Factors associated with cardiac rhythm disturbances in the early post-pneumonectomy period: a study on 259 pneumonectomies.

OBJECTIVE: To identify predisposing factors associated with cardiac rhythm disturbances during the early post-pneumonectomy period (first 7 postoperative days). MATERIALS AND METHODS: During the study period (1995-1999), 259 pneumonectomies were performed for malignant (244 cases) or benign disease (15 cases). Postoperative monitoring of patients included continuous arterial pressure - rhythm monitoring and pulse oximetry. Cardiac rhythm disturbances during the intensive care unit stay were detected on the monitor screen and recorded with a 12-lead electrocardiogram. Cardiac rhythm disturbances associated with electrolytes or fluid balance abnormality, mediastinal deviation or surgical postoperative complications were excluded from the study. Age of patients, preexisting cardiac disease, side of pneumonectomy, intrapericardial procedures, stage of the malignant disease, expected postoperative FEV(1)<1200 ml, intraoperative transfusions of packed red cells, elevated right heart pressures, low postoperative serum magnesium levels and long operative times were considered as predisposing factors for the development of post-pneumonectomy cardiac rhythm disturbances. Statistical analysis has been made using logistic regression analysis, Student t-test and chi-square test. RESULTS: Cardiac rhythm disturbances were detected in 49 patients (18.91%). Atrial fibrillation/flutter (31 cases), supraventricular tachycardia (14 cases), and premature ventricular contractions (four cases) were the observed rhythm disturbances. Right pneumonectomy versus left pneumonectomy (P<0.0001) and intrapericardial pneumonectomy versus standard pneumonectomy (P<0.0001) were identified as strong predisposing factors for the establishment of post-pneumonectomy cardiac rhythm disturbances. Patients who established post-pneumonectomy cardiac rhythm disturbances had significantly higher (P=0.024) right ventricular systolic pressure (42.50+/-15.50 mmHg) when compared with patients who had postoperative sinus rhythm (29.07+/-7.71 mmHg) and had also longer operative times than patients who did not develop rhythm disturbances (P=0.015). Mortality rate in patients who developed post-pneumonectomy rhythm disturbances was 20.40%. CONCLUSIONS: Cardiac rhythm disturbances observed early after pneumonectomy are mainly of supraventricular origin, complicating right and intrapericardial pneumonectomies, patients with elevated right heart pressures and long operative times, and are associated with high mortality rates.     

Antigen‐specific B lymphocytes acquire proteoglycan aggrecan from cartilage extracellular matrix resulting in antigen presentation and CD4+ T‐cell activation

The majority of studies examining antigen‐presenting cell (APC) function have focused on the capture and presentation of antigens released from pathogens or damaged cells. However, antigen‐specific B cells are also capable of efficiently extracting antigens that are either tethered to, or integrally part of the plasma membrane of various target cells. In this study we show that B cells are also highly efficient at extracting integral components of the extracellular matrix (ECM) for subsequent presentation. In particular we demonstrate that B cells specific for aggrecan, an integral component of cartilage ECM, acquire this rheumatoid arthritis candidate autoantigen in both a B‐cell‐receptor‐dependent and a contact‐dependent manner. We also demonstrate that the subsequent presentation of aggregan from ECM leads to CD4⁺ T‐cell activation and effector cell formation. Recent studies have identified B‐cell‐mediated antigen presentation as essential for the development of autoimmunity, but a unique role for B cells compared with other APC has yet to be defined. Our findings lead us to propose that the acquisition of ECM‐derived autoantigens represents a mechanism that defines the APC requirement for B cells in the development of autoimmunity.     

Achieving the optimal epinephrine effect in wide awake hand surgery using local anesthesia without a tourniquet

Background

In our experience, for all surgeries in the hand, the optimal epinephrine effect from local anesthesia—producing maximal vasoconstriction and visualization—is achieved by waiting significantly longer than the traditionally quoted 7 min from the time of injection.

Methods

In this prospective comparative study, healthy patients undergoing unilateral carpal tunnel surgery waited either 7 min or roughly 30 min, between the time of injection of 1 % lidocaine with 1:100,000 epinephrine and the time of incision. A standardized incision was made through dermis and into the subcutaneous tissue followed by exactly 60 s of measuring the quantity of blood loss using sterile micropipettes.

Results

There was a statistically significant reduction in the mean quantity of bleeding in the group that waited roughly 30 min after injection and before incision compared to the group that waited only 7 min (95 % confidence intervals of 0.06 + −0.03 ml/cm of incision, compared to 0.17 + −0.08 ml/cm, respectively) (P = 0.03).

Conclusions

Waiting roughly 30 min after injection of local anesthesia with epinephrine as oppose to the traditionally taught 7 min, achieves an optimal epinephrine effect and vasoconstriction. In the hand, this will result in roughly a threefold reduction in bleeding—making wide awake local anesthesia without tourniquet (WALANT) possible. This knowledge has allowed our team to expand the hand procedures that we can offer using WALANT. The benefits of WALANT hand surgery include reduced cost and waste, improved patient safety, and the ability to perform active intraoperative movement examinations.     

Circulating progenitor cells: a comparison of patients with glioblastoma or meningioma

Blood circulating endothelial cells and circulating hematopoietic progenitor cells (CPCs) are two cell populations that are thought to play important role in angiogenesis. In the present study, we investigated the role of CPCs in patients with brain tumors. We prospectively studied 19 brain tumor patients. Ten healthy individuals were used as controls. Variables that were analyzed included age, sex, Ki-67 index, symptom duration, tumor location, tumor size and preoperative Karnofsky performance status score (KPS). CPCs were determined as CD45^dim/CD34+/CD133+ in the peripheral blood. Twelve patients had glioblastoma (GBM), 1 patient had a grade II glioma and 6 patients had meningioma. Brain tumor patients had significantly higher CPC levels compared to healthy volunteers. Patients with gliomas had significantly higher CPC levels than patients with meningiomas. In GBM patients no correlation was found between CPC levels and sex, age, Ki-67 index, tumor location, size and KPS. Patients with CPC levels lower than 1,743 cells/ml had a higher progression-free survival but the difference was not statistically significant. Glioma patients had higher CPC levels compared to patients with meningiomas. Larger studies are obviously needed to verify the role of CPC levels in patients with brain tumors.     

Expansion of KPC-producing Klebsiella pneumoniae with various mgrB mutations giving rise to colistin resistance: the role of ISL3 on plasmids

mcr-1 has been reported as the first plasmid-encoded gene conferring colistin resistance. In KPC-producing Klebsiella pneumoniae (KPC-KP), however, colistin resistance is rapidly emerging through other mechanisms. Resistance is frequently due to disruption of the mgrB gene by insertion sequences, e.g. ISL3. The aim of this study was to investigate the expansion of mgrB-mutated KPC-KP isolates. In addition, the localisation and targets of ISL3 sequences within the core and accessory genome of common KPC-KP lineages were identified. A total of 29 clinical K. pneumoniae isolates collected from Italian patients were randomly selected. Whole genome sequences were analysed for resistance genes, plasmids and insertion sequences. In addition, 27 colistin-resistant KPC-KP isolates from a previous study from Crete (Greece) were assessed. Clonal expansion of KPC-KP isolates with various mutations in mgrB among all lineages was observed. In two Italian MLST ST512 isolates and eight Greek ST258 isolates, an identical copy of ISL3 was inserted in mgrB nucleotide position 133. ISL3, a transposable restriction–modification system of 8154 nucleotides, was located on pKpQIL-like plasmids and may transpose into the chromosome. In four isolates, chromosomal integration of ISL3 in diverse inner membrane proteins other than mgrB was identified. Colistin resistance is most often explained by clonal expansion of isolates with mutated mgrB. pKpQIL-like plasmids, which are omnipresent in KPC-KP, carry insertion sequences such as ISL3 that have mgrB as a target hotspot for transposition. Transposition of insertion sequences from plasmids and subsequent clonal expansion may contribute to the emerging colistin resistance in KPC-KP.