Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Single-institution experience with selective internal radiation therapy (SIRT) for the treatment of unresectable colorectal liver metastases

BACKGROUND

Liver metastases are the commonest cause of death for patients with colorectal cancer. Growing evidence supports the use of selective internal radiation therapy (SIRT) in combination with conventional chemotherapy regimens for liver-only or liver-dominant unresectable metastatic colorectal cancer.

AIMS

To measure and evaluate outcomes of the first 20 consecutive patients with unresectable colorectal liver metastasis selected for SIRT in addition to their chemotherapy at a single Irish institution.

METHODS

Retrospective case series was performed. Patient charts and medical records were reviewed.

RESULTS

All 20 patients (100%) selected for angiographic workup were subsequently successfully treated with radioembolization. All patients were discharged 1 day post-SIRT. At initial imaging evaluation, 12 (60%) had a partial response in their liver, 2 (10%) had stable disease, and 6 (30%) had liver-specific progressive disease. Median follow up was 10 months (range 6-26). At last follow up, 14 (70%) patients were alive and 6 (30%) deceased. Most recent imaging demonstrated 2 (10%) with a complete response, 7 (35%) had a partial response, 2 (10%) had stable disease, and 9 (45%) had progressive disease within their liver. One patient was downstaged to hepatic resection, and one with a complete hepatic response had his primary sigmoid tumor resected 11 months post-SIRT.

CONCLUSIONS

SIRT is a safe and effective therapy for certain patients with unresectable colorectal liver metastases. This case series supports our opinion that selected patients should be offered SIRT in concert with their medical oncologist, concomitant with their chemotherapy. Larger multi-center studies are required to more clearly define the patient groups that will derive most benefit from SIRT.

Asymptomatic Renal Pseudoaneurysm Following Laparoscopic Partial Nephrectomy

A 66-year-old-woman underwent a laparoscopic left partial nephrectomy for a 3 cm partially exophytic tumor arising from the posterior interpolar region of the left kidney. Follow-up surveillance computed tomography 6 months following the surgery found an incidental 4 cm lesion in the left kidney that is avidly enhanced in the arterial phase, consistent with a renal pseudoaneurysm. She was completely asymptomatic. Renal pseudoaneurysm is a rare complication following minimally invasive nephron-sparing surgery and typically presents in the early postoperative period with gross hematuria. However, a large renal pseudoaneurysm may also present as an asymptomatic incidental finding and is amenable to angioembolization.

Correlation of Peripheral Vein Tumour Marker Levels, Internal Iliac Vein Tumour Marker Levels and Radical Prostatectomy Specimens in Patients with Prostate Cancer and Borderline High Prostate-Specific Antigen: A Pilot Study

PURPOSE

To correlate prostate-specific antigen (PSA), free to total PSA percentage (fPSA%) and prostatic acid phosphatase (PAP) levels from peripheral and pelvic venous samples with prostatectomy specimens in patients with prostate adenocarcinoma and borderline elevation of PSA.

MATERIALS AND METHODS

In this prospective institutional review board approved study, 7 patients with biopsy proven prostate cancer had a venous sampling procedure prior to prostatectomy (mean 3.2 days, range 1-7). Venous samples were taken from a peripheral vein (PVS), the right internal iliac vein, a deep right internal iliac vein branch, left internal iliac vein and a deep left internal iliac vein branch. Venous sampling results were compared to tumour volume, laterality, stage and grade in prostatectomy surgical specimens.

RESULTS

Mean PVS PSA was 4.29, range 2.3-6 ng/ml. PSA and PAP values in PVS did not differ significantly from internal iliac or deep internal iliac vein samples (p > 0.05). fPSA% was significantly higher in internal iliac (p = 0.004) and deep internal iliac (p = 0.003) vein samples compared to PVS. One of 7 patients had unilateral tumour only. This patient, with left-sided tumour, had a fPSA% of 6, 6, 6, 14 and 12 in his peripheral, right internal iliac, deep right internal iliac branch, left internal iliac and deep left internal iliac branch samples respectively. There were no adverse events.

CONCLUSION

fPSA%, unlike total PSA or PAP, is significantly higher in pelvic vein compared to peripheral vein samples when prostate cancer is present. Larger studies including patients with higher PSA values are warranted to further investigate this counterintuitive finding.

Chest radiograph-based algorithm for managing malfunctioning ports

PURPOSE

To evaluate a chest x-ray-based algorithm for managing malfunctioning ports.

MATERIALS AND METHODS

A review of interventional radiology procedures on malfunctioning ports during the period 2000-2012 was performed. Events were divided into two periods: before and after implementation of an algorithm beginning with tip position evaluation using a chest x-ray. Time to return to usability, frequency of interventions to restore function, and frequency of malfunctioning ports remaining in use after the procedure were calculated.

RESULTS

The review included 303 procedures before implementation of the algorithm on 237 access sites in 227 patients (mean age, 56 y; 38% male) and 155 procedures after implementation of the algorithm on 131 access sites in 130 patients (mean age, 55 y; 35% male). Implementation of the algorithm was associated with significantly fewer repeat checks on the same access (27% before algorithm, 9% after algorithm, P < .001) and reduced frequency of a malfunctioning port remaining in use after the interventional radiology procedure (43% before algorithm to 14% after algorithm, P < .001). Median time from consultation to revision was significantly less after implementing the algorithm (13 days before algorithm, 1 day after algorithm, P < .001). Median time from consultation to port usability was also less after implementing the algorithm (2.7 days before algorithm, 1 day after algorithm, P < .001).

CONCLUSIONS

Implementation of the algorithm was associated with significantly less frequent repeat procedures on the same port and a lower frequency of malfunctioning ports remaining in place. Use of the algorithm was associated with significantly reduced time from consultation to revision and to return to usability. These findings suggest the algorithm allows triage of patients with malfunctioning ports to the appropriate intervention before undergoing a procedure.

Technical considerations for lower limb multidetector computed tomographic angiography

Multidetector computed tomography (MDCT) enables imaging of the entire arterial tree non-invasively. Optimal technical considerations for performing MDCT angiography (MDCTA) are essential for accurate diagnosis and atherosclerotic disease stratification. This review article focuses on the various technical aspects necessary for peripheral computed tomographic angiography (CTA) acquisition. Common clinical indications for peripheral MDCTA and the latest scan protocols are described. The essential issue of radiation dose reduction is discussed, along with methods of optimal contrast bolus detection and delivery. Post-processing techniques are also presented. Previously, digital subtraction angiography was the only established reliable imaging technique to quantify atherosclerotic disease load; however, MDCTA may now challenge this old gold standard, along with other non-invasive techniques such as magnetic resonance angiography (MRA).

Towards a more inclusive vision of the medical sciences

Progress in the medical sciences is largely determined by two things: (i) the questions we ask, and (ii) how rigorously and vigorously we attempt to answer them. How do we know which questions are the right questions to ask, and thus the correct questions to spend our time and energies trying to answer? Such evaluative concerns bring into sharper focus the question--'What is medicine for?' The international study of rosuvastatin is important not simply because of the health benefits it may confer, but because it inspires a more robust and inclusive vision of the medical sciences. A vision which recognizes that the primary goal of medicine is to promote health, and that includes the health of 'normal' people as well as those with illness and disease. This inclusive vision of the medical sciences is a transformative one, it departs from the 'disease-model' approach which has dominated distinct areas of medical research for decades.

Evaluation of early sequential 18F-FDG PET imaging as a prognostic indicator and predictor of response to platinum and pemetrexed chemotherapy in malignant pleural mesothelioma (MPM)

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Background: Recent evidence has suggested that baseline SUV and metabolic response measured on sequential PET scans early in the course of chemotherapy may predict for survival and response to chemotherapy. Methods: Patients with MPM suitable for platinum/pemetrexed chemotherapy were studied. Baseline pre-chemotherapy PET and CT scans were performed with a further PET scan before cycle 2. CT scans were repeated mid-treatment and at the end of 6 cycles. PET response was determined by measuring the change in the maximum and mean SUV, PET Vol (volume of tumor above SUV threshold of 3.5) and Total Lesion Glycolysis (TLG, calculated as PET Vol x SUV Max). Metabolic response (MR), as measured by a 25% drop in SUV Max, SUV Mean, PET Vol and TLG was compared to overall survival (OS) and to subsequent response to chemotherapy on CT. CT scans were read using Modified RECIST criteria and CT response was compared to OS. Results: 21 patients had baseline PET scans of whom 17 had a further PET before cycle 2. 19 patients had CT scans evaluable by Modified RECIST criteria. Baseline SUV Max and SUV Mean were found to predict for OS. Median survival was 17.2 months for patients with SUV Max less than 15 versus 6 months for those with SUV Max greater than 15 (p=0.0193). Median survival was 14.1 months for patients with SUV Mean less than 5 versus 6.5 months for those with SUV Mean greater than 5 (p=0.0681). MR defined by SUV Max, SUV Mean, PET Vol or TLG did not predict for OS. MR on PET correlated poorly with CT response with Kappa values of 0.01, 0.05, 0.15 and 0.31 for MR defined by SUV Max, PET Vol, SUV Mean and TLG respectively. CT response using Modified RECIST criteria correlated significantly with OS. Patients with partial response (PR), stable disease (SD) and progressive disease (PD) had median survivals of 25.6 months, 8.6 months and 4.6 months respectively (p=0.0072) Conclusions: MR measured by SUV Max, SUV Mean, PET Volume and TLG on early sequential PET scans did not correlate with CT assessed response to chemotherapy or OS. Baseline SUV Max >15 and SUV Mean >5 were indicative of poor prognosis. CT response as measured by Modified RECIST criteria correlated significantly with OS.

No significant financial relationships to disclose.

The case for re-thinking incest laws

The recent case of German siblings Patrick Stübing (age 30 years) and his sister Susan Karolewski (age 22 years) has reignited debate over the criminalisation of sexual intercourse among consanguine descendants. The primary justification for criminalising incest is the purported increased risk of genetic disabilities among offspring, but is criminalising sexual intercourse an empirically sound and proportionate response to this increased risk? To answer this question we must consider the specifics of the harm in question (eg, is it a harm to the child or a societal harm) and the magnitude of the harms of the intervention. The example of incest law has important implications for liberal societies. If we can justify imprisoning consenting adults for choosing partners who will increase the risk of having children with disabilities, then we set a troubling precedent for all couples who may pass on genetic disorders to their children.

Do all non-calcified echogenic renal lesions found on ultrasound need further evaluation with CT?

BACKGROUND

This is a study using Evidence Based Practice (EBP) technique to evaluate if non-calcified renal lesions detected with ultrasound, suspected to represent an angiomyolipoma (AML), need a CT to rule out a renal cell carcinoma (RCC).

METHODS

The secondary and primary literature were searched for all relevant information. This was appraised for validity and strength. The results from the papers with the highest level of evidence were grouped together and analyzed.

RESULTS

Three papers in the primary literature constituted the highest level of evidence. In total these three papers examined 220 lesions. The prevalence of AML was 45% in this sample. Overall, hyperechoic non-calcified renal lesions had a sensitivity of 0.99 (95% confidence interval (CI) 0.97-1.00), a specificity of 0.43 (95% CI 0.34-0.51), a positive predictive value (PPV) of 0.58 and a negative predictive value (NPV) of 0.98 for AMLs. 57.4% of RCCs were hyperechoic to renal parenchyma. Two of the studies found that posterior acoustic shadowing had a sensitivity of 0.34 (95% CI 0.40-0.56) and a specificity of 1.0 (95% CI 1.0-1.0) for AML.

CONCLUSIONS

From the surprisingly limited evidence available in the literature, it must be concluded that all non-calcified echogenic renal lesions detected with ultrasound need a CT to rule out an RCC.

Genes and equality

The way people think about equality as a value will influence how they think genetic interventions should be regulated. In this paper the author uses the taxonomy of equality put forth by Derek Parfit and applies this to the issue of genetic interventions. It is argued that telic egalitarianism is untenable and that deontic egalitarianism collapses into prioritarianism. The priority view maintains that it is morally more important to benefit the people who are worse off. Once this precision has been given to the concerns egalitarians have, a number of diverse issues must be considered before determining what the just regulation of genetic interventions would be. Consideration must be given to the current situation of the least advantaged, the fiscal realities behind genetic interventions, the budget constraints on other social programmes egalitarians believe should receive scarce public funds, and the interconnected nature of genetic information. These considerations might lead egalitarians to abandon what they take to be the obvious policy recommendations for them to endorse regarding the regulation of gene therapies and enhancements.

Sodium picosulphate compared with polyethylene glycol solution for large bowel lavage: a prospective randomised trial

Mechanical efficiency, patient acceptability and minimal biochemical perturbation are important factors in the choice of lavage solution for bowel preparation. This prospective randomised trial of 59 patients compared a polyethylene glycol bowel lavage solution (Klean Prep) to a sodium picosulphate solution (Picolax) considering their efficacy from both colonoscopists' and radiologists' points of view, patient acceptibility, and plasma biochemical changes. The sodium picosulphate solution was more acceptable to patients than the polyethylene glycol, and resulted in significantly less nausea and vomiting (p = 0.0025), and far fewer consumption difficulties (p < 0.0001). Mean plasma biochemical changes were significantly different for magnesium (p < 0.001), chloride (p < 0.01) and potassium (p < 0.02). Because neither lavage solution displayed a marked advantage for the colonoscopist or radiologist, and sodium picosulphate was more acceptable to patients, sodium picosulphate is the preferred solution for bowel preparation. The changes in plasma biochemistry values are unlikely to cause clinical problems.

Gas exchange in the insect tracheal system

The role of the insect tracheal system in gas exchange during cyclic ventilation is investigated using mathematical models. Three models are presented, one to describe the important elements of gas exchange during each of the three phases of cyclic ventilation. The effects of normobaric hypoxia on gas exchange are then examined, first assuming the initial parameter values set for the tracheal system and, second, assuming conditions of tracheal hypertrophy produced by an increase in the cross-sectional area of the tubes in the tracheal system. An increase in tracheal tube cross-sectional area is an important adaptation to normobaric hypoxia, but only if the tracheae themselves are the primary sites of resistance to gas exchange. Under conditions where the spiracles are the sites of resistance to gas exchange, volume expansion of the tracheae, not an increased cross-sectional area per se, is the important adaptation to normobaric hypoxia.

GAS EXCHANGE THROUGH THE LUNGS AND GILLS IN AIR-BREATHING CRABS

Lung and gill performance in gas exchange have been evaluated in eight species of air-breathing crabs with two different lung circulatory designs, those with portal systems and smooth lung linings, and those without portal systems and with invaginated and evaginated lung linings. In all species, the lungs were extremely effective in oxygen uptake whilst the performance of the gills was inferior. An exception to this was Gecarcoidea natalis, which has gills highly modified for aerial gas exchange; its gills and lungs were equally efficient in O2 uptake. The relative efficiencies of the lungs and gills in CO2 excretion differed between species, with the gills being the major site of CO2 loss in the more amphibious species and the lungs having an increasingly important role in the more terrestrial crabs. The presence or absence of lung portal systems was not found to correlate with either saturation rates or efferent oxygen concentrations, with both lung types being extremely efficient in O2 uptake. The lungs with portal systems showed a large increase in oxygen content in the first lacunar bed and progressively smaller increases in the next two; these lungs may, therefore, have some reserve for exercise.

Capillary perfusion in skeletal muscle

Timed perfusions of capillaries in soleus, vastus lateralis, and diaphragm of rats were determined by injecting a fluorescent dye into the aorta or right atrium. At preselected time intervals after dye injection, the circulation was interrupted, skeletal muscles were excised and frozen, and numerical counts of capillaries were made from transverse sections of the muscles. When fluorescent dye was injected into the right atrium or injected relatively slowly into the aorta, 100% of the capillaries contained dye by 3 s in vastus lateralis, 5 s in diaphragm, and 7 s in soleus. Rapid injection into the aorta delayed capillary filling. The rapid appearance of dye in skeletal muscle microvasculature suggests that either all capillaries are open to plasma flow all of the time or that the time constant for reopening of closed capillaries is very short. Furthermore, the patterns of capillary filling in skeletal muscle appear to be independent of muscle fiber type.

Adaptations in skeletal muscle capillarity following changes in oxygen supply and changes in oxygen demands

The effects of changes in oxygen supply and oxygen demands on fiber cross-sectional areas, capillary densities and capillary to fiber ratios were determined in three skeletal muscles of rat. The muscles examined were the vastus lateralis, soleus, and diaphragm. Reduced oxygen supply was produced by subjecting rats to ambient hypoxia, and increased oxygen demands were produced by subjecting rats to low ambient temperatures or treatment with thyroxin. Capillaries were visualized by injecting fluorescent dyes into the circulation. Muscles were quick frozen at resting lengths to preserve normal fiber geometry and were subsequently sectioned on a cryostat. All of the muscles sampled from animals in the experimental groups had elevated capillary densities. However, capillary to fiber ratios were not increased significantly in any muscle, for any experimental condition. Thus, all of the observed differences in capillarity were due to changes in the intrinsic rate of muscle fiber growth. Further, the relations of capillary density and capillary to fiber ratio to fiber area were the same as those obtained during normal maturation, suggesting that capillary growth is closely linked to the intrinsic rate of fiber growth.

CT manifestations of Menkes' kinky hair syndrome (trichopoliodystrophy)

A patient with Menkes' syndrome is reported. This patient has survived to the age of six years without mental retardation, and shows previously unreported computed tomographic (CT) findings of tortuous vessels and unusual osseous manifestations of undertubulation of long bones and posterior vertebral body scalloping.

Occult neuroblastoma presenting with opsomyoclonus: utility of computed tomography

The clinical and radiographic findings in 10 children with neuroblastoma presenting with opsomyoclonus are described and the literature is reviewed. Children with opsomyoclonus are often a diagnostic dilemma, as they may not have a palpable tumor or increased urinary catecholamines. Computed tomography (CT) is the most sensitive imaging method in locating tumors (100%) compared with plain radiography of the chest and abdomen (sensitivity 40%), excretory urography (50%), and 99mTc radionuclide bone scans (50%). The use of body CT significantly shortened the interval between initial presentation and final diagnosis and avoided multiple hospitalizations and unnecessary investigations for patients with persistent opsomyoclonus. Since most neuroblastomas are solitary lesions that may arise in the adrenal glands or along the sympathetic chain from the neck down into the pelvis, our policy is to use plain radiography, sonography, and 99mTc methylene diphosphonate (MDP) bone scans for the preliminary investigation of patients with opsomyoclonus. Body CT can then be tailored to suit the needs of the individual patients.