Reaching Consensus by Allowing Moments of Indecision.

Group decision-making processes often turn into a drawn out and costly battle between two opposing subgroups. Using analytical arguments based on a master equation description of the opinion dynamics occurring in a three-state model of cooperatively interacting units, we show how the capability of a social group to reach consensus can be enhanced when there is an intermediate state for indecisive individuals to pass through. The time spent in the intermediate state must be relatively short compared to that of the two polar states in order to create the beneficial effect. Furthermore, the cooperation between individuals must not be too low, as the benefit to consensus is possible only when the cooperation level exceeds a specific threshold. We also discuss how zealots, agents that remain in one state forever, can affect the consensus among the rest of the population by counteracting the benefit of the intermediate state or making it virtually impossible for an opposition to form.

Case of fulminant leptospirosis in a renal transplant patient.

We present a case of fulminant leptospirosis that was acquired in the suburban area by a 48-year-old male renal transplant recipient. He developed acute renal and hepatic failure with profound jaundice. Spirochetes were identified on liver biopsy. Weil's disease was suspected, and the diagnosis was further supported by a positive serum Leptospira interrogans icterohaemorrhagiae antibody titer. Unfortunately, he suffered from recurrent lower gastrointestinal bleeding, had a prolonged hospital course, and eventually succumbed to overwhelming sepsis. This case is the third report to our knowledge of leptospirosis in a renal transplant recipient in the English literature.

Contrast-induced acute kidney injury in renal transplant recipients after cardiac catheterization.

Renal transplant (RTX) recipients remain at high-risk for acute kidney injury (AKI) despite having improved renal function and quality of life after transplantation. We sought to identify the incidence and risk factors for contrast-induced AKI in RTX recipients after cardiac catheterization at our institute as identified by electronic records. After excluding patients on dialysis at time of procedure due to failed transplant and who did not have post-exposure creatinine values within 3 days, we reviewed 77 procedures on 57 patients. We studied one case per patient (the most recent procedure). Among the 57 patients, 42 were male, 42 were Caucasian and mean age was 58.2 +/- 10.1 years. Mean serum creatinine 24 h pre-procedure was 1.7 +/- 0.8 mg/dl. Contrast-induced AKI, defined as rise in serum creatinine of 25% or 0.5 mg/dl within 3 days post-catheterization, occurred in 9 procedures (15.8%). One procedure was complicated by AKI requiring dialysis. AKI occurred more frequently with use of low-osmolar contrast (ioxaglate or iohexol) in comparison with iso-osmolar contrast (iodixanol) (9/36 vs. 0/21, p = 0.019). Patients who received prophylactic N-acetylcysteine had lower incidence of AKI than those who did not (4/41 vs. 5/16, p = 0.046). Exact logistic regression analysis revealed odds ratio of developing AKI with use of low-osmolar vs. iso-osmolar contrast to be 7.747 (1.101 - yen); p = 0.0381). Contrast-induced AKI was common in RTX recipients after cardiac catheterization. Iso-osmolar contrast was associated with a lower risk of contrast-induced AKI in comparison with low-osmolar contrast.

Comparison of central venous and external jugular venous pressures during repair of proximal femoral fracture.

BACKGROUND: External jugular venous pressure (EJVP) is a close estimate of central venous pressure (CVP) in patients undergoing mechanical ventilation in the supine position, but the effects of spontaneous respiration and posture on this relationship are not known. In this study, we compared CVP with EJVP measurements in 36 patients undergoing repair of proximal femoral fracture breathing spontaneously in the supine or lateral positions. METHODS: A standard general anaesthetic was administered with patients breathing spontaneously via a laryngeal mask airway and i.v. fluids administered according to an algorithm guided by CVP measurements. CVP and EJVP catheters were placed on the right side of the neck where possible. RESULTS: In the supine position, 185 paired measurements of CVP and EJVP and 79 in the lateral position were recorded by a blinded observer during surgery. In the supine position, the mean difference between CVP and EJVP was -0.3 mm Hg (limits of agreement -2.6 to +1.9 mm Hg, 95% confidence intervals for both upper and lower limits of agreement, respectively, were -2.9 to -2.2 and +1.6 to +2.2 mm Hg). In the lateral position, the mean difference was -1.2 mm Hg (limits of agreement -5.8 to +3.8 mm Hg, 95% confidence intervals -6.8 to -4.5 and +2.7 to +4.9 mm Hg). CONCLUSIONS: These data suggest that EJVP is an acceptable estimate of CVP in the supine position. Agreement was poor in the lateral position but was stronger for estimates of trend rather than absolute values. This could be explained by the direct effects of posture.

Is intraperitoneal levobupivacaine with epinephrine useful for analgesia following laparoscopic cholecystectomy? A randomized controlled trial.

BACKGROUND AND OBJECTIVE: A randomized controlled trial of patients undergoing laparoscopic cholecystectomy. To evaluate whether the instillation of levobupivacaine, with epinephrine, intraperitoneally, reduces morphine consumption; further, to consider the degree of abdominal and shoulder pain in the presence of local anaesthetic at the site of surgical incision. METHODS: Patients received a standardized procedure and were allocated randomly to receive either (a) 2.5 mg mL(-1) levobupivacaine 30 mL, with epinephrine 5 microg mL(-1), or (b) normal saline 30 mL, with epinephrine 5 microg mL(-1), to the bed of the gall bladder and above the liver, immediately before wound closure. RESULTS: Median (interquartile range) total abdominal pain during inspiration in the levobupivacaine group was significantly (P = 0.041) lower (71 (21-129) mm) than that in the placebo group (123 (71-179) mm). However, there was no significant difference between the two groups with respect to total abdominal pain at rest, right shoulder pain or the consumption of rescue morphine and rescue dihydrocodeine. There were no differences between the two groups with respect to the administration of cyclizine, total nausea and total sedation scores. In addition, the number of episodes of vomiting was not significantly different. CONCLUSIONS: Intraperitoneal administration of levobupivacaine with epinephrine is associated with modest analgesia following laparoscopic cholecystectomy.

Randomized controlled trial investigating the effect of transcervical papaverine and bupivacaine on postoperative analgesia following laparoscopic sterilization.

BACKGROUND AND OBJECTIVE: A critical factor that delays patient discharge following day-surgery is severe postoperative pain and the requirement for strong analgesics. Laparoscopic sterilization is a day case procedure and is associated with additional postoperative pain compared with diagnostic laparoscopy. This pain, associated with application of Filshie clips, may be ischaemic or spasmodic in aetiology. Papaverine relaxes smooth muscle, and the aim of the study was to investigate if papaverine would be effective in improving postoperative pain if administered directly to the Fallopian tubes. Bupivacaine is used commonly in day-surgery and so we compared the effect of this local anaesthetic with saline placebo. METHODS: Sixty-six ASA I-II females undergoing laparoscopic sterilization were entered into the prospective, randomized, double-blind, placebo-controlled clinical trial. They received intrauterine papaverine (30 mg) or bupivacaine (0.375% 30 mL) or normal saline (30 mL) via the transcervical route before application of Filshie clips. RESULTS: There were no significant differences in the postoperative period between the three groups in the number of patients needing analgesia in the first 60 min postoperatively, the time to first analgesia, the rescue analgesic or antiemetic consumption, the incidence of postoperative nausea and vomiting, and the sedation and visual analogue pain scores. CONCLUSIONS: From the data presented, we would not recommend routine transcervical administration of papaverine or bupivacaine for pain following laparoscopic sterilization.

The analgesic effects of intraperitoneal and incisional bupivacaine with epinephrine after total abdominal hysterectomy.

UNLABELLED: The objective of our study was to see if incisional and intraperitoneal bupivacaine with epinephrine produces analgesia after total abdominal hysterectomy. Forty-six ASA physical status I and II patients received a standardized anesthetic, patient-controlled analgesia (PCA) morphine, and rectal paracetamol 1 g every 6 h. Patients were randomized to receive 50 mL of bupivacaine 0.25% with epinephrine 5 microg/mL or 50 mL of normal saline. Thirty milliliters and 20 mL of treatment solution were administered into the peritoneum and incision, respectively, before wound closure. Seventeen and 16 patients in the Placebo and Bupivacaine groups, respectively, completed the study. The reasons for withdrawal were PCA malfunction, PCA discontinued too early, nausea, chest infection, intraabdominal drain insertion, and protocol violation. There were no significant differences between the Bupivacaine and Placebo groups in age, height, weight, or duration of surgery. Pain on movement was significantly more intense in the Placebo group than in the Bupivacaine group on awakening. Morphine consumption (interquartile range) over 24 h was 62 mg (53-85 mg) in the Placebo group compared with 44 mg (33-56 mg) in the Bupivacaine group (P < 0.01). This significant difference was attributable to the larger morphine consumption in the Placebo group in the first 4 postoperative h. We conclude that a combination of intraperitoneal and incisional bupivacaine with epinephrine provides significant morphine-sparing analgesia for 4 h after total abdominal hysterectomy. IMPLICATIONS: A combination of intraperitoneal and incisional bupivacaine with epinephrine may be recommended because it provides significant morphine-sparing analgesia for 4 h after total abdominal hysterectomy.

Flow characteristics of long spinal needles.

A 120 mm, 27-gauge needle has recently been introduced for subarachnoid anaesthesia when using a single-space, combined spinal-extradural technique. The flow characteristics of this needle were compared with those of a 120 mm, 26-gauge needle using a pressure monitor infusion pump. Surprisingly, the resistance to fluid flow of the 26-gauge needle was twice that of the 27-gauge needle. The results of this experiment were confirmed by the findings of a clinical study undertaken in 100 obstetric patients who required regional anaesthesia. The time taken from dural puncture to appearance of cerebrospinal fluid at the hub of the needle was on average three times greater with the 26-gauge needle.

Posture and the spread of hyperbaric bupivacaine in parturients using the combined spinal epidural technique.

This study was undertaken to analyze the effect of posture on the spread of hyperbaric bupivacaine in pregnant women using a combined spinal extradural technique, and to assess the quality of analgesia provided by 10 mg bupivacaine when using this technique. Fifty parturients undergoing elective Caesarean section under regional anaesthesia were randomly allocated to receive 2.0 ml hyperbaric bupivacaine 0.5% in either the sitting or left lateral position. Spinal injection was performed with a 27 gauge, 120 mm long spinal needle using a single space combined spinal extradural technique. The onset time to analgesia at T4, and grade 3 motor block was on average 7.7 min and 6.9 min respectively in the lateral group, compared with 10.8 min (P < 0.05) and 9.4 min (P < 0.05) in the sitting group. Nine women in the sitting group and one woman (P < 0.05) in the lateral group required epidural supplementation. Hypotension occurred in 48% of the parturients in the lateral group and in 13% (P < 0.05) of the parturients in the sitting group. Nausea was noted in 61% of the parturients in the lateral group and in 22% (P < 0.05) of the parturients in the sitting group. There was no difference between the two groups in neonatal outcome. Overall, the position of the patient during induction of spinal anaesthesia does influence the rate of onset of analgesia and motor blockade. Injection of 10 mg hyperbaric bupivacaine in the sitting position would not provide adequate analgesia for Caesarean section when using a single space combined spinal extradural technique.

A comparison of the effects of captopril and flosequinan in patients with severe heart failure.

Angiotensin converting enzyme inhibitors have greatly improved the treatment of patients with chronic heart failure but they are not effective in all patients, and their use may be limited by side effects. There is, therefore, a need to investigate new drugs and to compare their efficacy with angiotensin converting enzyme inhibitors. Flosequinan is a new direct-acting vasodilator that has been shown to be effective in placebo-controlled studies. Patients with chronic heart failure in NYHA classes II or III who remained symptomatic despite at least 80 mg of frusemide daily were recruited from two centers. Following a single-blind placebo run-in period, the patients were randomized double blind to either the addition of captopril or flosequinan for 6 weeks. Following a further 2-week placebo washout period, they were then given the alternative treatment. Symptom-limited treadmill exercise times, scores of perceived exertion, and corridor walk tests were measured at two weekly intervals during the study. Twenty-five patients entered the study, 16 of whom completed without a change in diuretic dose. Five patients were withdrawn while taking captopril and two while taking flosequinan; two were withdrawn during the placebo washout period. For those patients who completed the study, flosequinan increased treadmill exercise tolerance from a mean (SEM) placebo time of 11.5 (1.0) minutes by 2.4 (0.6) (p = 0.0002) and captopril from 12.0 (0.8) minutes by 1.2 (0.6) minutes (p = 0.08). Comparison of the other measures of efficacy revealed no difference between the groups. In this short-term study flosequinan appeared to be equal in efficacy to captopril.

The pulmonary physician and critical care. 2. The injured lung: conventional and novel respiratory therapy.

Several alternatives to conventional ventilation in acute lung injury are now available and have been investigated to a varying degree. The assessment of all such techniques is limited by difficulties in designing proper comparative studies and by the time needed to recruit a large number of appropriate patients with acute lung injury. A common theme of lung volume maintenance combined with strategies designed to limit the extent of ventilator induced lung damage has emerged and should encourage reassessment of the conventional approach. The results of several large prospective comparative studies are eagerly awaited. Meanwhile we may reasonably suggest that improvements in respiratory support, together with advances in microbiological and pharmacological treatment, have the potential for improving the persistently disappointing survival rate in acute lung injury.

The transmission of signals by auditory-nerve fiber discharge patterns.

Recent developments in the theory of point processes are used to analyze the accuracy by which signals are conveyed by the discharges of single auditory-nerve fibers. It is shown that the only spike trains which can convey a signal without distortion are those well-described by a Poisson process model. Theoretical predictions are made of the distortion present in the transmission of signals by auditory-nerve fiber discharge patterns. Absolute refractory effects are shown to result in more distortion than relative refractory ones. Procedures are developed to compensate for these distortions. The procedures designed to compensate for absolute refractory effects operate on the PST histogram. Computer simulations are used to confirm the theoretical predictions and to assess the accuracy of the compensation techniques.