Quantification of Straylight Induced by Silicone Oil Adherent to Intraocular Lenses of Different Materials.

PURPOSE: A complication of using silicone oil as an intraocular endotamponade is its adhesion to intraocular lenses (IOLs). Forward light scattering is a measure to quantify the optical disturbance caused by adherent oil droplets. We tested the straylight caused by silicone oil adhesion to different IOLs and examined whether an approved cleaning solution, F4H5, reverses the induced straylight. DESIGN: An experimental study. METHODS: Two hydrophobic acrylic IOL models and 1 hydrophilic model with a hydrophobic surface (n = 8 per model: 24 lenses) had straylight measured before contact with silicone oils, providing a baseline for subsequent testing: 12 lenses with lighter-than-water silicone oil (Siluron 2000) and 12 with heavier-than-water oil (Densiron 68). The final measurement was performed after cleansing with F4H5 when we used scanning electron and light microscopy to detect surface changes. RESULTS: Straylight was majorly increased in IOLs with adherent silicone oil (baseline vs adherent oil median 3.1 [2.1, 3.9] and 39.7 [22.7, 87.8] deg2/sr, respectively; P < .001). No difference was seen between heavier- and lighter-than-water silicone oils. Between IOL types, induced straylight varied significantly, with 1 hydrophobic model reaching the highest average straylight. F4H5 significantly reduced straylight values in all IOL types (median 9.4 [5.4, 13.8] deg2/sr). The microscopy revealed surface changes on the IOLs even after cleaning. CONCLUSIONS: Silicone oil adhesion to IOLs can induce amounts of straylight known to cause severe optical disturbance. F4H5 cleansing solution reversed straylight values to only slightly increased values. We found no difference in straylight formation between the lighter- and heavier-than-water silicone oils.

Forward Light Scattering of First to Third Generation Vitreous Body Replacement Hydrogels after Surgical Application Compared to Conventional Silicone Oils and Vitreous Body.

To treat certain vitreoretinal diseases, the vitreous body, a hydrogel composed of mostly collagen and hyaluronic acid, must be removed. After vitrectomy surgery, the vitreous cavity is filled with an endotamponade. Previously, pre-clinical hydrogel-based vitreous body substitutes either made from uncrosslinked monomers (1st generation), preformed crosslinked polymers (2nd generation), or in situ gelating polymers (3rd generation) have been developed. Forward light scattering is a measure of Stray light induced by optical media, when increased, causing visual disturbance and glare. During pinhole surgery, the hydrogels are injected into the vitreous cavity through a small 23G-cannula. The aim of this study was to assess if and to what extent forward light scattering is induced by vitreous body replacement hydrogels and if Stray light differs between different generations of vitreous body hydrogel replacements due to the different gelation mechanisms and fragmentation during injection. A modified C-Quant setup was used to objectively determine forward light scattering. In this study, we found that the 1st and 3rd generation vitreous body replacements show very low stray light levels even after injection (2.8 +/- 0.4 deg2/sr and 0.2 +/- 0.2 deg2/sr, respectively) as gel fragmentation and generation of interfaces is circumvented. The 2nd generation preformed hydrogels showed a permanent increase in stray light after injection that will most likely lead to symptoms such as glare when used in patients (11.9 +/- 0.9 deg2/sr). Stray light of the 2nd generation hydrogels was 3- and 2-fold increased compared to juvenile and aged vitreous bodies, respectively. In conclusion, this significant downside in the forward light scattering of the 2nd generation hydrogels should be kept in mind when developing vitreous body replacement strategies, as any source of stray light should be minimized in patients with retinal comorbidities.

New approaches to explanting high-viscosity silicone oil in retinal surgery-polyimide cannulas vs extraction sleeves vs a luer-trocar.

BACKGROUND: The removal of high-viscosity silicone oil in retinal surgery is time-intensive. In this laboratory and porcine eye study, we evaluated the efficiency of novel extraction techniques, namely shortened polyimide-cannulas, an extraction sleeve and an experimental luer-trocar system, for commercially available silicone oils. METHODS: The volume of silicone oil after a 5-min removal time was quantified. The feasibility of all studied techniques was additionally tested in vitrectomized porcine eyes. Siluron 1000, 2000, 5000 and Xtra, as well as Densiron 68 and Densiron Xtra were examined. RESULTS: Shortening the 23G-polyimide-cannula from 6 mm up to 1.5 mm led to a significantly higher mean aspirated volume (e.g., 1 ml/min to 1.7 ml/min for Siluron Xtra). The extraction sleeve and luer-trocar increased the flow threefold compared to the shortest polyimide cannulas at 23G (5.2 ml/min and 5.2 ml/min vs 1.7 ml/min for Siluron Xtra, respectively). The extraction sleeve and luer-trocar system reached a similar flow at 27G as the best performing 23G-cannula. Angulation and movement of the eye was possible with the 2 mm-cannula, no angulation was possible when using the extraction sleeve. Stability and control were not impaired with the experimental luer-trocar setup. CONCLUSION: Shorter polyimide-cannulas and extraction sleeves increase the extraction flow but may decrease stability during surgery. The luer-trocar system facilitates rapid removal while offering great stability and control. Small 27G silicone oil removal is possible and time efficient.

Intravitreal Application: Physicochemical Properties of Drugs Dissolved in Silicone Oils of Different Density in Comparison to the Porcine Vitreous Body.

Silicone oil endotamponades provide a reservoir for drugs in the eye. Following vitrectomy surgery to treat retinal detachments, extensive diabetic retinopathy or endophthalmitis, they can be used as long-term lipophilic depots. This study aimed to investigate the physicochemical properties of intravitreally applied drugs of different lipophilicity, namely vancomycin, ceftazidime and voriconazole. For this purpose, an in vitro model of the silicone-oil-filled eye compared to porcine vitreous bodies (PVBs) was used. In a glass container, either light or heavy silicone oil or PVB was set into equilibrium with an aqueous fluid. Vancomycin, voriconazole and ceftazidime were added in concentrations commonly applied in clinical practice. The time course of the concentration of the drugs was determined in the hydrophilic phase for up to 24 h. With silicone oil present, the concentrations of vancomycin, voriconazole and ceftazidime were elevated in the aqueous humor when compared to the vitreous body (p < 0.001 for all drugs). With increasing lipophilicity, higher concentrations of the drug dissolved in silicone oil after 24 h (52.7%, 49.1% and 34.3% for vancomycin, ceftazidime and voriconazole, respectively). While no difference between lighter- and heavier-than-water silicone oil was apparent for vancomycin and ceftazidime (p = 0.17 and p = 0.72), voriconazole dissolved significantly better in the heavier-than-water silicone oil (p = 0.002). A higher-than-expected percentage of the glycopeptide vancomycin dissolved in the porcine vitreous body, possibly due to protein binding. In conclusion, silicone oils influence the drug concentration and distribution of intravitreally applied drugs depending on their lipophilicity. The addition of F6H8 used to create heavy silicone oils attenuates these effects for lipophilic drugs. Knowledge of the distribution of these intravitreally applied drugs is crucial to ensure the desired anti-infectious effect.

Physicochemical Properties of Explanted Silicone Oil After Use as an Intraocular Tamponade.

PURPOSE: We studied the effects of exposure to biological media within the eye, such as contamination with lipophilic and amphiphilic substances, on the physicochemical parameters of silicone oil used as an intraocular tamponade. METHODS: We removed silicone oil with visible emulsification from 15 patients and measured each sample for shear viscosity and surface tension. We induced in vitro emulsification with balanced salt solution. Using the zeta-potential, we evaluated the emulsion droplet's electrochemical stability. We repeated all experiments in a control group of unused oil. Electrochemical stability and viscosity were additionally measured in oils with high-molecular-weight components. RESULTS: We recovered silicone oils implanted between 30 and 506 days (mean, 196 days). Viscosity did not differ between explanted and control groups. Surface tension and zeta potential remained unchanged (P = 0.61 and P = 0.84, respectively). All oils showed a significant correlation of viscosity with temperature (P < 0.01 for all). Oils with added high-molecular-weight components showed a lower emulsion stability. CONCLUSIONS: Prolonged contact to hydrophilic biological media does not alter high-viscosity silicone oil's physicochemical parameters. During typical durations of intraocular use, lipophilic and amphiphilic molecules had no deleterious effect. The addition of high-molecular-weight components might decrease the silicone oil's electrochemical emulsion stability, possibly easing the confluence of emulsion droplets. TRANSLATIONAL RELEVANCE: Although the physicochemical parameters of silicone oils are not altered after clinically relevant durations within the eye, emulsion stability significantly differs between oil types.

THE NOVEL USE OF HIGH-FLOW POLYIMIDE CANNULAS TO IMPROVE SILICONE OIL INJECTABILITY IN VITREORETINAL SURGERY.

PURPOSE: The injection of high-viscosity silicone oil lengthens injection time. New polyimide cannulas offer a greater inner diameter than conventional metal cannulas at the same gauge. We compared the injection time for polyimide and metal cannulas at 23 G for a variety of silicone oils including a 12,500-mPas prototype oil. METHODS: In this laboratory study, injection time was measured three times per cannula and per oil. Warming the oil before injection to up to 42°C was also evaluated. Finally, the feasibility of polyimide cannulas was tested in vitrectomized porcine eyes. RESULTS: The 23-G polyimide cannula mostly decreased injection times. The time to inject 5 mL of Siluron Xtra and Siluron 5000 decreased by 6:02 (76.9%) minutes (483 vs. 121 seconds) and 12:01 (74.7%) minutes (973 vs. 252 seconds), respectively. Although the 23-G metal cannula failed to inject 12,500 mPas oil, 5 mL was injected in 10:21 minutes using the polyimide cannula. Prewarming Siluron 5000 to 42°C lowered the injection time by 9.0% and by 12.1% when using the metal or polyimide cannula, respectively. CONCLUSION: Polyimide cannulas allow a clinically relevant decrease in injection time. They may not only shorten surgery time but could also ease the use of next-generation ultra-high-viscosity silicone oils. Prewarming silicone oil leads to decreased injection times.

[Cataract surgery and the small eye: relative anterior microphthalmos, high hyperopia and nanophthalmos]. / Die Kataraktchirurgie und das kleine Auge: Relativer anteriorer Mikrophthalmus, hohe Hyperopie und Nanophthalmus.

Relative anterior microphthalmos, nanophthalmos and high-grade hyperopia are small eyes with different characteristic morphological relationships between the anterior segment and axis length. This article discusses the intraoperative challenges and surgical approaches to solutions for cataract operations in patients with one of the three named morphological alterations. Additionally, the article addresses possible comorbidities including glaucoma and preoperative planning.

Pupil dynamics after in-the-bag versus anterior and retropupillary iris-fixated intraocular lens implantation.

An Intraocular Lens (IOL) fixated on the iris either anteriorly, as a phakic IOL, or posteriorly, as an aphakic IOL, can influence pupil motility. In this interventional case series study, we evaluated pupil size under different levels of illumination (scotopic = 0.04 lx, low-mesopic = 0.4 lx and high-mesopic = 4 lx) for anterior iris-claw IOL fixation for correcting myopia or hyperopia (IFPH), retropupillary iris-claw IOL fixation to correct aphakia or as treatment for late in-the-bag IOL dislocation/subluxation (IFRP), and capsular-fixation IOL in-the-bag implantation (IB). Pupil size was measured preoperatively for the IFPH- and IB-group as well as 6 months after surgery for all groups. We analyzed a total of 70 eyes: 22 eyes of 11 patients with phakic IOLs, 22 eyes of 20 patients in the IFRP group and 26 eyes of 13 patients in the IB group. Both IFPH and IB showed a smaller postoperative scotopic pupil size, compared with the preoperative values. When compared to postoperative values of IB and IFPH, IFRP showed a significantly smaller postoperative scotopic pupil size (IFPH: 5.89 ± 0.83 mm, IFRP: 4.37 ± 0.83 mm, IB: 5.34 ± 0.98 mm, p < 0.001) while no differences were seen at high-mesopic lighting. Neither of the surgical techniques seems to impair the constriction of the pupil.

The association of nitrous oxide on length of stay in the postanesthesia care unit: a retrospective observational study.

PURPOSE: To assess whether intraoperative use of nitrous oxide (N2O) as an adjunct to general anesthesia is associated with a shorter length of stay in the postanesthesia care unit (PACU). METHODS: We analyzed data from adult patients who underwent non-cardiothoracic surgery under general anesthesia between May 2008 and December 2018. We assessed the association between intraoperative low- and high-dose N2O and PACU length of stay. RESULTS: A total of 148,284 patients were included in the primary analysis. After adjusting for a priori defined confounders, a high dose of N2O significantly decreased PACU length of stay, with a calculated difference of -9.1 min (95% confidence interval [CI], -10.5 to -7.7; P < 0.001). Patients who received high-dose N2O had a lower incidence of both short- and prolonged-duration of intraoperative hypotension (adjusted odds ratio [aOR], 0.85; 95% CI, 0.83 to 0.88; P < 0.001 and aOR, 0.76; 95% CI, 0.73 to 0.80; P < 0.001, respectively) and received a lower total intraoperative vasopressor dose (-0.04 mg of norepinephrine equivalents; 95% CI, -0.06 to -0.01; P = 0.01). The effect of high-dose N2O on PACU length of stay was modified by surgical complexity (adjusted absolute difference: -26.1 min; 95% CI, -29.2 to -23.1; P < 0.001; P for interaction < 0.001), and most pronounced in patients who underwent complex surgery and received intraoperative antiemetic therapy (adjusted absolute difference: -38.9 min; 95% CI, -43.1 to -34.6; P < 0.001; P for interaction < 0.001). CONCLUSIONS: Nitrous oxide was dose-dependently associated with a decreased PACU length of stay. The effect was clinically relevant (> 30 min difference) in patients who underwent complex surgical procedures and received intraoperative antiemetic therapy.

RéSUMé: OBJECTIF: L'objectif de cette étude était de déterminer si l'utilisation peropératoire de protoxyde d'azote (N2O) en complément à l'anesthésie générale était associée à une durée de séjour écourtée en salle de réveil (SDR). MéTHODE: Nous avons analysé les données de patients adultes qui ont subi une chirurgie non cardiothoracique sous anesthésie générale entre mai 2008 et décembre 2018. Nous avons évalué l'association entre une faible dose et une dose élevée de N2O peropératoire et la durée du séjour en SDR. RéSULTATS: Au total, 148 284 patients ont été inclus dans notre analyse primaire. Après ajustement tenant compte des facteurs de confusion définis a priori, une dose élevée de N2O a considérablement écourté la durée du séjour en salle de réveil, avec une différence calculée de −9,1 min (intervalle de confiance [IC] à 95 %, −10,5 à −7,7 ; P < 0,001). Chez les patients ayant reçu une dose élevée de N2O, l'incidence d'hypotension peropératoire de courte ou plus longue durée était plus faible (rapport de cotes ajusté [RCA], 0,85; IC 95 %, 0,83 à 0,88; P < 0,001 et RCA, 0,76; IC 95 %, 0,73 à 0,80; P < 0,001, respectivement); en outre, ces patients ont reçu une dose totale de vasopresseurs peropératoires inférieure (−0,04 mg d'équivalents de norépinéphrine; IC 95 %, −0,06 à −0,01; P = 0,01). L'effet d'une dose élevée de N2O sur la durée du séjour en SDR a été modifié par la complexité de la chirurgie (différence absolue ajustée : −26,1 min; IC 95 %, −29,2 à −23,1; P < 0,001; P pour l'interaction < 0,001), et était le plus prononcé chez les patients ayant subi une chirurgie complexe et reçu un traitement antiémétique peropératoire (différence absolue ajustée : −38,9 min; IC 95 %, −43,1 à −34,6; P < 0,001; P pour l'interaction < 0,001). CONCLUSION: Le protoxyde d'azote a été associé de façon dose-dépendante à une réduction de la durée du séjour en SDR. L'effet était cliniquement pertinent (différence > 30 minutes) chez les patients qui subissaient des interventions chirurgicales complexes et recevaient un traitement antiémétique peropératoire.

A Novel Approach for Assessing Visual Impairment Caused by Intraocular Lens Opacification: High-Resolution Optical Coherence Tomography.

PURPOSE: To quantify in vitro straylight induced by intraocular lens (IOL) localized opacification using an anterior segment optical coherence tomography (OCT) device. DESIGN: Laboratory investigation. METHODS: We obtained high-resolution OCT cross-section images of 44 explanted IOLs using a new in vitro application for an anterior segment OCT device, the Anterion (Heidelberg Engineering, Heidelberg, Germany). In 24 cases, the reason for IOL explantation was a centrally localized opacification, the sequela of a secondary ocular surgery. As a control, we used 20 IOLs removed after an IOL (sub-)luxation. Using image analysis, we found a threshold area value representing a metric for the amount of opacification in a region of interest in the IOL's central optic. We used a modified C-Quant straylight meter (Oculus, Wetzlar, Germany) to quantify light scattering. We derived a linear regression from calculating the correlation between the amount of opacification and straylight. RESULTS: We visualized different amounts of IOL opacification using the OCT device. The opacified lenses showed a mean threshold area of 6.7% ± 3.3% and mean straylight was 95.1 ± 75.6 deg2/sr. The clear group's mean threshold area was 2.0% ± 0.8% and 5.0 ± 3.4 deg2/sr mean straylight. Straylight correlated statistically significantly with the threshold area, with a correlation coefficient of R2 = 0.80, P < .001. CONCLUSIONS: This high-resolution OCT imaging technique can be used to visualize IOL opacities. The amount of opacification correlated well with the straylight induced by the lens. Anterior segment OCT imaging might be used in the future as a tool for predicting the extent of visual impairment and aid clinicians to quantify patients' complaints.

Effect of peripheral nerve blocks on postanesthesia care unit length of stay in patients undergoing ambulatory surgery: a retrospective cohort study.

BACKGROUND: Peripheral regional anesthesia and analgesia may increase the efficiency of ambulatory surgical centers by reducing pain and preventing nausea and vomiting, which are important modifiable causes of prolonged postanesthesia care unit (PACU) length of stay. We hypothesized that the use of peripheral nerve blocks (PNB) was associated with shorter PACU length of stay in ambulatory surgery. METHODS: In this retrospective cohort study, we analyzed data from adult ambulatory surgical cases, in which PNB was a viable anesthetic option (ie, was routinely performed for these procedures), at an academic medical center between 2008 and 2018. We assessed the association between the use of PNB and the primary endpoint of PACU length of stay. As key secondary endpoint, we compared intraoperative opioid doses. Analyses were adjusted for patient demographics, comorbidities and intraoperative factors. RESULTS: A total of 57 040 cases were analyzed, of whom 13 648 (23.9%) received a PNB. The use of PNB was associated with shorter PACU length of stay (a decrease of 7.3 min, 95% CI 6.1 to 8.6, p<0.001). This association was most pronounced in surgeries of long duration (decrease of 11.2 min, 95% CI 9.0 to 13.4) and in patients undergoing leg and ankle procedures (decrease of 15.1 min, 95% CI 5.5 to 24.6). Intraoperative opioid doses were significantly lower in patients receiving a nerve block (decrease of 9.40 mg oral morphine equivalents, 95% CI 8.34 to 10.46, p<0.001). CONCLUSION: The use of PNB significantly reduced PACU length of stay in ambulatory surgical patients, which may in part be attributed to lower intraoperative opioid requirements.

Discharge Prediction for Patients Undergoing Inpatient Surgery: Development and validation of the DEPENDENSE score.

BACKGROUND: A substantial proportion of patients undergoing inpatient surgery each year is at risk for postoperative institutionalization and loss of independence. Reliable individualized preoperative prediction of adverse discharge can facilitate advanced care planning and shared decision making. METHODS: Using hospital registry data from previously home-dwelling adults undergoing inpatient surgery, we retrospectively developed and externally validated a score predicting adverse discharge. Multivariable logistic regression analysis and bootstrapping were used to develop the score. Adverse discharge was defined as in-hospital mortality or discharge to a skilled nursing facility. The model was subsequently externally validated in a cohort of patients from an independent hospital. RESULTS: In total, 106 164 patients in the development cohort and 92 962 patients in the validation cohort were included, of which 16 624 (15.7%) and 7717 (8.3%) patients experienced adverse discharge, respectively. The model was predictive of adverse discharge with an area under the receiver operating characteristic curve (AUC) of 0.87 (95% CI 0.87-0.88) in the development cohort and an AUC of 0.86 (95% CI 0.86-0.87) in the validation cohort. CONCLUSION: Using preoperatively available data, we developed and validated a prediction instrument for adverse discharge following inpatient surgery. Reliable prediction of this patient centered outcome can facilitate individualized operative planning to maximize value of care.

Supraglottic airway device versus tracheal intubation and the risk of emergent postoperative intubation after general anaesthesia in adults: a retrospective cohort study.

BACKGROUND: We examined the association between emergent postoperative tracheal intubation and the use of supraglottic airway devices (SGAs) vs tracheal tubes. METHODS: We included data from adult noncardiac surgical cases under general anaesthesia between 2008 and 2018. We only included cases (n=59 991) in which both airways were deemed to be feasible options. Multivariable logistic regression, instrumental variable analysis, propensity matching, and mediation analysis were used. RESULTS: Use of a tracheal tube was associated with a higher risk of emergent postoperative intubation (adjusted absolute risk difference [ARD]=0.80%; 95% confidence interval (CI), 0.64-0.97; P<0.001), and a higher risk of post-extubation hypoxaemia (ARD=3.9%; 95% CI, 3.4-4.4; P<0.001). The effect was modified by the use of non-depolarising neuromuscular blocking agents (NMBAs); mediation analyses revealed that 28.9% (95% CI, 14.4-43.4%; P<0.001) of the main effect was attributable to NMBA. Airway management modified the association of NMBA and risk of emergent postoperative intubation (Pinteraction=0.02). Patients managed with an SGA had higher odds of NMBA-associated reintubation compared to patients managed with a tracheal tube (adjusted odds ratio [aOR]=3.65, 95% CI, 1.99-6.67 vs aOR=1.68, 95% CI, 1.29-2.18 [P<0.001], respectively). CONCLUSIONS: In patients undergoing procedures under general anaesthesia that could be managed with either SGA or tracheal tube, use of an SGA was associated with lower risk of emergent postoperative intubation. The effect can partly be explained by use of NMBAs. Use of NMBAs in patients with an SGA appears to increase the risk of emergent postoperative intubation.

What Factors Predict Adverse Discharge Disposition in Patients Older Than 60 Years Undergoing Lower-extremity Surgery? The Adverse Discharge in Older Patients after Lower-extremity Surgery (ADELES) Risk Score.

BACKGROUND: Adverse discharge disposition, which is discharge to a long-term nursing home or skilled nursing facility is frequent and devastating in older patients after lower-extremity orthopaedic surgery. Predicting individual patient risk allows for preventive interventions to address modifiable risk factors and helps managing expectations. Despite a variety of risk prediction tools for perioperative morbidity in older patients, there is no tool available to predict successful recovery of a patient's ability to live independently in this highly vulnerable population. QUESTIONS/PURPOSES: In this study, we asked: (1) What factors predict adverse discharge disposition in patients older than 60 years after lower-extremity surgery? (2) Can a prediction instrument incorporating these factors be applied to another patient population with reasonable accuracy? (3) How does the instrument compare with other predictions scores that account for frailty, comorbidities, or procedural risk alone? METHODS: In this retrospective study at two competing New England university hospitals and Level 1 trauma centers with 673 and 1017 beds, respectively; 83% (19,961 of 24,095) of patients 60 years or older undergoing lower-extremity orthopaedic surgery were included. In all, 5% (1316 of 24,095) patients not living at home and 12% (2797 of 24,095) patients with missing data were excluded. All patients were living at home before surgery. The mean age was 72 ± 9 years, 60% (11,981 of 19,961) patients were female, 21% (4155 of 19,961) underwent fracture care, and 34% (6882 of 19,961) underwent elective joint replacements. Candidate predictors were tested in a multivariable logistic regression model for adverse discharge disposition in a development cohort of all 14,123 patients from the first hospital, and then included in a prediction instrument that was validated in all 5838 patients from the second hospital by calculating the area under the receiver operating characteristics curve (ROC-AUC).Thirty-eight percent (5360 of 14,262) of patients in the development cohort and 37% (2184 of 5910) of patients in the validation cohort had adverse discharge disposition. Score performance in predicting adverse discharge disposition was then compared with prediction scores considering frailty (modified Frailty Index-5 or mFI-5), comorbidities (Charlson Comorbidity Index or CCI), and procedural risks (Procedural Severity Scores for Morbidity and Mortality or PSS). RESULTS: After controlling for potential confounders like BMI, cardiac, renal and pulmonary disease, we found that the most prominent factors were age older than 90 years (10 points), hip or knee surgery (7 or 8 points), fracture management (6 points), dementia (5 points), unmarried status (3 points), federally provided insurance (2 points), and low estimated household income based on ZIP code (1 point). Higher score values indicate a higher risk of adverse discharge disposition. The score comprised 19 variables, including socioeconomic characteristics, surgical management, and comorbidities with a cutoff value of ≥ 23 points. Score performance yielded an ROC-AUC of 0.85 (95% confidence interval 0.84 to 0.85) in the development and 0.72 (95% CI 0.71 to 0.73) in the independent validation cohort, indicating excellent and good discriminative ability. Performance of the instrument in predicting adverse discharge in the validation cohort was superior to the mFI-5, CCI, and PSS (ROC-AUC 0.72 versus 0.58, 0.57, and 0.57, respectively). CONCLUSION: The Adverse Discharge in Older Patients after Lower Extremity Surgery (ADELES) score predicts adverse discharge disposition after lower-extremity surgery, reflecting loss of the ability to live independently. Its discriminative ability is better than instruments that consider frailty, comorbidities, or procedural risk alone. The ADELES score identifies modifiable risk factors, including general anesthesia and prolonged preoperative hospitalization, and should be used to streamline patient and family expectation management and improve shared decision making. Future studies need to evaluate the score in community hospitals and in institutions with different rates of adverse discharge disposition and lower income. A non-commercial calculator can be accessed at www.adeles-score.org. LEVEL OF EVIDENCE: Level III, diagnostic study.

A Tool to Predict Readmission to the Intensive Care Unit in Surgical Critical Care Patients-The RISC Score.

BACKGROUND: Readmission to the Intensive Care Unit (ICU) is associated with a high risk of in-hospital mortality and higher health care costs. Previously published tools to predict ICU readmission in surgical ICU patients have important limitations that restrict their clinical implementation. We sought to develop a clinically intuitive score that can be implemented to predict readmission to the ICU after surgery or trauma. We designed the score to emphasize modifiable predictors. METHODS: In this retrospective cohort study, we included surgical patients requiring critical care between June 2015 and January 2019 at Beth Israel Deaconess Medical Center, Harvard Medical School, MA, USA. We used logistic regression to fit a prognostic model for ICU readmission from a priori defined, widely available candidate predictors. The score performance was compared with existing prediction instruments. RESULTS: Of 7,126 patients, 168 (2.4%) were readmitted to the ICU during the same hospitalization. The final score included 8 variables addressing demographical factors, surgical factors, physiological parameters, ICU treatment and the acuity of illness. The maximum score achievable was 13 points. Potentially modifiable predictors included the inability to ambulate at ICU discharge, substantial positive fluid balance (>5 liters), severe anemia (hemoglobin <7 mg/dl), hyperglycemia (>180 mg/dl), and long ICU length of stay (>5 days). The score yielded an area under the receiver operating characteristic curve of 0.78 (95% CI 0.74-0.82) and significantly outperformed previously published scores. The performance of the underlying model was confirmed by leave-one-out cross-validation. CONCLUSION: The RISC-score is a clinically intuitive prediction instrument that helps identify surgical ICU patients at high risk for ICU readmission. The simplicity of the score facilitates its clinical implementation across surgical divisions.

Development of an Instrument for Preoperative Prediction of Adverse Discharge in Patients Scheduled for Cardiac Surgery.

OBJECTIVE: Inability of home discharge occurs in nearly a third of patients undergoing cardiac surgery and is associated with increased mortality. The authors aimed to evaluate the incidence and risk factors for adverse discharge disposition (ADD) after cardiac surgery and develop a prediction tool for preoperative risk assessment. DESIGN: This retrospective cohort study included adult patients undergoing cardiac surgery between 2010 and 2018. The primary outcome was ADD, defined as in-hospital mortality, discharge to a skilled nursing facility, or transfer to a long-term care hospital. The authors created a prediction tool using stepwise backward logistic regression and used 5-fold and leave-one-out cross-validation. SETTING: University hospital network. PARTICIPANTS: Adult patients living at home prior to surgery, who underwent coronary artery bypass grafting and/or valve procedures at the authors' institution. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 3,760 patients were included in the final study cohort. The observed rate of ADD was 33.3%. The prediction model showed good discrimination and accuracy, with C-statistic of 0.78 (95% confidence interval [CI] 0.76-0.79) and unmodified Brier score of 0.177 (reliability 0.001). The final model comprised 14 predictors. Patients who experienced ADD were more likely to be older, of female sex, to have had higher length of hospital stay prior to surgery, and to have undergone emergency surgery. CONCLUSIONS: The authors present an instrument for prediction of loss of the ability to live independently in patients undergoing cardiac surgery. The authors' score may be useful in identifying high-risk patients such that earlier coordination of care can be initiated in this vulnerable patient population.

Study protocol for a randomised controlled trial evaluating the effects of the orexin receptor antagonist suvorexant on sleep architecture and delirium in the intensive care unit.

INTRODUCTION: Insomnia frequently occurs in patients admitted to an intensive care unit (ICU). Sleep-promoting agents may reduce rapid eye movement sleep and have deliriogenic effects. Suvorexant (Belsomra) is an orexin receptor antagonist with Food and Drug Administration (FDA) approval for the treatment of adult insomnia, which improves sleep onset and maintenance as well as subjective measures of quality of sleep. This trial will evaluate the efficacy of postoperative oral suvorexant treatment on night-time wakefulness after persistent sleep onset as well as the incidence and duration of delirium among adult cardiac surgical patients. METHODS AND ANALYSIS: In this single-centre, randomised, double-blind, placebo-controlled trial, we will enrol 120 patients, aged 60 years or older, undergoing elective cardiac surgery with planned postoperative admission to the ICU. Participants will be randomised to receive oral suvorexant (20 mg) or placebo one time a day starting the night after extubation. The primary outcome will be wakefulness after persistent sleep onset. The secondary outcome will be total sleep time. Exploratory outcomes will include time to sleep onset, incidence of postoperative in-hospital delirium, number of delirium-free days and subjective sleep quality. ETHICS AND DISSEMINATION: Ethics approval was obtained through the 'Committee on Clinical Investigations' at Beth Israel Deaconess Medical Center (protocol number 2019P000759). The findings will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: This trial has been registered at clinicaltrials.gov on 17 September 2019 (NCT04092894).

Succinylcholine and postoperative pulmonary complications: a retrospective cohort study using registry data from two hospital networks.

BACKGROUND: Neuromuscular blocking agents (NMBAs) with a non-depolarising mechanism of action carry the risk of postoperative residual paralysis and are associated with postoperative pulmonary complications (POPC). Owing to the shorter duration of action, the depolarising NMBA succinylcholine may be associated with less postoperative residual paralysis, and hence fewer POPC. We tested the association of succinylcholine administration during anaesthesia and POPC. METHODS: In a retrospective cohort study of registry data from two large US academic medical centres, 244 850 adult noncardiac surgical patients undergoing general anaesthesia were included. The primary outcome was POPC, defined as post-extubation haemoglobin oxygen de-saturation to <90%, or re-intubation requiring intensive care unit admission within 7 days after surgery. The association between succinylcholine and POPC and its dose-dependency were tested in a hierarchical fashion using a multivariable logistic regression model. RESULTS: A total of 13 206 patients (5.4%) experienced POPC. Use of succinylcholine was associated with increased risk of POPC (adjusted odds ratio [ORAdj]=1.11; 95% confidence interval [CI], 1.06-1.16; P<0.001; adjusted risk=5.18%; 95% CI, 5.06-5.30 without and 5.69%; 95% CI, 5.53-5.85 with succinylcholine), with a dose-dependent relationship (ORAdj=1.08; 95% CI, 1.05-1.11 per mg kg-1; P<0.001). In patients receiving non-depolarising NMBAs, succinylcholine further increased the risk of POPC (ORAdj=1.08; 95% CI, 1.03-1.14; P=0.001). The association between succinylcholine and POPC was modified (P=0.03 for interaction) by the duration of surgery with higher odds of POPC in patients undergoing surgeries of <2 vs ≥2 h (ORAdj=1.24; 95% CI, 1.15-1.33 and 1.05; 95% CI, 1.00-1.10, respectively). CONCLUSIONS: In contrast to our prediction, succinylcholine administration was associated with an increased risk of POPC. This association was dose-dependent and magnified in surgeries of shorter duration.

Ventilatory frequency during intraoperative mechanical ventilation and postoperative pulmonary complications: a hospital registry study.

BACKGROUND: High ventilatory frequencies increase static lung strain and possibly lung stress by shortening expiratory time, increasing intrathoracic pressure, and causing dynamic hyperinflation. We hypothesised that high intraoperative ventilatory frequencies were associated with postoperative respiratory complications. METHODS: In this retrospective hospital registry study, we analysed data from adult non-cardiothoracic surgical cases performed under general anaesthesia with mechanical ventilation at a single centre between 2005 and 2017. We assessed the association between intraoperative ventilatory frequency (categorised into four groups) and postoperative respiratory complications, defined as composite of invasive mechanical ventilation within 7 days after surgery or peripheral oxygen desaturation after extubation, using multivariable logistic regression. In a subgroup, we adjusted analyses for arterial blood gas parameters. RESULTS: A total of 102 632 cases were analysed. Intraoperative ventilatory frequencies ranged from a median (inter-quartile range [IQR]) of 8 (8-9) breaths min-1 (Group 1) to 15 (14-18) breaths min-1 (Group 4). High ventilatory frequencies were associated with higher odds of postoperative respiratory complications (adjusted odds ratio=1.26; 95% confidence interval, 1.14-1.38; P<0.001), which was confirmed in a subgroup after adjusting for arterial partial pressure of carbon dioxide and the ratio of arterial oxygen partial pressure to fractional inspired oxygen. We identified considerable variability in the use of high ventilatory frequencies attributable to individual provider preference (ranging from 22% to 88%) and temporal change; however, the association with postoperative respiratory complications remained unaffected. CONCLUSIONS: High intraoperative ventilatory frequency was associated with increased risk of postoperative respiratory complications, and increased postoperative healthcare utilisation.