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Background: The COVID-19 pandemic has markedly increased delays in oncologic surgeries because of the virus’s impact on traditional anesthetic management. Novel protocols, developed to protect patients and medical professionals, have altered the ways and instances in which general anesthesia (GA) can be safely performed. To reduce virus exposure related to aerosol-generating procedures, it is now recommended to avoid GA when feasible and promote regional anesthesia instead. At our institution, we observed faster postoperative recovery in patients who received paravertebral blocks for breast cancer surgery instead of GA. This led us to formally evaluate whether regional anesthesia instead of GA helped improve time to hospital discharge. Methods: We conducted a historical cohort study to retrospectively analyze two cohorts of patients: prepandemic vsintrapandemic. We obtained approval from our institutional ethics committee to review files of consecutive patients who underwent breast cancer surgery between 30 March 2020 and 30 June 2020 (intrapandemic group; N= 106) and consecutive patients—moving backwards—from 28 February 2020 to 6 December 2019 (prepandemic group; N= 104). The primary outcome was the length of time between the end of surgery to readiness for hospital discharge. Secondary outcomes included the incidence of postoperative nausea and vomiting (PONV), the need for postoperative analgesia, and the duration of stay in the postanesthesia care unit (PACU). Results: The median [interquartile range (IQR)] time to readiness for hospital discharge was significantly lower in patients who received paravertebral blocks for breast cancer surgery compared with GA (intrapandemic group, 119 [99–170] min vsprepandemic group, 191 [164–234] min; P< 0.001) as was the incidence of PONV (3% vs11%; P= 0.03) and median [IQR] PACU durations of stay (29 [21–39] min vs46 [37–63] min; P< 0.001). Conclusions: Patients who received paravertebral blocks for breast cancer surgery in the intrapandemic group were ready for hospital discharge earlier, spent less time in the PACU, and experienced less PONV than those who received GA in the prepandemic group. With growing surgical wait times, concerns related to aerosol-generating procedures, and recommendations to avoid GA when feasible, paravertebral blocks as the principal anesthetic modality for breast cancer surgery offered benefits for patients and medical teams.

In 2005, the first facial vascularized composite allotransplant was performed in France. In May 2018, our team at Maisonneuve-Rosemont Hospital, Montreal, Quebec, had the privilege to participate in the first facial transplant in Canada. Interdisciplinary collaboration, coordination, and communication formed the cornerstone of this medical undertaking and, ultimately, its success. This report details the anesthetic and organizational considerations of our experience.

Assessing fluid responsiveness is important in the management of patients with hemodynamic instability. Passive leg raising (PLR) is a validated dynamic method to induce a transient increase in cardiac preload and predict fluid responsiveness. Variations in end-tidal carbon dioxide (ETCO2) obtained by capnography correlate closely with variations in cardiac output when alveolar ventilation and carbon dioxide production are kept constant. In this prospective observational study, we tested the hypothesis that variations in ETCO2induced by a simplified PLR maneuver can track changes in the cardiac index (CI) and thus predict fluid responsiveness. A five-minute standardized PLR maneuver was performed in 90 paralyzed hemodynamically stable cardiac surgical patients receiving mechanical ventilation. Cardiac index was measured by thermodilution before and one minute after PLR. End-tidal CO2measurements using capnography were obtained during the entire PLR maneuver. Fluid responsiveness was defined as a 15% increase in the CI. The Chi square test and Student’s ttest were used to compare responders and non-responders. Logistic regression analyses were then performed to determine factors of responsiveness. There were no differences between responders and non-responders in demographic and baseline hemodynamic variables. Fluid responsiveness was associated with an ETCO2variation (ΔETCO2) of ≥ 2 mmHg during PLR [odds ratio (OR), 7.3; 95% confidence interval (CI), 2.7 to 20.2; P< 0.01; sensitivity 75%]. A low positive predictive value (54%) and a high negative predictive value (NPV) (86%) were observed. No other clinical or hemodynamic predictors were associated with fluid responsiveness. A logistic regression model established that a combination of ΔETCO2≥ 2 mmHg and a change in systolic blood pressure ≥ 10 mmHg induced by passive leg raising was predictive of fluid responsiveness (OR, 8.9; 95% CI, 2.5 to 32.2; P= 0.005). Use of a passive leg raising maneuver to induce variation in ETCO2is a noninvasive and useful method to assess fluid responsiveness in paralyzed cardiac surgery patients receiving mechanical ventilation. Given its high NPV, fluid responsiveness is unlikely if a passive leg raising maneuver induces ΔETCO2of < 2 mmHg. L’évaluation de la réponse au remplissage est importante dans la prise en charge des patients souffrant d’instabilité hémodynamique. L’élévation passive des jambes (EPJ) est une méthode dynamique validée pour induire une augmentation transitoire de la précharge cardiaque et prédire la réponse au remplissage. Les variations en matière de dioxyde de carbone télé-expiratoire (ETCO2) obtenues par capnographie sont étroitement corrélées aux variations de débit cardiaque lorsque la ventilation alvéolaire et la production de dioxyde de carbone sont maintenues constantes. Dans cette étude observationnelle prospective, nous avons testé l’hypothèse selon laquelle les variations de l’ETCO2induites par une manœuvre simplifiée d’EPJ peuvent refléter les changements d’index cardiaque (IC) et ainsi prédire la réponse au remplissage. Une manœuvre d’EPJ standardisée de cinq minutes a été réalisée auprès de 90 patients de chirurgie cardiaque hémodynamiquement stables et curarisés recevant une ventilation mécanique. L’index cardiaque a été mesuré par thermodilution avant et une minute après la manœuvre. Les mesures de CO2télé-expiratoire ont été obtenues par capnographie tout au long de la manœuvre d’EPJ. On a défini la réponse au remplissage en tant qu’une augmentation de 15 % de l’IC. Le test de Chi carré et le test tde Student ont été utilisés pour comparer les répondants et les non-répondants. Des analyses de régression logistique ont ensuite été réalisées afin de déterminer les facteurs de réponse. Aucune différence n’a été observée entre les répondants et les non-répondants en matière de variables démographiques ou hémodynamiques de base. La réponse au remplissage a été associée à une variation d’ETCO2(ΔETCO2) ≥ 2 mmHg pendant la manœuvre d’EPJ [rapport de cotes (RC), 7,3; intervalle de confiance (IC) 95 %, 2,7 à 20,2; P< 0,01; sensibilité 75 %]. Une valeur prédictive positive basse (54 %) et une valeur prédictive négative élevée (VPN) (86 %) ont été observées. Aucun autre prédicteur clinique ou hémodynamique n’a été associé à la réponse au remplissage. Le modèle de régression logistique a établi qu’une combinaison de ΔETCO2≥ 2 mmHg et une modification de la pression artérielle systolique ≥ 10 mmHg induite par une élévation passive des jambes était un prédicteur de réponse au remplissage (RC, 8,9; IC 95 %, 2,5 to 32,2; P= 0,005). L’utilisation d’une manœuvre d’élévation passive des jambes pour induire des variations d’ETCO2constitue une méthode non invasive et utile pour évaluer la réponse au remplissage chez des patients de chirurgie cardiaque paralysés recevant une ventilation mécanique. Étant donné sa VPN élevée, la réponse au remplissage est peu probable si une manœuvre d’élévation passive des jambes induit une ΔETCO2< 2 mmHg.

ABSTRACTClostridium difficileis the major causative agent of nosocomial antibiotic-associated diarrhea, colitis, and pseudomembranous colitis. The pathogenicity of C. difficileis closely related to the production of toxins A and B. Toxigenic C. difficiledetection by a tissue culture cytotoxin assay is often considered the “gold standard.” However, this assay is time consuming, as it implies an incubation period of at least 24 h. We have developed a rapid real-time fluorescence-based multiplex PCR assay targeting the C. difficiletoxin genes tcdAand tcdB, with the Smart Cycler. Two molecular beacons bearing different fluorophores were used as internal probes specific for each amplicon type. The analytical sensitivity of the assay was around 10 genome copies for all nine C. difficilestrains tested, representing the 6 most common toxinotypes. The specificity was demonstrated by the absence of amplification with DNA purified from bacterial species other than C. difficile(n= 14), including Clostridium sordelliifor which the lethal toxin gene sequence is closely related to the toxin genes of C. difficile. Following a rapid (15 min) and simple fecal sample preparation protocol, both tcdAand tcdBwere efficiently amplified from 28 of 29 cytotoxin-positive feces samples. There was no amplification observed with all 27 cytotoxin-negative feces samples tested. This is the first real-time PCR assay for the detection of C. difficile. It is rapid, sensitive, and specific and allows detection of C. difficiledirectly from feces samples.

ABSTRACTSite-directed mutagenesis of Ser-289 of the class C β-lactamase from Enterobacter cloacaeP99 was performed to investigate the role of this residue in β-lactam hydrolysis. This amino acid lies near the active site of the enzyme, where it can interact with the C-3 substituent of cephalosporins. Kinetic analysis of six mutant β-lactamases with five cephalosporins showed that Ser-289 can be substituted by amino acids with nonpolar or polar uncharged side chains without altering the catalytic efficiency of the enzyme. These data suggest that Ser-289 is not essential in the binding or hydrolytic mechanism of AmpC β-lactamase. However, replacement by Lys or Arg decreased by two- to threefold the kcatof four of the five β-lactams tested, particularly cefoperazone, cephaloridine, and cephalothin. Three-dimensional models of the mutant β-lactamases revealed that the length and positive charge of the side chain of Lys and Arg could create an electrostatic linkage to the C-4 carboxylic acid group of the dihydrothiazine ring of the acyl intermediate which could slow the deacylation step or hinder release of the product.

A study recently conducted across Canada showed that 64 of 2,503 clinical isolates of Haemophilus influenzae were resistant to beta-lactams without production of a beta-lactamase (L. D. Tremblay, J. L'Ecuyer, P. Provencher, M. G. Bergeron, and Canadian Study Group, Can. Med. Assoc. J. 143:895-900, 1990). The beta-lactamase-negative strains formed three distinct groups, with ampicillin MICs of 0.5 to 1, 2 to 4, and greater than or equal to 8 micrograms/ml for groups I, II, and III, respectively. We have investigated the mechanisms of resistance for eight strains originating from different infections and geographic areas. These strains were representative of groups I to III. Five strains were nontypeable, two were type B, and one was non-B. Chromosomal DNA extracted from each strain was used to transform the laboratory strain Rd. Transformants were selected on beta-lactam-containing plates and showed the same level of resistance to ampicillin as the donor strains. Differences in outer membrane proteins, porins, and lipopolysaccharide profiles on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) did not change with resistance. Functional analyses of purified porins in artificial lipid bilayer experiments did not explain resistance. Peptidoglycan synthesis was measured by incorporation of [14C]alanine into trichloroacetic acid-insoluble cell wall material in the presence of chloramphenicol. The growth rate and the rate of peptidoglycan synthesis observed for the transformants of the isogenic set did not correlate with resistance. Whole-cell labeling with 125I-penicillin revealed modifications in penicillin-binding proteins (PBPs) among the transformants. In particular, PBPs 3A and 3B (65 and 63 kDa, respectively) showed a decrease in affinity for beta-lactams in all transformants (groups I, II, and III) and correlated with an increased MIC except in the transformant of group III, which showed higher levels of resistance. Partial purification and proteolytic digestion of 125I-penicillin-labeled PBP 3B led to two types of CnBr peptide profiles on SDS-PAGE, the profiles of the transformed strains from groups I and II being different from those of the control group and group III. Finally, electron microscopy revealed a distinct cell filamentation for the group III transformants. These data clearly indicate that changes in PBPs are a common mechanism that results in a significant level of non-beta-lactamase-mediated beta-lactam resistance in H. influenzae despite serotype, origin of isolation, or geographic distribution.

A 4.4‐kb DNA fragment was cloned from Actinobacillus pleuropneumoniae(strain 4074, serotype 1) by genetic complementation with Escherichia coli groES‐groELmutant strains. Sequence analysis of this fragment revealed a purine nucleoside phosphorylase (DeoD)‐encoding gene homolog (deoD), heat‐shock response‐encoding genes for the small (groES) and large subunits (groEL) and a partial open reading frame encoding an alcohol dehydrogenase homolog (adhE). The predicted amino‐acid sequence of groESand groELgenes showed extensive sequence identity (80–95%) with other Pasteurellaceae. The gene organization surrounding the groElocus was different from that of Haemophilus infuenzae. When expressed in E. coli, groES‐groELgenes were capable of complementing the growth of a λ lytic phage, indicating a structural as well as functional conservation.

A 4.4-kb DNA fragment was cloned from Actinobacillus pleuropneumoniae (strain 4074, serotype 1) by genetic complementation with Escherichia coli groES-groEL mutant strains. Sequence analysis of this fragment revealed a purine nucleoside phosphorylase (DeoD)-encoding gene homolog (deoD), heat-shock response-encoding genes for the small (groES) and large subunits (groEL) and a partial open reading frame encoding an alcohol dehydrogenase homolog (adhE). The predicted amino-acid sequence of groES and groEL genes showed extensive sequence identity (80–95%) with other Pasteurellaceae. The gene organization surrounding the groE locus was different from that of Haemophilus infuenzae. When expressed in E. coli, groES-groEL genes were capable of complementing the growth of a λ lytic phage, indicating a structural as well as functional conservation.