Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

THE EFFECT OF VARIATIONS IN THE GENERAL COMPOSITION OF SAMPLES IN SPECTROGRAPHIC ANALYSIS

Variations that occur in intensity ratios belonging to pairs of elements on the addition of various extraneous substances to standard samples have been studied using a common type of condensed spark discharge. The extent of the variations depended on the test elements chosen, the nature of the added substance, the line pair investigated, and on whether or not the standard samples were buffered. The variations bore no apparent relation to the relative ionization potentials or atomic weights of the test elements, nor to any physical property of the added substances. In general, they were smaller for the line pairs having the most nearly equal excitation potentials. Usually, but not always, they were smaller for buffered than for unbuffered samples. Illumination of the electrodes with ultraviolet light, though resulting in steadier operation of the discharge, or alterations of the capacity in the sparking circuit did not reduce the variations materially. Operation of the discharge at constant current coupled with the use of a buffer however did reduce the variations considerably for the instances studied. </jats:p

EXCITATION IN SOURCES FOR SPECTROSCOPIC ANALYSIS

From the viewpoint of the spectroscopic analyst, it is desirable to obtain some knowledge concerning the phenomena that result in the emission of radiation from certain types of sources. Results of intensity measurements on the vibration bands of the violet cyanogen system, and on certain lines in the tin spectrum, indicate that in the condensed d-c. and a-c. spark discharges the excitation is predominantly thermal in character, just as in the freely burning carbon arc. The values for the maximum temperature in the discharge columns of these three sources were found to be very nearly 9500°, 7800°, and 7000° K., respectively. It was observed, however, that the Boltzmann character of the distribution over various energy states was lost when the usual inductance was removed from the d-c. spark circuit.One of the five investigated tin levels exhibited an abnormal behavior, which may possibly be accounted for by the occurrence of collisions of the second kind. There is also evidence to show that the emitting column is surrounded by a relatively cold layer of atoms originating in the material placed on the electrode. This layer absorbs some of the intensity of the lines ending on the ground level. </jats:p

ABSORPTION STEP-WEAKENERS OF ANTIMONY

It is of advantage to the spectroscopic analyst to have a means of quickly preparing a step-weakener of any required characteristics. A method has been developed in which antimony films are deposited by thermal decomposition of the trihydride. The apparatus required is simple, and a multi-step, weakener may be made in 20 min. The films are nearly neutral below λ 4000Å. Their optical density is quite uniform, and they are sufficiently strong for all practical purposes. For high precision work, the construction of the weakener must be such that undesirable interference effects are avoided. A consideration of the theory of interference phenomena in light transmitted through thin plates suggests several possible methods of construction. Some of these have been adopted and have been found to be satisfactory in practice. </jats:p

TRANSPORT OF MATERIAL IN SOURCES FOR SPECTROSCOPIC ANALYSIS

A study of the transport of material in the condensed d-c. spark discharge has been made, with the object of placing quantitative spectroscopic methods of analysis on a less empirical basis and thus permitting, (a) the recognition of certain conditions of source operation which lead to unreliable determinations, and (b) the determination of some of the criteria to be fulfilled for maximum precision in analytic measurements.Variations in the transport phenomena, as indicated by variations in the relative distributions of emitting atoms of various elements along the discharge axis on the addition of certain substances to a sample, appear to be closely connected with the ionization potentials and masses of the elements, and with the ionization potentials of other particles present in the discharge. The data indicate the necessity for the use of a spectroscopic buffer, and provide certain criteria for the choice of the buffer and of the internal standard element.The exact nature of the mechanism of transport is uncertain, but various considerations indicate that neither the motion of ions under the influence of the field nor diffusion in the ordinary sense is sufficient to account for observed features. </jats:p

THE SECRETION OF CRYSTALLOIDS AND PROTEIN MATERIAL BY THE PANCREAS IN RESPONSE TO SECRETIN ADMINISTRATION

The concentrations of sodium, potassium, calcium, chloride, bicarbonate, and protein and non-protein nitrogen were determined in series of samples of pancreatic juice secreted by dogs in response to (a) constant rate of administration of secretin, (b) varied rate of administration of secretin, and (c) interrupted administration of secretin (rest period, 2 hr.). Spectroscopic as well as chemical methods were used in the analysis of the samples.The data indicate that the membranes of the pancreatic gland offer little resistance to the passage of simple inorganic ions. The compensatory relation between the bicarbonate and chloride concentrations of the secretion is interpreted on the basis of (a) formation of at least part of the bicarbonate within the secretory cells, and (b) the action of membrane forces, probably of an electrical nature. Absorption spectrum studies indicate either (a) that only one type of absorbing protein is present in the secretion, or (b) that if several types are present, they are always secreted in constant proportions whether they are enzymatically active or not. The interpretation of the protein nitrogen and certain other data are given in a subsequent paper. </jats:p

THE SYNTHESIS AND SECRETION OF PROTEIN MATERIAL BY THE PANCREAS

A mathematical treatment of the process of synthesis of protein material in the pancreas, and its secretion in response to secretin administration, has been developed. It was based on assumptions inferred from experimental data and from analogy with a suggested mechanism for the submaxillary gland, published previously. It leads to expressions that quantitatively describe the protein output in samples of pancreatic juice obtained under widely varied experimental conditions. Inferences concerning the fundamental character of certain glandular mechanisms may be drawn from the treatment. In addition it permits provisional calculation of various factors not directly observable in critical experiments, and suggests further problems in connection with the secretory processes. </jats:p