Flow measurements: Can several “Wrongs” make a “Right”?

AIMS: Although measurement of maximum flow rate (Qmax) is a standard and straightforward test, it is often difficult to obtain reliable readings. We obtained multiple measurements using a simple home uroflow device which categorizes Qmax into ranges. We hypothesize that the average of a series of relatively coarse measurements of Qmax would be more repeatable and therefore more representative of an individual's voiding function than a single, albeit more precise measurement. METHODS: We studied 22 male volunteers with a wide range of Qmax. They were asked to record flow category (<10 ml/sec; 10-15 ml/sec; 15-20 ml/sec; >20 ml/sec) and voided volume twice daily for 12 days using the home flow device. In addition, a clinic-based flow recording using a spinning-disc uroflowmeter was obtained at both the start and the end of the 12-day period. RESULTS: Good agreement between mean home flow and mean clinic flow was seen with mean (SD) difference of 1.3 (5) ml/sec. The mean for consecutive halves of an individual's home flow data showed excellent agreement (-0.2 (1.3) ml/sec). The two clinic readings showed poorer agreement (2.3 (6.8) ml/sec) than the home readings, and poorer agreement even than between clinic and home flows. CONCLUSIONS: Although simple in design, the home flowmeter actually shows greater accuracy than might be expected when used repeatedly to study the flow rates of men. Simple flow devices such as this could be used in conjunction with voiding diaries to give a more representative picture of patients' day-to-day voiding function.     

Intensive Hemodialysis: Normalizing the “Unphysiology” of Conventional Hemodialysis?

Interest in intensified hemodialysis (HD) regimens is increasing internationally, as there is growing evidence that they are associated with improved outcomes. Appreciation that conventional hemodialysis (CHD), delivered as 4-hour sessions three times a week, is not providing optimal physiological replacement of renal function has led to the development of intensified dialysis therapies. These include long intermittent hemodialysis typically lasting 6-8 hours and delivered three times a week, short daily hemodialysis, providing more frequent sessions 4-7 days a week lasting 2-3.5 hours, and nocturnal hemodialysis, performed 5-7 days a week for 6-8 hours. Studies evaluating outcomes from these programs have indicated superior results to those achieved with CHD, including favorable modifications of cardiovascular risk factors and improvements in a variety of clinical measures. The objective of this review is to present available evidence supporting the hypothesis that in an attempt to provide a "more normal physiology," intensified HD regimens achieve outcomes superior to those historically achieved with CHD.     

Central venous catheters for chronic hemodialysis: Is “last choice” never the “right choice”?

Since the publication of the first vascular access clinical practice guidelines in 1997, the global nephrology community has dedicated significant time and resources toward increasing the prevalence of arteriovenous fistulas and decreasing the prevalence of central venous catheters for hemodialysis. These efforts have been bolstered by observational studies showing an association between catheter use and increased patient morbidity and mortality. To date, however, no randomized comparisons of the outcomes of different forms of vascular access have been conducted. There is mounting evidence that much of the difference in patient outcomes may be explained by patient factors, rather than choice of vascular access. Some have called into question the appropriateness of fistula creation for certain patient populations, such as those with limited life expectancy and those at high risk of fistula‐related complications. In this review, we explore the extent to which catheters and fistulas exhibit the characteristics of the “ideal” vascular access and highlight the significant knowledge gaps that exist in the current literature. Further studies, ideally randomized comparisons of different forms of vascular access, are required to better inform shared decision making.     

Rotary Blood Pumps for Cardiac Assistance: A “Must”?

Ventricular Assist Devices (VADs) were developed following the observation that most end-stage heart failure patients only required left heart support for survival. The trend toward left VAD implantation instead of a TAH has actually contributed to the development of nonpulsatile rotational devices. This article intends to evaluate the current and future technology of continuous flow pumps. Various issues pertaining to the long-term effects of continuous blood flow, biocompatibility of axial flow pumps, and the safety and reliability of such devices need to be addressed. Some of the advantages of rotary blood pumps include their small size, ease of implantation, and encouraging low infection rates. Certain issues such as automatic flow control, device components durability, and hemocompatibility remain unresolved. The quest for an ideal device combining optimal efficiency, ease of anatomical fit, and perfect bioacceptance, continues. Rotary blood pumps are not yet a "must."     

“Turn downs” in aortic emergencies: Reassurance or uncertainty?

“Turn‐down” rate has been reported to have a significant influence on outcomes, and being turned down for an operation is associated with significant short‐term mortality risk. A study examining the impact of the pandemic on the “turn‐down” rates of acute aortic syndromes in the United Kingdom reported an overall “turn‐down” rate of  7.3% in the early part of the pandemic. This review examines the significance of “turn‐downs” in this setting and scrutinizes the adequacy of reporting this complex variable.     

Does low-energy helium-neon laser irradiation alter “in vitro” replication of human fibroblasts?

Cultured human fibroblasts were treated in a controlled, randomized manner to assess the effect of low-energy (0.9 mW) helium-neon (HeNe) laser irradiation on cellular proliferation. Two trials were performed: one with fibroblasts in the third to fourth passage and the other with fibroblasts in the 13th to 14th passage. In each trial, separate plastic petri dishes were inoculated with the cells, maintained in a 5% CO2-95% air atmosphere, and nourished with HB 102 media. Treatment began 48 h after inoculation with daily 60-s irradiations of the "treated" cultures over a 5-d period. Control cultures underwent the same handling but were not irradiated. A significant stimulative, or inhibitive, effect on replication was not found in either trial.     

A 10 min “no‐touch” time – is it enough in DCD? A DCD Animal Study

Donation after cardiac death (DCD) is under investigation because of the lack of human donor organs. Required times of cardiac arrest vary between 75s and 27min until the declaration of the patients' death worldwide. The aim of this study was to investigate brain death in pigs after different times of cardiac arrest with subsequent cardiopulmonary resuscitation (CPR) as a DCD paradigm. DCD was simulated in 20 pigs after direct electrical induction of ventricular fibrillation. The "no-touch" time varied from 2min up to 10min; then 30min of CPR were performed. Brain death was determined by established clinical and electrophysiological criteria. In all animals with cardiac arrest of at least 6min, a persistent loss of brainstem reflexes and no reappearance of bioelectric brain activity occurred. Reappearance of EEG activity was found until 4.5min of cardiac arrest and subsequent CPR. Brainstem reflexes were detectable until 5min of cardiac arrest and subsequent CPR. According to our experiments, the suggestion of 10min of cardiac arrest being equivalent to brain death exceeds the minimum time after which clinical and electrophysiological criteria of brain death are fulfilled. Therefore shorter "no-touch" times might be ethically acceptable to reduce warm ischemia time.