Trigeminal Nerve Stimulation: A Novel Method of Resuscitation for Hemorrhagic Shock.

OBJECTIVES: To determine if trigeminal nerve stimulation can ameliorate the consequences of acute blood loss and improve survival after severe hemorrhagic shock. DESIGN: Animal study. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Severe hemorrhagic shock was induced in rats by withdrawing blood until the mean arterial blood pressure reached 27 ± 1 mm Hg for the first 5 minutes and then maintained at 27 ± 2 mm Hg for 30 minutes. The rats were randomly assigned to either control, vehicle, or trigeminal nerve stimulation treatment groups. The effects of trigeminal nerve stimulation on survival rate, autonomic nervous system activity, hemodynamics, brain perfusion, catecholamine release, and systemic inflammation after severe hemorrhagic shock in the absence of fluid resuscitation were analyzed. MEASUREMENTS AND MAIN RESULTS: Trigeminal nerve stimulation significantly increased the short-term survival of rats following severe hemorrhagic shock in the absence of fluid resuscitation. The survival rate at 60 minutes was 90% in trigeminal nerve stimulation treatment group whereas 0% in control group (p < 0.001). Trigeminal nerve stimulation elicited strong synergistic coactivation of the sympathetic and parasympathetic nervous system as measured by heart rate variability. Without volume expansion with fluid resuscitation, trigeminal nerve stimulation significantly attenuated sympathetic hyperactivity paralleled by increase in parasympathetic tone, delayed hemodynamic decompensation, and improved brain perfusion following severe hemorrhagic shock. Furthermore, trigeminal nerve stimulation generated sympathetically mediated low-frequency oscillatory patterns of systemic blood pressure associated with an increased tolerance to central hypovolemia and increased levels of circulating norepinephrine levels. Trigeminal nerve stimulation also decreased systemic inflammation compared with the vehicle. CONCLUSIONS: Trigeminal nerve stimulation was explored as a novel resuscitation strategy in an animal model of hemorrhagic shock. The results of this study showed that the stimulation of trigeminal nerve modulates both sympathetic and parasympathetic nervous system activity to activate an endogenous pressor response, improve cerebral perfusion, and decrease inflammation, thereby improving survival.

Perioperative bleeding management in pediatric patients.

PURPOSE OF REVIEW: Managing the bleeding pediatric patient perioperatively can be extremely challenging. The primary goals include avoiding hypotension, maintaining adequate tissue perfusion and oxygenation, and maintaining hemostasis. Traditional bleeding management has consisted of transfusion of autologous blood products, however, there is strong evidence that transfusion-related side-effects are associated with increased morbidity and mortality in children. Especially concerning is the increased reported incidence of noninfectious adverse events such as transfusion-related acute lung injury, transfusion-related circulatory overload and transfusion-related immunomodulation. The current approach in perioperative bleeding management of the pediatric patient should focus on the diagnosis and treatment of anemia and coagulopathy with the transfusion of blood products only when clinically indicated and guided by goal-directed strategies. RECENT FINDINGS: Current guidelines recommend that a comprehensive multimodal patient blood management strategy is critical in optimizing patient care, avoiding unnecessary transfusion of blood and blood product and limiting transfusion-related side-effects. SUMMARY: This article will highlight current guidelines in perioperative bleeding management for our most vulnerable pediatric patients with emphasis on individualized targeted intervention using point-of-care testing and specific coagulation products.

Fluid volume kinetics of dilutional hyponatremia; a shock syndrome revisited.

OBJECTIVE: To evaluate whether the pathophysiology of shock syndromes can be better understood by comparing central hemodynamics with kinetic data on fluid and electrolyte shifts. METHODS: We studied the dilutional hyponatremic shock that developed in response to overhydration with electrolyte-free irrigating fluid - the so-called 'transurethral resection syndrome' - by comparing cardiac output, arterial pressures, and volume kinetic parameters in 17 pigs that were administered 150 ml/kg of either 1.5% glycine or 5% mannitol by intravenous infusion over 90 minutes. RESULTS: Natriuresis appeared to be the key factor promoting hypovolemic hypotension 15-20 minutes after fluid administration ended. Excessive sodium excretion, due to osmotic diuresis caused by the irrigant solutes, was associated with high estimates of the elimination rate constant (k10) and low or negative estimates of the rate constant describing re-distribution of fluid to the plasma after translocation to the interstitium (k21). These characteristics indicated a high urinary flow rate and the development of peripheral edema at the expense of plasma volume and were correlated with reductions in cardiac output. The same general effects of natriuresis were observed for both irrigating solutions, although the volume of infused 1.5% glycine had a higher tendency to enter the intracellular fluid space. CONCLUSION: Comparisons between hemodynamics and fluid turnover showed a likely sequence of events that led to hypovolemia despite intravenous administration of large amounts of fluid.

Fluid volume kinetics of dilutional hyponatremia; a shock syndrome revisited

OBJECTIVE: To evaluate whether the pathophysiology of shock syndromes can be better understood by comparing central hemodynamics with kinetic data on fluid and electrolyte shifts. METHODS: We studied the dilutional hyponatremic shock that developed in response to overhydration with electrolyte-free irrigating fluid - the so-called ‘transurethral resection syndrome' - by comparing cardiac output, arterial pressures, and volume kinetic parameters in 17 pigs that were administered 150 ml/kg of either 1.5% glycine or 5% mannitol by intravenous infusion over 90 minutes. RESULTS: Natriuresis appeared to be the key factor promoting hypovolemic hypotension 15-20 minutes after fluid administration ended. Excessive sodium excretion, due to osmotic diuresis caused by the irrigant solutes, was associated with high estimates of the elimination rate constant (k10) and low or negative estimates of the rate constant describing re-distribution of fluid to the plasma after translocation to the interstitium (k21). These characteristics indicated a high urinary flow rate and the development of peripheral edema at the expense of plasma volume and were correlated with reductions in cardiac output. The same general effects of natriuresis were observed for both irrigating solutions, although the volume of infused 1.5% glycine had a higher tendency to enter the intracellular fluid space. CONCLUSION: Comparisons between hemodynamics and fluid turnover showed a likely sequence of events that led to hypovolemia despite intravenous administration of large amounts of fluid. .

[Case of Takotsubo cardiomyopathy after induction of general anesthesia].

Takotsubo cardiomyopathy is a cardiac syndrome characterized by transient left ventricular dysfunction. A 79-year-old woman was scheduled for posterior lumbar interbody fusion for spinal compression fracture. After induction of general anesthesia, her blood pressure collapsed with significant ST rise in I, aVL, V3-V5. Emergent transthoracic echocardiography revealed excessive contraction of the base and severe hypokinesis of the apex suggesting Takotsubo cardiomyopathy. Chronic hypovolemia and electrolyte disorder due to habitual glycerin enema were considered to be causes of this sudden cardiac collapse.

[An old lady with hyponatremia and recurrent falls]. / Eine alte Dame mit Hyponatriämie und rezidivierenden Stürzen.

BACKGROUND: Hyponatremia is one of the most commonly seen electrolyte abnormalities in hospitalized patients. The differential diagnoses are complex once the typical causes for hyponatremia such as congestive cardiac failure, liver failure, hyperglycemia, thiazides, antipsychotic drugs or chemotherapy are excluded. Especially the differentiation between the syndrome of inappropriate ADH secretion and salt-wasting nephropathy as seen in cerebral salt wasting (CSW) can be difficult. CASE REPORT: The case of a 79-year-old lady is discussed who presented to the Emergency Department with extreme dizziness after having fallen off a ladder. Biochemistry studies revealed severe hyponatremia (Na 114 mmol/l) as well as hypochloremia (Cl 85 mmol/l), all other laboratory studies were unremarkable. The intake of a thiazide diuretic, an adrenal insufficiency and other common causes of hyponatremia were excluded. On examination, there were clinical signs of volume depletion. The serum sodium initially improved adequately after the infusion of intravenous normal saline (0.9%) only to fall again along with clinical signs of volume depletion after ceasing the infusion. A high urinary sodium excretion persisted despite hyponatremia and volume depletion. Due to the clinical course the syndrome of inappropriate ADH secretion was considered unlikely and the diagnosis of CSW established. Under therapy with fludrocortisone her sodium stabilized within the normal range and she remained free of symptoms. CONCLUSION: CSW is an important differential diagnosis of hyponatremia in the hypovolemic patient. It is due to an inadequately high urinary sodium excretion. The response to intravenous normal saline can make the diagnosis likely and distinguish it from SIADH. The exact pathophysiological mechanism behind CSW is not yet completely understood. Therapy consists of fluid and salt supplementation or mineralocorticoid substitution.

Hypothalamic injury as a cause of refractory hypotension after sellar region tumor surgery.

INTRODUCTION: Fluid-resistant arterial hypotension can result in hypoperfusion of the brain and other organs. Well-known causes of arterial hypotension in neurosurgical practice include cardiac failure, septic shock, adrenal insufficiency, brainstem, and cervical spinal cord damage. Fluid-resistant arterial hypotension can occur in patients with brain edema without damage to brainstem when hypothalamic nuclei suffer. This phenomenon is not a well-documented cause of hypotension. METHODS: We prospectively investigated 15 cases with clinical syndrome of arterial hypotension in patients following surgery for sellar region tumors. These cases were taken from 1005 patients operated between May 2003 and December 2005. Pulmonary artery catheter was used to investigate hemodynamic profile. RESULTS: The mechanism of arterial hypotension consisted of decrease of vascular tone (SVRI was 1503 +/- 624 dyn x s x cm(5) x m(2)) and relative hypovolemia (CVP: 4.5 +/- 2.6 torr, PAWP: 7.4 +/- 3.5 torr). In all cases arterial hypotension was corrected with phenylephrine after failure to respond to fluid resuscitation alone. Fluid balance was positive over the next 72 h. Twenty-seven percent of patients had transitory thyroid insufficiency. In these situations dopamine was administrated as symptomatic therapy and dose of thyroid hormone was increased. Mortality was 53%. CONCLUSION: Hypothalamic damage can result in life-threatening vasodilatory arterial hypotension after sellar region tumor surgery. beta-Sympatomimetics are indicated in cases with thyroid insufficiency.

[Surviving sepsis: where we are today]. / "Survivre au sepsis": où en sommes-nous?

The mortality induced by severe sepsis and septic shock remains very elevated despite progress in diagnosis and treatment. All the experts in the field consider that further progress is possible with better and more prompt use of the treatments now available. The "Surviving Sepsis" campaign reviews the diverse treatments that can be used and the best ways to prescribe them. It also proposes two bundles of objectives to be completed systematically for all patients: the first within the first 6 hours, the second between the sixth and 24th hour. Encouraging results show that applying these therapeutic principles can reduce mortality by 30% (relative percentage) compared with a treatment without specific objectives.

Autologous blood donation in total knee arthroplasties is not necessary.

BACKGROUND: This study intends to prove the hypothesis that preoperative autologous blood donation in total knee arthroplasties (TKA) is dispensable. PATIENTS AND METHODS: The study comprises a prospective analysis of 81 consecutive TKA without preoperative autologous blood donation (AB-donation). Guidelines for blood retransfusion were used. Surgery, as well as the pre- and postoperative procedures were identical for each patient. In the analysis of the data, the consecutive TKAs were divided into patients who were eligible for preoperative autologous blood donation (group 1, n = 46) and those with relevant risk factors not permitting preoperative autologous blood donation (group 2, n = 35). RESULTS: None of the patients in group 1 needed a blood transfusion. 14 of 35 patients in group 2 needed an allogenic blood transfusion. INTERPRETATION: Total knee arthroplasty can be managed without preoperative AB-donation if it is performed using a tourniquet, if a postoperative collection and direct retransfusion system is used for the wound blood, and if the transfusion algorithm is defined according to compulsory and practical guidelines.

[Means of reducing blood loss and volume of the used transfused media in operative treatment of burn lesions of the liver]. / Puti snizheniia velichiny krovopoteri i ob"ema ispol'zuemykh transfuzionnykh sred pri operativnom lechenii ochagovykh porazhenii pecheni.

An experience with surgical treatment of 77 patients with focal lesions of the liver is described. The patients were divided into two groups. In the main group (42 patients) the treatment-and-prophylactic method was used including acute isovolemic and hypervolemic hemodilution, preliminary preparation of autoblood, isolation and ligation of the vascular-secretory elements, the application for local hemostasis with Takhokomb of "Tissucol", gelatinous sponge with gentamycin. In the group of comparison the compression of the hepatoduodenal ligament, isolation of the vascular-secretory elements by digitoclasia method, suturing the liver stump with polysorb were used in resection of the liver. The strategy used in the main group allowed to reduce the volume of blood loss, to lessen the number of doses of the transfused donor blood, to diminish the number of postoperative complications by 30.5%. The used complex is effective, simple and is not expensive.

[Two cases of TURP syndrome with severe cardiovascular depression].

We report two cases of TURP (transurethral resection of prostate) syndrome showing severe cardiovascular depression without any neurological disturbances. One patient developed hypotension (62/42 mmHg) and ST segment depression (-2.7 mm) on ECG during TURP. Another patient developed hypotension (60/38 mmHg) and nodal bradycardia (34.min-1) 15 minutes after the operation. No neurological signs were observed, despite severe hyponatremia (113 and 117 mEq.l-1, respectively). It is highly likely that hypovolemia and/or electrophysiological inhibition of pacemaker cell due to hyponatremia caused the symptoms. We emphasize that sudden circulatory depression as well as neurological disorders should be recognized as a major symptom of TURP syndrome.

Daily use of the physio dialysis system: long-term experience.

BACKGROUND: Hypovolaemia has been implicated as a major causal factor of morbidity during haemodialysis (HD). In order to avoid the appearance of destabilising hypovolaemia a biofeedback control system for intra-HD blood volume (BV) change modelling has been developed (Hemocontrol, Hospal Italy). It is based on an adaptive controller incorporated into a HD machine (Integra, Hospal Italy). The Hemocontrol biofeedback system (HBS) monitors BV contraction during HD with an optical device; furthermore, HBS modulates BV contraction rates (by adjusting the ultrafiltration rate--UFR) and the refilling rate (by adjusting dialysate conductivity--DC) in order to obtain the desired pre-determined BV trajectories. METHODS: Nineteen patients prone to hypotension (7 males, 12 females, mean age 64.5 +/- 3.0 SEM years, on maintenance HD for 80.5 +/- 13.2 months) volunteered for the prospective study which aimed to compare the efficacy and safety of bicarbonate HD treatmentequipped with HBS, as a whole (HBS),with the gold standard, bicarbonate treatment, equipped with a constant UFR and DC (BD). The study included one period of 6 months of BD always preceding a follow-up period of HBS treatment ranging from 14 to 30 months (mean 24.0 +/- 1.6). RESULTS: The overall occurrence of symptomatic hypotension and muscle cramps was significantly less in HBS treatment. Self-evaluation of intra- and inter-HD symptoms (the worst score was o and the best one 10) did reveal a statistically significant difference, as far as post-HD fatigue is concerned (6.2 +/- 0.2 in HBS vs. 4.3 +/- 0.1 in BD treatment, p < 0.0001). No difference between the two treatments was observed when comparing pre- and post-HD lying blood pressure, heart rate, body weights and body weight changes. CONCLUSIONS: HBS is an effective treatment. Hypovolaemia-associated morbidity occurs less in BD treatment than HBS. Furthermore, HBS is a safe treatment in the medium-term because these results are achieved without potentially harmful changes in blood pressure, body weight and serum sodium concentration.