Survival and functional outcome at hospital discharge following in-hospital cardiac arrest (IHCA): A prospective multicentre observational study

AIM

To evaluate the functional outcome of patients after in-hospital cardiac arrest (IHCA) and to identify associations with good functional outcome at hospital discharge.

METHOD

Emergency calls were prospectively screened and data collected for IHCAs in seven Australian hospitals. Patients were included if aged > 18 years, admitted as an acute care hospital in-patient and experienced IHCA; defined by a period of unresponsiveness with no observed respiratory effort and commencement of external cardiac compressions. Data collected included patient demographics, clinical and cardiac arrest characteristics, survival and functional outcome at hospital discharge using the modified Rankin Scale (mRS) and Katz Index of Independence in ADLs (Katz-ADL).

RESULTS

152 patients suffered 159 IHCAs (male 66.4%; mean age 70.2 (± 13.9) years). Sixty patients (39.5%) survived, of whom 43 (71.7%) had a good functional outcome (mRS ≤ 3) and 38 (63.3%) were independent with activities of daily living (ADLs) at hospital discharge (Katz-ADL = 6). Younger age (OR 0.95; 95% CI 0.91-0.98; p = 0.003), shorter duration of CPR (OR 0.84; 95% CI 0.77-0.91; p < 0.0001) and shorter duration of hospital admission prior to IHCA (OR 0.96; 95% CI 0.93-0.998; p = 0.04) were independently associated with a good functional outcome at hospital discharge.

CONCLUSION

The majority of survivors had a good functional outcome and were independent with their ADLs at hospital discharge. Factors associated with good functional outcome at hospital discharge were identified.

Nasopharyngeal Oxygen in Adult Intensive Care—Lower Flows and Increased Comfort

Nasopharyngeal oxygen therapy, the delivery of supplementary oxygen into the nasopharynx via a fine catheter placed through the nose, is a simple technique used in postoperative anaesthetic care units and paediatric intensive care, but never described in the setting of adult intensive care. In a prospective crossover design, we compared nasopharyngeal oxygen therapy with semi-rigid plastic mask (Hudson Mask) in 50 unintubated adult patients receiving supplemental oxygen. We measured oxygen flow rate to achieve cutaneous saturations 93 to 96%, and patient comfort by visual analogue score. Nasopharyngeal oxygen therapy consumed significantly less oxygen than mask administration (3.0±0.9 vs 6.7±2.1 l/min, P<0.001) and was associated with significantly higher comfort than the mask (7.5± 1.6 cm vs 5.2±1.8, P<0.001).

A Two Centre Observational Study of Simultaneous Pulse Oximetry and Arterial Oxygen Saturation Recordings in Intensive Care Unit Patients

The influence of variables that might affect the accuracy of pulse oximetry (SpO2) recordings in critically ill patients is not well established. We sought to describe the relationship between paired SpO2/SaO2 (oxygen saturation via arterial blood gas analysis) in adult intensive care unit (ICU) patients and to describe the diagnostic performance of SpO2 in detecting low SaO2 and PaO2. A paired SpO2/SaO2 measurement was obtained from 404 adults in ICU. Measurements were used to calculate bias, precision, and limits of agreement. Associations between bias and variables including vasopressor and inotrope use, capillary refill time, hand temperature, pulse pressure, body temperature, oximeter model, and skin colour were estimated. There was no overall statistically significant bias in paired SpO2/SaO2 measurements; observed limits of agreement were +/-4.4%. However, body temperature, oximeter model, and skin colour, were statistically significantly associated with the degree of bias. SpO2 <89% had a sensitivity of 3/7 (42.9%; 95% confidence intervals, CI, 9.9% to 81.6%) and a specificity of 344/384 (89.6%; 95% CI 86.1% to 92.5%) for detecting SaO2 <89%. The absence of statistically significant bias in paired SpO2/SaO2 in adult ICU patients provides support for the use of pulse oximetry to titrate oxygen therapy. However, SpO2 recordings alone should be used cautiously when SaO2 recordings of 4.4% higher or lower than the observed SpO2 would be of concern. A range of variables relevant to the critically ill had little or no effect on bias.

Non-Invasive Estimation of Cardiac Index in Healthy Volunteers

The primary objective was to non-invasively measure the cardiac index (CI) and associated haemodynamic parameters of healthy volunteers and their changes with age. This was a single centre, prospective, observational study of healthy volunteers aged between 20 and 59 years, using the ClearSight™ (Edwards Life Sciences, Irvine, CA, USA) device. We recorded 514 observations in 97 participants. The mean CI was 3.5 l/min/m2 (95% confidence interval [95% CI] 3.4 to 3.7 l/min/m2). The mean stroke volume index (SVI) was 47 ml/m2 (95% CI 45 to 49 ml/m2) and the mean systemic vascular resistance index was 2,242 dyne·s/cm5/m2 (95% CI 2,124 to 2,365 dyne·s/cm5/m2). There was an inverse linear relationship between increasing age and CI (P <0.0001), which decreased by 0.044 l/min/m2 (95% CI −0.032 to −0.056 l/min/m2) per year. This change was mostly due to a decrease in SVI of 0.45 ml/m2 (95% CI 0.32 to 0.57 ml/m2) per year (P <0.0001). The mean CI of young healthy humans is approximately 3.5 l/min/m2 and declines by approximately 40 ml/min/m2 per year, mostly due to a decline in stroke volume (SV). These findings have significant implications regarding the clinical interpretation of haemodynamic parameters and the application of these results to individual patients.

A feasibility study of functional status and follow-up clinic preferences of patients at high risk of post intensive care syndrome

After prolonged mechanical ventilation patients may experience the 'post intensive care syndrome' (PICS) and may be candidates for post-discharge follow-up clinics. We aimed to ascertain the incidence and severity of PICS symptoms in patients surviving prolonged mechanical ventilation and to describe their views regarding follow-up clinics. In a teaching hospital, we conducted a cohort study of all adult patients discharged alive after ventilation in ICU for ≥7 days during 2013. We administered the EuroQol-5D (EQ-5D) and Hospital Anxiety and Depression Scale (HADS) via telephone interview and asked patients their views about the possible utility of a follow-up clinic. We studied 48 patients. At follow-up (average 19.5 months), seven (15%) patients had died and 14 (29%) did not participate (eight declined; two were non-English speakers; four were non-contactable). Among the 27 responders, 16 (59%) reported at least moderate problems in ≥1 EQ-5D dimension; 10 (37%) in ≥2 dimensions, and 8 (30%) in ≥3 dimensions. Moreover, 10 (37%) patients reported marked psychological symptoms; six (22%) scored borderline or abnormal on the HADS for both anxiety and depression; and four (15%) scored borderline or abnormal for one component. Finally, 21/26 (81%) patients stated that an ICU follow-up clinic would have been beneficial. At long-term follow-up, the majority of survivors of prolonged mechanical ventilation reported impaired quality of life and significant psychological symptoms. Most believed that a follow-up clinic would have been beneficial.

The effect of augmenting early nutritional energy delivery on quality of life and employment status one year after ICU admission

Augmenting energy delivery during the acute phase of critical illness may reduce mortality and improve functional outcomes. The objective of this sub-study was to evaluate the effect of early augmented enteral nutrition (EN) during critical illness, on outcomes one year later. We performed prospective longitudinal evaluation of study participants, initially enrolled in The Augmented versus Routine approach to Giving Energy Trial (TARGET), a feasibility study that randomised critically ill patients to 1.5 kcal/ml (augmented) or 1.0 kcal/ml (routine) EN administered at the same rate for up to ten days, who were alive at one year. One year after randomisation Short Form-36 version 2 (SF-36v2) and EuroQol-5D-5L quality of life surveys, and employment status were assessed via telephone survey. At one year there were 71 survivors (1.5 kcal/ml 38 versus 1.0 kcal/ml 33; P=0.55). Thirty-nine (55%) patients consented to this follow-up study and completed the surveys (n = 23 and 16, respectively). The SF-36v2 physical and mental component summary scores were below normal population means but were similar in 1.5 kcal/ml and 1.0 kcal/ml groups (P=0.90 and P=0.71). EuroQol-5D-5L data were also comparable between groups (P=0.70). However, at one-year follow-up, more patients who received 1.5 kcal/ml were employed (7 versus 2; P=0.022). The delivery of 1.5 kcal/ml for a maximum of ten days did not affect self-rated quality of life one year later.

Intravenous fluid bolus therapy: a bi-national survey of critical care nurses' self-reported practice

Knowledge of critical care nurses' intravenous fluid bolus therapy (FBT) practice remains underexplored. Using a multi-choice online survey conducted between September and October 2014, we sought to describe the self-reported practice of critical care nurses located in Australia and New Zealand. Two hundred and ninety-five critical care nurses responded to the survey with most practising in adult ICUs. Overall, 0.9% saline solution was the preferred solution for FBT. However, more Australian than New Zealand respondents preferred 'albumin 4%' (31% versus 3.6%, P <0.01) for FBT. In contrast, more New Zealand respondents preferred 'Plasma-Lyte®' (33.3% versus 6.4%, P <0.01). Half of the respondents defined FBT as 250 ml administered as quickly as possible. However, FBT volumes ranged from 100 ml to >1000 ml and administration duration from as quickly as possible to 60 minutes. In response to FBT, almost half of the respondents expected an increase in mean arterial pressure of between 11 to 20 mmHg. Similarly, >40% expected a central venous pressure increase >3 mmHg, >70% expected a urinary output increase of 0.5 to 1.0 ml/kg/hr, and >60% expected a decrease in heart rate of >11 /min. Overall, 0.9% saline remains the most common solution for FBT, but there are significant national differences in the preference for albumin and Plasma-Lyte. A volume of 250 ml defines a fluid bolus, with a range from 100 ml to >1000 ml, and speed of delivery from stat to 60 minutes. Most nurses expect substantial physiological effects with FBT.

Urinary neutrophil gelatinase-associated lipocalin to hepcidin ratio as a biomarker of acute kidney injury in intensive care unit patients

BACKGROUND

Labile iron is important in the pathogenesis of acute kidney injury (AKI). Neutrophil gelatinase-associated lipocalin (NGAL) and hepcidin control iron metabolism and are upregulated during renal stress. However, higher levels of urinary NGAL are associated with AKI severity whereas higher urinary hepcidin levels are associated with absence of AKI. We aimed to investigate the value of combining both biomarkers to estimate the severity and progression of AKI in intensive care unit (ICU) patients.

METHODS

Urinary NGAL and hepcidin were quantified within 48 hours of ICU admission in patients with the systemic inflammatory response syndrome and early kidney dysfunction (oliguria for ≥ 2 hours and/or a 25 µmol/L creatinine rise from baseline). Diagnostic and prognostic characteristics were assessed by logistic regression and receiver operating characteristics (ROC) analysis.

RESULTS

Of 102 patients, 26 had mild AKI and 28 patients had severe AKI on admission. Sepsis (21%), cardiac surgery (17%) and liver failure (9%) were primary admission diagnoses. NGAL increased (P=0.03) whereas hepcidin decreased (P=0.01) with increasing AKI severity. The value of NGAL/hepcidin ratio to detect severe AKI was higher than when NGAL and hepcidin were used individually and persisted after adjusting for potential confounders (adjusted OR 2.40, 95% CI 1.20-4.78). The ROC areas for predicting worsening AKI were 0.50, 0.52 and 0.48 for NGAL, 1/hepcidin and the NGAL/hepcidin ratio.

CONCLUSION

The NGAL/hepcidin ratio is more strongly associated with severe AKI than the single biomarkers alone. NGAL and hepcidin, alone or combined as a ratio, were unable to predict progressive AKI in this selected ICU cohort.

A pilot study of the relationship between Doppler-estimated carotid and brachial artery flow and cardiac index

We measured carotid and brachial artery blood flow by Doppler ultrasound in 11 human volunteers, and related these to cardiac index and to each other. The median (IQR [range]) carotid arterial blood flow was 0.334 (0.223-0.381 [0.052-0.563]) l.min(-1) on the right and 0.315 (0.223-0.369 [0.061-0.690]) l.min(-1) on the left. The brachial arterial blood flow was 0.049 (0.033-0.062 [0.015-0.204]) l.min(-1) on the right and 0.039 (0.027-0.054 [0.011-0.116]) on the left. Cardiac index was 3.2 (2.8-3.5 [1.9-5.4]) l.min(-1) .m(-2) . There was a moderate to good correlation between right-and left-sided flows (brachial: ρ = 0.45; carotid: ρ = 0.567). Brachial and carotid flow had no or a negative correlation with cardiac index (right brachial: ρ = -0.145, left brachial: ρ = -0.349; right carotid: ρ = -0.376, left carotid: ρ = -0.285). In contrast to some previous studies, we found that Doppler-estimated peripheral arterial blood flows only show a weak correlation with cardiac index and cannot be used to provide non-invasive estimates of cardiac index in man.

The association between early arterial oxygenation in the ICU and mortality following cardiac surgery

Many studies have been conducted to investigate the relationship between hyperoxia and mortality in cohorts of intensive care unit (ICU) patients with varied and often contradictory results. The impact of early hyperoxia post ischaemia remains uncertain in various ICU cohorts. We aimed to investigate the association between arterial oxygenation (PaO2) in the first 24 hours in ICU and mortality in patients following cardiac surgery, using a retrospective cohort study of data from the Australian and New Zealand Intensive Care Society adult patient database. Participants were adults admitted to the ICU following cardiac surgery in Australia and New Zealand between 2003 and 2012. Patients were divided according to worst PaO2 level or alveolar-arterial O2 gradient in the 24 hours from admission. We defined 'hyperoxia' as PaO2 ≥300 mmHg, 'hypoxia/poor O2 transfer' as either PaO2 <60 mmHg or ratio of PaO2 to fraction of inspired oxygen <300 and 'normoxia' as between hypoxia and hyperoxia. The primary outcome was mortality at hospital discharge. Secondary outcomes were ICU mortality and ICU and hospital length-of-stay. Of the 83,060 patients, 12,188 (14.7%) had hyperoxia, 54,420 (65.5%) had hypoxia/poor O2 transfer and 16,452 (19.8%) had normoxia. There was no association between hyperoxia and in-hospital or ICU mortality compared to normoxia. There was a small increased hospital and ICU length-of-stay for hyperoxic compared to normoxic patients. We concluded that there was no association between mortality and hyperoxia in the first 24 hours in ICU after cardiac surgery.

Intensivists' opinion and self-reported practice of oxygen therapy

Intensivists frequently prescribe oxygen therapy for critically ill patients, however little is known about how intensivists manage oxygen therapy, or what factors influence their decisions. We surveyed intensivists listed on the Australian and New Zealand Intensive Care Society Clinical Trials Group database to investigate how intensivists report their approach to the monitoring, prescription and management of risks associated with oxygen therapy. The response rate was 60.4% (99/164 intensivists). Overall 81 (83.5%) respondents practised in metropolitan units and 50 (50.5%) had > or =14 years of intensive care unit specialty practice. All respondents reported using pulse oximetry and > 93% reported having access to a blood gas machine within their intensive care unit. Sixty-one percent of respondents (60/98) reported assessing other indices of tissue oxygenation (pH, lactate, MvO2). Twelve respondents (12.8%) believed that oxygen toxicity was a greater threat to lung injury than barotrauma when commencing mechanical ventilation. A significantly (P = 0.016) greater proportion of regional (5/16) than metropolitan (7/70) respondents were concerned that a high FiO2 is a greater threat to the lungs than barotrauma. For a ventilated acute respiratory distress syndrome patient, 36.8% (36/98 respondents) would not allow an SaO2 of < 85% for < or =15 minutes, and 27.6% (27/96 respondents) would not allow an SaO2 < 90% for > 24 hours. Respondents with < or = 14 years of specialty practice were more likely to specify the oxygen delivery device to be used (P = 0.014). Recognising the factors that currently influence oxygen administration decisions is a necessary prelude to the potential conduct of interventional studies, as well as for the development of better guidance for oxygen therapy in critical care.

Oxygen administration and monitoring for ward adult patients in a teaching hospital

AIM

The aims of this study were to describe oxygen administration and respiratory monitoring of ward patients in a tertiary teaching hospital, and to assess differences in characteristics and outcomes between patients who are receiving versus are not receiving oxygen.

METHODS

Prospective clinical audit of all non-ventilated adult ward patients in a tertiary teaching hospital in Melbourne, Victoria on 26 August 2009.

RESULTS

All 323 eligible patients were audited (medical 218, surgical 105). At assessment, 76 patients (24%) were on oxygen therapy and of these, 57 patients (74%) received oxygen by nasal prongs. Overall, oxygen saturation was documented in 301 (93.2%) patients and respiratory rate (RR) documented in 283 patients (87.6%). Patients receiving oxygen had a lower median SpO(2) (94% vs 96%, P < 0.0001), higher median RR (20/min vs 18/min, P < 0.0005); and were older (68.8 v 63.1 years, P= 0.0094). The in-hospital mortality of patients receiving oxygen therapy was 15.8% compared with 5.3% for those not on oxygen (P < 0.0056).

CONCLUSION

Oxygen is administered to one-quarter of ward patients in our hospital. Oxygen saturation and RR are not documented in approximately 10% of patients. Oxygen therapy in ward patients identifies individuals with increased mortality. Continuing educational interventions to increase awareness of the high-risk status of these patients and strategies to detect patients at risk of hypoxaemia are needed.

Evaluation of Nasopharyngeal Oxygen, Nasal Prongs and Facemask Oxygen Therapy Devices in Adult Patients: A Randomised Crossover Trial

Nasopharyngeal oxygen (NPO) therapy may overcome some of the difficulties associated with nasal prongs and facemask oxygen delivery devices. In response to a lack of published studies of NPO therapy in adults, we conducted a prospective randomised crossover trial to compare the effectiveness of NPO, nasal prongs (NP) and facemasks (FM) when used in an adult population (n=37) from the intensive care unit and general hospital wards. We measured oxygen saturation (SpO 2 using pulse oximetry, oxygen flow (litres per minute), respiration rate (per minute) and comfort using a horizontal visual analogue scale. All three devices were effective in maintaining a Sp0 2 of ≥95% (NP 97.0±1.9, NPO 97.7±1.7, FM 98.8±1.3%). NPO therapy consumed less oxygen than NP and FM therapy (NP 2.6±1.0, NPO 2.2±0.9, FM 6.1 ±0.4 l/min, P <0.001). There was no significant difference in patients’ respiratory rates (NP 19.9±3.2, NPO 19.9±3.0, FM 19.8±3.1 per minute, P=0.491). In terms of comfort, patients rated NP higher than NPO and FM using a horizontal visual analogue scale (100 mm=most comfortable) (NP 65.5±14.3, NPO 62.8±19.4, FM 49.4 ± 21.4 mm, P <0.001). We conclude that for adult patients, nasal prongs and nasopharyngeal oxygen therapy consume less oxygen and provide greater comfort than facemasks while still maintaining Sp0 2 ≥95%.

Lifestyle pattern change in males following percutaneous transluminal coronary angioplasty/intracoronary stenting

Utilizing a naturalistic inquiry approach, a semi-structured interview schedule and non-probability purposive sampling, this study provided detail on the rationale and influences behind the decisions of four males participants to change or not change their lifestyle patterns 3 months after a percutaneous transluminal coronary angioplasty/intracoronary stent procedure. One of the participants made a noticeable lifestyle pattern change in this period. The remaining participants failed to exhibit any discernible lifestyle pattern change or had continued with their previous behaviours. Results suggest a new 'positive' psychological health perspective, family considerations, return-to-work issues and a reluctance to participate in cardiac rehabilitation as the major factors influencing lifestyle pattern change. Because nurses spend the greatest amount of time with percutaneous transluminal coronary angioplasty/intracoronary stent patients during hospitalization, they have the best opportunity to provide up-to-date and relevant information to patients that will enable them to then make decisions concerning cardiac healthy lifestyle changes.