Experiences of Renal Replacement Therapy Delivery in Swedish Intensive Care Units during the COVID-19 Pandemic.

BACKGROUND: The COVID-19 pandemic led to a rapidly increased demand for intensive care unit (ICU) and renal replacement therapy (RRT) worldwide. RRT delivery was threatened by a lack of specially trained staff and equipment. We investigated how the first wave of COVID-19 affected RRT delivery in Swedish ICUs. METHODS: An Internet-based questionnaire was sent to ICU lead physicians which included quantitative and qualitative questions regarding RRT demand, equipment availability, and use of continuous renal replacement therapy (CRRT), intermittent haemodialysis (IHD), and peritoneal dialysis (PD) during spring 2020. RESULTS: Twenty-five ICUs responded and these treated 64% of COVID-19 ICU patients in Sweden. ICU capacity increased by 292% (IQR 171-347%). Median peak capacity was reached during the 18th week of the year. RRT use increased overall by 133% and in Stockholm by 188%. 36% of units sequestered CRRT machines. IHD was used in 68% and PD in 12% of ICUs. RRT fluid and filter shortages were experienced by 45% and 33% of wards, respectively; consequently, prescription alterations were made by 24% of ICUs. Calcium solution shortages were reported in 12% of units that led to citrate protocol changes. Staffing shortages resulted in RRT sometimes being delivered by non-RRT-trained staff, safety incidents relating to this occurred, although no patient harm was reported. CONCLUSION: During the first wave of the COVID-19 pandemic, RRT demand increased extensively causing staff and equipment shortages, altered CRRT protocols, and increased use of IHD and PD. The impact on patient outcomes should be assessed to effectively plan for further surge capacity RRT demand.

Elimination of CO2 insufflation-induced hypercapnia in open heart surgery using an additional venous reservoir.

OBJECTIVES: Carbon dioxide (CO2) gas insufflation is used for continuous de-airing during open heart surgery. The aim was to evaluate if an additional separate venous reservoir eliminates CO2 insufflation-induced hypercapnia and keeps sweep gas flow of the oxygenator constant. METHODS: A separate reservoir was used during cardiopulmonary bypass in addition to a standard venous reservoir. The additional reservoir received drained blood and CO2 gas continuously via a suction drain (1 l/min) and handheld suction devices from the surgical wound. CO2 gas was insufflated via a gas diffuser in the open wound at 10 l/min. In a cross-over design for each patient, gas and blood were either continuously drained from the additional to the standard venous reservoir or not. CO2 pressure in arterial blood (PaCO2) was measured after adjustment of sweep gas flow as necessary and after steady state of PaCO2 was observed. Mean values for each setup (median 4 times) for each patient were analysed with Wilcoxon rank-sum test. RESULTS: Ten adult patients undergoing open aortic valve replacement were included. Median PaCO2 did not differ between setups (5.41; 5.29-5.57, interquartile range vs 5.41; 5.24-5.58, P = 0.92), whereas sweep gas flow (l/min) was lower (2.58; 2.50-3.16 vs 4.42; 4.0-5.40, P = 0.002) when CO2 gas was not drained from the additional to the standard reservoir. CONCLUSIONS: An additional venous reservoir for the evacuation of blood from the open surgical wound eliminates CO2 insufflation-induced hypercapnia in open heart surgery keeping PaCO2 and sweep gas flow constant. This prevents possible CO2-induced hyperperfusion of the brain and decreases the risk of cerebral particulate embolization during CO2 insufflation for de-airing in open heart surgery. CLINICAL TRIAL REGISTRATION: NCT04202575. IRB APPROVAL DAT AND NUMBER: 2018-07-13 and 2018/1091-31.

Carbon dioxide de-airing in minimal invasive cardiac surgery, a new effective device.

BACKGROUND: Arterial air embolism during open heart surgery may cause postoperative complications including cerebral injury, myocardial dysfunction, and dysrhythmias. Despite standard de-airing techniques during surgery large amounts of arterial air emboli may still occur, especially during weaning from cardiopulmonary bypass. To prevent this insufflation of carbon dioxide in the wound cavity has been used since the 1950s. The aim of this study was to assess a new mini-diffuser for efficient carbon dioxide de-airing of a minimal invasive cardiothoracic wound cavity model. Up until now no device has been evaluated for this purpose. METHODS: A new insufflation device, a mini-diffuser, was tested. A thin plastic tube was used as control. The end of the mini-diffuser or the control, respectively, was positioned in a minimal invasive thoracic wound model. Remaining air content was measured during steady state and during intermittent suction with a rough suction device at different carbon dioxide flow rates. Measurements were also carried out in the open surgical wound during minimal invasive aortic surgery in six patients. RESULTS: The air content was below 1% 4 cm below the surface of the open wound model during continuous carbon dioxide inflow of 2-10 L/min with the mini diffuser. In comparison, carbon dioxide insufflation via the open-ended tube resulted in a mean air content between 10 and 75%. The mean air content of the wound model remained below 1% at a carbon dioxide flow rate of 3-5 L/min during intermittent application of a suction device with a suction rate of 15 L/min. In 6 patients undergoing minimal invasive aortic valve replacement air content in the open surgical wound remained below 1% at a continuous carbon dioxide flow rate of 5 and 8 L/min via the mini-diffuser, respectively. CONCLUSIONS: The mini diffuser was effective for carbon dioxide de-airing, i.e. < 1% remaining air, of a minimal invasive cardiothoracic wound cavity model with and without intermittent rough suction as well as in patients undergoing minimal invasive aortic valve surgery.

Cerebral microembolism during coronary angiography: a randomized comparison between femoral and radial arterial access.

BACKGROUND AND PURPOSE: Microemboli observed during coronary angiography can cause silent ischemic cerebral lesions. The aim of this study was to investigate if the number of particulate cerebral microemboli during coronary angiography is influenced by access site used. METHODS: Fifty-one patients with stable angina pectoris referred for coronary angiography were randomized to right radial or right femoral arterial access. The number of particulate microemboli passing the middle cerebral arteries was continuously registered with transcranial Doppler. RESULTS: The median (minimum-maximum range) numbers of particulate emboli were significantly higher with radial 10 (1-120) than with femoral 6 (1-19) access. More particulate microemboli passed the right middle cerebral artery with the radial access. CONCLUSIONS: This study indicates that the radial access used for coronary angiography generates more particulate cerebral microemboli than the femoral access and thus may influence the occurrence of silent cerebral injuries.