Michael Baram

Does Central Venous Pressure Predict Fluid Responsiveness?: A Systematic Review of the Literature and the Tale of Seven Mares

BACKGROUND Central venous pressure (CVP) is used almost universally to guide fluid therapy in hospitalized patients. Both historical and recent data suggest that this approach may be flawed. OBJECTIVE A systematic review of the literature to determine the following: (1) the relationship between CVP and blood volume, (2) the ability of CVP to predict fluid responsiveness, and (3) the ability of the change in CVP (DeltaCVP) to predict fluid responsiveness. DATA SOURCES MEDLINE, Embase, Cochrane Register of Controlled Trials, and citation review of relevant primary and review articles. STUDY SELECTION Reported clinical trials that evaluated either the relationship between CVP and blood volume or reported the associated between CVP/DeltaCVP and the change in stroke volume/cardiac index following a fluid challenge. From 213 articles screened, 24 studies met our inclusion criteria and were included for data extraction. The studies included human adult subjects, healthy control subjects, and ICU and operating room patients. DATA EXTRACTION Data were abstracted on study design, study size, study setting, patient population, correlation coefficient between CVP and blood volume, correlation coefficient (or receive operator characteristic [ROC]) between CVP/DeltaCVP and change in stroke index/cardiac index, percentage of patients who responded to a fluid challenge, and baseline CVP of the fluid responders and nonresponders. Metaanalytic techniques were used to pool data. DATA SYNTHESIS The 24 studies included 803 patients; 5 studies compared CVP with measured circulating blood volume, while 19 studies determined the relationship between CVP/DeltaCVP and change in cardiac performance following a fluid challenge. The pooled correlation coefficient between CVP and measured blood volume was 0.16 (95% confidence interval [CI], 0.03 to 0.28). Overall, 56+/-16% of the patients included in this review responded to a fluid challenge. The pooled correlation coefficient between baseline CVP and change in stroke index/cardiac index was 0.18 (95% CI, 0.08 to 0.28). The pooled area under the ROC curve was 0.56 (95% CI, 0.51 to 0.61). The pooled correlation between DeltaCVP and change in stroke index/cardiac index was 0.11 (95% CI, 0.015 to 0.21). Baseline CVP was 8.7+/-2.32 mm Hg [mean+/-SD] in the responders as compared to 9.7+/-2.2 mm Hg in nonresponders (not significant). CONCLUSIONS This systematic review demonstrated a very poor relationship between CVP and blood volume as well as the inability of CVP/DeltaCVP to predict the hemodynamic response to a fluid challenge. CVP should not be used to make clinical decisions regarding fluid management.

Principles of pulmonary artery catheterization in the critically ill.

The pulmonary artery catheter (PAC) may be helpful in determining the etiology of shock, lactic acidosis, pulmonary edema, oliguric renal failure, pulmonary hypertension, and a number of cardiac abnormalities. In addition, it may also be useful in guiding fluid and vasoactive therapy. However, although hemodynamic data from the pulmonary artery catheter (PAC) is widely used diagnostically and therapeutically in the care of critically ill patients, the use of the catheter has not been shown to provide outcomes benefit. In fact, there is some evidence to suggest that placement of the PAC may actually be detrimental. The reasons for this are unclear, but it has been shown that both physicians and nurses frequently misinterpret waveforms and other data obtained from the PAC. Presently, there are a number of ongoing randomized, controlled trials investigating the use of the PAC in specific clinical situations and/or patient populations as well as using specific treatment strategies. In the meantime, if any benefit is to be achieved, it is imperative that clinicians have a thorough understanding of the indications, contraindications, complications, and pitfalls of data interpretation prior to using the catheter. These are reviewed in this article.

ACE inhibitor-induced angioedema.

Angiotensin-converting enzyme inhibitors (ACEI) are commonly prescribed for blood pressure control and renal protection. ACEI angioedema is a common problem in patients who are taking ACEI, although, in most cases, the disorder is self-limited, and spontaneous episodes of apparently unprovoked angioedema stop with the discontinuation of the medication. In a subset of patients, hospitalization and even intubation are required for airway protection. The diagnosis is made clinically. There are no laboratory studies that establish the diagnosis. However, such investigations help exclude alternative diagnoses as the cause for the patients presentation. Conventional treatment with regimens used to control allergic angioedema is ineffective in this condition. The mechanism of ACEI-induced angioedema is thought to be related to its effect on the kallikrein-kinin system. Kallikrein is a protease that converts high-molecular-weight kininogens into kinins, primarily bradykinin. Medications recently developed, primarily icatibant and ecallantide, to control hereditary angioedema, a disorder also associated with kallikrein-kinin activation, have been used to treat ACEI angioedema with some success. The efficacy of these agents and their optimal use remains to be established by randomized and placebo controlled trials.

What intensivists need to know about hemophagocytic syndrome: an underrecognized cause of death in adult intensive care units.

Hemophagocytic syndrome, also known as hemophagocytic lymphohistiocytosis (HLH), is a rare and frequently fatal disorder caused by an uncontrollable and ineffective systemic immune response. Patients initially present with fever, cytopenia, and hepatosplenomegaly, and subsequently develop multiorgan failure (MOF). Hemophagocytosis can be found on biopsy specimen but is not required. Acquired forms of HLH can occur in apparently healthy adults, while children present more often with an inherited form of the disease. Since HLH often presents with sepsis-like symptoms and organ dysfunction, patients are usually treated for presumed sepsis, which inevitably leads to delayed diagnosis and treatment. Intensivists need to have a low threshold for suspecting this disorder when previously healthy individuals present with a fulminant sepsis-like syndrome, which are unresponsive to conventional treatment. We present 3 patients with HLH who were admitted to our adult medical intensive care unit (MICU) over a 2-year period with fatal outcomes and emphasize the diagnostic importance of markedly elevated serum ferritin levels and the need for tissue biopsy in making an accurate diagnosis in a timely manner.

Use of Mechanical Ventilation and Renal Replacement Therapy in Critically Ill Hematopoietic Stem Cell Transplant Recipients

Hematopoietic stem cell transplantation (HSCT) is a treatment option for both malignant and nonmalignant disorders. HSCT patients remain at high risk for multiorgan failure, with previous studies noting mortality rates exceeding 90% when mechanical ventilation (MV) is required. We propose that advancements in critical care management and HSCT practices have improved these dismal outcomes. We performed a retrospective review of admissions to our bone marrow transplant unit between 2006 and 2010. All HSCT recipients requiring admission to the bone marrow transplant unit who received MV or renal replacement therapy (RRT) were evaluated. A total of 68 patients required MV. Twenty patients required RRT, all of whom required MV. Fifty-nine of the 68 ventilated patients died, for an overall mortality rate of 86.8%. The presence of renal failure and concomitant respiratory or liver dysfunction at the time of intubation was associated with a mortality rate of 100%. High mortality persists in our HSCT population requiring artificial support despite overall advances in critical care and HSCT practices. Critical care triage and management decisions in this high-risk population remain challenging.

Utilidad de la broncoscopia flexible en la evaluación de infiltrados pulmonares en la población con trasplante de células madre hemopoyéticas: Experiencia de 14años en un solo centro

INTRODUCTION Pulmonary infiltrates are common within the hematopoietic stem cell transplant (HSCT) population and unfortunately portend an increased mortality. Bronchoscopy is often utilized as an initial diagnostic tool, but the literature supporting its diagnostic utility and effect on clinical management varies significantly. The aim of this study was to investigate the diagnostic ability, complication rate, and clinical impact of flexible bronchoscopy (FB) in evaluating pulmonary infiltrates in a large HSCT population. PATIENTS AND METHOD Retrospective review of all patients undergoing FB after HSCT in the Bone Marrow Transplant Unit from 1996 to 2009. RESULTS FB was performed 162times in 144patients with pulmonary infiltrates yielding positive results in 52.5%. The most common positive results were bacterial pneumonia (31%), fungal pneumonia (15%), and alveolar hemorrhage (11%). Treatment changes occurred in 44% of patients after FB. Treatment changes included antibiotic modification (59%), addition of corticosteroids (21%), antifungal modification (12%), and antiviral modification (7%). The overall complication rate associated with FB was 30%, although 84% of these complications were considered minor. CONCLUSIONS FB in patients with pulmonary infiltrates after HSCT should still be considered a valuable tool in the evaluation and management of pulmonary infiltrates in the HSCT population. Future prospective, multicenter randomized studies are needed to evaluate the overall clinical impact that bronchoscopic results and management changes have in this unique population.

Poor positive predictive value of McConnell's sign on transthoracic echocardiography for the diagnosis of acute pulmonary embolism.

Abstract Background: Acute pulmonary embolism (PE) is a life-threatening condition. Making a definitive diagnosis with radiologic studies may delay therapy or be unsafe for the patient. Echocardiography is readily available and can suggest PE by demonstrating right ventricular (RV) dysfunction. McConnells sign on echocardiogram (ECHO-CG) (RV dysfunction with characteristic sparing of the apex) has been reported to have high sensitivity and specificity for the diagnosis of acute PE. It is hypothesized that McConnells sign on ECHO-CG in patients hospitalized with suspected acute PE would have a high positive predictive value (PPV). Methods: Data, from 2005 to 2010, were retrospectively collected on all patients with an ECHO-CG interpreted as revealing McConnells sign, who had undergone another diagnostic study (computed tomography pulmonary angiography, ventilation-perfusion scan, upper or lower extremity Doppler ultrasound, or autopsy) for venous thromboembolic disease (VTE). The PPV on transthoracic ECHO-CG was calculated for the diagnostic accuracy of McConnells sign in all patients. To minimize the potential for ECHO-CG reader bias of patients already confirmed to have had a PE by another modality, the PPV was then recalculated only on the patients in whom the ECHO-GM was the first diagnostic study. Results: Seventy-three patients had findings of McConnells sign on ECHO-CG. The PPV of McConnells sign on ECHO-CG was 57% (CI, 45%-67%). Of the 37 patients who underwent an ECHO-CG in the first study for suspected acute PE, 15 patients had VTE confirmed; the PPV in this subset was only 40% (CI, 24%-56%). There were 20 patient deaths overall; of these, only 9 of the patients were confirmed to have VTE. Conclusion: We concluded that the presence of McConnells sign has a relatively poor PPV for the diagnosis of acute PE and should not be used in isolation when making a diagnosis of PE in patients.

Blood and volume resuscitation for variceal hemorrhage.

A 60-year-old man with hepatitis C–induced cirrhosis complicated by refractory ascites and esophageal varices presented to the emergency department after the acute onset of abdominal pain and hematemesis. The patient had a blood pressure of 109/56 mm Hg, a heart rate of 134 beats/min, and a respiratory rate of 22 breaths/min. His arterial oxygen saturation measured by pulse oximetry was 94% while breathing ambient air. Examination was remarkable for scleral icterus; a moderately tense, distended abdomen that was tender to palpation in the epigastric area; multiple dilated abdominal wall vessels; shifting dullness; and a fluid wave. His initial hemoglobin concentration was 10.2 g/dl. While in the emergency department, the patient had an episode of massive hematemesis that was accompanied by hypotension and a marked decline in mental status. He was intubated, given normal saline, octreotide, a proton-pump inhibitor, and antibiotics, and admitted to the medical intensive care unit. The patient’s blood pressure increased to 110/58 mm Hg after he received 4 L of crystalloid and blood products. Four hours later, however, he had another episode of massive hematemesis. His blood pressure fell to 68/31 mm Hg and his hemoglobin was 4.6 g/dl. Bilateral large-bore femoral venous catheters were inserted, and the patient was given crystalloid and blood products and started on a vasopressor.

Caution for Anabolic Androgenic Steroid Use: A Case Report of Multiple Organ Dysfunction Syndrome

We report a 42-year-old male amateur body builder and user of anabolic androgenic steroids, who developed ARDS, acute kidney injury, and refractory supraventricular tachycardia. He required extracorporeal membrane oxygenation, continuous veno-venous hemodialysis, and catheter ablation. We believe that long-term anabolic androgenic steroid abuse predisposed the patient to multiple organ dysfunction syndrome, from its immunomodulatory effects in an otherwise healthy patient. Anabolic androgenic steroid use should be part of the history taking process, since it may complicate diagnosis, disease progression, and prognosis.

Thrombolytic Therapy in a Patient With Suspected Pulmonary Embolism Despite a Negative Computed Tomography Pulmonary Angiogram

We report a case of a 62-year-old male who presented to our intensive care unit with hypoxemia 6 hours after retinal surgery. He had a negative computed tomography (CT) pulmonary angiogram, but an emergency echocardiogram revealed the McConnell sign. He was thrombolysed and had rapid improvement in oxygenation and hemodynamics. Thrombolysis in hemodynamically unstable pulmonary embolism is not controversial, but most algorithms require confirmation of the diagnosis. Our patient had a negative CT pulmonary angiogram but was thrombolysed based on the clinical picture. Autopsy confirmed the diagnosis of multiple pulmonary emboli and unexpectedly discovered a patent foramen ovale that explained paradoxical embolism to the brain.