Replacing the Anterior Mitral Valve Leaflet With Autologous Jugular Vein in a Sheep Model.

BACKGROUND: This study evaluated the use of an autologous vein graft, supported by expanded polytetrafluoroethylene (ePTFE) chordae tendineae, to replace an anterior mitral valve leaflet. METHODS: A double-layered autologous jugular vein graft, supported by ePTFE chords, was used to create an anterior mitral valve leaflet in 21 sheep. Mitral valve function was monitored with echocardiography for up to 10 months. Surviving sheep were euthanized between 6 and 10 months later, and vein implants were examined histologically. RESULTS: One sheep died intraoperatively. Fourteen sheep had trace to mild mitral regurgitation (MR), 5 had mild to moderate MR, and 1 had moderate to severe MR. Ten sheep died between 2 days and 6.2 months. Echocardiography at 6 months showed MR progression in 8 of 11 sheep. The vein leaflet developed intimal fibroplasia and fibrous proliferation in response to the increased stress on the tissue, but the vein remained flexible without shortening or contracture. The 6- to 10-month vein implants showed viability with intact endothelium, myofibroblasts, collagen, and elastin. A normal healing pattern was seen at the suture lines, and no calcification was observed in the vein leaflet apart from the ePTFE sutures. CONCLUSIONS: Autologous vein has the potential to function as a mitral valve leaflet substitute because it adapted morphologically and remained viable in the intracardiac position. Technical refinement in creating and implanting the leaflet is needed to improve the progression of MR.

Umbilical Cord Coiling and Zygosity: Is there a Link?

INTRODUCTION: The aim of this study was to analyze abnormalities of umbilical coiling index (UCI) in twin gestation to test whether the coiling is genetically influenced by zygosity. METHODS: Data retrieved comprised gestational age (GA), chorionicity, fetal gender, and UCI. RESULTS: The mean UCI of hypercoiled cords in monochorionic placentas was 0.55 coils/cm and 0.49 coils/cm in dichorionic placentas with discordant fetal gender (P = 0.2629). DISCUSSION: In conclusion, no significant statistical difference between UCI in monochorionic and dichorionic twin placentas with discordant fetal gender was identified, suggesting that zygosity does not play a role in umbilical coiling induction.

Measurement of nucleated red blood cells in the peripheral blood as a marker of hypoxia in sudden unexpected death in infancy.

AIMS: A recently proposed classification of sudden unexpected infant death incorporates consideration of possibly asphyxia. This depends on an adequate postmortem, scene investigation and history. A reliable marker of asphyxia has yet to be identified. Such a marker could assist in classifying these deaths. Our aim was to determine if the level of nucleated red blood cells (nRBCs) in the peripheral blood could help identify those possibly asphyxia-related deaths and if risk factors could influence this level in the peripheral blood. METHODS: Cases of sudden unexpected deaths in infancy and sudden infant death syndrome (SIDS) which occurred over a period of 6 years (2007-2013) and were autopsied at Sheffield Children's Hospital were reviewed and categorised according to a new classification proposed by Randall et al. The cases were then correlated with the blood level of nRBCs determined at the time of post mortem examination. The study was approved by the Clinical Governance Department, number SE331. RESULTS: 139 deaths were classified into Group A (true SIDS, 67 cases), Group B (possible asphyxia related, 24 cases), Group C (non-asphyxia-related, 6 cases), Group D (no crime scene investigation, 0 cases) and Group E (identifiable cause, 42 cases). The levels were significantly increased in ex-premature babies, in infants with an underlying condition (Group C) and in deaths related to illness or trauma (Group E). There was a trend towards higher levels of nRBCs in younger age groups and in babies born to smoking mothers. CONCLUSIONS: SIDS remains a difficult diagnosis to make despite the current medical technological advances where no marker of hypoxia has yet been identified.

Heparinase thromboelastography compared with activated coagulation time for protamine titration after cardiopulmonary bypass.

OBJECTIVE: The present study is a comparison of two point-of-care (POC) tests as endpoints of protamine titration after CPB. The authors hypothesized that using the heparinase-kaolin thromboelastography (TEG-HK) R-time difference would more readily identify residual heparin necessitating additional protamine than when using activated coagulation time (ACT). The primary endpoint was the between-group difference in protamine dose. Whether this approach would lessen postoperative bleeding and sequelae also was investigated. DESIGN: Single center, blinded, prospective, randomized study. SETTING: University teaching hospital. PARTICIPANTS: Eighty-two adult patients for on-pump coronary artery bypass and/or valve surgery. INTERVENTIONS: Patients were randomized. In the ACT group, protamine was titrated until ACT did not exceed baseline by more than 10%. In the TEG group, a TEG-HK R-time difference less than 20% was targeted. Protamine was repeated to achieve the endpoints. Clinicians in the ACT group were blinded to TEG data and vice versa. MEASUREMENTS AND MAIN RESULTS: There was no between-group difference in total protamine dose (3.9 ± 0.6 and 4.2 ± 0.7; 95% CI of the difference between means: -0.544 to 0.008 mg/kg; p = 0.057) or protamine:heparin ratios (1.3:1 and 1.4:1; 95% CI of the difference between means: -0.05 to 0.03 mg/mg; p = 0.653). In the ACT group, 17% of patients required a second protamine dose, and in the TEG group, 24% of patients required a second protamine dose. No between-group differences in the postoperative transfusion requirements or intensive care unit length of stay were demonstrated. CONCLUSION: No difference was identified in protamine dosing using either ACT or TEG-HK R-time difference as endpoints. Heparinase TEG may be useful for monitoring heparin reversal.

The way in which a physiotherapy service is structured can improve patient outcome from a surgical intensive care: a controlled clinical trial.

INTRODUCTION: The physiological basis of physiotherapeutic interventions used in intensive care has been established. We must determine the optimal service approach that will result in improved patient outcome. The aim of this article is to report on the estimated effect of providing a physiotherapy service consisting of an exclusively allocated physiotherapist providing evidence-based/protocol care, compared with usual care on patient outcomes. METHODS: An exploratory, controlled, pragmatic, sequential-time-block clinical trial was conducted in the surgical unit of a tertiary hospital in South Africa. Protocol care (3 weeks) and usual care (3 weeks) was provided consecutively for two 6-week intervention periods. Each intervention period was followed by a washout period. The physiotherapy care provided was based on the unit admission date. Data were analyzed with Statistica in consultation with a statistician. Where indicated, relative risks with 95% confidence intervals (CIs) are reported. Significant differences between groups or across time are reported at the alpha level of 0.05. All reported P values are two-sided. RESULTS: Data of 193 admissions were analyzed. No difference was noted between the two patient groups at baseline. Patients admitted to the unit during protocol care were less likely to be intubated after unit admission (RR, 0.16; 95% CI, 0.07 to 0.71; RRR, 0.84; NNT, 5.02; P = 0.005) or to fail an extubation (RR, 0.23; 95% CI, 0.05 to 0.98; RRR, 0.77; NNT, 6.95; P = 0.04). The mean difference in the cumulative daily unit TISS-28 score during the two intervention periods was 1.99 (95% CI, 0.65 to 3.35) TISS-28 units (P = 0.04). Protocol-care patients were discharged from the hospital 4 days earlier than usual-care patients (P = 0.05). A tendency noted for more patients to reach independence in the transfers (P = 0.07) and mobility (P = 0.09) categories of the Barthel Index. CONCLUSIONS: A physiotherapy service approach that includes an exclusively allocated physiotherapist providing evidence-based/protocol care that addresses pulmonary dysfunction and promotes early mobility improves patient outcome. This could be a more cost-effective service approach to care than is usual care. This information can now be considered by administrators in the management of scarce physiotherapy resources and by researchers in the planning of a multicenter randomized controlled trial. TRIAL REGISTRATION: PACTR201206000389290.

Assessment of proliferation markers in metastatic melanoma in sentinel lymph nodes.

AIM: Some views on sentinel nodes for melanoma seem to cast doubt on the relevance of micrometastases in the sentinel nodes of patients with melanoma, suggesting that small metastases or isolated tumour cells can be ignored. Tumour dormancy has been proposed for their postulated lack of progression. The implication of the argument seems to be that minute metastases are inactive and therefore non-threatening, whereas larger ones are proliferative and therefore have aggressive potential. METHODS: 54 sentinel lymph nodes were studied with histologically identified micrometastatic melanoma using the protocol accepted by the European Organisation for Research and Treatment of Cancer melanoma group. These were studied with respect to metastasis size and by use of immunohistochemical markers of proliferation (MIB-1) and dormancy (p16). RESULTS: The authors have demonstrated no correlation between the size of metastases and their proliferative activity. Very small metastases may not show proliferative activity, but this may be a reflection of the small number of assessable cells rather than a genuine reflection of the tumoural characteristics. Furthermore, the minute size of some of these metastases resulted in no residual tumour being present in adjacent sections. Where further sections did show more tumour, these small metastases were invariably p16 negative, suggesting dormancy was not the explanation for the lack of measurable proliferation. Occasionally, larger metastases, clearly not clinically insignificant, showed no proliferative activity presumably, considering their size, a transient phenomenon. CONCLUSION: These findings suggest that variable phases in proliferation occur in metastases, and no conclusion of clinical insignificance can be made on the basis of small size.

Repeat surgery for coronary artery bypass grafting: the role of the left thoracotomy approach.

OBJECTIVE: Repeat coronary artery bypass surgery has increased risks compared with the first operation, including low cardiac output and injury to patent grafts. The left thoracotomy approach has been advocated specifically in patients with intact grafts of the left internal mammary artery (LIMA) to the left anterior descending coronary artery (LAD) needing lateral wall grafting. We have evaluated this technique in conjunction with an off-pump procedure in all patients. METHODS: There were 55 patients over an 8-year period, and 6 (10.9%) were female. The mean age was 63.2 years (range, 41-82 years), and the age at the time of the previous operation was 51.7 years (range, 31-69 years). Four patients (7.2%) underwent a third operation. Comorbidities were diabetes mellitus (25 patients, 45.5%), renal impairment (8 patients, 14.5%), calcified ascending aorta (9 patients, 16.4%), carotid disease (4 patients, 7.2%), and peripheral vascular disease (11 patients, 20.0%). Fifteen patients (27.2%) had previous coronary stents. Nine patients (16.4%) had a preoperative intra-aortic balloon pump. Predicted mortality (logistic EuroSCORE) was 14.2%. RESULTS: Forty-three patients (78.1%) had intact LIMA-to-LAD grafts. Twenty-two patients (40.0%) required a major posterolateral thoracotomy, and 33 patients (60.0%) had a minor thoracotomy. Thirteen patients (23.6%) had stents placed as a hybrid procedure during the same admission. Thirteen patients (23.6%) additionally underwent anterior wall grafting (LAD to the first marginal area). The LIMA was used in 7 patients where it had not been used before. There were 91 distal grafts (including 4 sequentials). We performed 54 venous grafts and 26 radial artery grafts. Twenty-one patients (38.1%) had 1 distal graft, 32 patients (58.1%) had 2 grafts, and 2 patients (3.6%) had 3 distal grafts performed (mean, 1.6 grafts/patient). The proximal graft site was the proximal descending aorta in 20.0% of the patients, the distal aorta in 67.5%, and the subclavian artery in 12.5%. In 10 patients (18.2%), the distal branches of the right coronary (posterior descendens or right posterolateral) were grafted. No patient required conversion to cardiopulmonary bypass or sternotomy. No patient needed an intra-aortic balloon pump postoperatively. The mean blood loss (24 hours) was 380 mL (range, 125-1100 mL), the mean ventilation time was 4.8 hours (range, 0-12 hours), the mean intensive care unit stay was 2.7 days (range, 2-8 days), and the mean hospital stay was 6.3 days (range, 5-20 days). There was 1 postoperative death (1.8% mortality). One late death occurred on follow-up. Four patients underwent cardiac catheterization for chest pain, and the grafts were shown to be open. CONCLUSION: The procedure is safe, especially in patients with intact LIMA-to-LAD grafts needing lateral and inferior wall revascularization. Multislice computed tomography scanning allows better preoperative planning, especially regarding the site of implantation of the proximal graft, allowing a less invasive incision. The off-pump technique preserves cardiac and pulmonary function. The in-hospital death rate (1.8%) compares very well with the EuroSCORE-predicted mortality (14.2%).

Recurrence of cardiotoxicity after lipid rescue from bupivacaine-induced cardiac arrest.

Accidental intravascular administration of bupivacaine during performance of a brachial block precipitated convulsions followed by asystole. The patient was rapidly resuscitated using cardiopulmonary resuscitation, supplemented by 150 mL of 20% lipid emulsion. Nonetheless, cardiac toxicity reappeared 40 min after completion of the lipid emulsion. In the absence of further lipid emulsion, amiodarone and inotropic support were used to treat cardiotoxicity. This case suggests that local anesthetic systemic toxicity may recur after initial lipid rescue. Since recurrence of toxicity may necessitate administration of additional doses of lipid emulsion, a sufficient quantity of lipid emulsion should be available when regional anesthesia is performed.

Arterial oxygenation and one-lung anesthesia.

PURPOSE OF REVIEW: In the presence of the obligatory shunt during one-lung ventilation, arterial oxygenation is determined by the magnitude of the shunt in addition to the oxygen content of the mixed venous blood coursing through that shunt. The present discussion aims to heighten awareness of factors determining arterial oxygenation during one-lung anesthesia, other than the magnitude of the shunt and dependent lung low-ventilation perfusion units. RECENT FINDINGS: A convenient way to increase mixed venous and thereby arterial oxygenation is to raise cardiac output. While this approach has achieved some success when increasing cardiac output from low levels, other studies have highlighted limitations of this approach when cardiac output attains very high levels. The effect of anesthesia techniques on the relationship between oxygen consumption and cardiac output could also explain unanswered questions regarding the pathophysiology of arterial oxygenation during one-lung anesthesia. SUMMARY: The effects of anesthesia techniques on oxygen consumption, cardiac output and therefore mixed venous oxygenation can significantly affect arterial oxygenation during one-lung anesthesia. While pursuing increases in cardiac output may, under limited circumstances, benefit arterial oxygenation during one-lung ventilation, this approach is not a panacea and does not obviate the necessity to optimize dependent lung volume.

Calcium antagonist verapamil and reperfusion injury of the heart.

OBJECTIVE: An experimental study to examine the effect of verapamil, given into a coronary artery, on reperfusion injury. DESIGN: The study was randomized but not blinded. SETTING: This study was conducted in the animal laboratory of the Department of Anesthesiology and Critical Care in an academic institution. PARTICIPANTS: The study was performed in an anesthetized open-chest pig model. INTERVENTIONS: Left anterior coronary artery (LAD) occlusion for 15 minutes followed by 90 minutes of reperfusion. Verapamil or saline was given into the LAD artery either at the time the coronary artery was occluded (ie, during acute severe ischemia or during the reperfusion period). MEASUREMENTS: LAD artery blood flow, regional myocardial function, and metabolism were assessed by the end-systolic pressure length relationship, regional systolic shortening, postsystolic shortening, regional myocardial oxygen consumption, and local cardiac vein lactate. CONCLUSIONS: Verapamil given during ischemia resulted in a shorter period of regional myocardial stunning when compared with saline or verapamil during reperfusion. The difference in the verapamil strategies (ie, verapamil administered during ischemia versus verapamil during the reperfusion period) can probably be explained by a difference in the effective dose of the drug present in the heart at the time reperfusion started rather than the period of administration per se.

Outcomes research in the ICU: an aid in defining the role of physiotherapy.

The economic reality of consumers, funders, and regulatory agencies demanding evidence regarding the quality of care patients are receiving in the intensive care unit (ICU) will have an effect on many of the routinely used practices in ICU, including physiotherapy. Outcomes research is a method that has been used to obtain evidence for the medical and respiratory management of patients in ICU. An overview of the literature was conducted to answer the following questions: 1. What is outcomes research? 2. Which outcomes should be measured in the adult critical care environment? 3. Which outcomes are physiotherapists currently including in research reports? Outcomes research is recognized by critical care specialists as a cost-effective method of determining what works in the real world. The value of physiologic measures is questioned, whereas the importance of patient centered, economic, and traditionally accepted outcome measures is increasingly being recognized. Most physiotherapy research reports still include physiologic measurements as the primary outcome of an intervention. Outcomes research provides researchers with the tools to define the role of the physiotherapist in the critical care environment. The outcomes measured must be relevant to patients, families, and funders.

Beta-adrenergic blockade during severe ischemia.

OBJECTIVE: To examine the effect of acebutolol, a beta-adrenergic-receptor blocker, on severe regional myocardial ischemia, specifically the effects on regional myocardial function and metabolism. DESIGN: Randomized study. SETTING: Animal laboratory of the Department of Anesthesiology and Critical Care, University of Stellenbosch Medical School. PARTICIPANTS: Anesthetized open-chest pig model (n = 18). INTERVENTIONS: Regional left ventricular function and metabolism were evaluated. Severe stenosis was applied to the left anterior descending coronary artery. After establishing regional myocardial ischemia, acebutolol was administered intravenously, and results were compared with controls who did not receive acebutolol. Animals were prospectively randomized to 1 of the groups. MEASUREMENTS AND MAIN RESULTS: Regional myocardial function and metabolism were assessed by end-systolic pressure relationship, regional systolic shortening, postsystolic shortening, regional myocardial oxygen consumption, and lactate dynamics. Coronary blood flow was determined with a Doppler flow probe. Results indicated that acebutolol increased regional myocardial blood flow, and this resulted in less severe regional myocardial ischemia, improved function, and an increase in regional myocardial oxygen consumption. CONCLUSION: The beta-Adrenergic-receptor antagonist was successful in reducing regional myocardial ischemia in this model. This reduction was achieved by an increase in coronary blood flow, which resulted in an improvement in regional mechanical function and an increase in oxygen consumption.

Effect of 1% and 2% propofol on blood lipids during longterm sedation.

OBJECTIVES: To compare the effects of 1% and 2% propofol on the maximum and average lipid levels, the relative frequency of hyperlipidaemia, the propofol dose required to achieve an equivalent degree of sedation, the pharmacodynamic effects at the required infusion rates, and the effect on respiratory function. DESIGN: Open, randomised, parallel group, multicentre comparison study. SETTING: Intensive care units (ICUs) at the Faculty of Medicine, University of Stellenbosch and at Vergelegen Medicity, Somerset West. SUBJECTS: Patients who were artificially ventilated for at least 72 hours in the ICUs and who required sedation or analgesia. OUTCOME MEASURES: Continuous intravenous infusion of 1% or 2% propofol to provide an administration rate in the range of 1-4 mg/kg/h. The initial infusion rate was about 2 mg/kg/h, adjusted to achieve the appropriate level of sedation. RESULTS AND CONCLUSIONS: Seventy-five patients were enrolled in the study, of which 72 were evaluable for safety analysis and 58 were evaluable for efficacy analysis. The total daily dose of propofol (ml/day) in the 2% propofol group was about 60% of that in the 1% propofol group, indicating that the lipid load in the 2% propofol group had only slightly more than half the lipid load in the 1% propofol group. Thirteen of 27 patients (48%) in the 2% propofol group had abnormally.