture and biochemistry and humeral and scapular morphological parameters were measured three days, eight weeks, and sixteen weeks after dual tenotomy with and without chemical paralysis via botulinum toxin A (BTX). Muscle mass and physiological cross-sectional area increased over time in the age-matched control animals, decreased over time in the tenotomy+BTX group, and remained nearly the same in the tenotomy-alone group. Tenotomy+BTX led to increased extracellular collagen in the muscle. Changes in scapular bone morphology were observed in both experimental groups, consistent with reductions in load transmission across the joint. These data suggest that tenotomy alone interferes with normal age-related muscle growth. The addition of chemical paralysis yielded profound structural changes to the muscle and bone, potentially leading to impaired muscle function, increased muscle stiffness, and decreased bone strength. Structural musculoskeletal changes occur after tendon injury, and these changes are severely exacerbated with the addition of neuromuscular compromise.

Application and Clinical Utility of the Glasgow Coma Scale Over Time

To examine possible changes in Glasgow Coma Scale (GCS) scores related to changes in emergency management, such as intubation and chemical paralysis, and the potential impact on outcome prediction. 10 228 patients from the Traumatic Brain Injury Model Systems national database. Retrospective study examining 5-year epochs from 1987 to 2012. GCS score assessed in the Emergency Department (GCS scores for intubated, but not paralyzed, patients were estimated with a formula using 2 of the 3 GCS components), Outcome: Functional Independence Measure (FIM) assessed at rehabilitation admission. The rate of intubation prior to GCS scoring averaged 43% and did not increase across time. However, a clear increase over time was observed in the use of paralytics or heavy sedatives, with 27% of patients receiving this intervention in the most recent epoch. Estimated GCS scores classified 69% of intubated patients as severely brain injured and 8% as mildly injured. The GCS accounted for a modest, yet consistent, amount of variability (approximately 5%-7%) in FIM scores during most epochs. Given the frequency of intubation and/or paralysis following brain injury in this sample, estimating GCS or exploring other means to gauge injury severity is beneficial, particularly because a portion likely did not sustain severe brain injury. There is no evidence for declining predictive utility of the GCS over time.

Abdominal Compartment Syndrome and Acute Kidney Injury Due to Excessive Auto–Positive End-Expiratory Pressure

Abdominal compartment syndrome is an under-recognized cause of acute kidney injury in critically ill patients. We report a case of a patient with severe obstructive lung disease who, while intubated for respiratory failure, developed abdominal compartment syndrome and oliguric acute kidney injury due to air-trapping and excessive auto-positive end-expiratory pressure (auto-PEEP; also known as intrinsic PEEP). When chemical paralysis was initiated and the auto-PEEP resolved, the patient's intra-abdominal hypertension rapidly improved and kidney function recovered immediately. Abdominal compartment syndrome secondary to excessive auto-PEEP appears to be unreported in the literature; however, any process that significantly increases intrathoracic pressure conceivably could cause increased pressure to be transmitted to the abdominal compartment, resulting in organ failure. Patients undergoing mechanical ventilation, which puts them at risk of airflow obstruction and the development of intra-abdominal hypertension, should be evaluated for air-trapping and excessive auto-PEEP.

Using the Abbreviated Injury Severity and Glasgow Coma Scale Scores to Predict 2-Week Mortality After Traumatic Brain Injury

Prediction of outcome after traumatic brain injury (TBI) remains elusive. We tested the use of a single hospital Glasgow Coma Scale (GCS) Score, GCS Motor Score, and the Head component of the Abbreviated Injury Scale (AIS) Score to predict 2-week cumulative mortality in a large cohort of TBI patients admitted to the eight U.S. Level I trauma centers in the TBI Clinical Trials Network. Data on 2,808 TBI patients were entered into a centralized database. These TBI patients were categorized as severe (GCS score, 3-8), moderate (9-12), or complicated mild (13-15 with positive computed tomography findings). Intubation and chemical paralysis were recorded. The cumulative incidence of mortality in the first 2 weeks after head injury was calculated using Kaplan-Meier survival analysis. Cox proportional hazards regression was used to estimate the magnitude of the risk for 2-week mortality. Two-week cumulative mortality was independently predicted by GCS, GCS Motor Score, and Head AIS. GCS Severity Category and GCS Motor Score were stronger predictors of 2-week mortality than Head AIS. There was also an independent effect of age (<60 vs. ≥60) on mortality after controlling for both GCS and Head AIS Scores. Anatomic and physiologic scales are useful in the prediction of mortality after TBI. We did not demonstrate any added benefit to combining the total GCS or GCS Motor Scores with the Head AIS Score in the short-term prediction of death after TBI.

Nursing Considerations for Children Undergoing Delayed Sternal Closure After Surgery for Congenital Heart Disease

Nursing Considerations for Children Undergoing Delayed Sternal Closure After Surgery for Congenital Heart Disease

Prolonged Hypothermia as a Bridge to Recovery for Cerebral Edema and Intracranial Hypertension Associated with Fulminant Hepatic Failure

To review evidence-based treatment options in patients with cerebral edema complicating fulminant hepatic failure (FHF) and discuss the potential applications of hypothermia. Case-based observations from a medical intensive care unit (MICU) in a tertiary care facility in a 27-year-old female with FHF from acetaminophen and resultant cerebral edema. Our patient was admitted to the MICU after being found unresponsive with presumed toxicity from acetaminophen which was ingested over a 2-day period. The patient had depressed of mental status lasting at least 24 h prior to admission. Initial evaluation confirmed FHF from acetaminophen and cerebral edema. The patient was treated with hyperosmolar therapy, hyperventilation, sedation, and chemical paralysis. Her intracranial pressure remained elevated despite maximal medical therapy. We then initiated therapeutic hypothermia which was continued for 5 days. At re-warming, patient had resolution of her cerebral edema and intracranial hypertension. At discharge, she had complete recovery of neurological and hepatic functions. In patients with FHF and cerebral edema from acetaminophen overdose, prolonged therapeutic hypothermia could potentially be used as a life saving therapy and a bridge to hepatic and neurological recovery. A clinical trial of hypothermia in patients with this condition is warranted.

Fracture of a Reverse Total Shoulder Arthroplasty Retentive Liner

Reverse shoulder arthroplasty may be indicated in shoulders that cannot be effectively managed by conventional reconstruction procedures. Reported complications include instability, infection, hematoma, scapular notching, and premature component loosening. To our knowledge, however, fracture of a humeral component polyethylene inlay has not been described. A 72-year-old man presented with unstable, painful shoulders after undergoing unsuccessful open repairs and acromioplasties at an outside institution for bilateral massive rotator cuff tears. We performed a left reversed shoulder arthroplasty with a 36-mm glenosphere and a +9-mm polyethylene liner. In the operating room under general anesthesia with chemical paralysis and an interscalene block, his shoulder was stable. The patient required revision with a metal 9-mm lateralizer following an atraumatic dislocation 4 weeks postoperatively. Four weeks following the revision, the patient again presented with a dislocated left shoulder without antecedent trauma. During this second revision, the +6-mm standard polyethylene liner was replaced with a +6-mm lateral retentive polyethylene liner. A third revision surgery was performed after the patient experienced 2 more dislocations with minor activity. Intraoperatively, a fracture of the previously placed +6-mm retentive polyethylene liner was noted. This article may represent a case of dramatic scapular impingement by the humeral components. More subtle forms of scapular notching are common and may suggest significant long-term problems. Many reverse shoulder prostheses are being refined or modified in an attempt to eliminate or reduce the scapular notching phenomenon.

Structural Aging: The Facial Recurve Concept

During the remaining three-fourths of a century that followed the introduction of the modern face-lift by Bettman in 1920, the dominant theory of facial aging remained soft tissue descent under gravity, abetted by senescent loss of skin support, turgor, and elasticity. The paranasal soft tissue redundancy at the nasolabial fold became the key marker for facial aging, and its effacement the key yardstick for measuring success in facial rejuvenation. By the 1990s, deeper soft tissues were added to the targeted list for resuspension, particularly the socalled ‘‘malar fat pad,’’ as first pursued by Hamra, but named and popularized by Owsley. Others broadened the target to include the entire midface. After Chajchir s introduction of effective and reliable fat transfer by the injection technique, Coleman, who expanded upon and codified the concept, added to the prevailing aging theory of descent his fin-de-siecle theory of soft tissue volume attrition through atrophy. Whereas the vast majority of plastic surgeons (including myself) continued to regard gravitational descent as the primary factor in facial aging, some (including myself) came to regard volume attrition and loss the more important factor in at least the periorbital zone. In any case, soft tissue facial augmentation, whether by fat addition, fat transfer, or nonautologous means, has become an important adjuvant to suspensory techniques. Now 7 years into the new century, LeLouran and colleagues would have us believe there is a third and more dominant force at work, as they present their theory of facial aging based on mimetic muscle activity. Specific facial muscles or muscle segments (‘‘age marker fascicules,’’ they call them) through their frequent and powerful contractions eject their underlying deep fat pads into superficial locations as they themselves flatten and shorten, developing increased muscle tone at rest and diminished amplitude of contraction over time. Only then, the authors reason, does gravity begin its work on these superficial ectopic fat deposits of age, abetting the structural aging we recognize in the jowl, the nasolabial and marionette lines, the tear trough, and the upper orbital hollow. It is no particular surprise that the predominant theory of aging focused so long on the gravitational descent of skin and soft tissue alone. From the time of Madam Noel and before, such soft tissue redundancy was the obvious marker for facial aging. Nor is it surprising that Hamra, stimulated by Skoog as he delved ever deeper into more invasive mobilizations of the facial soft tissues, would come to advocate a need to resuspend deeper components of the facial mass. It also is not surprising that Coleman, having become adept at fat transfer by needle, would conclude that fatty volume loss is more critical in facial aging than fatty descent. Of course, it is equally unsurprising that LeLouran, an acknowledged master of chemical paralysis of the facial muscles for rejuvenation, would formulate an aging theory based on the actions of these muscles he understands so well. I find enormous value in the concepts that the authors propose and suspect they are correct in much of their analysis. Most important, their theory adds an engine for facial aging, a kinetic force with major energy implications. And although this surely is important in soft tissue aging, I am certain that it is even more important in a widely overlooked component of facial aging that they touch on only tangentially, that of bony aging. Pessa s radiologic investigations into such aging concluded that there is a maxillary and nasal spine retrusion in the face of zygomatic stability. Correspondence to J. William Little, M.D.; email: jwilliamlittle@erols.com Aesth. Plast. Surg. 31:754 756, 2007 DOI: 10.1007/s00266-006-0249-7

Traumatic Brain Injury in the Pediatric Population

Traumatic brain injury (TBI) is a common injury among children. Most TBIs are mild and do not require hospitalization. However, whether or not the patients require acute hospitalization, TBIs may have long-lasting consequences. There is little research on the nutrient needs of these patients, and recommendations are frequently based on data from adults with TBI. It is clear that calorie and protein needs are elevated with acute TBI. However, calorie needs are also decreased by therapies such as sedation, chemical paralysis, and barbiturate coma. Long-term calorie needs may be lower for "comatose" patients. Enteral feeding is preferred and possible for patients with TBI, though gastric feeding may be problematic in some patients. In the acute phase, patients with TBI can also have dysregulation of fluid and electrolyte balance, which may require alterations in nutrition care. Dysphagia is common after moderately severe TBI and requires a multidisciplinary approach for treatment. Future opportunities for research on pediatric TBI are numerous and may include ongoing clarification of macronutrient needs, as well as investigation into the roles of specific nutrients such as zinc, antioxidants, and anti-inflammatory compounds.

Sleep in Critically Ill Chemically Paralyzed Patients Requiring Mechanical Ventilation

To determine sleep characteristics in patients receiving mechanical ventilation who require a neuromuscular blocking agent (NMBA). Observational study. Adult medical ICU at a university hospital. Eighteen patients with respiratory failure requiring mechanical ventilation were classified into three groups based on medication regimen determined a priori: intermittent sedation (IS), continuous sedation (CS), or CS and an NMBA. Twenty-four-hour polysomnography was performed to determine sleep architecture and fragmentation. Measurement of severity of illness, laboratory indexes, patient-care interventions, and drug dosage were compared between groups, and the effects on sleep staging and fragmentation were analyzed. Sleep stages were scored manually using criteria of Rechtschaffen and Kales, as well as by a modified 50-muV voltage criteria for scoring delta activity. All patients demonstrated abnormal sleep architecture. In each group of patients, the total sleep time (TST) was > 10 h. There was no statistical difference in the delta activity between the two scoring methods; delta activity was increased in all groups: 32.9%, 49.6%, and 43.7% in the IS, CS, and CS/NMBA groups, respectively. Patients receiving NMBAs spent 22% of the sleep period awake. Rapid eye movement sleep could not be detected in the patients receiving NMBAs and was reduced in the other two groups (3.5%). TST, sleep stage, or arousal/awakening index were not statistically correlated with either severity of illness, clinical laboratory indexes, drug dosage, patient-care interventions, or mode of mechanical ventilation. TST during a 24-h period is not reduced in patients requiring mechanical ventilation. Delta activity is increased and may reflect age, drug, or a contributing metabolic process. The effect of wakefulness in patients receiving chemical paralysis on recovery and weaning from mechanical ventilation, and overall clinical outcome is unknown.