Improving the emergency department management of post-chemotherapy sepsis in haematological malignancy patients.

OBJECTIVE: To review the result of the implementation of treatment protocol for post-chemotherapy sepsis in haematological malignancy patients. DESIGN: Case series with internal comparison. SETTING: Accident and Emergency Department, Queen Elizabeth Hospital, Hong Kong. PATIENTS: Febrile patients presenting to the Accident and Emergency Department with underlying haematological malignancy and receiving chemotherapy within 1 month of Accident and Emergency Department visit between June 2011 and July 2012. Similar cases between June 2010 and May 2011 served as historical referents. MAIN OUTCOME MEASURES: The compliance rate among emergency physicians, the door-to-antibiotic time before and after implementation of the protocol, and the impact of the protocol on Accident and Emergency Department and hospital service. RESULTS: A total of 69 patients were enrolled in the study. Of these, 50 were managed with the treatment protocol while 19 patients were historical referents. Acute myeloid leukaemia was the most commonly encountered malignancy. Overall, 88% of the patients presented with sepsis syndrome. The mean door-to-antibiotic time of those managed with the treatment protocol was 47 minutes versus 300 minutes in the referent group. Overall, 86% of patients in the treatment group met the target door-to-antibiotic time of less than 1 hour. The mean lengths of stay in the emergency department (76 minutes vs 105 minutes) and hospital (11 days vs 15 days) were shorter in those managed with the treatment protocol versus the historical referents. CONCLUSION: Implementation of the protocol can effectively shorten the door-to-antibiotic time to meet the international standard of care in neutropenic sepsis patients. The compliance rate was also high. We proved that effective implementation of the protocol is feasible in a busy emergency department through excellent teamwork between nurses, pharmacists, and emergency physicians.

Hearts from DCD donors display acceptable biventricular function after heart transplantation in pigs.

Cardiac transplantation is in decline, in contrast to other solid organs where the number of solid organ transplants from donors after circulatory death (DCD) is increasing. Hearts from DCD donors are not currently utilized due to concerns that they may suffer irreversible cardiac injury with resultant poor graft function. Using a large animal model, we tested the hypothesis that hearts from DCD donors would be suitable for transplantation. Donor pigs were subjected to hypoxic cardiac arrest (DCD) followed by 15 min of warm ischemia and resuscitation on cardiopulmonary bypass, or brainstem death (BSD) via intracerebral balloon inflation. Cardiac function was assessed through load-independent measures and magnetic resonance imaging and spectroscopy. After resuscitation, DCD hearts had near normal contractility, although stroke volume was reduced, comparable to BSD hearts. DCD hearts had a significant decline in phosphocreatine and increase in inorganic phosphate during the hypoxic period, with a return to baseline levels after reperfusion. After transplantation, cardiac function was comparable between BSD and DCD groups. Therefore, in a large animal model, the DCD heart maintains viability and recovers function similar to that of the BSD heart and may be suitable for clinical transplantation. Further study is warranted on optimal reperfusion strategies.

Improved outcome with organs from carbon monoxide poisoned donors for intrathoracic transplantation.

BACKGROUND: The success of intrathoracic organ transplantation has lead to a growing imbalance between the demand and supply of donor organs. Accordingly, there has been an expansion in the use of organs from nonconventional donors such as those who died from carbon monoxide poisoning. We describe our experience with 7 patients who were transplanted using organs after fatal carbon monoxide poisoning. METHODS: A retrospective study of the 1,312 intrathoracic organ transplants between January 1979 and February 2000 was completed. Seven of these transplants (0.5%) were fulfilled with organs retrieved from donors after fatal carbon monoxide poisoning. There were six heart transplants and one single lung transplant. The history of carbon monoxide inhalation was obtained in all of these donors. RESULTS: Five of 6 patients with heart transplant are alive and well with survival ranging from 68 to 1,879 days (mean, 969 +/- 823 days). One patient (a 29-year-old male) died 12 hours posttransplant caused by donor organ failure. The patient who had a right single lung transplant did well initially after the transplant, but died after 8 months caused by Pneumocystis carinii pneumonia. All those recipients who were transplanted from carbon monoxide poisoned donors and ventilated for more than 36 hours, survived for more than 30 days. Moreover, these donors were assessed and optimized by the Papworth donor management protocol. CONCLUSIONS: Carbon monoxide poisoned organs can be considered for intrathoracic transplantation. In view of the significant risk of donor organ failure, a cautious approach is still warranted. Ideally, the donor should be hemodynamically stable for at least 36 hours from the time of poisoning and on minimal support. A formal approach of invasive monitoring and active management further improves the chances of successful outcome.

Heart-lung transplantation for Eisenmenger syndrome: early and long-term results.

BACKGROUND: Heart-lung transplantation (HLT) for Eisenmenger syndrome (ES) provides superior early and intermediate survival when compared with other forms of transplantation. The early risk factors and long-term outcome of HLT for ES are less well defined. METHODS: We analyzed 263 patients who had undergone HLT at our institution during more than 15 years. Fifty-one consecutive patients with ES who underwent HLT, 33 (65%) of which had simple anatomy, were compared with 212 cases having HLT for other indications (non-ES). RESULTS: Female sex and previous thoracotomy were more prevalent in the ES group. Patients with ES had greater postoperative blood loss and returned more frequently to the operating room for control of bleeding. There were 8 (16%) early deaths in the ES group compared with 27 (13%) in non-ES (p = 0.65). One-, 5-, and 10-year survival rates for ES were 72.6%, 51.3%, and 27.6%, respectively, compared with non-ES of 74.1%, 48.1%, and 26.0%, respectively, and there was no difference in survival overall (p = 0.54). Among ES patients, previous thoracotomy was a risk factor for hospital death. A subgroup analysis based on simple versus complex type of ES did not show statistically significant differences in terms of postoperative course or early or late survival. CONCLUSIONS: Heart-lung transplantation is a successful procedure for ES. Despite a greater frequency of risk factors and a more difficult operative course, early and late outcome with HLT is comparable to non-ES recipients.

The effects of a leukocyte-depleting filter on cerebral and renal recovery after deep hypothermic circulatory arrest.

OBJECTIVE: The purpose of this study was to determine the effects of a leukocyte-depleting filter on cerebral and renal recovery after deep hypothermic circulatory arrest. METHODS: Sixteen 1-week-old piglets underwent cardiopulmonary bypass, were cooled to 18 degrees C, and underwent 60 minutes of circulatory arrest, followed by 60 minutes of reperfusion and rewarming. Global and regional cerebral blood flow, cerebral oxygen metabolism, and renal blood flow were determined before cardiopulmonary bypass, after the institution of cardiopulmonary bypass, and at 1 hour of deep hypothermic circulatory arrest. In the study group (n = 8 piglets), a leukocyte-depleting arterial blood filter was placed in the arterial side of the cardiopulmonary bypass circuit. RESULTS: With cardiopulmonary bypass, no detectable change occurred in the cerebral blood flow, cerebral oxygen metabolism, and renal blood flow in either group, compared with before cardiopulmonary bypass. In control animals, after deep hypothermic circulatory arrest, blood flow was reduced to all regions of the brain (P <.004) and the kidneys (P =.02), compared with before deep hypothermic circulatory arrest. Cerebral oxygen metabolism was also significantly reduced to 60.1% +/- 11.3% of the value before deep hypothermic circulatory arrest (P =.001). In the leukocyte-depleting filter group, the regional cerebral blood flow after deep hypothermic circulatory arrest was reduced, compared with the value before deep hypothermic circulatory arrest (P <.01). Percentage recovery of cerebral blood flow was higher in the leukocyte filter group than in the control animals in all regions but not significantly so (P >.1). The cerebral oxygen metabolism fell to 66.0% +/- 22.3% of the level before deep hypothermic circulatory arrest, which was greater than the recovery in the control animals but not significantly so (P =.5). After deep hypothermic circulatory arrest, the renal blood flow fell to 81.0% +/- 29.5% of the value before deep hypothermic circulatory arrest (P =.06). Improvement in renal blood flow in the leukocyte filter group was not significantly greater than the recovery to 70.2% +/- 26.3% in control animals (P =.47). CONCLUSIONS: After a period of deep hypothermic circulatory arrest, there is a significant reduction in cerebral blood flow, cerebral oxygen metabolism, and renal blood flow. Leukocyte depletion with an in-line arterial filter does not appear to significantly improve these findings in the neonatal piglet.

Intermittent perfusion protects the brain during deep hypothermic circulatory arrest.

BACKGROUND: Deep hypothermic circulatory arrest (DHCA) has been shown to cause impairment in recovery of cerebral blood flow (CBF) and cerebral metabolism (CMRO2) proportional to the duration of the DHCA period. This effect on CMRO2 may be a marker for brain injury, because CMRO2 recovers normally after cardiopulmonary bypass (CPB) when DHCA is not used. The aim of this study was to investigate the effects of intermittent perfusion during DHCA on the recovery of CMRO2 after CPB and to correlate these findings with electron microscopy (EM) of the cerebral microcirculatory bed. METHODS: Fifteen neonatal piglets were placed on CPB and cooled to 18 degrees C. Each animal then underwent either: (1) 60 minute continuous CPB (control), (2) 60 minute uninterrupted DHCA (UI-DHCA), or (3) 60 minute DHCA with intermittent perfusion (1 minute every 15 minutes) (I-DHCA). All animals were then rewarmed and weaned from CPB. Measurements of CBF and CMRO2 were taken before and after CPB. A further 9 animals underwent CPB without DHCA (2 animals) or with DHCA (7 animals), under various conditions of arterial blood gas management, intermittent perfusion, and reperfusion time. RESULTS: UI-DHCA resulted in significant impairment to recovery of CMRO2 after CPB (p < 0.05). Regardless of the blood gas strategy used, the EM after UI-DHCA revealed extensive damage characterized by perivascular intracellular and organelle edema, and vascular collapse. I-DHCA, on the other hand, produced a pattern of normal CMRO2 recovery identical to controls, and the EM was normal for both these groups. CONCLUSIONS: Intermittent perfusion during DHCA is clinically practical and results in normal cerebral metabolic and ultrastructural recovery. Furthermore, the correlation between brain structure and CMRO2 suggests that monitoring CMRO2 during the operation may be an outstanding way to investigate new strategies for neuroprotection designed to reduce cerebral damage in children undergoing correction of congenital cardiac defects.

Thromboxane A2-receptor blockade improves cerebral protection for deep hypothermic circulatory arrest.

OBJECTIVE: Following the use of deep hypothermic circulatory arrest in cardiac surgery, cerebral blood flow and cerebral oxygen metabolism are impaired. These may result from abnormal cerebral vasospasm. Powerful vasoconstrictors including endothelins and thromboxane A2 could mediate these processes. We investigated possible involvement of these two factors by assessing the effects of (a) phosphoramidon-an inhibitor of endothelin converting enzyme, and (b) vapiprost (GR32191B)-a specific thromboxane A2-receptor antagonist, on the recovery of cerebral blood flow and cerebral oxygen metabolism following deep hypothermic circulatory arrest. METHODS: A total of 18 1-week-old piglets were randomised into three groups (n = 6 per group). At induction, the control group received saline; group PHOS received phosphoramidon 30 mg kg-1 intravenously. Group VAP received vapiprost 2 mg kg-1 at induction and at 30 min intervals thereafter. All groups underwent cardiopulmonary bypass cooling to 18 degrees C, exposed to 60 min of deep hypothermic circulatory arrest, rewarmed and reperfused for 1 h. Cerebral blood flow was measured with radio-labeled microspheres: cerebral oxygen metabolism was calculated at baseline before deep hypothermic circulatory arrest and at 1 h of reperfusion and rewarming. RESULTS: In the control group, cerebral blood flow decreased to 40.2 +/- 2.0% of baseline after deep hypothermic circulatory arrest and cerebral oxygen metabolism decreased to 50.0 +/- 5.5% (P < 0.0005). The responses in group PHOS were similar. In group VAP, cerebral blood flow and cerebral oxygen metabolism were 64.3 +/- 10.6 and 80.1 +/- 9.8% of baseline, respectively, after deep hypothermic circulatory arrest. Thus, treatment with vapiprost significantly improved recovery of cerebral blood flow (P = 0.046) and cerebral oxygen metabolism (P = 0.020) following deep hypothermic circulatory arrest. No such improvement was seen after treatment with phosphoramidon. CONCLUSIONS: Thromboxane A2 mediates impairments in cerebral perfusion and metabolism following deep hypothermic circulatory arrest. These changes were attenuated by blockade of thromboxane A2-receptors using vapiprost. Endothelins are not shown to be involved. Better knowledge of injury mechanisms will enable development of more effective cerebral protection strategies and allow safer application of deep hypothermic circulatory arrest.

Cardiopulmonary bypass and circulatory arrest increase endothelin-1 production and receptor expression in the lung.

BACKGROUND: Endothelin-1 has been shown to be a mediator of pulmonary hypertension after cardiopulmonary bypass and deep hypothermic circulatory arrest. It is not known whether the mechanism is increased production of endothelin-1 or alterations in expression of endothelin-1 receptors in the lung. This study was designed to test the hypothesis that circulatory arrest increases endothelin-1 mRNA levels and endothelin-1 receptor expression in the lung. METHODS AND RESULTS: Twenty-four piglets (7 to 30 days old) were studied randomly either at baseline (controls, n = 12) or after cardiopulmonary bypass with 30 minutes of circulatory arrest (deep hypothermic circulatory arrest, n = 12). Lungs and pulmonary arteries were harvested immediately after hemodynamic data collection. Deep hypothermic circulatory arrest significantly increased pulmonary vascular resistance (p < 0.01). Deep hypothermic circulatory arrest also produced a significant increase in endothelin-1 mRNA levels in the pulmonary arteries (149 +/- 55 pg vs 547 +/- 111 pg, p = 0.007). There was no significant change in the pulmonary parenchymal endothelin-1 mRNA levels (4102 +/- 379 pg vs 4623 +/- 308 pg, p = 0.32). Ligand binding studies of the lung parenchyma revealed a single specific endothelin-1 binding site with an EC50 value (effective concentration causing 50% of the maximum response) of about 1 x 10(-8) mol/L, consistent with the endothelin B subtype. Deep hypothermic circulatory arrest resulted in a significant increase in the number of endothelin-1 receptors in the lung (109 +/- 6 fmol/mg total protein to 135 +/- 9 fmol/mg total protein, p = 0.02). CONCLUSIONS: Deep hypothermic circulatory arrest increases production of endothelin-1 by the pulmonary vascular endothelium. Endothelin-1 production in the pulmonary parenchyma does not change. Expression of endothelin B receptors in the pulmonary parenchyma also increases after cardiopulmonary bypass with deep hypothermic circulatory arrest. This study supports the hypothesis that deep hypothermic circulatory arrest results in pulmonary vascular endothelial activation with increased endothelin-1 mRNA production.

Nitric oxide production affects cerebral perfusion and metabolism after deep hypothermic circulatory arrest.

BACKGROUND: Use of deep hypothermic circulatory arrest (DHCA) in infant cardiac surgery is associated with reduced cerebral perfusion and metabolism during the recovery period. We investigated the impairment of nitric oxide production as a possible cause. METHODS: A group of 1-week-old piglets underwent normothermic cardiopulmonary bypass (group A); three other groups (B, C, and D; n = 6 per group) underwent 60 minutes of DHCA at 18 degrees C and 60 minutes of rewarming. The animals were then treated as follows: Groups A and B received L-omega-nitro-arginine-methyl-ester (L-NAME, 50 mg.kg-1); group C, saline solution; and group D, L-arginine (600 mg.kg-1). RESULTS: In group A, global cerebral blood flow decreased to 37.3% +/- 4.2% of baseline after L-NAME administration (p < 0.005). In group B, global cerebral blood flow decreased to 44.6% +/- 4.4% of baseline after DHCA and 28.9% +/- 3.4% after L-NAME administration (p < 0.001). Following L-arginine treatment after DHCA (group D), global cerebral blood flow increased from 43.8% +/- 3.0% of baseline to 61.6% +/- 9.1% (p < 0.05); cerebral oxygen metabolism increased from 1.93 +/- 0.16 mL.min-1.100 g-1 after DHCA to 2.42 +/- 0.25 mL.min-1.100 g-1 (p < 0.05). CONCLUSIONS: Tonal production of nitric oxide is impaired in the brain after DHCA and is partly responsible for the circulatory and metabolic changes observed. Stimulation of nitric oxide production (L-arginine) significantly improved recovery of cerebral blood flow and cerebral oxygen metabolism after DHCA.

Effects of cardiopulmonary bypass and circulatory arrest on endothelium-dependent vasodilation in the lung.

Endothelial injury with failure of pulmonary endothelium-dependent vasodilatation has been proposed as a possible cause for the increased pulmonary vascular resistance observed after cardiopulmonary bypass, but the mechanisms underlying this response are not understood. An in vivo piglet model was used to investigate the role of endothelium-dependent vasodilatation in postbypass pulmonary hypertension. The pulmonary vascular responses to acetylcholine, a receptor-mediated endothelium-dependent vasodilator, and nitric oxide, an endothelium-independent vasodilator, were studied in one group of animals after preconstriction with the thromboxane A2 analog U46619 (n = 6); a second group was studied after bypass with 30 minutes of deep hypothermic circulatory arrest (n = 6). After preconstriction with U46619, both acetylcholine and nitric oxide caused significant decreases in pulmonary vascular resistance (34% +/- 6% decrease, p = 0.007, and 39% +/- 4% decrease, p = 0.001). After cardiopulmonary bypass with circulatory arrest, acetylcholine did not significantly change pulmonary vascular resistance (0% +/- 8% decrease, p = 1.0), whereas nitric oxide produced a 32% +/- 4% decrease in pulmonary vascular resistance (p = 0.007). These results demonstrate a loss of receptor-mediated endothelium-dependent vasodilatation with normal vascular smooth muscle function after circulatory arrest. Administration of the nitric oxide synthase blocker Ngamma-nitro-L-arginine-methyl-ester after circulatory arrest significantly increased pulmonary vascular resistance; thus, although endothelial cell production of nitric oxide may be diminished, it continues to be a major contributor to pulmonary vasomotor tone after cardiopulmonary bypass with deep hypothermic circulatory arrest. In summary, cardiopulmonary bypass with deep hypothermic circulatory arrest results in selective pulmonary endothelial cell dysfunction with loss of receptor-mediated endothelium-dependent vasodilatation despite preserved ability of the endothelium to produce nitric oxide and intact vascular smooth muscle function.

Blockade of endothelin-converting enzyme reduces pulmonary hypertension after cardiopulmonary bypass and circulatory arrest.

BACKGROUND: Pulmonary dysfunction associated with elevated pulmonary vascular resistance is a significant problem after cardiopulmonary bypass (CPB) and circulatory arrest. Mediators of the pulmonary hypertensive response to CPB have not been fully elucidated. The purpose of this study was to examine the contribution of the endothelium-derived vasoconstrictor endothelin-1 to postbypass pulmonary hypertension. METHODS: Twelve 1-month-old piglets were instrumented with left atrial and pulmonary artery (PA) micromanometers and a PA flow probe. Phosphoramidon (Phos, n = 6) pigs received a 30 mg/kg bolus of Phos, an endothelin converting enzyme inhibitor. Controls (n = 6) received saline solution. All animals were placed on CPB and underwent a 60-minute period of circulatory arrest. The indexed pulmonary vascular resistance (PVRI) was calculated at baseline for controls, both before and 10 minutes after drug infusion in the Phos group, and 15 minutes after separation from CPB in both groups. RESULTS: Pre-CPB, mean PA pressure, and PVRI were not different between the control and Phos groups (14.6 +/- 1.1 versus 14.5 +/- 1.1 mm Hg and 7322 +/- 1269 versus 7260 +/- 947 dyne/sec/kg/cm-5, respectively). After CPB mean PA pressure was significantly higher in control than Phos animals (32.1 +/- 1.1 versus 22.5 +/- 1.3 mm Hg, p = 0.0003). PVRI was also significantly higher in the controls (30896 +/- 4714 versus 14972 +/- 1710, dyne/sec/kg/cm-5, p = 0.02). CONCLUSIONS: Production of endothelin-1 during CPB and circulatory arrest is a mediator of postbypass pulmonary hypertension.

Leg ischaemia following bilateral internal thoracic artery and inferior epigastric artery harvesting.

There is increasing evidence that the use of arterial conduits for coronary artery bypass grafting provides superior long-term results when compared to using saphenous veins alone. Major complications of using internal thoracic arteries (ITAs) and inferior epigastric arteries (IEAs) are uncommon. We report the case of a 42-year-old man who underwent coronary revascularisation in which harvesting of these arteries resulted in critical ischaemia of the lower limbs requiring aortobifemoral grafting. This patient had a long-standing occluded abdominal aorta which was asymptomatic and relied on the ITAs and IEAs as important collateral blood supply to the legs. The enormous size of these conduits found at operation suggested their role. Management strategies to avoid such a serious complication are discussed.

Maze 3 for atrial fibrillation: two cuts too few?

The Maze procedure has been developed as a surgical approach to the management of patients with atrial fibrillation refractory to medical treatment. The recent modification of the technique (Maze 3) achieves good rate control with coordinated AV contractions. However, the procedure involves cuts that completely isolate a block of left atrial (LA) wall, including the four ostia of the pulmonary veins. The electrical and mechanical activity of this isolated LA block are dissociated from the rest of the atrium, and the area may, in fact, continue to fibrillate. This may provide a nidus for the development of mural thrombus. The weight and endocardial surface area of the LA block and of the entire LA were estimated in ten formalin fixed hearts from trauma victims with no evidence of cardiac disease. In these samples, the LA block represented 35% of the endocardial surface area of the entire LA and 29% of the weight. The LA block is of sufficient size to allow macroreentrant circuits to form and has the potential to fibrillate if isolated from the rest of the atrium. We modified the Maze 3 procedure to recruit the otherwise isolated LA block by using two additional cuts around each pair of pulmonary veins as they enter the LA. The first patient who underwent the modified procedure demonstrated sinus rhythm on Holter monitoring postoperatively and remained in sinus rhythm following burst atrial pacing at 300 and 420 beats/min each for 30 seconds. In addition, atrial contractions were found to contribute 19% of the cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined subclavian artery rupture and delayed bronchial stenosis from blunt chest trauma.

A 23-year-old man suffered crush injury to the thorax resulting in rupture of the left subclavian artery and left main bronchus. The arterial injury was diagnosed immediately and successfully repaired. Despite the presence of bilateral pneumothoraces and mediastinal and chest wall emphysema the bronchial injury was not initially diagnosed because both lungs re-expanded with tube thoracostomies. The patient re-presented 5 weeks later with complete atelectasis of the left lung. Bronchoscopy revealed a fibrotic stenosis of the left main bronchus. The stenosed segment was completely excised and the cut ends anastomosed with full re-inflation of the lung.