The risks of long-term use of proton pump inhibitors: a critical review

Proton pump inhibitors (PPIs) are among the most frequently prescribed medications. Their use is likely even higher than estimated due to an increase in the number of PPIs available without a prescription. Appropriate indications for PPI use include Helicobacter pylori infection, erosive esophagitis, gastric ulcers, and stress ulcer prevention in high-risk critically ill patients. Unfortunately, PPIs are often used off-label for extended periods of time. This increase in PPI usage over the past two decades has called into question the long-term effects of these medications. The association between PPI use and infection, particularly Clostridium difficile and pneumonia, has been the subject of several studies. It’s proposed that the alteration in gastrointestinal microflora by PPIs produces an environment conducive to development of these types of infections. At least one study has suggested that long-term PPI use increases the risk of dementia. Drug interactions are an important and often overlooked consideration when prescribing any medication. The potential interaction between PPIs and antiplatelet agents has been the subject of multiple studies. One of the more recent concerns with PPI use is their role in the development or progression of chronic kidney disease. There is also some literature suggesting that PPIs contribute to the development of various micronutrient deficiencies. Most of the literature examining the potential adverse effects of PPI use is composed of retrospective, observation studies. There is a need for higher quality studies exploring this relationship.

Balanced Crystalloids versus Saline in Critically Ill Adults

BACKGROUND

Both balanced crystalloids and saline are used for intravenous fluid administration in critically ill adults, but it is not known which results in better clinical outcomes.

METHODS

In a pragmatic, cluster-randomized, multiple-crossover trial conducted in five intensive care units at an academic center, we assigned 15,802 adults to receive saline (0.9% sodium chloride) or balanced crystalloids (lactated Ringer's solution or Plasma-Lyte A) according to the randomization of the unit to which they were admitted. The primary outcome was a major adverse kidney event within 30 days - a composite of death from any cause, new renal-replacement therapy, or persistent renal dysfunction (defined as an elevation of the creatinine level to ≥200% of baseline) - all censored at hospital discharge or 30 days, whichever occurred first.

RESULTS

Among the 7942 patients in the balanced-crystalloids group, 1139 (14.3%) had a major adverse kidney event, as compared with 1211 of 7860 patients (15.4%) in the saline group (marginal odds ratio, 0.91; 95% confidence interval [CI], 0.84 to 0.99; conditional odds ratio, 0.90; 95% CI, 0.82 to 0.99; P=0.04). In-hospital mortality at 30 days was 10.3% in the balanced-crystalloids group and 11.1% in the saline group (P=0.06). The incidence of new renal-replacement therapy was 2.5% and 2.9%, respectively (P=0.08), and the incidence of persistent renal dysfunction was 6.4% and 6.6%, respectively (P=0.60).

CONCLUSIONS

Among critically ill adults, the use of balanced crystalloids for intravenous fluid administration resulted in a lower rate of the composite outcome of death from any cause, new renal-replacement therapy, or persistent renal dysfunction than the use of saline. (Funded by the Vanderbilt Institute for Clinical and Translational Research and others; SMART-MED and SMART-SURG ClinicalTrials.gov numbers, NCT02444988 and NCT02547779 .).

A Novel Method of Evaluating Key Factors for Success in a Multifaceted Critical Care Fellowship Using Data Envelopment Analysis

BACKGROUND

The current system of summative multi-rater evaluations and standardized tests to determine readiness to graduate from critical care fellowships has limitations. We sought to pilot the use of data envelopment analysis (DEA) to assess what aspects of the fellowship program contribute the most to an individual fellow's success. DEA is a nonparametric, operations research technique that uses linear programming to determine the technical efficiency of an entity based on its relative usage of resources in producing the outcome.

DESIGN

Retrospective cohort study.

SUBJECTS AND SETTING

Critical care fellows (n = 15) in an Accreditation Council for Graduate Medical Education (ACGME) accredited fellowship at a major academic medical center in the United States.

METHODS

After obtaining institutional review board approval for this retrospective study, we analyzed the data of 15 anesthesiology critical care fellows from academic years 2013-2015. The input-oriented DEA model develops a composite score for each fellow based on multiple inputs and outputs. The inputs included the didactic sessions attended, the ratio of clinical duty works hours to the procedures performed (work intensity index), and the outputs were the Multidisciplinary Critical Care Knowledge Assessment Program (MCCKAP) score and summative evaluations of fellows.

RESULTS

A DEA efficiency score that ranged from 0 to 1 was generated for each of the fellows. Five fellows were rated as DEA efficient, and 10 fellows were characterized in the DEA inefficient group. The model was able to forecast the level of effort needed for each inefficient fellow, to achieve similar outputs as their best performing peers. The model also identified the work intensity index as the key element that characterized the best performers in our fellowship.

CONCLUSIONS

DEA is a feasible method of objectively evaluating peer performance in a critical care fellowship beyond summative evaluations alone and can potentially be a powerful tool to guide individual performance during the fellowship.

ECMO in major burn patients: feasibility and considerations when multiple modes of mechanical ventilation fail

BACKGROUND

We report two cases of acute respiratory distress syndrome in burn patients who were successfully managed with good outcomes with extra corporeal membrane oxygenation (ECMO) after failing multiple conventional modes of ventilation, and review the relevant literature.

CASE PRESENTATION

The two patients were a 39-year-old male and 53-year-old male with modified Baux Scores of 79 and 78, respectively, with no known inhalation injury. After the initial modified Parkland-based fluid resuscitation and partial escharotomy, both patients developed worsening hypoxemia and acute respiratory distress syndrome. The hypoxemia continued to worsen on multiple modes of ventilation including volume control, pressure regulated volume control, pressure control, airway pressure release ventilation and volumetric diffusive ventilation. In both cases, the PaO₂ ≤ 50 mm Hg on a FiO₂ 100% during the trial of mechanical ventilation. The deterioration was rapid (<12 h since onset of worsening oxygenation) in both cases. A decision was made to trial the patients on ECMO. Veno-Venous ECMO (V-V ECMO) was successfully initiated following cannulation-under transesophgeal echo guidance-with the dual lumen Avalon® (Maquet, NJ, USA) cannula. ECMO support was maintained for 4 and 24 days, respectively. Both patients were successfully weaned off ECMO and were discharged to rehabilitation following their complex hospital course.

CONCLUSION

Early ECMO for isolated respiratory failure in the setting on maintained hemodynamics resulted in a positive outcome in our two burn patients suffered from acute respiratory distress syndrome.

Balanced crystalloids versus saline in the intensive care unit: study protocol for a cluster-randomized, multiple-crossover trial

Background

Saline, the intravenous fluid most commonly administered to critically ill adults, contains a high chloride content, which may be associated with acute kidney injury and death. Whether using balanced crystalloids rather than saline decreases the risk of acute kidney injury and death among critically ill adults remains unknown.

Methods

The Isotonic Solutions and Major Adverse Renal Events Trial (SMART) is a pragmatic, cluster-level allocation, cluster-level crossover trial being conducted between 1 June 2015 and 30 April 2017 in five intensive care units at Vanderbilt University Medical Center in Nashville, TN, USA. SMART compares saline (0.9% sodium chloride) with balanced crystalloids (clinician’s choice of lactated Ringer’s solution or Plasma-Lyte A®). Each intensive care unit is assigned to provide either saline or balanced crystalloids each month, with the assigned crystalloid alternating monthly over the course of the trial. All adults admitted to participating intensive care units during the study period are enrolled and followed until hospital discharge or 30 days after enrollment. The anticipated enrollment is approximately 14,000 patients. The primary outcome is Major Adverse Kidney Events within 30 days—the composite of in-hospital death, receipt of new renal replacement therapy, or persistent renal dysfunction (discharge creatinine ≥200% of baseline creatinine). Secondary clinical outcomes include in-hospital mortality, intensive care unit-free days, ventilator-free days, vasopressor-free days, and renal replacement therapy-free days. Secondary renal outcomes include new renal replacement therapy receipt, persistent renal dysfunction, and incidence of stage 2 or higher acute kidney injury.

Discussion

This ongoing pragmatic trial will provide the largest and most comprehensive comparison to date of clinical outcomes with saline versus balanced crystalloids among critically ill adults.

Trial registration

For logistical reasons, SMART was prospectively registered separately for the medical ICU (SMART-MED; ClinicalTrials.gov identifier: NCT02444988; registered on 11 May 2015; date of first patient enrollment: 1 June 2015) and the nonmedical ICUs (SMART-SURG; ClinicalTrials.gov identifier: NCT02547779; registered on 9 September 2015; date of first patient enrollment: 1 October 2015).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1871-1) contains supplementary material, which is available to authorized users.

Tension pneumomediastnum: A rare cause of acute intraoperative circulatory collapse in the setting of unremarkable TEE findings

DESIGN

Case report.

SETTING

Operating room.

PATIENT

25YF, ASA IV E who underwent an emergent decompressive craniectomy for refractory intracranial hypertension secondary to acute intracranial hemorhage.

INTERVENTIONS

A 25Y caucasian female presented with acute intracranial hemorrhage with intraventricular extension secondary to Moya Moya disease. Post admisison, she underwent an emergent decompressive craniectomy for medically refractory intracranial hypertension. Introperatively (post dural closure and bone flap removal) the patient developed acutely worsening peak and plateau pressures followed by pulseless electrical activity necessitating CPR with epinephrine and Vasopressin before return of circulation before return of circulation. Intraoperative TEE done during return of circulation, was essentially non diagnostic, the patient had normal breath sounds throughout, and non-contributory bronchoscopy findings.

MEASUREMENTS

EKG, arterial blood pressure, heart rate, resp. rate, introperative tranesophageal echocardiogram (TEE), Pulse oximetry, serial arterial blood gases, introperative bronchoscopy, ventilatory peak pressures.

MAIN RESULTS

A post operative chest CT revealed extensive pneumomediastinum with subcutaneous emphysema. The focussed introperative echocardiogram showed preserved left ventricular function and no evidence of tamponade physiology.

CONCLUSIONS

Tension pneumomediastinum was the likely etiologic factor for the acute hemodynamic collapse and should be considered in the differential diagnosis of intraoperative circulatory arrest.

Fluid resuscitation mediates the association between inhalational burn injury and acute kidney injury in the major burn population

BACKGROUND

It is known that acute respiratory distress syndrome and acute lung injury are independent risk factors for developing acute kidney injury (AKI) through complex pathophysiologic mechanisms. Our specific aim is to evaluate the risk factors for AKI postburn injury and whether inhalation thermal injury is an independent risk factor for developing AKI in the major burn population.

METHODS

This is an institutional review board-approved, retrospective cohort study of patients admitted to a tertiary burn intensive care unit between 2011 and 2013. We included adults (age 18 years or older) with major burn injury greater than or equal to 20% total burn surface area (TBSA) and patients with confirmed inhalation injury (±major burn). Acute kidney injury was defined using the acute kidney injury network serum creatinine criteria up to 5 days after admission. Patient demographics and clinical data were compared across cohorts using the Wilcoxon rank sum test or Pearson χ² test, as appropriate. Multiple logistic regression was used to assess the effect of inhalation injury and major burn on the incidence of AKI, adjusting for clinical and demographic confounders.

RESULTS

Two hundred fifty-four patient records (90 with inhalation injury and 164 with major burn only) were evaluated. The mean age on admission was 47±19 years and 72% of the cohort were men. There were more men in the major burn group (78% vs 62%; P=.007). No other significant differences were observed in the baseline demographics. The overall incidence of AKI was 28% (95% confidence interval, 22, 33). The unadjusted odds of AKI were nearly double (odds ratio, 1.99; 95% confidence interval, 1.13, 3.49) among those with inhalation injury relative to those with major burn only. However, there was no evidence of an independent inhalational injury effect after adjusting for potential confounders. In particular, TBSA (P=.051), daily 24-hour fluid balance (P<.001), and most recent 24-hour albumin transfusion status (P=.002) were all significantly associated with AKI in the adjusted analysis. Age and packed red blood cell transfusion status were not significant.

CONCLUSION

Inhalation thermal injury is not an independent risk factor for AKI after adjusting for TBSA and surrogates for fluid resuscitation. In patients with major burns, intensity of fluid resuscitation may mediate the development of AKI.

A Secure, Social Media-Based "Case of the Month" Module in a Neurocritical Care Unit

BACKGROUND

Systems to meet the on-demand learning needs of nurses in intensive care units are not well studied beyond the traditional classroom models.

OBJECTIVE

To study the feasibility and effect of implementing an online discussion forum for nurses in a busy neuroscience intensive care unit.

METHODS

A baseline survey was done to highlight the areas of educational need in the unit. Freeform-a password-protected, online discussion forum supported by the university-was used for the pilot project. Freeform has functions similar to Facebook, with "likes," "follow," discussion/comment spaces, and the capacity for uploading images and files. A page called "All things NeuroCritical Care" was created. All nurses working in the intensive care unit were automatically enrolled. Clinical vignettes relevant to neurocritical care were posted once a month with 1 to 2 lead questions. All participation was voluntary, and topics were chosen on the basis of the needs survey. At the end of each case, a recent review article on the topic was posted for secure download.

RESULTS

Eight sentinel diagnoses have been presented as clinical vignettes, and 34 of 76 members formally follow the page. The mean number of discussion strings per case is 8.3 posts. The number of unique visitors to the page during active case discussions exceeds 100.

CONCLUSION

A secure, online, problem-based learning discussion format is a feasible point-of-care learning opportunity that can help overcome some of the traditional barriers to ongoing nursing education needs in a busy intensive care unit.

Identification of Major Adverse Kidney Events Within the Electronic Health Record

Acute kidney injury is common among critically ill adults and is associated with increased mortality and morbidity. The Major Adverse Kidney Events by 30 days (MAKE30) composite of death, new renal replacement therapy, or persistent renal dysfunction is recommended as a patient-centered outcome for pragmatic trials involving acute kidney injury. Accurate electronic detection of the MAKE30 endpoint using data within the electronic health record (EHR) could facilitate the use of the EHR in large-scale kidney injury research. In an observational study using prospectively collected data from 200 admissions to a single medical intensive care unit, we tested the performance of electronically-extracted data in identifying the MAKE30 composite compared to the reference standard of two-physician manual chart review. The incidence of MAKE30 on manual-review was 16 %, which included 8.5 % for in-hospital mortality, 3.5 % for new renal replacement therapy, and 8.5 % for persistent renal dysfunction. There was strong agreement between the electronic and manual assessment of MAKE30 (98.5 % agreement [95 % CI 96.5-100.0 %]; kappa 0.95 [95 % CI 0.87-1.00]; P < 0.001), with only three patients misclassified by electronic assessment. Performance of the electronic MAKE30 assessment was similar among patients with and without CKD and with and without a measured serum creatinine in the 12 months prior to hospital admission. In summary, accurately identifying the MAKE30 composite outcome using EHR data collected as a part of routine care appears feasible.

Hypernatremia is a significant risk factor for acute kidney injury after subarachnoid hemorrhage: a retrospective analysis

BACKGROUND

Hypertonic saline therapy is often used in critically ill subarachnoid hemorrhage (SAH) patients for indications ranging from control of intracranial hypertension to managing symptomatic hyponatremia. The risk factors for developing acute kidney injury (AKI) in this patient population are not well defined.

SPECIFIC AIM

To study the role of serum sodium in developing AKI (based on the AKIN definition) in the SAH population admitted to a large academic neurocritical care unit.

METHODS

This is an IRB-approved, retrospective cohort study of patients admitted to a tertiary neuro intensive care unit. We included adult (age ≥ 18 years) SAH patients admitted to the neuro intensive care unit for at least 72 h. Development of AKI after admission to the ICU was defined using the AKIN serum creatinine criteria between 72 h and 14 days following admission. A Cox proportional hazards survival model with multiple time varying covariates was developed to evaluate the effect of maximum sodium exposure on the risk of AKI. Sodium exposure was captured as the running maximum of daily maximum serum sodium concentration (mEq/L). Sodium exposure was used as a surrogate for hypertonic saline therapy.

RESULTS

The final cohort of patients included 736 patients admitted to the neuro intensive care unit between 2006 and 2012. The number of patients who developed AKI was 64 (9 %). These patients had an increased length of stay (15.6 ± 9.4 vs. 12.5 ± 8.7 days). The odds of death were more than two fold greater among patients who developed AKI (odds ratio 2.33 95 % CI 1.27, 4.3). Sodium exposure was significantly associated with the hazard of developing AKI, adjusting for age, sex, preexisting renal disease, diabetes mellitus, radiocontrast exposure, number of days on mechanical ventilation, and admission Glasgow Coma Scale score. For each 1 mEq/L increase in the running maximum daily serum sodium, the hazard of developing AKI was increased by 5.4 % (95 % CI 1.4, 9.7).

CONCLUSION

The maximum daily sodium is a significant risk factor for developing AKI in patients with SAH.

Heparin Resistance and Anticoagulation Failure in a Challenging Case of Cerebral Venous Sinus Thrombosis

We report a challenging case of cerebral venous sinus thrombosis (multiple etiologic factors) that was complicated by heparin resistance secondary to suspected antithrombin III (ATIII) deficiency. A 20-year-old female previously healthy and currently 8 weeks pregnant presented with worsening headaches, nausea, and decreasing Glasgow Coma Scale/Score (GCS), necessitating mechanical ventilatory support. Imaging showed extensive clots in multiple cerebral venous sinuses including the superior sagittal sinus, transverse, sigmoid, jugular veins, and the straight sinus. She was started on systemic anticoagulation and underwent mechanical clot removal and catheter-directed endovascular thrombolysis with limited success. Complicating the intensive care unit care was the development of heparin resistance, with an inability to reach the target partial thomboplastin time (PTT) of 60 to 80 seconds. At her peak heparin dose, she was receiving >35 000 units/24 h, and her PTT was subtherapeutic at <50 seconds. Deficiency of ATIII was suspected as a possible etiology of her heparin resistance. Fresh frozen plasma was administered for ATIII level repletion. Given her high thrombogenic risk and challenges with conventional anticoagulation regimens, we transitioned to argatroban for systemic anticoagulation. Heparin produces its major anticoagulant effect by inactivating thrombin and factor X through an AT-dependent mechanism. For inhibition of thrombin, heparin must bind to both the coagulation enzyme and the AT. A deficiency of AT leads to a hypercoagulable state and decreased efficacy of heparin that places patients at high risk of thromboembolism. Heparin resistance, especially in the setting of critical illness, should raise the index of suspicion for AT deficiency. Argatroban is an alternate agent for systemic anticoagulation in the setting of heparin resistance.

How we created a targeted teaching tool using blog architecture for anesthesia and critical care education--the A/e anesthesia exchange blog

BACKGROUND

The time constraints on a clinical educator have increased immensely over the past decade. Technology has served to significantly bridge the challenge over the past decade. WHAT WE DID: We created a method of delivering targeted educational content for point of care learning in anesthesia and critical care. Our blog platform allows clinician-educators to deliver content as videopodcasts and presentations to learners in a straightforward and easily accessible manner both on the web and through mobile platforms. The A/e Anesthesia exchange "pushed" content at predetermined time intervals to learners and content was based on timely topics that were clinically relevant to their daily practice. The A/e Blog allowed multiple authors across disciplines to contribute content, thus providing learners potentially access to resources of knowledge from the entire team of clinician-educators at an institution. During the pilot phase of A/e blog implementation, the authors gained valuable insights into the use and limitations of web-based technology as a teaching tool. These included challenges with faculty and student participation, managing techno stress of faculty not fluent with the technology, tailoring content based on analytics data and web platform robustness and spam protection.

CONCLUSION

With these insights in hand, we anticipate the launch of an even more robust A/e: Anesthesia Exchange (version 2.0) by the end of 2013.

The effect of the pressure-volume curve for positive end-expiratory pressure titration on clinical outcomes in acute respiratory distress syndrome: a systematic review

PURPOSE

Methods to optimize positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS) remain controversial despite decades of research. The pressure-volume curve (PVC), a graphical ventilator relationship, has been proposed for prescription of PEEP in ARDS. Whether the use of PVC's improves survival remains unclear.

METHODS

In this systematic review, we assessed randomized controlled trials (RCTs) comparing PVC-guided treatment with conventional PEEP management on survival in ARDS based on the search of the National Library of Medicine from January 1, 1960, to January 1, 2010, and the Cochrane Central Register of Controlled Trials. Three RCTs were identified with a total of 185 patients, 97 with PVC-guided treatment and 88 with conventional PEEP management.

RESULTS

The PVC-guided PEEP was associated with an increased probability of 28-day or hospital survival (odds ratio [OR] 2.7, 95% confidence interval [CI] 1.5, 4.9) using a random-effects model without significant heterogeneity (I (2) test: P = .75). The PVC-guided ventilator support was associated with reduced cumulative risk of mortality (-0.24 (95% CI -0.38, -0.11). The PVC-managed patients received greater PEEP (standardized mean difference [SMD] 5.7 cm H2O, 95% CI 2.4, 9.0) and lower plateau pressures (SMD -1.2 cm H2O, 95% CI -2.2, -0.2), albeit with greater hypercapnia with increased arterial pCO2 (SMD 8 mm Hg, 95% CI 2, 14). Weight-adjusted tidal volumes were significantly lower in PVC-guided than conventional ventilator management (SMD 2.6 mL/kg, 95% CI -3.3, -2.0).

CONCLUSION

This analysis supports an association that ventilator management guided by the PVC for PEEP management may augment survival in ARDS. Nonetheless, only 3 randomized trials have addressed the question, and the total number of patients remains low. Further outcomes studies appear required for the validation of this methodology.

Secondary oxalosis induced acute kidney injury in allograft kidneys

Secondary oxalosis causing acute kidney injury (AKI) has been widely reported in native kidneys but its occurrence in allograft kidneys is relatively uncommon. We present three patients with acute kidney allograft dysfunction secondary to tubular oxalate microcrystal deposits confirmed on allograft biopsy in the setting of acute gastrointestinal dysfunction. These three patients presented with AKI that was preceded by episodes of ongoing diarrhea ranging from 10 to 90 days. All patients were on vitamin C and/or multivitamin supplementation. Two of the three patients needed long-term renal replacement therapy with the third patient recovering his kidney function after 2 months. The risks versus benefits of vitamin C supplementation in renal transplant patients should be carefully evaluated especially in the setting of gastrointestinal dysfunction.

Implementing a hybrid web-based curriculum for an elective medical student clerkship in a busy surgical intensive care unit (ICU): effect on test and satisfaction scores

OBJECTIVE

To determine whether a hybrid traditional and web-based curriculum improves test scores and enrollment among senior medical students in an elective critical care rotation.

DESIGN AND SETTING

Retrospective study in a surgical ICU at a major academic center.

SUBJECTS

One hundred twenty-one fourth year medical students completing an elective ICU clerkship between 2007 and 2010.

INTERVENTIONS

Pre-test and post-test during a 4-week rotation.

METHODS

We implemented a hybrid curriculum that involved both traditional teaching methods and a new online core curriculum that incorporating audio, video, and text using screen capture technology. The curriculum was hosted on a secure online portal called ICON (Desire2Learn Inc., Ontario, Canada). The core curriculum covered topics that were considered essential to meet the didactic objectives of the rotation. MEASUREMENTS AND EVALUATIONS: A pre-test was administered online on day 1 of the rotation. A post-test was administered on the second to last day of the rotation. Both tests were composed of 20 questions randomly chosen from a question bank of 100 questions. The tests are managed (administering, grading, and reporting) exclusively online.

RESULTS

One hundred twenty-one medical students have successfully completed the clerkship since implementing the new curriculum. Each group of students showed an improvement in the mean post-test score by at least 17%+ to 10%. The satisfaction scores of the clerkship improved consistently from 2007 and is currently rated at 4.31 ± 0.85 (on a 5-point scale). The rotation is in the top 25(th) percentile of all clinical clerkships offered at the University of Iowa.

CONCLUSION

A systematically implemented hybrid web-based critical care curriculum can improve knowledge based test scores and overall clerkship satisfaction scores in a busy surgical ICU.

Intraoperative use of a chest physiotherapy system during whole lung lavage for pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare condition caused by the excessive alveolar accumulation of surfactant proteins. The current standard of care for removing these secretions is through therapeutic whole lung lavage (WLL). We describe two successful cases of bilateral WLL involving the novel use of the Vest™ chest physiotherapy system thereby avoiding the need for extensive changes in patient position in the intraoperative period. In brief, it involves the induction of general anesthesia followed by single-lung ventilation while simultaneously performing large volume lavages on the nonventilated lung. The washout was enhanced using the Vest™ system.

Association between postoperative acute kidney injury and duration of cardiopulmonary bypass: a meta-analysis

OBJECTIVE

This meta-analysis examined the association between cardiopulmonary bypass (CPB) time and acute kidney injury (AKI).

DESIGN

Meta-analysis of previously published studies.

SETTING

Each single-center study was conducted in a surgical intensive care unit and/or academic or university hospital.

PARTICIPANTS

Adult patients undergoing heart surgery with CPB.

INTERVENTIONS

A systematic literature review was conducted using PubMed, EMBASE, and Cochrane Library databases and Google Scholar from January 1980 through September 2009. Initial search results were refined to include human subjects, age >18 years, randomized controlled trials, and prospective and retrospective cohort studies, meet the Acute Kidney Injury Network definition of renal failure, and report times on CPB.

MEASUREMENTS AND MAIN RESULTS

The length of time on CPB has been implicated as an independent risk factor for development of AKI after CPB (AKI-CPB). The 9 independent studies included in the final meta-analysis had 12,466 patients who underwent CPB. Out of these, 756 patients (6.06%) developed AKI-CPB. In 7 of the 9 studies, the mean CPB times were statistically longer in the AKI-CPB cohort compared with the control group (cohort without AKI). The absolute mean differences in CPB time between the 2 groups were 25.65 minutes with the fixed-effects model and 23.18 minutes with the random-effects model.

CONCLUSIONS

Longer CPB times are associated with a higher risk of developing AKI-CPB, which, in turn, has a significant effect on overall mortality as reported by the individual studies.

The acute effectiveness and safety of the constant-flow, pressure-volume curve to improve hypoxemia in acute lung injury

OBJECTIVE

To investigate the effectiveness of the constant-flow, pressure-volume curve (PVC) to prescribe positive end-expiratory pressure (PEEP) in acute lung injury (ALI) and risk of cardiopulmonary deterioration during the PVC process.

DESIGN

A retrospective, cohort study.

SETTING

A surgical intensive care unit (ICU) of a tertiary, university hospital.

PATIENTS

Fifty consecutive ventilated patients diagnosed with ALI undergoing the PVC maneuver from 1999 to 2003.

INTERVENTIONS

Titration of PEEP based on the lower inflection point of the constant-flow, pressure-volume curve.

MEASUREMENTS AND MAIN RESULTS

Patients were divided into 2 groups based on PVC-guided PEEP changes of <3 cm H2O (PVC-NC or "no change") or ≥3 cm H2O (PVC-CHG or "change") from the initial empiric prescription. There was a greater increase in partial pressure of arterial oxygen (PaO2)/fractional concentration of inspired oxygen (FiO2) in the PVC-CHG group, with a mean change of 80 ± 50 (95% confidence interval [CI] 61, 98) versus 42 ± 54 (95% CI 17, 67) in the PVC-NC group. Eighty-two percent of patients (41/50) showed an increase in ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) by 20% within 6 to 24 hours after the PVC test-greater in the PVC-CHG group (OR 1.44, 95% CI 1.02, 2.01). Thirteen percent (4/30) within the PVC-CHG group and none within the PVC-NC group (0/20) required a 25% increase in vasoactive infusion rates (P = .089) in relation to the procedure. Univariate logistic regression showed that PVC-CHG was significantly associated with a 20% change in PaO2/FiO2 (OR 7.54, 95% CI 1.37, 41.41). Multivariate logistic modeling showed that PVC-guided PEEP changes of ≥3 cm H2O, age ≤65 years, and pre-PVC FiO2 ≥ .85 were significantly associated with a 20% increase in PaO2/FiO2 (receiver operator area under the curve = .86).

CONCLUSIONS

In the setting of acute lung injury, use of the constant-flow, pressure-volume curve to prescribe PEEP appears associated with improvement in oxygenation with limited risk of acute, process-related, cardiopulmonary deterioration.

Cryosurgery for prostate cancer: improved glandular ablation by use of 6 to 8 cryoprobes

OBJECTIVES

To describe and assess the efficacy for increased glandular destruction by using 6 to 8 cryoprobes in place of the traditional 5 probes.

METHODS

In April 1996, a revised method for cryosurgery was begun that uses 6 to 8 cryoprobes, and by July 1997, 81 men had been treated. This group was compared retrospectively to our last 82 cases done before April 1996 using 5 cryoprobes. All cases were consecutive. To ensure that the groups were similar, comparison was performed of entrance prostate-specific antigen (PSA), clinical stage, and Gleason score. Six months after cryosurgery, PSA and residual epithelial acini were compared between the two groups.

RESULTS

The two groups were comparable for all the above parameters (P >0.05). The degree of overall glandular kill was greater for the 6 to 8-probe method (P = 0.023). Complete glandular ablation for the 5-probe and 6 to 8-probe methods was 39% and 53%, respectively, and the difference was not significant (P = 0.072). However, when one combined the complete glandular ablation group with the none to few residual acini group, 67.5% for the 5-probe method and 88.9% for the 6 to 8-probe method, a significant difference was found (P = 0.001). The odds of having many remaining acini versus having none to few were 3.5 times greater in the 5-probe group than in the 6 to 8-probe group. The mean and median PSA for the 5- and 6 to 8-probe groups were 0.19 and 0.1 versus 0.11 and 0.07 ng/mL, respectively, a significant difference (P = 0.02). No difference was found in rates of tumor persistence or complications.

CONCLUSIONS

A revised method for cryosurgery using 6 to 8 cryoprobes has proved to be more effective for near-glandular ablation than the traditional 5-probe method. It was easily applied, had a wide margin of safety, and even shortened learning time. These innovations have permitted a closer approach to the goal of complete glandular destruction.

Acute pulmonary embolism: diagnosis with MR angiography

PURPOSE

To prospectively evaluate pulmonary magnetic (MR) angiography as a diagnostic examination for acute pulmonary embolism (PE).

MATERIALS AND METHODS

Thirty-six consecutive patients (19 women, 17 men; age range, 28-84 years) underwent pulmonary digital subtraction angiography (DSA) and pulmonary MR angiography. MR angiograms were obtained during suspended respiration and the pulmonary arterial phase of gadolinium-based contrast medium injection. A steady-state gradient-recalled-echo sequence with free induction decay sampling was used. DSA studies were interpreted for the presence of acute PE by two independent radiologists; an adjudicator made the final decision on discordant interpretations.

RESULTS

By using DSA, a total of 19 acute pulmonary emboli were depicted in 13 patients. Prospectively, 13 of these emboli were depicted by using MR angiography. MR angiography missed six emboli: Four required the DSA adjudicator to make the decision, and one was in a patient whose MR angiogram was acquired during breathing. Four of these six emboli were small subsegmental emboli, and two were segmental.

CONCLUSION

Performed without pulmonary arterial catheterization, iodinated contrast media, or ionizing radiation, pulmonary MR angiography had a high accuracy for depicting lobar and segmental emboli, but was unable to depict four of five subsegmental emboli.

Patterns of Doppler recordings and its relationship to varicocele in infertile men

Incompetence of the testicular vein appears to be the basic pathology of testicular dysfunction in varicocele. Doppler recording is a very sensitive method for detecting this reflux even when varicocele is not evident clinically. One hundred and seventy-eight men with infertility were studied. The presence of reflux in the pampiniform plexus as demonstrated by Doppler recording was compared with clinical varicocele. Reflux patterns were recorded on graph paper and various grades of reflux were observed. The three grades of reflux identified varied between a momentary reflux during vigorous Valsalva manoeuvre to significant reflux on minimal increase in intra-abdominal pressure brought about by normal respiration and deep breathing. Ninety-four per cent of the patients with clinical signs of varicocele had refluxes of grade 2 and 3 on Doppler study. Forty per cent of the patients without clinical evidence of varicocele were found to have reflux of grade 1 and 2 in the testicular veins.