Right ventricle-to-pulmonary artery shunt and modified Blalock–Taussig shunt in preparation to hemi-Fontan procedure in children with hypoplastic left heart syndrome

Objective: The advantageous effect of right ventricle-to-pulmonary artery shunt (RV–PA) on the early postoperative hemodynamics in the Norwood procedure for hypoplastic left heart syndrome (HLHS) is well known. Numerous controversies still exist with respect to the late consequences of this new palliation method in preparation for the second stage procedure. Methods: Between September 1997 and September 2004, a consecutive series of 78 children with HLHS from a single institution underwent the hemi-Fontan procedure: Group 1 (n=27) after Blalock–Taussig shunt (BT), and Group 2 (n=51) after RV–PA. Hemodynamic, echocardiographic and clinical perioperative data were analyzed. Results: There were no significant differences in the age and operative weight (Group 1: 6.9±1.04 months, 6.22±0.99 kg; Group 2: 6.57±1.12 months, 6.36±0.86 kg). Children after RV–PA were characterized by a significantly higher preoperative hematocrit value (P=0.014), lower aortic and superior vena cava oxygen blood saturation (P<0.001, P=0.024), severe right ventricle hypertrophy more rarely diagnosed in echocardiography (P<0.004), lower Qp:Qs ratio (P=0.011), larger right (P=0.001) and left (P=0.006) pulmonary artery index and a shorter intensive care unit stay after the hemi-Fontan procedure (P=0.004). Conclusions: The Norwood procedure with the RV–PA shunt provides satisfactory late hemodynamics and improves the development of the pulmonary arteries. Children with hypoplastic left heart syndrome subjected to this new method of palliation are good candidates for the hemi-Fontan procedure.     

Anesthetic management for an adult patient with secundum atrial septal defect associated with a large left-to-right shunt

We describe the case of a 68-year-old woman with secundum atrial septal defect associated with a large left-to-right shunt and congestive heart failure. The patient with a pancreatic tumor was scheduled for hepatic cholangiojejunostomy and cholecystectomy. To determine the ratio of pulmonary to systemic flow (Qp/Qs) as an indicator for the magnitude of left-to-right shunt, oxymetric catheters were placed in the superior vena cava and pulmonary artery. In addition, oxygen delivery was assessed using superior vena cava oxygen saturation (SsvcO2). Although the patient was anesthetized with high-dose fentanyl to supplement nitrousoxide and sevoflurane, the Qp/Qs markedly increased after skin incision. Epidural local anesthetic was then administered. The Qp/Qs decreased to the preoperative value and the hemodynamic condition was improved thereafter. The operative course was uneventful. This case illustrates the potential usefulness of continuous measurement of the Qp/Qs and SsvcO2 for anesthetic management of adult patients with secundum atrial septal defect.     

Mitral valve repair by Alfieri''s technique does not limit exercise tolerance more than Carpentier''s correction

Objective: The main goal of this study was to evaluate if the edge-to-edge mitral repair could be a limiting factor for exercise tolerance and to compare these results to those of classical techniques. Methods: Between 2000 and 2002, 54 consecutive patients were operated on for mitral valve regurgitation (MR). Twenty-five patients were operated with Alfieri's technique (group A) and 29 patients with Carpentier's technique (group C). The mean age was 63.9 years in group A and 63.8 years in group C (p = 0.98). After a mean follow-up of 16.2 ± 12 months, survivor patients were seen at the outpatient clinic, by the same physician for a clinical evaluation, an echocardiogram at rest and at peak exercise, and received a cardiorespiratory exercise testing with maximal oxygen uptake (VO₂ max) recording. Results: Clinical status improved with 0% of the patients in class NYHA III or IV in either group postoperatively versus 77% preoperatively. There was no significant MR in 80% of cases in group A versus 89.6% in group C (p = 0.54). The mean mitral valve area was 2.5 and 2.9 cm² in groups A and C, respectively (p = 0.018). The mitral gradient at rest was 3.8 and 3.3 mmHg (p = 0.31) and the mitral gradient at peak exercise was 8.5 and 9.7 mmHg (p = 0.22) in groups A and C, respectively. Cardiorespiratory exercise testing showed a mean VO₂ max of 73.7 ± 15% of normal value in group A versus 79.6 ± 13.1% in group C (p = 0.18). Conclusion: Alfieri's technique has the same efficiency on improvement of MR and clinical status than classical repair. Despite a higher restriction of mitral valve area at rest in group A, gradient and mean VO₂ max at peak exercise were similar in both groups.     

Does sodium nitroprusside reduce lung injury under cardiopulmonary bypass?

Objective: We hypothesized that direct pulmonary arterial infusion of sodium nitroprusside (SNP) would ameliorate lung injury under cardiopulmonary bypass. Methods: Experiments were performed on 12 adult mongrel dogs of both sexes weighing 20–28 kg. The animals were randomly divided into two groups of six animals each. All animals were subjected to total cardiopulmonary bypass (CPB) and moderate hypothermia (28°C core temperature). During total CPB, the aorta was clamped together with the pulmonary artery to prevent any antegrade flow to the lungs. After cardioplegic arrest for 120 min, the animals were rewarmed, weaned from CPB, and their condition stabilized for another 90 min. After the release of the aortic cross-clamp, the dogs received either a 5% glucose solution as a placebo (group I) or SNP (0.5 μg/kg per min) (group II), both infused into the pulmonary arterial line. The infusion was stopped after 60 min. To measure lung tissue malondialdehyde (MDA), water content and polymorphonuclear leukocytes count, lung tissue samples were taken before CPB and after weaning from CPB. In addition, alveolar-arterial oxygen difference (AaDO₂) for tissue oxygenation was calculated by obtaining arterial blood gas samples. Results: Values of MDA before CPB of 42.0±5.3 nmol/g of tissue rose to 67.6±5.7 nmol/g of tissue after weaning from CPB in group I (P=0.028). In group II MDA values also increased from 43.1±4.3 to 52.4±5.7 nmol MDA/g of tissue after weaning from CPB (P=0.046). The MDA increase in group II after CPB was found to be significantly lower than that for group I (P=0.004). The wet-to-dry lung weight ratio in the sodium nitroprusside group was 5.1±0.2, significantly lower than in the control group (6.8±0.4), (P=0.01). AaDO₂ increased significantly in group I (P=0.028). There was no statistically significant difference (P=0.065) between groups I and II. During histopathological examination it was observed that neutrophil counts in the lung parenchyma rose significantly after CPB in both groups. The increase in group I was significantly larger than that in group II (P<0.001). Conclusions: The results represented in our study indicate that pulmonary arterial infusion of sodium nitroprusside during reperfusion can reduce lung injury under cardiopulmonary bypass.     

Atrial septal defect in adults: echocardiography and cardiopulmonary exercise capacity associated with hemodynamics before and after surgical closure

The study aimed to evaluate pre and postoperative echocardiographic data and exercise capacity in relation to age and hemodynamics in adults with atrial septal defect (ASD). Fifty-two subjects with ASD (mean age: 38.6+/-15 years) were enrolled. Echocardiography and cardiopulmonary exercise test were performed before and a year after surgery. Pre and postoperative data were analyzed for the entire group and then compared in terms of age: <40 and >or=40 years, right ventricular systolic pressure (RVSP): 30 mmHg and pulmonary to systemic flow ratio (Qp/Qs): <2.5 and >or=2.5. After surgery right ventricle dimension decreased in all patients, although it remained significantly larger in patients over 40 years. There was a negative correlation between peak oxygen uptake and preoperative RVSP (r=-0.69, P<0.001). Exercise capacity improved irrespective of the age at surgery, preoperative RVSP and Qp/Qs, although it failed to normalize in patients with RVSP >30 mmHg. Adults with ASD benefit from surgical closure irrespective of the actual age at surgery. Patient's age at surgery and pulmonary hypertension crucially impact the results of surgical intervention. Early defect correction is therefore highly recommendable, specifically with a view to preventing the hemodynamic consequences of ASD.     

A prospective randomized study to evaluate splanchnic hypoxia during beating-heart and conventional coronary revascularization

Objective: Cardiopulmonary bypass (CPB) is associated with gut mucosal hypoxia, which may contribute to gastrointestinal complications. We examined gastric mucosal oxygenation together with whole-body oxygen flux in low-risk patients undergoing coronary artery bypass grafting (CABG) with and without CPB. Methods: Fifty-four patients undergoing primary CABG by the same surgeon were randomized into either on-pump (ONCAB, n=27) or off-pump (OPCAB, n=27) groups. The ONCAB group underwent mild hypothermic (35°C) pulsatile CPB with arterial line filtration. Each patient underwent perioperative monitoring with continuous tonometry and cardiac output devices. Gastric intramucosal pH (pHi), gastric-arterial carbon dioxide partial pressure difference (CO₂ gap), whole-body oxygen delivery (DO₂) and consumption (VO₂) and whole-body oxygen extraction fraction were measured at sequential time-points intraoperatively and up to 6 h postoperatively. Anaesthetic management was standardized. Results: Both groups had similar demographic makeup and extent of revascularization (ONCAB 2.6±0.9 grafts versus OPCAB 2.5±0.8 grafts; P=0.55). The ONCAB group had a mean (±SD) CPB time of 62±25 min and aortic cross-clamp time of 32±11 min. In both groups there was a similar and progressive drop in pHi intraoperatively. Postoperatively, there was a gradual separation between the groups with ONCAB patients showing no further decline in pHi, while further deterioration was observed in the OPCAB group up to 6 h postoperatively. There was a significant difference between the groups over time (P=0.03). There was a corresponding progressive rise in CO₂ gap perioperatively in both groups, with ONCAB patients demonstrating superior preservation of gastric mucosal oxygenation in the early postoperative period. Global oxygen utilization measurements showed superior DO₂ and VO₂ in the OPCAB group throughout the study. Conclusions: Despite superior global oxygen flux associated with beating-heart revascularization, gastric mucosal hypoxia occurred to similar extents in both groups with worsening trends for the OPCAB patients postoperatively. The splanchnic pathophysiology during beating-heart revascularization should be further explored.     

Pulmonary preservation with Bretscheider''s HTK and Celsior solution in minipigs

Background: Pulmonary preservation with high potassium/low oncotic pressure Euro-Collins (EC) solution is associated with endothelial dysfunction and reduced surfactant function. We compared two low potassium solutions, histidine-tryptophane-ketoglutarate (HTK) and Celsior, to EC in lung ischemia-reperfusion injury. Methods: In 19 minipigs, the left lung was perfused in situ with cold preservation solution (EC, n=6; HTK, n=6; Celsior, n=7). Reperfusion was started after 90 min of warm ischemia. The right pulmonary artery and main bronchus were clamped. Bronchoalveolar lavage (BAL) was obtained before ischemia and after 2 h of reperfusion. Surfactant activity was determined from the BAL in a pulsating bubble surfactometer. Results: Animals in the EC group survived 3.7±1.4 h. Six Celsior and five HTK treated animals survived the observation period of 7 h (P<0.001). Compliance of the reperfused lung deteriorated less in both Celsior and HTK groups (P<0.001). In EC and HTK animals, the pO₂/FiO₂ ratio was lower (P=0.002), and pulmonary vascular resistance was higher (P=0.02) than in Celsior animals. Surfactant function was impaired after reperfusion in all groups. Conclusions: Compared to EC, HTK solution showed moderate and Celsior distinct improvement of post-ischemic pulmonary function. However, surfactant function was not well preserved in any group.     

Hibernating myocardium: clinical and functional response to revascularisation

Objective: We assessed the effects of coronary bypass grafting on left ventricular (LV) function, exercise capacity and symptom profile in patients with LV impairment and evaluated the role of identifying myocardial hibernation in a prospective non-randomised study. Methods: Of 120 patients screened, 47 patients with LV ejection fraction <35% and three vessel coronary artery disease were studied. All underwent stress/redistribution and separate day rest/redistribution Tl-201 imaging together with cine MRI at enrolment, and cine MRI at follow-up. Group 1, 30 patients undergoing bypass surgery, underwent symptom limited treadmill exercise testing with peak VO₂ measurement, and symptom profile evaluation less than 3 months before, and 3–6 months after operation. Revascularisation was assessed by post-operative Tl-201 imaging and repeat coronary angiography. Group 2, 17 patients treated on medical therapy alone underwent symptom profile assessment at enrolment and follow-up for those who survived. Segmental hibernation was defined as the equivalent of greater than 50% of maximal Tl-201 uptake where wall motion was severely impaired on resting imaging. Patients were considered to be hibernating where two of nine LV segments fulfilled these criteria. Results: In group 1, five patients died (17%), peri-or post-operatively, two defaulted and 23 attended follow-up studies. In group 2, three patients died prior to follow-up (18%). In the surgical group there was an increase in mean LVEF from 24.0±8% to 29.7±11% (P<0.05) while in the medical group there was a fall from 25.7±10% to 20.6±8% (P<0.05). In group 1, the mean NYHA dyspnoea grade improved from 2.7 to 1.4 while in the medical group it was unchanged, 2.6 to 2.5. In patients with myocardial hibernation identified pre-operatively, 18/19 (95%) improved LVEF after CABG compared with 2/4 (50%) of patients without hibernation. 17/19 (86%) patients with hibernation improved NYHA dyspnoea class compared with 2/4 (50%) of patients without. 60/93 (65%) of hibernating segments improved function after revascularisation while 47/53 (89%) hibernating segments showed no improvement on medical therapy alone. Conclusion: In patients with severe LV impairment with myocardial hibernation, coronary artery bypass grafting improves both global and regional systolic LV function, and symptom profile. Medical treatment of patients with LV impairment and myocardial hibernation does not improve LV contractile function or symptoms. Both surgical and medical therapy carry a high mortality rate.     

Left-to-right shunt assessed by thermodilution during surgery for congenital heart disease

In nine children with congenital heart defects, left-to-right shunting was assessed during open-heart surgery by injecting cold 5% glucose solution through a left atrial line and detecting temperature change with a pulmonary arterial thermistor. The shunt was quantified by recording the temperature after injecting the same amount of cold glucose solution also through a central venous line. Oximetric determination of the left-to-right shunt was used as a reference. The result was expressed as shunt flow divided by pulmonary blood flow (Qshunt/Qp). The regression equation then obtained was Qshunt/Qp by thermodilution = 0.05 + 0.87 x Qshunt/Qp by oximetry. The residual standard deviation around the line of regression was 0.03. The thermodilution technique can be used for rapid assessment of the presence and magnitude of left-to-right shunting, provided that there is opportunity for the indicator to mix adequately in the main blood stream before shunting occurs.     

Respiratory dysfunction after coronary artery bypass grafting employing bilateral internal mammary arteries: the influence of intact pleura

Objective: To evaluate the role of intact pleurae regarding the postoperative respiratory functional status in patients undergoing coronary revascularization employing both internal mammary arteries (IMAs), according to the pedunculated or skeletonized technique (SKT) with opened or intact pleurae. Materials and methods: Using both IMAs, 299 patients underwent elective coronary revascularization. They were randomized and divided into group I (n=82, undergoing IMA harvesting according to the SKT without opening the pleurae); group II (n=186, undergoing IMA harvesting according the pedunculated technique with open pleurae); and group III (n=31, undergoing IMA harvesting according the SKT with incidentally opened pleurae). There were no differences regarding the preoperative patient characteristics and the anaesthetic and surgical management. Results: There were two deaths in group I versus seven in group II and one in group III (P=ns). The number of total arterial myocardial revascularization and arterial composite grafts was significantly higher in groups I and III than in group II, (P<0.001 and P<0.005, respectively). The incidence of postoperative complications was similar between groups. Blood loss of >1000 ml was significantly higher in group II than group I (P<0.028); but the incidence of re-thoracotomy and blood transfusion was similar between groups. The mechanical ventilation time was significantly higher in groups II and III versus group I (P<0.018 and P<0.02, respectively). The incidence of prolonged ventilation (>24 h), pleural effusion, thoracocentesis and atelectasis, resulted in being significantly higher in group II than group I. The incidence of thoracocentesis was significantly higher in group III than group I. The pain score and analgesic requirements at 1–12 h after awakening were significantly higher in groups II and III versus group I, becoming similar after the chest tubes were removed. PaO₂ was significantly higher, and PaCO₂ and FiO₂ were significantly lower in group I than groups II and III at 1 and 4 h before extubation and at 1 and 4 h after extubation. PaO₂ and PaCO₂ became similar between groups at the 5th postoperative day. Conclusions: According to our results, we may conclude that pleural integrity has beneficial effects on the respiratory functional status after coronary revascularization using both IMAs. A meticulous and more careful IMA harvesting approach significantly reduces the postoperative morbidity regarding the pulmonary functional status, and as a consequence, reduces the hospital costs.     

Change of serum growth factors in infants with isolated ventricular defect undergoing surgical repair

Background. Despite increasing clinical use and recent evidence that insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3), and human growth hormone (hGH) target the heart, the clinical manifestations following the change in the serum growth factors in infants with isolated ventricular septal defect (VSD) undergoing surgical repair have not been clearly defined.

Methods. Twenty normal infants (group I) and 44 consecutive infants with echocardiography established isolated VSD (aged from 3 months to 1 year; body weight from 6.0 ± 1.8 kg to 8.2 ± 1.6 kg) were investigated. Among 44 infants with VSD, 20 with shunt fraction, Qp/Qs ≤1.5 were free of symptoms of congestive heart failure (group II); 24 with shunt fraction, Qp/Qs ≥2.0 were in congestive heart failure (group IIIa); and 20 of these 24 infants had undergone VSD repair 6 months before their second study (group IIIb). Serum IGF-1, IGFBP-3, and hGH factors were determined by enzyme-linked immunosorbent assay using a monoclonal antibody.

Results. The serum levels of IGF-1, IGFBP-3, and hGH factors were 111.9 ± 2.3 ng/mL, 22.0 ± 2.3 ng/mL, and 3.6 ± 0.7 μIU/mL for group I; 63.8 ± 8.2 ng/mL, 17.1 ± 1.6 ng/mL, and 4.1 ± 1.2 μIU/mL for group II; 24.0 ± 2.6 ng/mL, 9.4 ± 0.7 ng/mL, and 14.7 ± 3.5 μIU/mL for group IIIa; 79.4 ± 12 ng/mL, 20.3 ± 1.3 ng/mL, and 4.3 ± 0.7 μIU/mL for group IIIb. In comparison to group I, the decrease in serum levels of IGF-1 and IGFBP-3 in groups II and IIIa were statistically significant (in group II 43% and 32%, p < 0.05; in group IIIa 79% and 37%, p < 0.01). Also the increase in serum level of hGH concentration in group IIIa was significant (increased threefold, p < 0.01). Interestingly, the change in serum levels of IGF-1, IGFBP-3 (decrease), and hGH (increase), returned to the normal range of serum levels after VSD repair in group IIIb. All congestive heart failure symptoms subsided in group IIIb during follow-up.

Conclusions. Improvement in serum levels of IGF-1, IGFBP-3, and hGH were identified in infants with VSD after surgical repair.     

β2 Adrenoceptor gene therapy ameliorates left ventricular dysfunction following cardiac surgery

Objective: Heart surgery is associated with impairment of the myocardial β-adrenoceptor (βAR) system. Effective therapies for post-operative ventricular dysfunction are limited. Prolonged inotrope exposure is associated with further βAR down-regulation. Left ventricular (LV) dysfunction and myocardial βAR impairment were assessed following cardiopulmonary bypass (CPB) and cardioplegic arrest in a pig model. Transfer of the human β₂-adrenoceptor transgene (Adeno-β₂AR) during cardioplegic arrest was then tested as a potential therapy. Methods: Five groups of six neonatal piglets were studied. One group did not undergo surgery (Group A). Adeno-β₂AR or phosphate buffered saline (PBS) were delivered via the aortic root during cardioplegic arrest. Groups B (PBS) and C (Adeno-β₂AR) were assessed at 2 days while Groups D (PBS) and E (Adeno-β₂AR) were assessed at 2 weeks from the time of surgery. An LV micromanometer was inserted under sedation to obtain pressure recordings following surgery. βAR density was measured subsequently. Results: Following cardiac surgery LV βAR density was reduced (104±5.7 vs 135±6.1 fmol/mg membrane protein; P=0.007), and, in response to β agonist stimulation, LV dP/dt_max was reduced (4337±405 vs 5328±194 mmHg/s; P<0.05) compared to animals which did not undergo surgery. Adeno-β₂AR therapy during cardiac surgery resulted in elevated LV βAR density (520±250.9 fmol/mg) 2 days post-operatively compared to PBS (104±5.7 fmol/mg; P=0.002) and compared to the no surgery group (135±6.1 fmol/mg; P=0.002). Elevated LV βAR density was also present at 2 weeks (315±74.1 vs 119±7.1 fmol/mg; P=0.002). In addition, Adeno-β₂AR therapy enhanced β agonist stimulated LV dP/dt_max (5348±121 vs 4337±405 mmHg/s; P<0.05) and heart rate (209±6.9 vs 173±11.0 bpm; P<0.05), and reduced LVEDP (2.1±0.4 vs 6.4±1.8 mmHg; P<0.05) compared to PBS treatment. Interestingly, gene delivery was cardiac-selective and beneficial effects on function persisted for 2 weeks. Moreover, β₂AR gene transfer ameliorated LV dysfunction following surgery such that there were no significant differences between non-operated controls and animals treated with Adeno-β₂AR during CPB and cardioplegic arrest. Conclusions: Reduced βAR density and impaired LV function were present following CPB and cardioplegic arrest. Cardiac-selective β₂AR gene transfer during CPB resulted in amelioration of LV dysfunction after cardiac surgery. Such a technique may offer a new approach to post-operative ventricular support.     

Does size matter? Larger Blalock-Taussig shunt in the modified Norwood operation correlates with better hemodynamics.

OBJECTIVE: Excess pulmonary to systemic blood flow ratio (Qp/Qs) correlates with hemodynamic instability and mortality after modified Norwood operation. Studies suggest that maximal oxygen delivery occurs at a Qp/Qs of around 1. The use of a rather small modified Blalock-Taussig shunt (MBTS) is believed to achieve this goal. However, optimal MBTS size with respect to postoperative hemodynamics remains unclear. METHODS: Between 2/2002 and 2/2004, 20 consecutive patients underwent Norwood operation; there were 19 operative survivors: nine with a normalized MBTS area (NSA) > or = 3.3 mm2/kg (group 1) and 10 with NSA < 3.3 mm2/kg (group 2). Mean arterial pressure (MAP) and common atrial pressures (CAP), arterial and superior vena cava oxygen saturations, urinary output and inotropes recorded for the postoperative hours 0, 6, 12, 18, 24 and 48 were analyzed. RESULTS: Hospital mortality was 11.1% (1/9) in group 1 and 30% (3/10) in group 2 (P = 0.6). For group 1 significantly higher MAP of 52+/-1.3 versus 46+/-0.8 mmHg (P < 0.001), higher urinary output of 6.2+/-0.5 versus 4.2+/-0.5 ml/kg per h (P < 0.01), lower CAP of 8+/-0.3 versus 10+/-0.4 mmHg (P < 0.001), and lower heart rate of 145+/-2.6 versus 160+/-1.6 bpm were recorded than for group 2. In group 1, lower doses of adrenaline (0.03+/-0.01 versus 0.15+/-0.01 microg/kg per min, P < 0.05) and noradrenaline (0.01+/-0.01 versus 0.13+/-0.04 microg/kg per min, P < 0.01) were needed. Although Qp/Qs was more often calculated to be > 1.5 in group 1 (51 versus 31%), arteriovenous oxygen difference and oxygen excess factor were not significantly different, indicating similar oxygen delivery. CONCLUSIONS: Monitoring of the central venous oxygen saturations and application of afterload reduction in cases of high Qp/Qs allows the insertion of a larger MBTS without association with lower oxygen delivery. In fact, better hemodynamic status with less inotropic support was noted with a larger MBTS early after Norwood operation.     

The outcome following major trauma in the elderly. Predictors of survival

Objectives: To assess the reliability of the predicted probability of survival calculated using TRISS methodology by the UK Trauma Network for elderly patients.

Method: Analysis of 100 consecutive trauma patients 65 years and over, prospectively entered into the UK Trauma Network database from a single centre. The probability of survival (P_s) was calculated from the UK Trauma database and retrospectively related to survival, premorbid medical condition and mobility.

Results: Of 100 patients, 16 died and 84 survived. Eleven of the 16 who died and 12 of the survivors had pre-existing medical disease (ASA grade III–V) and social dependency suggesting a poor outcome, these factors being significantly associated with mortality (P<0.005). The mean P_s for the 11 with severe medical disease who died was 0.85 (±0.07) with a mean age 85 (±3.5). The remaining five patients who died suffered high energy injuries, had a mean age of 70 (±4.8) and a low probability of survival (P_s 0.40±0.24). The median pre-injury mobility score was 8 in patients who survived and 4.5 in those who died. Mobility score <5 was associated with an increased mortality following admission from Trauma (P<0.05)

Conclusions: There is a significant association between severe preexisting medical disease (ASA III–V) and death during admission for trauma. The P_s score is unrealistically high in this group of patients. A simple mobility score correlates well with outcome in this group.     

Pulmonary-to-systemic blood flow ratio effects of sevoflurane,isoflurane, halothane,and fentanyl/midazolam with 100% oxygen in children with congenital heart disease

The cardiovascular effects of volatile anesthetics in children with congenital heart disease have been studied, but there are limited data on the effects of anesthetics on pulmonary-to-systemic blood flow ratio (Qp:Qs) in patients with intracardiac shunting. In this study, we compared the effects of halothane, isoflurane, sevoflurane, and fentanyl/midazolam on Qp:Qs and myocardial contractility in patients with atrial (ASD) or ventricular (VSD) septal defects. Forty patients younger than 14 yr old scheduled to undergo repair of ASD or VSD were randomized to receive halothane, sevoflurane, isoflurane, or fentanyl/midazolam. Cardiovascular and echocardiographic data were recorded at baseline, randomly ordered 1 and 1.5 mean alveolar anesthetic concentration (MAC) levels, or predicted equivalent fentanyl/midazolam plasma levels. Ejection fraction (using the modified Simpson's rule) was calculated. Systemic (Qs) and pulmonary (Qp) blood flow was echocardiographically assessed by the velocity-time integral method. Qp:Qs was not significantly affected by any of the four regimens at either anesthetic level. Left ventricular systolic function was mildly depressed by isoflurane and sevoflurane at 1.5 MAC and depressed by halothane at 1 and 1.5 MAC. Sevoflurane, halothane, isoflurane, or fentanyl/midazolam in 1 or 1.5 MAC concentrations or their equivalent do not change Qp:Qs in patients with isolated ASD or VSD. IMPLICATIONS: Sevoflurane, halothane, isoflurane, and fentanyl/midazolam do not change pulmonary-to-systemic blood flow ratio in children with atrial and ventricular septal defects when administered at standard anesthetic doses with 100% oxygen.     

Amelioration of respiratory and circulatory changes in established endotoxic shock by ketoprofen

In an intensive–care setting we studied the effects of ketoprofen, a dual inhibitor of cyclooxygenase and lipoxygenase, on circulatory and respiratory changes during established endotoxic shock in sheep. Two groups (n = 7 in each) were exposed to E. coli endotoxin, which caused a sharp increase in pulmonary artery pressure (200%; PAP), intrapulmonary shunt fraction (300%; Qs/Q_T%), and oxygen extraction ratio (50%; Vo₂/ Do₂%). There was also a significant decrease in mean arterial pressure (25%; MAP), respiratory compliance (60%; C_T), arterial oxygen tension (65%; Pao₂), and oxygen delivery index (15%; Do₂) in both groups. After 30 min of endotoxin infusion, group K received ketoprofen, 2.5 mg/kg b.w. i.v., while group E served as shock controls. After 4 h there had been a significant improvement in MAP, Pao₂, Do₂, Qs/Q_T%, and C_T in the ketoprofen–treated group compared with the controls ( P < 0.01). In addition, the oxygen extraction ratio normalised in group K, but remained 70–100% increased in group E ( P < 0.01). The wet–to–dry weight ratios of the lungs and the liver were significantly lower in the ketoprofen–treated group compared with the controls ( P <0.05). It was concluded that ketoprofen significantly ameliorated the respiratory and circulatory effects of established endotoxic shock in sheep.     

Cardiac events after combined surgery for coronary and carotid artery disease

Objective: To evaluate serious cardiac events after combined (either single or two stage) coronary artery surgery (CAS) and carotid endarterectomy (CEA) for concomitant coronary and carotid artery disease. Methods: We have analyzed our 15 year experience (January 1981–September 1996) with 201 consecutive patients operated on using both approaches. Group A consisted of 48 patients with the single-stage procedure, while in group B (153 patients), two stage procedure was carried out, either as carotid endarterectomy (CEA), followed by coronary artery bypass surgery (CAS) (group B₁⁻ 103 patients), or as CAS followed by CEA (group B₂⁻ 50 patients). Five patients from B₁ group died after the CEA procedure, but were included, despite the fact they never reached the second stage. Left main coronary artery disease was found in 41 patients (20.4%), poor left ventricular function in 49 (24.4%) previous MI in 133 (66.2%), while 136 (67.7%) were in NYHA functional class III or IV. Bilateral carotid involvement was present in 61 patients (30.3%). Unstable angina was more prevalent in groups A and B₂ (P<0.0001), NYHA class III/IV in group A (versus B₁, P=0.001 and versus B₂, P=0.02), low ejection fraction in groups A and B₂ (P<0.0001), bilateral carotid stenosis in group B₁ (versus A, P=0.003 and versus B₂, P<0.0001), and ulcerated plaque in group B₁ (P<0.0001). These differences dictated the surgical strategy, which resulted in different protocols for clinical and operative management. Results: Early mortality for the entire group was 5.5% (11/201) 6.2% in group A, 7.8% in group B₁ and 0% in group B₂, respectively; (P>0.05). Serious morbidity occurred in 7.5% of patients (8.3% in group A, 7.8% in group B₁ and 6% in group B₂, respectively; P>0.05). Univariate analysis revealed only bilateral carotid stenosis to influence early outcome (P=0.04). Conclusion: Patients with concomitant coronary and carotid artery disease have relatively good immediate operative results, providing all existing lesions are corrected. Despite it did not reach the statistical significance, cardiac events were less frequent in groups A and B₂ indicating possible protective effect of prior CAS in patients with concomitant disease.     

Role of histamine receptors in the regulation of edema and circulation postburn

Despite histamine being a potent endogenous vasoactive agent released in increasing amounts postburn, its role in postburn oedema formation has been controversial and its effect on burn circulation poorly investigated. The present study investigated the involvement of H₁, H₂ and H₃ receptors in postburn edema in rats exposed to skin and muscle burns and their influence on skin circulation postburn. We used the selective antagonists clemastine (H₁), ranitidine (H₂), thioperamide (H₃) and the selective H₃ receptor agonist, imetit. Results showed that none of the antagonists or the H₃ agonist had significant effect on postburn edema measured by quantitative spectrophotometric analysis of extravasated Evans blue-albumin in the full-thickness burned skin or muscle. Clemastine and thioperamide failed to induce significant effect on blood flow in the partial- or full-thickness skin burn injury as measured by laser Doppler flowmetry, while ranitidine significantly (P<0.01) reduced blood flow in the full-thickness burn. In contrast, the H₃ receptor agonist, imetit, significantly increased blood flow, both in the partial-thickness burn injury (P<0.05) and in the full-thickness burn (P<0.01). Moreover, imetit significantly (P<0.01) increased mean arterial pressure while thioperamide significantly (P<0.01) reduced systemic pressure. In conclusion, H₁, H₂ and H₃ receptors are not important actors in the regulation of vascular patency permeability, whereas H₃ receptors play an important role by increasing skin circulation postburn, presumably by relaxation of vascular smooth muscle and/or by interacting with other inflammatory neurotransmitters. Data also suggest that H₂ receptor blockers may not be best choice for stress ulcer prophylaxis in burn patients.     

Inhibition of myosin light chain kinase provides prolonged attenuation of radial artery vasospasm

Objective: Current treatments for conduit vessel vasospasm are short-acting and do not inhibit all vasospastic stimuli. This study tests the hypothesis that irreversible inactivation of myosin light chain kinase provides sustained inhibition of arterial vasoconstriction stimulated by a spectrum of vasopressors. Methods: Canine radial artery segments were soaked for 60 min in control buffer or buffer with wortmannin, an irreversible inhibitor of myosin light chain kinase. The vessels were then thoroughly washed and contractile responses were quantified in response to a spectrum of vasopressors at 2 and 48 h after treatment. After 48 h, selected vessels were examined for morphologic changes and development of apoptosis. Results: Two hours after treatment, wortmannin-soaked vessels contracted significantly less than controls in response to norepinephrine (0.19±0.07 g vs. 7.22±0.37 g, P<0.001), serotonin (0.92±0.35 g vs. 9.64±0.67 g, P<0.001), thromboxane-mimetic U46619 (1.25±0.17 g vs. 10.99±0.50 g, P<0.001), and KCl (1.98±0.27 g vs.15.00±0.48 g, P<0.001). At 48 h, vasoconstriction remained significantly inhibited in wortmannin-treated vessels compared to control vessels in response to norepinephrine (2.36±0.17 vs. 6.95±0.47 g, P<0.001), serotonin (4.67±0.39 vs. 12.42±0.70 g, P<0.001), U46619 (5.42±0.34 vs. 9.29±0.74 g, P=0.008), and KCl (7.49±0.48 vs. 13.32±0.60 g, P<0.001). Histology of wortmannin-treated vessels revealed no overt smooth muscle or endothelial cell damage. TUNEL staining revealed a significantly greater proportion of apoptotic smooth muscle and endothelial cells in wortmannin-treated vessels as compared to controls. Conclusions: Disengaging the smooth muscle contractile apparatus by irreversibly binding myosin light chain kinase with wortmannin significantly attenuates radial artery vasoconstriction up to 48 h after brief treatment. This novel strategy may prevent vasospasm of arterial grafts from all causes for several postoperative days.     

A new outside stent – does it prevent vein graft intimal proliferation?

Objective: The saphenous vein subjected to arterial pressure stretches to its elastic limits and constitutes intimal hyperplasia. Sheathing of the vein graft with pressure-resistant tubing might prolong vein graft patency. Methods: Twenty-one sheep received radial vein grafts or hybrid grafts composed of radial vein, collagen fibrin glue and highly flexible torlen/dacron mesh tubing transplanted into the carotid artery position. Veins were examined with the use of light and electron microscopy. Proliferating cell antigen (Ki-67) stains served as markers of proliferation. Results: The mean wall thickness of both intimal and medial layers was evaluated. The mean intimal wall thickness was 19±11 μm in hybrid grafts vs. 24±7 μm in unsheathed grafts (P<0.001); 22±6 vs. 26±10 μm (P<0.001); 23±8 vs. 52±15 μm (P<0.001); 37±21 vs. 90±31 μm (P<0.001); 57±31 vs. 104±28 μm (P<0.001); 58±21 vs. 133±32 μm (P<0.001); and 72±22 vs. 244±100 μm (P<0.001) after respectively 5 days, 9 days, 4 weeks, 6 weeks, 8 weeks, 10 weeks and 12 weeks from implantation. Electronic microscope examination of hybrid grafts revealed a smooth endothelial layer with intact nuclei and an intima composed of layers of collagen and muscle fibers. In unsheathed grafts endothelial edema and nuclear destruction were observed. Conclusions: The external vein graft support with mesh tubing reduces intimal and medial layer thickening and cell proliferation in composite vein grafts transplanted in the arterial position.