Cardiac autonomic ganglia ablation suppresses atrial fibrillation in a canine model of acute intermittent hypoxia.

BACKGROUND: Atrial fibrillation (AF) is associated with hypoxia in which cardiac autonomic nerve system (ANS) plays an important role. Our previous studies indicated that ANS is activated in an intermittent hypoxia model and contributes to AF initiation. This study aimed to investigate the effects of cardiac ganglionated plexus (GP) ablation on AF in this model. METHODS AND RESULTS: In thirteen anesthetized male dogs, GP ablation was applied after 1h of intermittent hypoxia in the first group (n=7) and before that in the second group (n=6). The heart rate (HR), blood pressure (BP), arterial blood gases, heart rate viability indices, atrial effective refractory period (ERP) and window of vulnerability (WOV), the sum of WOVs (ΣWOV) were measured. In both groups, HR, BP increased and then declined during hypoxia, and not significantly affected by GP ablation. Hypoxemia, hypercapnia and acidosis were observed after intermittent hypoxia. In the first group, both of low frequency power (LF) and high frequency power (HF) increased during hypoxia. At the end of intermittent hypoxia, LF/HF ratio decreased, ERP shortened and ΣWOV increased. The following GP ablation resulted in increases in LF, LF/HF, ERP and decreases in HF, ΣWOV. In the second group, GP ablation caused increases in LF, LF/HF, ERP and decrease in HF. Subsequently, ERP shortened at several sites after intermittent hypoxia. However, there were no significant changes in LF/HF ratio or ΣWOV. CONCLUSIONS: Cardiac ANS plays an important role in hypoxia-induced AF. AF associated with hypoxia might be prevented or reversed by GP ablation.

A critical appraisal of the evidence for using cardiotocography plus ECG ST interval analysis for fetal surveillance in labor. Part II: the meta-analyses.

We appraised the methodology, execution and quality of the five published meta-analyses that are based on the five randomized controlled trials which compared cardiotocography (CTG)+ST analysis to cardiotocography. The meta-analyses contained errors, either created de novo in handling of original data or from a failure to recognize essential differences among the randomized controlled trials, particularly in their inclusion criteria and outcome parameters. No meta-analysis contained complete and relevant data from all five randomized controlled trials. We believe that one randomized controlled trial excluded in two of the meta-analyses should have been included, whereas one randomized controlled trial that was included in all meta-analyses, should have been excluded. After correction of the uncovered errors and exclusion of the randomized controlled trial that we deemed inappropriate, our new meta-analysis showed that CTG+ST monitoring significantly reduces the fetal scalp blood sampling usage (risk ratio 0.64; 95% confidence interval 0.47-0.88), total operative delivery rate (0.93; 0.88-0.99) and metabolic acidosis rate (0.61; 0.41-0.91).

A critical appraisal of the evidence for using cardiotocography plus ECG ST interval analysis for fetal surveillance in labor. Part I: the randomized controlled trials.

We reappraised the five randomized controlled trials that compared cardiotocography plus ECG ST interval analysis (CTG+ST) vs. cardiotocography. The numbers enrolled ranged from 5681 (Dutch randomized controlled trial) to 799 (French randomized controlled trial). The Swedish randomized controlled trial (n = 5049) was the only trial adequately powered to show a difference in metabolic acidosis, and the Plymouth randomized controlled trial (n = 2434) was only powered to show a difference in operative delivery for fetal distress. There were considerable differences in study design: the French randomized controlled trial used different inclusion criteria, and the Finnish randomized controlled trial (n = 1483) used a different metabolic acidosis definition. In the CTG+ST study arms, the larger Plymouth, Swedish and Dutch trials showed lower operative delivery and metabolic acidosis rates, whereas the smaller Finnish and French trials showed minor differences in operative delivery and higher metabolic acidosis rates. We conclude that the differences in outcomes are likely due to the considerable differences in study design and size. This will enhance heterogeneity effects in any subsequent meta-analysis.

Early coagulopathy in patients with ruptured abdominal aortic aneurysm.

Ruptured abdominal aortic aneurysm (AAA) is associated with a high mortality despite surgical management. Earlier reports indicate that a major cause of immediate intraoperative death in patients with ruptured AAA is related to hemorrhage due to coagulopathy. Acidosis is, besides hypothermia and hemodilution, a possible cause of coagulopathy. The aim of the present study was to investigate the incidence of coagulopathy and acidosis preoperatively in patients with ruptured AAA in relation to the clinical outcome with special regard to the influence of shock. For this purpose, 95 consecutive patients who underwent surgery for AAA (43 ruptured with shock, 12 ruptured without shock, and 40 nonruptured) were included. Coagulopathy was defined as prothrombin time (international normalized ratio [INR]) ≥1.5 and acidosis was defined as base deficit ≥6 mmol/L. Mortality and postoperative complications were recorded. The present study shows a state of acidosis at the start of surgery in 30 of 55 patients with ruptured AAA. However, only in 7 of 55 patients with ruptured AAA a state of preoperative coagulopathy was demonstrated. Furthermore, in our patients with shock due to ruptured AAA only 2 of 12 deaths were due to coagulopathy and bleeding. Indeed, our results show a relatively high incidence of thrombosis-related causes of death in patients with ruptured AAA, indicating a relation to an activated coagulation in these patients. These findings indicate that modern emergency management of ruptured AAA has improved in the attempt to prevent fatal coagulopathy.

[Hyperchloraemic metabolic acidosis in a patient with an ureteroileostomy according to Bricker]. / Hyperchloremische metabole acidose bij een patiënt met een brickerlis.

A 79-year-old male with a Bricker loop and chronic renal failure was admitted to hospital because progressive dyspnoea. This was due to severe hyperchloraemic metabolic acidosis. Hyperchloraemic acidosis can occur if urinary diversions are constructed from the colon or ileum. Contact between intestinal mucosa and urine may cause reabsorption of ammonium and chloride, and secretion of bicarbonate. Hyperchloraemic acidosis is rarely seen with an incontinent ileal loop due to its small absorbing surface area and the rapid drainage of urine from the loop. Hyperchloraemic acidosis in a patient with a Bricker loop may point to prolonged contact between the ileum and urine. A loopogram is necessary to investigate the cause. In our patient the loopogram showed that the incorporated bowel segment was too long. After shortening of the Bricker loop, the patient recovered from the hyperchloraemic metabolic acidosis.

Damage control surgery--physiopathological benchmarks.

The following article, submitted in two complementary parts deals with an important and also modern concept developed under the name of damage-control surgery. Physiopathologically, the multiple injured patient is characterised by the probable, not just possible, appearance of the "blood's vicious cycle" of hypocoagulability, hypothermia and acidosis with death as a result. The first part of the article addresses the changes that are the reasons and the basis for applying damage-control surgery. Hypothermia is a direct result of trauma and patient's exposure to it but can also emerge throughout transportation, evaluation, emergency and surgical procedures to which the patient undergoes. Surgical procedures are directly a source that decreases the core temperature. While blood losses accompany trauma for certain and affect clot formation, the patient's coagulation system is impaired by these losses and the dysfunction is further enhanced by hypotermia, different mechanisms being involved. The third lethal component is acidosis. While being at first metabolically produced because of tissular injury, it is further enhanced by the other two elements. From a practical point of view, hypothermia and hypocoagulability can be though, more theoretically addressed, acidosis is more difficult to correct. As fav as the emergency specialist is concerned for the moment, the best solution to deal with this deadly triad is to prevent it. Damage-control surgery is just one type of measure in the process of prevention.

Severe metabolic acidosis and hypokalemia in a patient with enterovesical fistula.

We report a case of a 59-year-old woman who had severe metabolic acidosis and hypokalemia due to an enterovesical fistula. The patient came to our hospital complaining of systemic weakness and numbness of the fingers. She was found to have hyperchloremic metabolic acidosis (arterial bicarbonate, 2.8 mEq/l) and hypokalemia (serum potassium, 1.9 mEq/l) and was admitted for treatment. Following the correction of metabolic acidosis and hypokalemia, the patient was examined for the underlying cause of these electrolyte and acid-base disorders. She had a history of total hysterectomy followed by radiotherapy due to uterine cancer 30 years previously. After the surgery, she had suffered postoperative neurogenic bladder dysfunction, necessitating intermittent self-catheterization. Two years before admission, she had begun to experience watery diarrhea. A radiographic study after recovery from the acid-base and electrolyte disorders revealed the presence of an enterovesical fistula. The fistula was surgically resected and the metabolic acidosis completely cleared. Unexplained hyperchloremic metabolic acidosis with hypokalemia may suggest the presence of an enterovesical fistula in patients with a surgical history of malignant pelvic tumor and neurogenic bladder dysfunction.

Multi-institutional experience with the gastrointestinal composite reservoir.

PURPOSE: We evaluated multi-institutional experience with the gastrointestinal composite reservoir in patients with metabolic acidosis, the short bowel syndrome, severe pelvic radiation and/or renal insufficiency. MATERIALS AND METHODS: At 4 institutions 33 patients underwent construction of a gastrointestinal composite reservoir, including 19 with the short bowel syndrome, 13 with metabolic acidosis and 7 who also had renal insufficiency. A total of 16 patients underwent conversion of a previous diversion and the remaining 17 received new urinary diversion. Charts were reviewed for the metabolic impact of the gastrointestinal reservoir as well as any long-term sequelae. RESULTS: At a mean followup of 54 months there was a significant (p < or =0.05) improvement in mean preoperative and postoperative serum chloride (106 versus 102 mEq./l.), serum bicarbonate (23.3 versus 25 mEq./l.) and serum pH (7.36 versus 7.4). Mean serum creatinine did not significantly differ during followup in patients with normal renal function or renal insufficiency. Complications were not different than those of standard intestinal or gastric reservoirs. CONCLUSIONS: The gastrointestinal reservoir has provided an excellent metabolic balance in a large series of compromised patients with few side effects. We believe that the gastrointestinal composite reservoir represents the urinary diversion of choice when standard intestinal urinary reservoirs cannot be created in the setting of metabolic acidosis, the short bowel syndrome and severe pelvic radiation. However, the value of the gastrointestinal composite in the setting of renal insufficiency remains undetermined.

Outcome of gastrocystoplasty in tertiary pediatric urology practice.

PURPOSE: Although the use of stomach for bladder reconstruction has become popular during the last decade, it is not a panacea. We review our experience with gastrocystoplasty. MATERIALS AND METHODS: We completed a retrospective chart review of 11 females and 12 males, 1.5 to 22.5 years old (mean age 10) who underwent gastrocystoplasty at Hôpital Sainte-Justine, Montreal, Quebec and Children's Hospital, Winnipeg, Manitoba, Canada between December 1990 and 1998. Primary diagnoses included spinal dysraphism in 14 patients, posterior urethral valves in 3, cloacal exstrophy in 2, cloacal outlet anomaly in 2, multiple failed ureteral reimplantations with bladder dysfunction in 1 and neurogenic bladder of uncertain etiology in 1. Three patients presented with chronic renal failure. Concurrent reconstructive surgery included ureteral reimplantation in 10 patients, bladder neck plasty in 4 or closure in 4, and continent urinary diversion in 5. RESULTS: Acute postoperative complications included urosepsis in 2 cases, bowel obstruction in 2 and ureteral obstruction in 1. Followup ranged from 4 to 86 months (mean 45). Long-term complications consisted of intractable hematuria-dysuria syndrome in 5 cases, inability to catheterize in 3, perineal urinary fistula in 2, new onset hydronephrosis in 2, continent stomal stenosis in 1 and bladder calculus in 1. Proton pump inhibitors and/or histamine 2 antagonists were used in 16 of the 23 patients to prevent the hematuria-dysuria syndrome. In 5 cases the hematuria-dysuria syndrome was poorly controlled medically and 3 were converted to another form of urinary reconstruction. In 18 of 20 cases voiding cystourethrography revealed no vesicoureteral reflux, and in 18 of 21 ultrasound documented stable or improved upper tracts. Socially acceptable urinary continence was attained in 19 of the 21 patients. CONCLUSIONS: The use of stomach for bladder augmentation may be considered in patients with cloacal exstrophy and/or metabolic acidosis. Histamine blockers and/or proton pump inhibitors may be required to prevent the hematuria-dysuria syndrome. Symptoms of the hematuria-dysuria syndrome may be disabling and may mandate alternative forms of urinary tract reconstruction.

Conversion from bladder to enteric drainage after pancreaticoduodenal transplantations.

BACKGROUND: Bladder drainage is the most common technique for managing the exocrine secretions of pancreaticoduodenal grafts. However, bladder drainage can cause urinary, pancreatic, and metabolic complications that may require conversion to enteric drainage. With enteric drainage, urinary amylase levels cannot be monitored as a marker for rejection. After enteric conversion, rejection is the major cause of graft loss. Timing the conversion to reduce immunologic graft loss would greatly improve patient and graft survival rates. Our study was designed to assess the incidence of, indications for, and complications of converting from bladder to enteric drainage after pancreaticoduodenal transplantations. METHODS: We retrospectively reviewed our experience with 80 recipients who underwent enteric conversion. We studied the recipient category, the interval from transplantation to conversion, the interval from the last rejection episode to conversion, the indications for conversion, the type of enteric drainage at conversion (loop versus Roux-en-Y), the results of the conversion, and postconversion complications. RESULTS: The major indications for conversion were metabolic acidosis (n = 26, 33%), recurrent urinary tract infections (UTIs) (n = 16, 20%), reflux pancreatitis (n = 15, 19%), and hematuria (n = 12, 15%). For most recipients, their symptoms resolved after conversion (n = 76, 95%). The cumulative probability of undergoing conversion was 13% at 12 months, 21% at 36 months, and 25% at 60 months. Of the recipients with surgical complications after conversion (n = 12, 15%), one lost his graft as a result of pancreatitis. Overall, of the 80 recipients who underwent conversion, 12 (15%) lost their graft, most due to rejection (n = 8, 75%). Immunologic graft loss was highest for recipients of pancreas transplants alone who underwent conversion < or = 6 months after transplantation or < or = 1 year after their last rejection episode. CONCLUSIONS: Enteric conversion is safe and therapeutic in recipients with complications related to the exocrine secretions of bladder-drained pancreas grafts. After conversion, rejection accounted for 75% of the grafts lost. However, waiting at least 1 year after the last rejection episode significantly reduced immunologic graft loss.

Thomas G. Orr Memorial Lecture. Staged laparotomy for the hypothermia, acidosis, and coagulopathy syndrome.

The recent history, indications, physiologic objectives, and technical aspects of staged laparotomy are discussed in this overview. While postinjury refractory coagulopathy is the most common scenario for this life-saving concept, there are many other potential applications during both emergency and elective procedures in the neck, chest, pelvis, and extremities as well as the abdomen.

Liver transplantation in two cases of propionic acidaemia.

Orthotopic liver transplantation (OLT) was performed in two patients with propionic acidaemia, a 7-year-old boy and a 9-year-old girl, diagnosed with a severe neonatal form with high risk of metabolic decompensation. In both cases the metabolic liver functions recovered within the 12 postoperative hours; no clinical symptoms of propionic acid toxicity, metabolic acidosis, severe hyperammonaemia, hyperglycinaemia or haematological abnormalities were observed. In both cases insulin-dependent diabetes mellitus occurred early after OLT (persisting in the boy's case). Severe post-transplantation complications were observed (acute rejection and CMV infection in both patients) which did not trigger metabolic decompensation. The boy developed chronic rejection and vanishing bile duct syndrome due to incomplete hepatic arterial thrombosis. He required permanent in-patient care with chronic hyperammonaemia and neurological sequelae involving the basal ganglia and died 15 months after OLT. The girl left hospital after 2 months and is presently leading a normal life with almost no dietary protein restriction (40 g protein per day). Urinary urea excretion and daily protein intake increased after liver transplantation. Propionyl- and tiglylglycine disappeared immediately after OLT. Urinary methylcitrate and 3-hydroxypropionate remained at concentrations corresponding to those before OLT. However, the total of all characteristic metabolites of organic acid analysis was reduced to 50-60% of the values before OLT in both patients. Propionylcarnitine was still detected at significant concentrations. Plasma odd-chain fatty acid concentrations decreased continuously after OLT only in the girl's case. Tissue of both transplanted livers showed increased odd-chain fatty acid concentrations 9 and 15 months after OLT, respectively, in both patients. We consider that at present OLT should only be performed in severe forms of propionic acidaemia.

Results of the Senning operation for transposition of the great arteries with intact ventricular septum in neonates.

In spite of an adequate balloon atrial septostomy, some neonates (less than 28 days of age) with transposition of the great arteries and intact ventricular septum (TGA, IVS) remain hypoxemic and acidotic and require operative treatment. Our entire experience with the Senning operation in neonates with TGA, IVS is reviewed. From March 1978 to March 1983 there were 104 infants who underwent the Senning operation for TGA, IVS. Of these, 19 were neonates (18%). The mean age at operation was 12 days (2 to 24) and mean weight was 3.52 kg (3 to 4.38). Two died early (10%) and one died late (5%). The last 16 are alive and well. Causes of early mortality were sepsis and severe obstruction of the superior vena cava. The cause of late mortality was severe pulmonary venous obstruction. Among the 16 survivors, postoperative courses, both early and late, have been remarkably benign. Ten patients have undergone postoperative cardiac catheterization (mean follow up 17 months). Two (12%) had severe pulmonary venous obstruction (one diagnosed by two-dimensional echocardiography), but both were successfully repaired. Atrial shunt was noted in two patients (12%), one of which underwent elective repair. Five infants have dynamic subvalvular pulmonary stenosis of various gradients (9 to 93 mm Hg). One infant has mild tricuspid regurgitation. There are no cases of superior vena caval obstruction or right ventricular dysfunction. Twenty-four hour electrocardiographic monitoring (mean follow-up 25 months) showed predominant normal sinus rhythm in 15 infants and predominant junctional rhythm in one.(ABSTRACT TRUNCATED AT 250 WORDS)