To Örebro University

Background: Delirium is a common neurological complication after cardiac surgery. The purpose of the present study was to analyze the association between hemodynamic fluctuations during cardiopulmonary bypass (CPB) and the incidence of postoperative delirium (POD) in patients undergoing cardiac surgery with CPB.

Methods: This post hoc analysis included one-hundred-ninety-five (n = 195) patients aged >= 65 years of whom seventy (n = 70) patients developed POD. Intraoperative hemodynamic variables specifically related to the conduct of CPB were digitally recorded at 1-minute intervals. Variables outside the presumed safe boundaries for mean arterial pressure (MAP), systemic perfusion flow index- L/min/BSA (QBSA(I)), systemic venous oxygen saturation (SVO2) and arterial oxygen delivery- ml/min/BSA (DO2) were defined and analyzed with reference to indices of area under the curve (AUC) and the relative proportion of registrations related to POD. POD was diagnosed according to DSM-5 criteria based on a test battery performed preoperatively and repeated twice postoperatively. Statistical tests used to verify observations outside the predefined norm included the Mann-Whitney U test and the chi-squared test.

Results: Markers of hemodynamic control during CPB showed significant associations with POD. Both DO2 (P = 0.02) and QBSA(I) (P < 0.001) identified POD patients outside the predefined upper and lower safety limits. SVO2 values > 84% (P < 0.001) werealso associated with the development of POD. The number of SVO2 registrations below the lower safety limit was negligible, why statistical analysis seemed not useful. No association between MAP and POD registrations was identified.

Conclusions: This study revealed a clear association between markers of hemodynamic control and POD. These associations were most pronounced for DO2 and QBSA(I). The detected association between high SVO2 and POD warrants further insight.

Introduction: The study objective was to investigate whether a Ringer’s acetate based priming solution with addition of Mannitol and sodium concentrate increases the risk of cardiac surgery associated kidney injury (CSA-AKI).

Methods: This is a double blind, prospective randomized controlled trial from a single tertiary teaching hospital in Sweden including patients aged ≥65 years (n = 195) admitted for routine cardiac surgery with cardiopulmonary bypass. Patients in the study group received Ringer’s acetate 1000 mL + 400 mL Mannitol (60 g) + sodium chloride 40 mL (160 mmol) and heparin 2 mL (10 000 IU) 966 mOsmol (n = 98), while patients in the control group received Ringer’s acetate 1400 mL + heparin 2 mL (10 000 IU), 388 mOsmol (n = 97) as pump prime. Acute kidney injury was analysed based on the Kidney Disease Improving Outcomes (KDIGO 1-3) definition.

Results: The overall incidence of CSA-AKI (KDIGO stage 1) was 2.6% on day 1 in the ICU and 5.6% on day 3, postoperatively. The serum creatinine level did not show any postoperative intergroup differences, when compared to baseline preoperative values. Six patients in the Ringer and five patients in the Mannitol group developed CSA-AKI (KDIGO 1-3), all with glomerular filtration rates <60 mL/min/1.73 m2. These patients showed significantly higher plasma osmolality levels compared to preoperative values. Hyperosmolality together with patient age and the duration of the surgery were independent risk factors for postoperative acute kidney injury (KDIGO 1-3).

Conclusions: The use of a hyperosmolar prime solution did not increase the incidence of postoperative CSA-AKI in this study, while high plasma osmolality alone increased the associated risk by 30%. The data suggests further examination of plasma hyperosmolality as a relative risk factor of CSA-AKI.

Objective: Postoperative delirium (POD) is common after cardiac surgery. We have previously identified plasma sodium concentration and the volume of infused fluids during surgery as possible risk factors. Both are linked to the selection and composition of the pump prime used for cardiopulmonary bypass (CPB). Present study aims to examine whether hyperosmolality increases the risk for POD.

Design: Patients ≥65 years (n = 195) scheduled for cardiac surgery were prospectively enrolled into this double blinded randomised clinical trial. Study group received a pump prime containing mannitol and ringer-acetate (966 mOsmol) (n = 98) vs. ringer-acetate (388 mOsmol) (n = 97) in the control group. Postoperative delirium was defined according to DSM-5 criteria based on a test-battery pre- and postoperatively (days 1–3). Plasma osmolality was measured on five occasions and coordinated with the POD assessments. The primary outcome was the POD incidence related to hyperosmolality as the secondary outcome.

Results: The incidence of POD was 36% in the study group and 34% in the control group, without intergroup difference (p=.59). The plasma osmolality was significantly higher in the study group, both on days 1 and 3 and after CPB (p<.001). Post hoc analysis indicated that high osmolality levels increased the risk for delirium on day 1 by 9% (odds ratio (OR) 1.09, 95% CI 1.03–1.15) and by 10% on day 3 (OR 1.10, 95% CI 1.04–1.16).

Conclusions: Use of a prime solution with high osmolality did not increase the incidence of POD. However, the influence of hyperosmolality as a risk factor for POD warrants further investigation.

It is important that operating room personnel monitor the correct amount of blood loss during surgery in order to properly replace lost volume. The aim of this study was to investigate the accuracy of operating room personnel in visually estimating blood loss in surgical sponges. We performed an observational study with comparative descriptive design at a university hospital including all members of the surgical team. In total, 163 observations were completed. The participants estimated the amount of blood in surgical sponges in 4 stations with varying amounts of blood and/or numbers of sponges. Data were analyzed using the Wilcoxon signed rank, Kruskal-Wallis, and Mann-Whitney tests. Both overestimations and underestimations occurred. Underestimations dominated and tended to increase with major amounts of blood. Operating room personnel miscalculated the amount of blood by a median value of 30% regardless of profession, years of experience, and self-assessed ability about visual estimation. This study highlights that assessments of patients’ conditions can be partially based on methods often demonstrated to be inaccurate. Inaccurate visual estimation of blood loss might endanger patient safety.

INTRODUCTION: In the literature addressing cardiopulmonary bypass (CPB) prime composition, there is a considerable lack of discussion concerning plasma osmolality changes induced by using a hyperosmolar prime. With this study, we try to determine the magnitude and temporal relationship of plasma osmolality changes related to the use of a hyperosmolar CPB prime.

METHOD: In this prospective observational study performed in a university hospital setting, we enrolled thirty patients scheduled for elective coronary bypass surgery. Plasma osmolality was analysed on eight occasions. A hyperosmolar CPB prime was used.

RESULTS: Analyses of the perioperative plasma osmolality on eight occasions gave the following results: the preoperative osmolality level was normal (297±4 mOsm/kg); a significant increase to 322±17 mOsm/kg (p<0.001) was observed at the commencement of CPB and remained elevated after 30 minutes (310±4 mOsm/kg) and throughout the procedure (309±4 mOsm/kg); the osmolality level returned to 291±5 mOsm/kg on day 1 postoperatively and remained normal the following day (291±6 mOsm/kg).

CONCLUSIONS: Use of hyperosmolar CPB prime resulted in a dramatic and instant elevation of the plasma osmolality. Rapid changes in plasma osmolality are associated with organ dysfunction (e.g. osmotic demyelination syndrome), therefore, effects on plasma osmolality related to the CPB prime composition should be recognised. Influence on organ function and clinical outcome warrants further investigations. - Clinical Trials.gov (NCT03060824). Changes in Plasma Osmolality Related to the Use of Cardiopulmonary Bypass With Hyperosmolar Prime. URL: https://clinicaltrials.gov/ct2/show/NCT03060824?term=cpb&cond=osmolality&rank=1.

AIMS AND OBJECTIVES: This study analyzed postoperative delirium (POD) in clinical practice after cardiac surgery, how it is detected and documented and if the use of a screening scale improves the detection rate.

BACKGROUND: Cardiac surgery is considered a routine procedure with few complications. However, POD remains a concern, although often being overlooked in clinical practice.

DESIGN: Retrospective observational analysis.

METHODS: Patients 70 years and older with POD (n=78) undergoing cardiac surgery were included in the study. Discharge summaries of both nurses and physicians were reviewed together with the clinical database for information about POD, to be compared with symptom screening using the Nursing Delirium Screening Scale (Nu-DESC). A quantitative content analysis was used for the review of discharge summaries, with a coding scheme adopted from the Nu-DESC method. The STROBE checklist was followed.

RESULTS: In discharge summaries 41 of the 78 POD patients were correctly recognized, and 22 of these were identified in the clinical database. Screening by the Nu-DESC identified delirium at a measurably higher rate, 56/78 patients. The review of discharge summaries showed that patients expressing 'inappropriate behaviour' was the most easily identified sign for POD for both nurses and physicians.

CONCLUSIONS: Healthcare professionals underdiagnose delirium after cardiac surgery, with a low detection rate described in both discharge summaries and in the clinical database. Recognition of delirium improved when Nu-DESC was used for systematic screening.

RELEVANCE TO CLINICAL PRACTICE: This study emphasizes the need for better screening for the detection of delirium in daily clinical practice. This article is protected by copyright. All rights reserved.

Objective: The aim of this study was to determine risk factors for postoperative delirium after cardiac surgery, specifically associated with the conduct of cardiopulmonary bypass (CPB).

Design: Prospective observational study.

Setting: Heart Centre, University Hospital.

Participants: The study included 142 patients aged 70 years and older scheduled for elective cardiac surgery with CPB.

Interventions: Risk factor analysis comprised information collected from the hospital clinical and CPB dedicated databases in addition to the medical chart. Delirium was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision criterion using the Mini Mental State Examination and the Organic Brain Syndrome scale.

Measurements and Main Results: Assessments of delirium diagnosis were executed preoperatively and on the following first and fourth postoperative days. Delirium occurred in 55% (78/142) of the patients. Patients with delirium were identified with significantly higher body weight and body surface area preoperatively, accompanied with longer CPB time, higher positive fluid balance per CPB, and lower systemic pump flow related to body surface area. Furthermore, the duration of the mixed venous oxygen saturation (S_vO₂) below 75% was significantly longer during CPB. The result from the multivariable logistic regression analysis included the duration of S_vO₂ below 75%, fluid balance per CPB and patient age as independent risk factors for postoperative delirium.

Conclusions: The influence of the S_vO₂ level during CPB, fluid balance, and patient age should be recognized as risk factors for postoperative delirium after cardiac surgery in patients 70 years and older.

Objective: To investigate if postoperative delirium was associated with the development of dementia within 5 years after cardiac surgery.

Design: Longitudinal cohort study.

Setting: Cardiothoracic Division, Umeå University Hospital, Sweden.

Patients: Patients aged 70 years old or older (n = 114) scheduled for routine cardiac procedures with cardiopulmonary bypass without documented dementia were enrolled in 2009.

Intervention: Structured assessments were performed preoperatively, 1 and 4 days after extubation, and 1, 3, and 5 years postoperatively.

Measurements and Main Results: Patients were assessed comprehensively, including cognitive and physical function, coexisting medical conditions, demographic characteristics, and medications. Diagnoses of delirium, depression, and dementia were made according to Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision criteria. During the 5-year period, 30 of 114 participants (26.3%) developed dementia. Postoperative delirium had occurred in 87% of those who later developed dementia. A multivariable logistic regression model showed a lower preoperative Mini-Mental State Examination score (p < 0.001; odds ratio, 0.68; 95% CI, 0.54–0.84) and the occurrence of postoperative delirium (p = 0.002; odds ratio, 7.57; 95% CI, 2.15–26.65) were associated with dementia occurrence.

Conclusions: Our findings suggest that older patients with reduced preoperative cognitive functions or who develop postoperative delirium are at risk of developing dementia within 5 years after cardiac surgery. Cognitive functions should be screened for preoperatively, those who develop postoperative delirium should be followed up to enable early detection of dementia symptoms, and management should be implemented.

Background:

Delirium is common in older people undergoing cardiac surgery. Delirium is an acute or subacute neuro-psychiatric syndrome, characterized by a change in cognition, disturbances in consciousness; it fluctuates, develops over a short period of time and always has an underlying cause. It is associated with a disturbance in psychomotor activity, and is classified according to different clinical profiles such as hypoactive, hyperactive and mixed delirium. Delirium after cardiac surgery is not harmless, it increases the risk of complications such as prolonged stay in hospital, falls, reduced quality of life, reduced cognitive function and increased mortality.

Aim:

The overall aim of this thesis was to investigate postoperative delirium in older people undergoing cardiac surgery with Cardiopulmonary Bypass (CPB), focusing on risk factors, dementia and patients’ experiences; and to evaluate an assessment for screening delirium.

Methods:

This thesis compromises four studies. All participants (n=142) were scheduled for cardiac surgery with use of CPB at the Cardiothoracic Surgery Department, Heart Centre, Umeå University Hospital, Sweden, between February and October 2009. Six structured interviews were conducted preoperatively, day one and day four postoperatively, and in home visits, one, three and five years after surgery (2010, 2012 and 2014). The assessment scales used in Studies I, II and IV were: the Mini-Mental State Examination (MMSE) for cognition, the Organic Brain Syndrome Scale (OBS) for delirium, Geriatric Depression Scale 15 (GDS-15) for depression, Katz staircase with Activities of Daily Living (ADL) for participants’ functional status and the Numerical Rating Scale (NRS) for pain. During the hospital stay, nursing staff used the Swedish version of the Nursing Delirium Screening Scale (Nu-DESC) to assess delirium. Semi-structured interviews were also carried out (III) in the one-year follow up. Delirium, dementia and depression were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders (DSM IV TR).

Results:

Out of 142 participants 54.9% (78/142) developed delirium after cardiac surgery (I). Independent risk factors, predisposing and precipitating, associated with delirium were: age, diabetes, gastritis/peptic ulcer, volume load during operation, longer time on ventilator in intensive care, increased temperature and plasma sodium concentration in the intensive care unit. Out of 114 participants thirty (26.3%) developed dementia within the five years of follow-up. It was shown that a lower preoperative MMSE score and postoperative delirium were factors independently associated with development of dementia (II). One year after cardiac surgery, participants diagnosed with postoperative delirium described in detail feelings of extreme vulnerability and frailty. Despite this, the participants were grateful for the care they had received (III). Hypoactive was the most common symptom profile for delirium. The Swedish version of Nu-DESC showed high sensitivity in detecting hyperactive delirium, but low sensitivity in detecting hypoactive delirium (IV).

Conclusion:

Delirium was common among older patients undergoing cardiac surgery. Both predisposing and precipitating factors contributed to postoperative delirium. Preventive strategies should be considered in future randomized studies. It might also be suggested that cognitive function should be screened for preoperatively and patients who develop delirium should be followed up to enable early detection of symptoms of dementia. Whether prevention of postoperative delirium can reduce the risk of future dementia remains to be studied. To minimise unnecessary suffering, patients and next of kin should be informed about and prepared for the risk of delirium developing during hospitalization. The Swedish version of Nu-DESC should be combined with cognitive testing to improve detection of hypoactive delirium, but further research is needed. Healthcare professionals need knowledge concerning postoperative delirium in order to prevent, detect and treat delirium so as to avoid and relieve the suffering it might cause.

Akut förvirringstillstånd (delirium) hos äldre personer som genomgått hjärtkirurgi –riskfaktorer, demens, patienternas erfarenheter och skattningsinstrument.

Bakgrund:

Delirium är vanligt hos äldre personer som genomgår hjärtkirurgi. Delirium är ett akut eller subakut neuropsykiatriskt syndrom, som kännetecknas av förändrad kognitiv förmåga samt en förändad medvetande nivå. Delirium utvecklas under en kort tidsperiod, tenderar att fluktuera och har alltid en bakomliggande orsak. Delirium kan klassificeras som hypoaktivt, hyperaktivt eller en blandform av båda dessa. Delirium efter hjärtkirurgi kan öka risken för andra komplikationer som tillexempel; förlängd vårdtid, fall, försämrad livskvalité, nedsatt kognitiv förmåga samt mortalitet.

Syfte:

Det övergripande syftet med denna avhandling var att undersöka postoperativt delirium bland äldre personer som genomgått hjärtkirurgi med hjärt-lungmaskin med fokus på riskfaktorer, demens, patienters erfarenheter samt utvärdering av skattningsinstrument för delirium

Metod:

Denna avhandling består av fyra studier. Alla deltagare (n = 142) genomgick rutinmässig hjärtkirurgi med hjärt-lungmaskin vid Thoraxkirurgiska kliniken, Hjärtcentrum, Umeå Universitetssjukhus, mellan februari till oktober 2009. Sex intervjuer genomfördes; preoperativt, dag ett och dag fyra postoperativt, samt vid hembesök ett, tre och fem år efter operationen (2010, 2012 och 2015). Skattningsinstrument som användes i studie I, II och IV var; The Mini-Mental Test (MMSE) för kognition, The Organic Brain Syndrome Scale (OBS) för delirium, Geriatric Depression Scale (GDS-15) för depression, Katz ADL trappa-Katz-index aktiviteter för dagliga livet och Numerisk Rating Scale (NRS) för smärta. Under vårdtiden använde vårdpersonalen Nursing Delirium Screening Scale (Nu-DESC) tre gånger dagligen för att skatta delirium. Nu-DESC jämfördes med en sammanvägning av MMSE och OBS-skalan. Vid uppföljningen år 2010 genomfördes dessutom semistrukturerade intervjuer. Delirium, demens och depression diagnostiserades enligt Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR).

Resultat:

Studie I visade att 54.9% (78/142) av patienterna utvecklade delirium efter hjärtkirurgi. Oberoende riskfaktorer (bakomliggande och utlösande) för delirium var; ålder, diabetes, gastrit/magsår, volymbelastning under operation samt respiratortid, förhöjd kroppstemperatur och förhöjd natriumkoncentration i plasma på intensivvårds avdelning. Studie II visade att 26.3% (30/114) av deltagarna utvecklade demens under en femårs uppföljning. En nedsatt preoperativ kognitiv förmåga (indikerad av lägre MMSE-poäng) och förekomsten av postoperativ delirium var faktorer som ökade risken för att utveckla demens. Ett år efter operation kunde deltagarna som diagnostiserats med postoperativt delirium i detalj beskriva sin sårbarhet och skörhet under vårdtiden. Deltagarna beskrev också sin tacksamhet över den vård de fått (Studie III). Den vanligaste formen var hypoaktivt delirium. Den svenska versionen av Nu-DESC kunde upptäcka hyperaktivt men inte hypoaktivt delirium (Studie IV).

Slutsats:

Delirium var vanligt bland äldre patienter som genomgått hjärtkirurgi. Både bakomliggande och utlösande faktorer utgjorde ökad risk för att utveckla postoperativt delirium. Förebyggande strategier bör övervägas i framtida randomiserade studier. Kognitiv funktion bör skattas preoperativt och patienter bör skattas för delirium under vårdtiden och följas upp efter hemgång för att upptäcka tidiga demenssymtom. Huruvida förebyggandet av postoperativt delirium kan minska risken för demens senare återstår att studeras. För att minska onödigt lidande bör patienter och anhöriga bli informerade och förberedda på risken att utveckla delirium under vårdtiden. Den svenska versionen av Nu-DESC behöver förmodligen kombineras med ett kognitiv test för att upptäcka hypoaktivt delirium. För att lindra det lidande som syndromet kan orsaka behöver vårdpersonal fördjupad kunskap i syfte att förebygga, upptäcka och behandla postoperativt delirium.

BACKGROUND: Cardiovascular disease is common among old people and many undergo cardiac surgery. Scientific knowledge is available on cardiac surgery from several perspectives. However, we found few studies focusing on older patients' experiences of cardiac surgery. The aim of this study was to illuminate experiences of undergoing cardiac surgery among older people diagnosed with postoperative delirium, a one year follow-up.

METHODS: Qualitative interviews were conducted with 49 participants (aged ≥70 years) diagnosed with delirium after cardiac surgery. Data were collected in Sweden during 2010 through individual, semi-structured interviews in participants' homes one year after surgery. The interviews were analyzed using qualitative content analysis.

RESULTS: Four themes with sub-themes were formulated: Feeling drained of viability includes having a body under attack, losing strength and being close to death. Feeling trapped in a weird world describes participants having hallucinations, being in a nightmare and being remorseful for their behavior. Being met with disrespect includes feeling disappointed, being forced, and feeling like cargo. On the other hand, Feeling safe, including being in supportive hands and feeling grateful, points to participants' experiences of good care and the gift of getting a second chance in life.

CONCLUSIONS: Even one year after cardiac surgery, participants described in detail feelings of extreme vulnerability and frailty. They also had felt completely in the hands of the health care professionals. Participants described experiences of hallucinations and nightmares during hospitalization. Cardiac surgery was a unique, fearful, traumatic and unpleasant experience yet could also include pleasant or rewarding aspects. It seems that health care professionals need deeper knowledge on postoperative delirium in order to prevent, detect and treat delirium to avoid and relieve the suffering these experiences might cause.