Exploring the utility of bedside tests for predicting cardiorespiratory fitness in older adults

Objectives

Cardiorespiratory fitness (CRF) declines with advancing and has also, independent of age, been shown to be predictive of all-cause mortality, morbidity, and poor clinical outcomes. In relation to the older patient, there is a particular wealth of evidence highlighting the relationship between low CRF and poor surgical outcomes. Cardiopulmonary exercise testing (CPET) is accepted as the gold-standard measure of CRF. However, this form of assessment has significant personnel and equipment demands and is not feasible for those with certain age-associated physical limitations, including joint and cardiovascular comorbidities. As such, alternative ways to assess the CRF of older patients are very much needed.

Methods

Sixty-four participants (45% female) with a median age of 74 (65-90) years were recruited to this study via community-based advertisements. All participants completed three tests of physical function: (1) a step-box test; (2) handgrip strength dynamometry; and (3) a CPET on a cycle ergometer; and also had their muscle architecture (vastus lateralis) assessed by B-mode ultrasonography to provide measures of muscle thickness, pennation angle, and fascicle length. Multivariate linear regression was then used to ascertain bedside predictors of CPET parameters from the alternative measures of physical function and demographic (age, gender, body mass index (BMI)) data.

Results

There was no significant association between ultrasound-assessed parameters of muscle architecture and measures of CRF. VO2peak was predicted to some extent from fast step time during the step-box test, gender, and BMI, leading to a model that achieved an R 2 of 0.40 (p < 0.001). Further, in aiming to develop a model with minimal assessment demands (i.e., using handgrip dynamometry rather than the step-box test), replacing fast step time with non-dominant HGS led to a model which achieved an R 2 of 0.36 (p < 0.001). Non-dominant handgrip strength combined with the step-box test parameter of fast step time and BMI delivered the most predictive model for VO2peak with an R 2 of 0.45 (p < 0.001).

Conclusions

Our findings show that simple-to-ascertain patient characteristics and bedside assessments of physical function are able to predict CPET-derived CRF. Combined with gender and BMI, both handgrip strength and fast step time during a step-box test were predictive for VO2peak. Future work should apply this model to a clinical population to determine its utility in this setting and to explore if simple bedside tests are predictive of important clinical outcomes in older adults (i.e., post-surgical complications).

Pre-emptive and preventive NSAIDs for postoperative pain in adults undergoing all types of surgery

BACKGROUND

Postoperative pain is a common consequence of surgery and can have many negative perioperative effects. It has been suggested that the administration of analgesia before a painful stimulus may improve pain control. We defined pre-emptive nonsteroidal anti-inflammatories (NSAIDs) as those given before surgery but not continued afterwards and preventive NSAIDs as those given before surgery and continued afterwards. These were compared to a control group given the NSAIDs after surgery instead of before surgery.

OBJECTIVES

To assess the efficacy of preventive and pre-emptive NSAIDs for reducing postoperative pain in adults undergoing all types of surgery.

SEARCH METHODS

We searched the following electronic databases: CENTRAL, MEDLINE, Embase, AMED and CINAHL (up to June 2020). In addition, we searched for unpublished studies in three clinical trial databases, conference proceedings, grey literature databases, and reference lists of retrieved articles. We did not apply any restrictions on language or date of publication.

SELECTION CRITERIA

We included parallel-group randomized controlled trials (RCTs) only. We included adult participants undergoing any type of surgery. We defined pre-emptive NSAIDs as those given before surgery but not continued afterwards and preventive NSAIDs as those given before surgery and continued afterwards. These were compared to a control group given the NSAIDs after surgery instead of before surgery. We included studies that gave the medication by any route but not given on the skin.

DATA COLLECTION AND ANALYSIS

We used the standard methods expected by Cochrane, as well as a novel publication bias test developed by our research group. We used GRADE to assess the certainty of the evidence for each outcome. Outcomes included acute postoperative pain (minimal clinically important difference (MCID): 1.5 on a 0-10 scale), adverse events of NSAIDs, nausea and vomiting, 24-hour morphine consumption (MCID: 10 mg reduction), time to analgesic request (MCID: one hour), pruritus, sedation, patient satisfaction, chronic pain and time to first bowel movement (MCID: 12 hours).

MAIN RESULTS

We included 71 RCTs. Seven studies are awaiting classification. We included 45 studies that evaluated pre-emptive NSAIDs and 26 studies that evaluated preventive NSAIDs. We considered only four studies to be at low risk of bias for most domains. The operations and NSAIDs used varied, although most studies were conducted in abdominal, orthopaedic and dental surgery. Most studies were conducted in secondary care and in low-risk participants. Common exclusions were participants on analgesic medications prior to surgery and those with chronic pain. Pre-emptive NSAIDs compared to post-incision NSAIDs For pre-emptive NSAIDs, there is probably a decrease in early acute postoperative pain (MD -0.69, 95% CI -0.97 to -0.41; studies = 36; participants = 2032; I² = 96%; moderate-certainty evidence). None of the included studies that reported on acute postoperative pain reported adverse events as an outcome. There may be little or no difference between the groups in short-term (RR 1.00, 95% CI 0.34 to 2.94; studies = 2; participants = 100; I² = 0%; low-certainty evidence) or long-term nausea and vomiting (RR 0.85, 95% CI 0.52 to 1.38; studies = 5; participants = 228; I² = 29%; low-certainty evidence). There may be a reduction in late acute postoperative pain (MD -0.22, 95% CI -0.44 to 0.00; studies = 28; participants = 1645; I² = 97%; low-certainty evidence). There may be a reduction in 24-hour morphine consumption with pre-emptive NSAIDs (MD -5.62 mg, 95% CI -9.00 mg to -2.24 mg; studies = 16; participants = 854; I² = 99%; low-certainty evidence) and an increase in the time to analgesic request (MD 17.04 minutes, 95% CI 3.77 minutes to 30.31 minutes; studies = 18; participants = 975; I² = 95%; low-certainty evidence). There may be little or no difference in opioid adverse events such as pruritus (RR 0.40, 95% CI 0.09 to 1.76; studies = 4; participants = 254; I² = 0%; low-certainty evidence) or sedation (RR 0.51, 95% CI 0.16 to 1.68; studies = 4; participants = 281; I² = 0%; low-certainty evidence), although the number of included studies for these outcomes was small. No study reported patient satisfaction, chronic pain or time to first bowel movement for pre-emptive NSAIDs. Preventive NSAIDs compared to post-incision NSAIDs For preventive NSAIDs, there may be little or no difference in early acute postoperative pain (MD -0.14, 95% CI -0.39 to 0.12; studies = 18; participants = 1140; I² = 75%; low-certainty evidence). One study reported adverse events from NSAIDs (reoperation for bleeding) although the events were low which did not allow any meaningful conclusions to be drawn (RR 1.95; 95% CI 0.18 to 20.68). There may be little or no difference in rates of short-term (RR 1.26, 95% CI 0.49 to 3.30; studies = 1; participants = 76; low-certainty evidence) or long-term (RR 0.85, 95% CI 0.52 to 1.38; studies = 5; participants = 456; I² = 29%; low-certainty evidence) nausea and vomiting. There may be a reduction in late acute postoperative pain (MD -0.33, 95% CI -0.59 to -0.07; studies = 21; participants = 1441; I² = 81%; low-certainty evidence). There is probably a reduction in 24-hour morphine consumption (MD -1.93 mg, 95% CI -3.55 mg to -0.32 mg; studies = 16; participants = 1323; I² = 49%; moderate-certainty evidence). It is uncertain if there is any difference in time to analgesic request (MD 8.51 minutes, 95% CI -31.24 minutes to 48.27 minutes; studies = 8; participants = 410; I² = 98%; very low-certainty evidence). As with pre-emptive NSAIDs, there may be little or no difference in other opioid adverse events such as pruritus (RR 0.56, 95% CI 0.09 to 3.35; studies = 3; participants = 211; I² = 0%; low-certainty evidence) and sedation (RR 0.84, 95% CI 0.44 to 1.63; studies = 5; participants = 497; I² = 0%; low-certainty evidence). There is probably little or no difference in patient satisfaction (MD -0.42; 95% CI -1.09 to 0.25; studies = 1; participants = 72; moderate-certainty evidence). No study reported on chronic pain. There is probably little or no difference in time to first bowel movement (MD 0.00; 95% CI -15.99 to 15.99; studies = 1; participants = 76; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

There was some evidence that pre-emptive and preventive NSAIDs reduce both pain and morphine consumption, although this was not universal for all pain and morphine consumption outcomes. Any differences found were not clinically significant, although we cannot exclude this in more painful operations. Moreover, without any evidence of reductions in opioid adverse effects, the clinical significance of these results is questionable although few studies reported these outcomes. Only one study reported clinically significant adverse events from NSAIDs administered before surgery and, therefore, we have very few data to assess the safety of either pre-emptive or preventive NSAIDs. Therefore, future research should aim to adhere to the highest methodology and be adequately powered to assess serious adverse events of NSAIDs and reductions in opioid adverse events.

The internal dynamic modes of charged self-assembled peptide fibrils

Photon correlation spectroscopy is used to study the internal dynamics of self-assembled charged peptide fibrils. Short neutral and charged polymeric aggregates have diffusive modes due to whole macromolecular motion. For long semiflexible fibrils the logarithm of the intermediate scattering function follows a q(2)t(3/4) scaling at long times consistent with a Kratky-Porod free energy and preaveraged Oseen hydrodynamics. Persistence lengths on the order of micrometers are calculated for the peptide fibrils consistent with estimates from the liquid-crystalline phase behavior. Fibril diameters (5-35 nm) calculated from the initial decay of the correlation functions are in agreement with transmission electron microscopy measurements.

Hierarchical self-assembly of chiral rod-like molecules as a model for peptide beta -sheet tapes, ribbons, fibrils, and fibers

A generic statistical mechanical model is presented for the self-assembly of chiral rod-like units, such as beta-sheet-forming peptides, into helical tapes, which with increasing concentration associate into twisted ribbons (double tapes), fibrils (twisted stacks of ribbons), and fibers (entwined fibrils). The finite fibril width and helicity is shown to stem from a competition between the free energy gain from attraction between ribbons and the penalty because of elastic distortion of the intrinsically twisted ribbons on incorporation into a growing fibril. Fibers are stabilized similarly. The behavior of two rationally designed 11-aa residue peptides, P(11)-I and P(11)-II, is illustrative of the proposed scheme. P(11)-I and P(11)-II are designed to adopt the beta-strand conformation and to self-assemble in one dimension to form antiparallel beta-sheet tapes, ribbons, fibrils, and fibers in well-defined solution conditions. The energetic parameters governing self-assembly have been estimated from the experimental data using the model. The 8-nm-wide fibrils consist of eight tapes, are extremely robust (scission energy approximately 200 k(B)T), and sufficiently rigid (persistence length l(fibril) approximately 20-70 microm) to form nematic solutions at peptide concentration c approximately 0.9 mM (volume fraction approximately 0.0009 vol/vol), which convert to self-supporting nematic gels at c > 4 mM. More generally, these observations provide a new insight into the generic self-assembling properties of beta-sheet-forming peptides and shed new light on the factors governing the structures and stability of pathological amyloid fibrils in vivo. The model also provides a prescription of routes to novel macromolecules based on a variety of self-assembling chiral units, and protocols for extraction of the associated energy changes.

Pain as a quality management initiative

A 320-bed surgical nursing department's pain management quality improvement initiative is presented. Clinical indicators were designed through literature review and consultation with pain management experts. Results for pain assessment compliance, patient perception of relief, and the perceived impact of pain on activity--analyzed by nursing care unit, physician service, and pain medication type--are detailed, as are selected strategies to improve pain management outcomes.

Influence of Trichinella spiralis infection on development of sarcoma-180 ascites tumors

Long-term infection of mice with Trichinella spiralis has been shown to stimuate increased host protection aginst transplantable solid tumors. The present investionation was initiated to determine whether parasitized mice were similarly protected from induction and progression of an ascites tumor. ICR/CD-1 mice were orally infected with 50, 100, 200, 300, or 400 T. spiralis larvae, and subsequently challenged intraperitoneally with 5 X 10(4) Sarcoma-180 (S-180) ascites cells. Animals were observed and weighed daily for development and progression of malignancy. Protection from fatal ascites neoplasia was found to be statistically significant under selected conditions of larval dose and challenge interval. Mice infected with 100 or 200 larvae were more resistant to S-180 progression than both uninfected controls or other infected groups. Protection was observed in groups challenged 2 weeks after nematode intubation but not at 6, 8 or 34 weeks. This finding is in contrast with long-term protection seen previously with B-16 melanoma tumors, and suggests that antineoplastic effects of T. spiralis infection differ for ascitic and solid murine tumors.

Experimental pulmonary infection of mice by tracheal intubation of Pseudomonas aeruginosa: the use of antineoplastic agents to overcome natural resistance

Tracheal intubation of viable Pseudomonas aeruginosa ATCC 19660 into the lungs of mice had no significant effect on the animals even with administration of organisms as high as 5.0 X 10(9) CFU. Animals treated with a single injection of an antineoplastic drug were, however, susceptible to bacterial challenge into the lungs. LD50 values of 4.1 X 10(7), 4.8 X 10(7), and 1.0 X 10(8) CFU were obtained when animals were simultaneously infected and treated with methotrexate, vincristine sulfate, or cytosine arabinoside, respectively.

Murine gastrointestinal tract as a portal of entry in experimental Pseudomonas aeruginosa infections

Peroral administration of viable Pseudomonas aeruginosa into the stomach of mice resulted in an acute systemic infection, with death occurring within 72 h. One strain, ATCC 19660, a non-encapsulated form of P. aeruginosa, had a median lethal dose of 5.3 X 10(6) colony-forming units, whereas two encapsulated strains, ATCC 17933 and 17934, had median lethal dose values of 5.0 x 10(7) and 5.6 x 10(7) colony-forming units, respectively. Each strain required fewer organisms to establish a lethal infection via the stomach than by intravenous or intraperitoneal routes. The non-encapsulated strain, ATCC 19660, did not cause any diarrhea in the infected animals, whereas the two encapsulated strains, although less virulent, caused diarrhea when administered perorally. No signs of necrosis were noted within the gastrointestinal tract; however, hematogenous spread of the organism resulted in a vasculitis associated with the pulmonary vessels and bacterial invasion of the renal tissues. Treatment of animals with antineoplastic drugs 24 h before or simultaneously with peroral challenge resulted in an increased susceptibility to infection.

Experimental studies on mice subcutaneously challenged with heat-killed cells of Pseudomonas aeruginosa

Mice were found to be generally refractory to sc challenge with heat-killed cells of Pseudomonas aeruginosa and did not die unless unusually high concentrations were employed. Approximately 38.6% of the animals receiving a single, sublethal dose of 1 X 10(10) dead cells developed black, crusty, necrotic skin lesions within 3 to 5 days. No major gross and histopathological changes were detected in internal organs. If the animals were sc administered sublethal doses of either live or dead cells of P aeruginosa 16 days prior to sc challenge, then the incidence of black lesions rose to 78.6 and 50% of the animals, respectively. Of several antineoplastic agents tested, only methotrexate significantly affected the 72-hr LD50 resulting in a drop to 1.8 X 10(9) afrom 3.4 X 10(10) cells. However, both methotrexate and actinomycin D decreased the incidence of the black lesions.

Experimental studies on mice challenged subcutaneously with Pseudomonas aeruginosa

By use of the subcutaneous route, chronic Pseudomonas aeruginosa infections were established in normal mice undebilitated by burn wounds or leukopenic agents. Using a 21-day holding period, an LD50 value of 4.6 times 10(8) colony forming units was obtained. After subcutaneous infection, the dermis was completely necrosed with the lesions reaching deep into the subcutaneous tissue and musculature within 3-4 days. Ecthyma gangrenosum-like skin lesions at the site of infection appeared during this time period. By 7-15 days all mice exhibited a systemic infection. Both the livers and lungs showed a great deal of hemorrhage and frequently contained large necrotic foci, while the kidneys showed petechial hemorrhage and occasional renal abscesses. The susceptibility to infection was markedly increased by use of various antineoplastic agents and suprarenal hormones. However, the type of tissue damage or severity was not significantly altered as compared to infected mice which had not received any of the chemical agents.

Purification and partial characterization of a collagenolytic enzyme from Pseudomonas aeruginosa

A proteinase from Pseudomonas aeruginosa exhibiting collagenolytic activity was purified 1575-fold with a recovery of 24% by use of chemical and chromatographic technics. The enzyme preparation appeared to be homogeneous when subjected to chromatographic, electrophoretic and ultracentrifugational analyses. A standard state sedimentation coefficient of 2.10 S was calculated and further analyses indicated that the enzyme had a molecular weight of 17 500 and dimerizes under certain conditions to yield an apparent molecular weight of 34 000. In addition to insoluble collagen, the enzyme catalyzed the hydrolysis of congocoll, azocoll, soluble collagen and casein, but did not attack orcein-elastin, azoalbumin, p-toluene eulfonyl-L-arginine methyl ester, benzoyl-L-tyrosine ethyl ester, and the hexapeptide N-benzyloxycarbonyl-glycyl-L-prolyglycylglycyl-L-prolyl-L-alanine. Enzymatic activity against congocoll was 6-fold greater at pH 7.5 in Tris with HCl than in phosphate buffer at the same ionic strength. Cobalt, and to a lesser extent, Zn2+ appeared to activate the enzyme, especially in phosphate buffer. NcCN and p-chloromercuribenzoate did not appreciably inhibit enzyme activity, while (NH4)2 SO4, EDTA and cysteine displayed a significant inhibitory effect under certain conditions.

Experimental studies on hematogenously induced renal damage in the rabbit due to Pseudomonas aeruginosa

Chronic systemic infections of rabbits were established by intravenous inoculation of 4 times 10-8 P. aeruginosa cells in order to study the sequence of events leading to severe kidney damage. Renal lesions were detected by the fifth- to seventh-day postinfection, as were lesions in the liver and lungs. Progressive azotemia led to death by the 12th-16th day. Lesions in the kidneys, lungs and liver were characterized terminally by intense mononuclear cell infiltrates, hemorrhage, and microabscess formation. Mononuclear cells also appeared to be the predominant responsive cell early in infection. There appeared to be no difference in the susceptibility to infection or severity of renal lesions between rabbits with surgically induced unilateral ureteral obstruction and nonobstructed rabbits.

In vivo studies with collagenase from Pseudomonas aeruginosa

An extracellular protease from Pseudomonas aeruginosa having collagenase activity was assayed in vivo. The lethality of the enzyme for white female mice was determined by use of intravenous, intraperitoneal, intranasal, and subcutaneous routes, respectively. The collagenase exhibited the following 72-hr mean lethal dose values: intranasally, 55 collagenase units; intraperitoneally, 148 collagenase units; and intravenously, 288 collagenase units. In the concentrations tested, no lethality was obtained when the subcutaneous route was employed. Gross and microscopic studies revealed that the collagenase was capable of eliciting a variety of tissue responses in mice depending upon its route of administration. Intranasal instillation resulted in confluent pulmonary hemorrhage, whereas intraperitoneal injections resulted in severe abdominal hemorrhage with foci on the intestinal serosa. Intravenous injections elicited abdominal hemorrhage and petechial hemorrhage with focal necrosis of the lungs, whereas subcutaneous injections resulted in necrotic, ulcerating lesions.

Membranous inclusions of Pseudomonas aeruginosa

Electron microscopy of sectioned cells of Pseudomonas aeruginosa treated with a double fixative in N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid revealed a number of membranous inclusions varying in size and morphology. One round, electron transparent form was frequently observed which did not routinely appear to be attached to the cytoplasmic membrane and varied in size from 120 to 300 nm in diameter. However, in one case, several tubular structures between an inclusion and the cytoplasmic membrane was observed. On rare occasions, a large and unusual multilayered inclusion consisting of three thick and distinct layers was also encountered. In addition, two small mesosomal structures were singly observed in cells and were situated proximal to the cytoplasmic membrane. One type appeared to consist of a single thin membrane, whereas the other type consisted of a delicate, multilayered structure.