An investigation into the effects of commencing haemodialysis in the critically ill

<b>Introduction:</b> We have aimed to describe haemodynamic changes when haemodialysis is instituted in the critically ill. 3 hypotheses are tested: 1)The initial session is associated with cardiovascular instability, 2)The initial session is associated with more cardiovascular instability compared to subsequent sessions, and 3)Looking at unstable sessions alone, there will be a greater proportion of potentially harmful changes in the initial sessions compared to subsequent ones. <b>Methods:</b> Data was collected for 209 patients, identifying 1605 dialysis sessions. Analysis was performed on hourly records, classifying sessions as stable/unstable by a cutoff of >+/-20% change in baseline physiology (HR/MAP). Data from 3 hours prior, and 4 hours after dialysis was included, and average and minimum values derived. 3 time comparisons were made (pre-HD:during, during HD:post, pre-HD:post). Initial sessions were analysed separately from subsequent sessions to derive 2 groups. If a session was identified as being unstable, then the nature of instability was examined by recording whether changes crossed defined physiological ranges. The changes seen in unstable sessions could be described as to their effects: being harmful/potentially harmful, or beneficial/potentially beneficial. <b>Results:</b> Discarding incomplete data, 181 initial and 1382 subsequent sessions were analysed. A session was deemed to be stable if there was no significant change (>+/-20%) in the time-averaged or minimum MAP/HR across time comparisons. By this definition 85/181 initial sessions were unstable (47%, 95% CI SEM 39.8-54.2). Therefore Hypothesis 1 is accepted. This compares to 44% of subsequent sessions (95% CI 41.1-46.3). Comparing these proportions and their respective CI gives a 95% CI for the standard error of the difference of -4% to 10%. Therefore Hypothesis 2 is rejected. In initial sessions there were 92/1020 harmful changes. This gives a proportion of 9.0% (95% CI SEM 7.4-10.9). In the subsequent sessions there were 712/7248 harmful changes. This gives a proportion of 9.8% (95% CI SEM 9.1-10.5). Comparing the two unpaired proportions gives a difference of -0.08% with a 95% CI of the SE of the difference of -2.5 to +1.2. Hypothesis 3 is rejected. Fisher’s exact test gives a result of p=0.68, reinforcing the lack of significant variance. <b>Conclusions:</b> Our results reject the claims that using haemodialysis is an inherently unstable choice of therapy. Although proportionally more of the initial sessions are classed as unstable, the majority of MAP and HR changes are beneficial in nature

Successfully initiating an escalation of care in acute ward settings—A qualitative observational study

Aims: To address knowledge gaps by (i) developing a theoretical understanding of escalation and (ii) identifying escalation success factors. Design: Non‐participant observations were used to examine deteriorating patient escalation events. Methods: Escalation event data were collected by a researcher who shadowed clinical staff, between February 16th 2021 and March 17th 2022 from two National Health Service Trusts. Events were analysed using Framework Analysis. Escalation tasks were mapped using a Hierarchical Task Analysis diagram and data presented as percentages, frequency and 95% CI. Results: A total of 38 observation sessions were conducted, totaling 105 h, during which 151 escalation events were captured. Half of these were not early warning score‐initiated and resulted from bleeding, infection, or chest pain. Four communication phenotypes were observed in the escalation events. The most common was Outcome Focused Escalation, where the referrer expected specific outcomes like blood cultures or antibiotic prescriptions. Informative Escalations were often used when a triggering patient's condition was of low clinical concern and ranked as the second most frequent escalation communication type. General Concern Escalations occurred when the referrer did not have predetermined expectations. Spontaneous Interaction Escalations were the least frequently observed, occurring opportunistically in communal workspaces. Conclusion: Half of the events were non‐triggering escalations and understanding these can inform the design of systems to support staff better to undertake them. Escalation is not homogenous and differing escalation communication phenotypes exist. Informative Escalations represent an organizational requirement to report triggering warning scores and a targeted reduction of these may be organizationally advantageous. Increasing the frequency of Spontaneous Escalations, through hospital designs, may also be beneficial. Impact Statement: Our work highlights that a significant proportion of escalation workload occurs without a triggering early warning score and there is scope to better support these with designed systems. Further examination of reducing Informative and increasing Spontaneous Escalations is also warranted. Patient and Public Contribution: Extensive PPIE was completed throughout the lifecycle of this study. PPIE members validated the research questions and overarching aims of the overall study. PPIE members contributed to the design of the study reviewed documents and the final data generated

Cardiac Arrest Associated with Endotracheal Suctioning Following Surgery for Congenital Heart Disease

(CHD) describes the most common congenital defect and represents a significant health burden worldwide. Yearly, there are more than a million newborns diagnosed with congenital heart disease, many of the defects require surgical correction. The cost of surgical correction can be significant, of the ten congenital defects with the highest hospital cost, six are CHD. Cardiac arrest, like other postoperative complications, can increase the length of intensive care and hospital stay, and is associated with hospital-acquired infections, errors, and poorer long-term outcomes. Several studies included physiological data and hemodynamic monitoring or assigned causation for cardiac arrest to broad categories, such as respiratory, arrhythmia, metabolic or central nervous system, but did not describe specific clinical signs of impending cardiac arrest with the exception of rising serum lactate. The paucity of data in this area demonstrates a gap in the literature on cardiac arrest in children following cardiac surgery. The first manuscript in this dissertation describes the current literature on the effect of endotracheal suctioning in pediatrics, guided by the Neuman Systems model. The second manuscript, using the Knowledge-to-Action theoretical framework, explores available tools for risk adjustment in congenital heart surgery. Lastly, the third manuscript describes the hemodynamic variability preceding cardiac arrest associated with endotracheal suctioning in children following surgery for congenital heart defects compared to others. This dissertation establishes a basis for further research and interventions to avert cardiac arrest in the vulnerable child with congenital heart disease

Strain threshold for ventilator-induced lung injury

Introduction Unphysiological lung strain (tidal volume/functional residual capacity, TV/FRC) may cause ventilator-induced lung injury (VILI) [1]. Whether VILI develops proportionally to the applied strain or only above a critical threshold remains unknown. Methods In 20 healthy, mechanically ventilated pigs, FRC and lung weight were measured by computed tomography. Animals were then ventilated for up to 54 hours with a TV set to produce a predetermined strain. At the end, lung weight was measured with a balance. VILI was defi ned as fi nal lung weight exceeding the initial one. Results Lung weight either did not increase at all (no-VILI group; lung weight change \u201373 \ub1 42 g, n = 9) or markedly augmented (VILI group; 264 \ub1 80 g, n = 11). In the two groups, strain was 1.38 \ub1 0.68 and 2.16 \ub1 0.50 (P <0.01), respectively. VILI occurred only when lung strain reached or exceeded a critical threshold, between 1.5 and 2.1 (Figure 1). Conclusions In animals with healthy lungs VILI only occurs when lung strain exceeds a critical threshold. Reference 1. Gattinoni L, Carlesso E, Cadringher P, et al.: Physical and biological triggers of ventilator-induced lung injury and its prevention [review]. Eur Respir J 2003, 22(Suppl 47):15s-25s

Contribution of red blood cells to the compensation for hypocapnic alkalosis through plasmatic strong ion difference variations

Introduction Chloride shift is the movement of chloride between red blood cells (RBC) and plasma (and vice versa) caused by variations in pCO2. The aim of our study was to investigate changes in plasmatic strong ion diff erence (SID) during acute variations in pCO2 and their possible role in the compensation for hypocapnic alkalosis.Methods Patients admitted in this year to our ICU requiring extracorporeal CO2 removal were enrolled. Couples of measurements of gases and electrolytes on blood entering (v) and leaving (a) the respiratory membrane were analyzed. SID was calculated as [Na+] + [K+] + 2[Ca2+] \u2013 [Cl\u2013] \u2013 [Lac\u2013]. Percentage variations in SID (SID%) were calculated as (SIDv \u2013 SIDa) x 100 / SIDv. The same calculation was performed for pCO2 (pCO2%). Comparison between v and a values was performed by paired t test or the signed-rank test, as appropriate. Results Analysis was conducted on 205 sample-couples of six enrolled patients. A signifi cant diff erence (P <0.001) between mean values of v\u2013a samples was observed for pH (7.41 \ub1 0.05 vs. 7.51 \ub1 0.06), pCO2 (48 \ub1 6 vs. 35 \ub1 7 mmHg), [Na+] (136.3 \ub1 4.0 vs. 135.2 \ub1 4.0 mEq/l), [Cl\u2013] (101.5 \ub1 5.3 vs. 102.8 \ub1 5.2 mEq/l) and therefore SID (39.5 \ub1 4.0 vs. 36.9 \ub1 4.1 mEq/l). pCO2% and SID% signifi cantly correlated (r2 = 0.28, P <0.001). Graphical representation by quartiles of pCO2% is shown in Figure 1. Conclusions As a reduction in SID decreases pH, the observed movement of anions and cations probably limited the alkalinization caused by hypocapnia. In this model, the only source of electrolytes are blood cells (that is, no interstitium and no infl uence of the kidney is present); it is therefore conceivable to consider the observed phenomenon as the contribution of RBC for the compensation of acute hypocapnic alkalosi

Safety and tolerability of an ovine-derived polyclonal anti-TNFα Fab fragment (AZD9773) in patients with severe sepsis

Sepsis remains a significant medical problem. TNFα is a central cytokine in sepsis pathophysiology. We conducted a phase IIa trial in patients with severe sepsis to assess the safety and tolerability of an intravenously infused ovine-derived polyclonal anti-TNFα Fab fragment (AZD9773)

Metformin increases skeletal muscle lactate production in pigs: a microdialysis study

Introduction Lactic acidosis during metformin intoxication is mainly attributed to impaired hepatic lactate clearance [1]. The aim of this present work was to clarify whether metformin at high dose also increases skeletal muscle lactate production. Methods Reverse microdialysis was used in six healthy, sedated and mechanically ventilated pigs, equipped with two skeletal muscle catheters (CMA Microdialysis AB, Sweden). Following a baseline recording, a continuous infusion of saline (control) or metformin diluted in saline (1 mol/l) began. Outfl ow lactate concentration was measured every 3 hours, up to 12 hours. Results Data are presented as the mean and standard deviation in Figure 1. The interaction between infusion (saline vs. metformin) and time was statistically signifi cant (P = 0.02; two-way repeated-measures ANOVA). Conclusions In skeletal muscle, a high dose of metformin increases interstitial lactate levels, a fi nding consistent with local lactate overproduction. Reference 1. Lalau JD: Drug Saf 2010, 33:727-740

Optimal positive end-expiratory pressure in mechanically ventilated patients: a clinical study

The optimal level of positive end-expiratory pressure (PEEP) is still widely debated in treating acute respiratory distress syndrome (ARDS) patients. Current methods of selecting PEEP only provide a range of values and do not provide unique patient-specific solutions. Model-based methods offer a novel way of using non-invasive pressure-volume (PV) measurements to estimate patient recruitability. This paper examines the clinical viability of such models in pilot clinical trials to assist therapy, optimise patient-specific PEEP, assess the disease state and response over time