Clinical outcomes in patients undergoing elective coronary artery bypass graft surgery with and without utilization of pulmonary artery catheter-generated data

OBJECTIVE: The purpose of this study was to determine the frequency of pulmonary artery catheter (PAC) quantitative data requirements for modifying patient management during and after elective coronary artery bypass graft (CABG) surgery. DESIGN: A prospective observational clinical trial. SETTING: University tertiary referral center. PARTICIPANTS: Two hundred patients undergoing elective CABG surgery. Interventions: Attending anesthesiologist and surgeon were blinded to PAC numeric values. These data could be revealed in the presence of at least 2 of the following criteria: (1) systolic blood pressure <90 mmHg, (2) central venous pressure >15 mmHg, (3) urine output <0.5 mL/kg/h, (4) pH <7.35/HCO(3) <18 mmol/L, (5) SaO(2) <95%/F(I)O(2) >80%, and (6) ST changes +/- 2 mm if the empiric treatment failed to restore normal hemodynamics within 10 minutes. All patients were classified into either blinded or unblinded PAC groups. MEASUREMENTS AND MAIN RESULTS: PAC data were unblinded in 46 (23%) patients. Preliminary diagnosis was confirmed in 28 (14%), and treatment was modified in 18 (9%) of these patients. Four (2%) patients were given additional fluid challenges, 10 (5%) patients received a combination of fluid challenges and inotropic support, 3 (1.5%) patients were started on vasoconstrictors, and 1 (0.5%) patient required insertion of an intra-aortic balloon pump. Patients in the unblinded PAC group had a higher prevalence of perioperative myocardial infarction, atrial fibrillation, and inotropic support; longer intubation times; and increased intensive care unit (ICU) and hospital lengths of stay. CONCLUSIONS: This study confirmed the contention that insertion of a PAC can be safely delayed until the clinical need arises either in the operating room or in the ICU after elective CABG surgery.     

Peripherally applied neuropeptide SF is equally algogenic in wild type and ASIC3-/- mice

RFa-related peptides play a significant role in the processing of pain in the CNS of mammals. Recently it has been found that, when applied subcutaneously, these peptides elicit a powerful algogenic effect. The question arises whether this peripheral effect can be connected with the ability of RFa-related peptides to decrease the rate of desensitization of acid sensing ionic channels (ASICs) expressed in primary sensory neurons. We have addressed this question by comparing the effects of neuropeptide SF (NPSF), mammalian RFa peptide, in ASIC3-/- and wild-type C57BL/6J mice. Knockout of ASIC3 gene results in the changes in some of the behavioral parameters. However, subcutaneous injections of the NPSF into the n.saphenous innervation area result in a clearly nociceptive behavior in both strains of mice. There is no significant difference in the total time of licking of injected paw in the ASIC3-/- (194+/-22s) and C57BL/6J (227+/-25s) animals. Thus peripheral algogenic effects of NPSF cannot be explained only in terms of their action on the ASIC3 channels and involves some other, still unidentified mechanism.     

Brick tunnel randomization for unequal allocation to two or more treatment groups

Studies with unequal allocation to two or more treatment groups often require a large block size for permuted block allocation. This could present a problem in small studies, multi-center studies, or adaptive design dose-finding studies. In this paper, an allocation procedure, which generalizes the maximal procedure by Berger, Ivanova, and Knoll to the case of K≥2 treatment groups and any allocation ratio, is offered. Brick tunnel (BT) randomization requires the allocation path drawn in the k-dimensional space to stay close to the allocation ray that corresponds to the targeted allocation ratio. Specifically, it requires the allocation path to be confined to the set of the k-dimensional unitary cubes that are pierced by the allocation ray (the 'brick tunnel'). The important property of the BT randomization is that the transition probabilities at each node within the tunnel are defined in such a way that the unconditional allocation ratio is the same for every allocation step. This property is not necessarily met by other allocation procedures that implement unequal allocation.