Physical and Chemical Compatibility of Medications Commonly Used in Critically Ill Patients With Balanced Crystalloids: A Systematic Review

OBJECTIVE

Evaluate available evidence of physical and/or chemical compatibility of commonly used medications in critically ill patients with balanced crystalloids.

DATA SOURCES

Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews were queried from inception to September 2022.

STUDY SELECTION AND DATA EXTRACTION

This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. English-language studies reporting physical and/or chemical compatibility data between 50 selected medications and balanced crystalloids were included. A previously designed tool to assess risk of bias was adapted for use.

DATA SYNTHESIS

Twenty-nine studies encompassing 39 (78%) medications and 188 unique combinations with balanced crystalloids were included. Combinations included 35 (70%) medications with lactated Ringer's, 26 (52%) medications with Plasma-Lyte, 10 (20%) medications with Normosol, and one (2%) medication with Isolyte. Studies commonly evaluated physical and chemical compatibility (55.2%). More medications were evaluated via Y-site than admixture. Incompatibilities were identified in 18% of combinations comprising 13 individual drugs.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This systematic review evaluates the compatibility of select critical care medications with balanced crystalloid solutions. Results may be used as a tool to guide clinicians on balanced crystalloid compatibility, potentially increasing ubiquitous use and reducing patient exposure to normal saline.

CONCLUSION AND RELEVANCE

Data are limited regarding chemical/physical compatibility of commonly used medications in critically ill patients with balanced crystalloids. Additional compatibility studies are warranted, particularly methodologically rigorous studies assessing Plasma-Lyte, Normosol, and Isolyte. Of the evaluated medications, there was a low frequency of incompatibilities with balanced crystalloids.

A Comprehensive, Retrospective Analysis of Variables for Potential Mortality Impact in Patients With Thermal or Inhalation Injury

Age, percentage TBSA burned, and the presence of inhalation injury have been used historically in the prediction of mortality in thermally injured patients despite other factors being also associated with mortality. Recent literature has identified novel factors associated with increased length of stay (LOS) and may provide a better prediction model for mortality in burn patients. The study objective was to perform a subset analysis of a multitude of known and novel variables for potential association with mortality. Demographics and injury characteristics along with during stay variables were collected and analyzed. This study is a re-analysis of a retrospective study examining variables associated with increased LOS. Of the 629 patients screened, 396 were included in the analysis. After univariable analysis, 35 variables had significant associations with mortality, including age, house fire, acute kidney injury, heart failure, inhalation injury, and history of diabetes. After multivariable analysis, the best performing model included heart failure, acute kidney injury, admission Glasgow Coma Scale score, and revised Baux score. Quantile analysis of age revealed greater than 60 years was most predictive of mortality. The best multivariable model for patients greater than 60 years old included heart failure, vasopressor use, acute respiratory distress syndrome, and TBSA burned. Considering only variables present on admission, the best multivariable model for patients greater than 60 years old included heart failure, % TBSA burned, and inhalation injury. The addition of variables into current prediction models and databases may be warranted.

Protein requirements for critically ill ventilator-dependent patients with COVID-19

Background

Recent studies indicate critically ill patients with coronavirus disease 2019 (COVID‐19) are hypermetabolic; however, protein requirements in critically ill COVID‐19 patients are unknown. Our intent was to evaluate the nitrogen accretion response to varying protein intakes for critically ill ventilator‐dependent patients with COVID‐19.

Methods

Adult patients (age ≥ 18 years) with COVID‐19, admitted to the intensive care unit (ICU) and who required mechanical ventilation were retrospectively evaluated. Patients received continuous enteral nutrition (EN), including supplemental protein boluses, and had a 24‐h urine collection for determination of nitrogen balance (NBAL). Data are expressed as mean ± SD with a P‐value < .05 as significant.

Results

Twenty‐two patients provided 29 NBAL determinations. Protein intake from EN and protein supplements was 0.9 ± 0.7 g/kg/day at the time of the NBAL with an NBAL of –12.1 ± 10.9 g/day at 7 ± 4 days in the ICU. Combined caloric intake from EN and propofol at the time of the NBAL was 12 ± 8 kcal/kg/day. Nitrogen equilibrium (NBAL of –4 g/day or better) occurred in five patients. Patients achieving nitrogen equilibrium received more protein than those with a negative NBAL (1.2 ± 0.4 g/kg/day vs 0.8 ± 0.8 g/kg/day, P = .046). The linear regression for NBAL in response to graded increases in protein intake was as follows: NBAL = 8.5 × protein intake (g/kg/day) – 18.8 (r = 0.450, P < .001).

Conclusion

Critically ill ventilator‐dependent patients with COVID‐19 exhibit significant variability in nitrogen accretion response to increases in protein intake and often have a markedly negative NBAL.

Priming as a strategy to overcome detrimental pH effects on cells for intervertebral disc regeneration

Disc disease is characterised by degeneration of the nucleus pulposus (NP), the central gelatinous tissue of the intervertebral disc (IVD). As degeneration progresses, the microenvironment of the IVD becomes more hostile (i.e. decrease in oxygen, glucose and pH), providing a significant challenge for regeneration using cell-based therapies. Tissue engineering strategies such as priming cells or micro tissues with growth factors prior to implantation may overcome some of these issues by providing a pre-formed protective niche composed of extracellular matrix. The present study investigated the effect of priming on bone-marrow-derived stem cells (BMSCs) and articular chondrocytes (ACs) using transforming growth factor β3 (TGF-β3), cultured at different pH levels (pH 7.1, 6.8 and 6.5) representative of the in vivo disc microenvironment. Low pH was found to have a detrimental effect on both cell viability and matrix accumulation, which could be mitigated by priming cells using TGF-β3. Investigating the activation of the transmembrane acid-sensing ion channels (ASIC-1 and -3) showed an increased expression of ASIC-1 in BMSCs and ASIC-3 in ACs at lower pH levels post-priming. Metabolic activity in terms of lactic acid production was also found to be affected significantly by priming, whereas oxygen and glucose consumptions did not change considerably. Overall, the study demonstrated that cells could be equipped to sustain the harsh environment of the IVD and promote accumulation of NP-like matrix through priming. Such an approach may open new avenues to engineer tissues capable of sustaining challenging microenvironments such as those found in the IVD.

Analysis of Vasopressor Discontinuation and the Incidence of Rebound Hypotension in Patients With Septic Shock

Purpose: The purpose of this study was to examine the incidence of rebound hypotension in patients with septic shock requiring both norepinephrine and vasopressin infusions once discontinuation of 1 of these agents is warranted. Methods: A multicenter, retrospective study was conducted in 3 hospitals within a single health system between January 1, 2016, and December 31, 2017. The study population included adults, 18 years and older, diagnosed with septic shock and requiring concurrent infusions of norepinephrine and vasopressin. The primary outcome evaluated the incidence of rebound hypotension within 24 hours after the first vasopressor was discontinued. Secondary outcomes included intensive care unit length of stay, hospital length of stay, total vasopressor duration, and the time to rebound hypotension after first vasopressor discontinuation. Results: A total of 69 patients were included in the study, 38 in the vasopressin discontinued first group and 31 in the norepinephrine discontinued first group. Rebound hypotension occurred in 82% of patients in the vasopressin discontinued first group compared with 48% in the norepinephrine discontinued first group ( P = .004). No differences were observed in secondary outcomes, including intensive care unit or hospital length of stay, total vasopressor duration, or the time to rebound hypotension. Conclusions: Discontinuation of norepinephrine before vasopressin may lead to less incidence of rebound hypotension in patients with septic shock who require concurrent norepinephrine and vasopressin infusions. Similar to previous studies, this study found no difference in secondary outcomes.

Cenobamate: A New Adjunctive Agent for Drug-Resistant Focal Onset Epilepsy

OBJECTIVE

To review the pharmacology, efficacy, and safety of oral cenobamate in the treatment of uncontrolled focal epilepsy.

DATA SOURCES

The PubMed database and ClinicalTrials.gov were searched using the following terms: cenobamate, Xcopri, and YKP3089.

STUDY SELECTION AND DATA EXTRACTION

Articles published in English between January 2000 and April 2020 related to pharmacology, safety, and clinical trials were assessed.

DATA SYNTHESIS

In a phase 2 trial, cenobamate reduced the median percentage change in seizure frequency from baseline by 56% compared with 22% for placebo (P < 0.0001). In another phase 2 trial of multiple cenobamate doses, cenobamate reduced seizure frequency by 36% (P = 0.0071) in the 100-mg group and 55% (P < 0.0001) in both the 200- and 400-mg groups, compared to 24% with placebo. Adverse effects of cenobamate appear to be similar to those of other antiseizure medications and primarily affect the neurological system.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

In patients taking antiseizure medications who continue to have focal seizures, cenobamate has efficacy at multiple doses and is generally well tolerated. Cenobamate may be distinguished from other antiseizure medications by high rates of seizure freedom not seen in previous placebo-controlled trials, which has the potential to significantly improve quality of life. However, despite this efficacy, Drug Reaction with Eosinophilia and Systemic Symptoms may remain a significant concern with cenobamate.

CONCLUSION

As seen in clinical trials, cenobamate as an adjunctive, once-daily treatment represents an efficacious and generally well-tolerated therapy for patients with drug-resistant focal epilepsy.

Improvement in Protein Delivery for Critically Ill Patients Requiring High-Dose Propofol Therapy and Enteral Nutrition

BACKGROUND

Patients with traumatic brain (TBI) injury often require a high dosage of propofol, which can provide an excessive caloric intake. We evaluated our strategy of using liquid protein supplement boluses concurrently with high protein-containing enteral nutrition (EN) formulas and formula rate reduction to avoid caloric overfeeding and inadequate protein intake.

METHODS

Adult patients (aged >17 years) with TBI admitted to the trauma intensive care unit (TICU) who received concurrent propofol and EN were retrospectively reviewed. Caloric intakes from propofol and EN were obtained. Actual protein intake was compared with projected protein intakes from high protein content and standard protein content enteral formulas when given at an isocaloric intake.

RESULTS

Fifty-one patients were enrolled. Average caloric intake from propofol was 356 ± 243 kcal/d or 5 ± 3 kcal/kg/d (range, <1-15 kcal/kg/d). Daily EN caloric intake ranged from 7 ± 4 kcal/kg/d (day 2) to 16 ± 9 kcal/kg/d (day 5; P < .001). Average protein intake ranged from 0.6 ± 0.4 g/kg/d (day 2) to 1.5 ± 0.7 g/kg/d (day 5; P < .001). The modified EN strategy resulted in daily delivery of 24%-38% more protein than an isocaloric regimen with a high protein-content formula and twice as much protein than the standard protein-content formula (P < .001).

CONCLUSION

The strategy of providing an EN regimen comprised liquid protein boluses, and high and very high protein-containing EN formulas at a reduced rate improved protein delivery without caloric overfeeding.

In vitro co-culture and ex vivo organ culture assessment of primed and cryopreserved stromal cell microcapsules for intervertebral disc regeneration

Priming towards a discogenic phenotype and subsequent cryopreservation of microencapsulated bone marrow stromal cells (BMSCs) may offer an attractive therapeutic approach for disc repair. It potentially obviates the need for in vivo administration of exogenous growth factors, otherwise required to promote matrix synthesis, in addition to providing 'off-the-shelf' availability. Cryopreserved and primed BMSC microcapsules were evaluated in an in vitro surrogate co-culture model system with nucleus pulposus (NP) cells under intervertebral disc (IVD)-like culture conditions and in an ex vivo bovine organ culture disc model. BMSCs were microencapsulated in alginate microcapsules and primed for 14 d with transforming growth factor beta-3 (TGF-β3) under low oxygen conditions prior to cryopreservation. For the in vitro phase, BMSC microcapsules (unprimed or primed) were cultured for 28 d in a surrogate co-culture model system mimicking that of the IVD. For the ex vivo phase, microcapsules (unprimed or primed) were injected into the NP of bovine discs that underwent nucleotomy. In vitro results revealed that although NP cells produced significantly more matrix components in co-culture with BMSC microcapsules regardless of the differentiation state, unprimed microcapsules were inadequate at synthesising matrix as compared to primed microcapsules. However, this difference was diminished when evaluated in the ex vivo organ culture model,withboth unprimed and primed BMSC microcapsules accumulating large amounts of sulphated glycosaminoglycan (sGAG) and collagen and filling the defect cavity. Both models demonstrated that cryopreservation of BMSC microcapsules may offer a feasible strategy for predesigned delivery through cryobanking for on-demand regeneration of the IVD.

In vitro extracellular matrix accumulation of nasal and articular chondrocytes for intervertebral disc repair

Chondrocyte based regenerative therapies for intervertebral disc repair such as Autologous Disc Cell Transplantation (ADCT, CODON) and allogeneic juvenile chondrocyte implantation (NuQu^®, ISTO Technologies) have demonstrated good outcomes in clinical trials. However concerns remain with the supply demand reconciliation and issues surrounding immunoreactivity which exist for allogeneic-type technologies. The use of stem cells is challenging due to high growth factor requirements, regulatory barriers and differentiation towards a stable phenotype. Therefore, there is a need to identify alternative non-disc cell sources for the development and clinical translation of next generation therapies for IVD regeneration. In this study, we compared Nasal Chondrocytes (NC) as a non-disc alternative chondrocyte source with Articular Chondrocytes (AC) in terms of cell yield, morphology, proliferation kinetics and ability to produce key extracellular matrix components under 5% and 20% oxygen conditions, with and without exogenous TGF-β supplementation. Results indicated that NC maintained proliferative capacity with high amounts of sGAG and lower collagen accumulation in the absence of TGF-β supplementation under 5% oxygen conditions. Importantly, osteogenesis and calcification was inhibited for NC when cultured in IVD-like microenvironmental conditions. The present study provides a rationale for the exploration of nasal chondrocytes as a promising, potent and clinically feasible autologous cell source for putative IVD repair strategies.

Tissue engineering scaled-up, anatomically shaped osteochondral constructs for joint resurfacing

Arthroplasty is currently the only surgical procedure available to restore joint function following articular cartilage and bone degeneration associated with diseases such as osteoarthritis (OA). A potential alternative to this procedure would be to tissue-engineer a biological implant and use it to replace the entire diseased joint. The objective of this study was therefore to tissue-engineer a scaled-up, anatomically shaped, osteochondral construct suitable for partial or total resurfacing of a diseased joint. To this end it was first demonstrated that a bone marrow derived mesenchymal stem cell seeded alginate hydrogel could support endochondral bone formation in vivo within the osseous component of an osteochondral construct, and furthermore, that a phenotypically stable layer of articular cartilage could be engineered over this bony tissue using a co-culture of chondrocytes and mesenchymal stem cells. Co-culture was found to enhance the in vitro development of the chondral phase of the engineered graft and to dramatically reduce its mineralisation in vivo. In the final part of the study, tissue-engineered grafts (~ 2 cm diameter) mimicking the geometry of medial femorotibial joint prostheses were generated using laser scanning and rapid prototyped moulds. After 8 weeks in vivo, a layer of cartilage remained on the surface of these scaled-up engineered implants, with evidence of mineralisation and bone development in the underlying osseous region of the graft. These findings open up the possibility of a tissue-engineered treatment option for diseases such as OA.

Cyclic hydrostatic pressure promotes a stable cartilage phenotype and enhances the functional development of cartilaginous grafts engineered using multipotent stromal cells isolated from bone marrow and infrapatellar fat pad

The objective of this study was to investigate how joint specific biomechanical loading influences the functional development and phenotypic stability of cartilage grafts engineered in vitro using stem/progenitor cells isolated from different source tissues. Porcine bone marrow derived multipotent stromal cells (BMSCs) and infrapatellar fat pad derived multipotent stromal cells (FPSCs) were seeded in agarose hydrogels and cultured in chondrogenic medium, while simultaneously subjected to 10MPa of cyclic hydrostatic pressure (HP). To mimic the endochondral phenotype observed in vivo with cartilaginous tissues engineered using BMSCs, the culture media was additionally supplemented with hypertrophic factors, while the loss of phenotype observed in vivo with FPSCs was induced by withdrawing transforming growth factor (TGF)-β3 from the media. The application of HP was found to enhance the functional development of cartilaginous tissues engineered using both BMSCs and FPSCs. In addition, HP was found to suppress calcification of tissues engineered using BMSCs cultured in chondrogenic conditions and acted to maintain a chondrogenic phenotype in cartilaginous grafts engineered using FPSCs. The results of this study point to the importance of in vivo specific mechanical cues for determining the terminal phenotype of chondrogenically primed multipotent stromal cells. Furthermore, demonstrating that stem or progenitor cells will appropriately differentiate in response to such biophysical cues might also be considered as an additional functional assay for evaluating their therapeutic potential.

The use of the reamer-irrigator-aspirator to harvest mesenchymal stem cells

The scarcity of mesenchymal stem cells (MSCs) in iliac crest bone marrow aspirate (ICBMA), and the expense and time in culturing cells, has led to the search for alternative harvest sites. The reamer-irrigation-aspirator (RIA) provides continuous irrigation and suction during reaming of long bones. The aspirated contents pass via a filter, trapping bony fragments, before moving into a 'waste' bag from which MSCs have been previously isolated. We examined the liquid and solid phases, performed a novel digestion of the solid phase, and made a comparative assessment in terms of number, phenotype and differentiation capacity with matched ICBMA. The solid fraction from the filtrate was digested for 60 minutes at 37° C with collagenase. Enumeration was performed via the colony-forming unit fibroblast (CFU-F) assay. Passage (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages, and their phenotypes assessed using flow cytometry (CD33, CD34, CD45, CD73, CD90, and CD105). MSCs from the RIA phases were able to differentiate at least as well as those from ICBMA, and all fractions had phenotypes consistent with other established sources. The median number of colonies for the three groups was: ICBMA = 8.5 (2 to 86), RIA-liquid = 19.5 (4 to 90), RIA-solid = 109 (67 to 200) per 200 μl. The mean total yield of cells for the three groups was: ICBMA = 920 (0 to 4275), RIA-liquid = 114,983 (16,500 to 477,750), RIA-solid = 12,785 (7210 to 28 475). The RIA filtrate contains large numbers of MSCs that could potentially be extracted without enzymatic digestion and used for bone repair without prior cell expansion.

Oxygen tension differentially regulates the functional properties of cartilaginous tissues engineered from infrapatellar fat pad derived MSCs and articular chondrocytes

BACKGROUND

For current tissue engineering or regenerative medicine strategies, chondrocyte (CC)- or mesenchymal stem cell (MSC)-seeded constructs are typically cultured in normoxic conditions (20% oxygen). However, within the knee joint capsule a lower oxygen tension exists.

OBJECTIVE

The objective of this study was to investigate how CCs and infrapatellar fad pad derived MSCs will respond to a low oxygen (5%) environment in 3D agarose culture. Our hypothesis was that culture in a low oxygen environment (5%) will enhance the functional properties of cartilaginous tissues engineered using both cell sources.

EXPERIMENTAL DESIGN

Cell-encapsulated agarose hydrogel constructs (seeded with CCs or infrapatellar fat pad (IFP) derived MSCs) were prepared and cultured in a chemically defined serum-free medium in the presence (CCs and MSCs) or absence (CCs only) of transforming growth factor-beta3 (TGF-β3) in normoxic (20%) or low oxygen (5%) conditions for 42 days. Constructs were assessed at days 0, 21 and 42 in terms of mechanical properties, biochemical content and histologically.

RESULTS

Low oxygen tension (5%) was observed to promote extracellular matrix (ECM) production by CCs cultured in the absence of TGF-β3, but was inhibitory in the presence of TGF-β3. In contrast, a low oxygen tension enhanced chondrogenesis of IFP constructs in the presence of TGF-β3, leading to superior mechanical functionality compared to CCs cultured in identical conditions.

CONCLUSIONS

Extrapolating the results of this study to the in vivo setting, it would appear that joint fat pad derived MSCs may possess a superior potential to generate a functional repair tissue in low oxygen tensions. However, in the context of in vitro cartilage tissue engineering, CCs maintained in normoxic conditions in the presence of TGF-β3 generate the most mechanically functional tissue.