Where to now with carbon monoxide poisoning?

The controversy regarding the role of hyperbaric oxygen (HBO) in the treatment of carbon monoxide (CO) poisoning has been re-ignited following the publication of a further randomized controlled trial by Weaver et al., the results of which appear to conflict with our findings. Comparative analysis suggests that the apparent outcome differences may be secondary to the design, analysis and interpretation of the results of the two studies. Following careful analysis of these two papers and further results from a study by Raphael et al on 385 CO-poisoned patients, we can still find no convincing evidence favouring HBO therapy. Pending further research to determine optimal oxygen therapy for CO-poisoning, current therapy should involve stratifying patients for risk of a poor outcome. This stratification may be aided by the evolving availability of biochemical markers of brain injury and the finding that patients with transient loss of consciousness and poor performance on neuropsychological tests of the supervisory attention system are at higher risk of neuropsychological sequelae. We propose that those patients most at risk be admitted and receive more prolonged normobaric oxygen therapy whilst those with more minor CO-poisoning should be provided with normobaric oxygen of no less than 6 h duration and certainly until sign and symptom free.

Periprocedural cessation of nutrition in the intensive care unit: opportunities for improvement.

PURPOSE: Delivery of enteral nutrition (EN) to ICU patients is commonly interrupted for diagnostic and therapeutic procedures. We investigated this practice in a cohort of trauma and surgical ICU patients. METHODS: This was a retrospective single-center study conducted in a 15-bed trauma ICU of a university-affiliated teaching hospital. Descriptive statistics were used. RESULTS: Of 69 patients assessed, 41 had 121 planned procedures over a mean ICU length of stay of 18.7 days (SD 9.6 days). EN was stopped prior to 108 (89 %, 95 % CI 82-94 %) of these 121 procedures, and 102 of these cessation episodes were related to the planned procedure. EN was stopped in 37 patients for a mean cumulative duration of 30.8 h (SD 22.7 h) per patient, which represented 7.9 % (SD 6.9 %) of the mean total time spent in the ICU leading to a mean energy and protein deficit of 7.2 % (SD 8.5 %) and 7.7 % (SD 9.6 %), respectively. Of the 121 planned procedures, 27 (22 %, 95 % CI 16-31 %) were postponed beyond the scheduled day. For 32 (31 %, 95 % CI 23-41 %) of the 102 EN cessation episodes, EN was stopped without a documented order and 23 (23 %, 95 % CI 16-32 %) episodes were not deemed necessary based on the institution's guidelines. CONCLUSION: In this ICU cohort, EN cessation for planned procedures was frequent and led to a nutritional deficit due to long periods without EN being delivered. Postponement of procedures and clinically unnecessary EN cessation were important factors that prevented delivery of planned nutrition. EN cessation practice should be a focus for improving EN delivery in ICU patients.

Hyperoxia in the intensive care unit and outcome after out-of-hospital ventricular fibrillation cardiac arrest.

BACKGROUND: Laboratory and clinical studies have suggested that hyperoxia early after resuscitation from cardiac arrest may increase neurological injury and worsen outcome. Previous clinical studies have been small or have not included relevant prehospital data. We aimed to determine in a larger cohort of patients whether hyperoxia in the intensive care unit in patients admitted after out-of-hospital cardiac arrest (OHCA) was associated with increased mortality rate after correction for prehospital variables. METHODS: Data from the Victorian Ambulance Cardiac Arrest Registry (VACAR) of patients transported to hospital after resuscitation from OHCA and an initial cardiac rhythm of ventricular fibrillation between January 2007 and December 2011 were linked to the Australian and New Zealand Intensive Care Society Adult Patient Database (ANZICS-APD). Patients were allocated into three groups (hypoxia [PaO2<60mmHg], normoxia [PaO2,60-299mmHg] or hyperoxia [PaO2≥300mmHg]) according to their most abnormal PaO2 level in the first 24 hours of ICU stay. The relationship between PaO2 and hospital mortality was investigated using multivariate logistic regression analysis to adjust for confounding prehospital and ICU factors. RESULTS: There were 957 patients identified on the VACAR database who met inclusion criteria. Of these, 584 (61%) were matched to the ANZICS-APD and had hospital mortality and oxygen data available. The unadjusted hospital mortality was 51% in the hypoxia patients, 41% in the normoxia patients and 47% in the hyperoxia patients (P=0.28). After adjustment for cardiopulmonary resuscitation by a bystander, patient age and cardiac arrest duration, hyperoxia in the ICU was not associated with increased hospital mortality (OR, 1.2; 95% CI, 0.51-2.82; P=0.83). CONCLUSIONS: Hyperoxia within the first 24 hours was not associated with increased hospital mortality in patients admitted to ICU following out-of-hospital ventricular fibrillation cardiac arrest.

Nutritional support in adult patients receiving extracorporeal membrane oxygenation.

BACKGROUND: Patients receiving extracorporeal membrane oxygenation (ECMO) are some of the most critically ill in the intensive care unit. In such patients, malnutrition is associated with increased morbidity and mortality. OBJECTIVES: To describe the use, methods and adequacy of nutritional support in a consecutive group of patients receiving ECMO; to determine differences between the periods during and after ECMO support; and to determine differences in nutritional adequacy between ECMO survivors and ECMO non-survivors. DESIGN, SETTING AND PARTICIPANTS: We conducted a retrospective study of patients who received ECMO at the Alfred Hospital between January 2005 and December 2007. Patients who received venoarterial (VA) or venovenous (VV) ECMO had their case notes reviewed for clinical and nutritional outcomes. Nutritional adequacy was defined as the ratio of delivered nutrition to target nutrition, expressed as a percentage. RESULTS: Of 48 patients included in our analysis, 35 had VA ECMO and 13 had VV ECMO. Overall, the mean nutritional adequacy achieved for all patients over the periods during and after ECMO support was 62% (SD, 19%). Nutritional adequacy was lower during ECMO support (55%) than after ECMO removal (71%) (P = 0.003). Survivors did not achieve better nutritional adequacy than non-survivors (52% v 61%; P = 0.345). CONCLUSIONS: Patients receiving ECMO received inadequate nutritional support, with only 55% of their nutritional targets being achieved while receiving ECMO. Optimal nutritional support should be a major goal in the care of these patients, and measures to improve nutritional delivery require careful consideration.

Interventions to circumvent intensive care access block: a retrospective 2-year study across metropolitan Melbourne.

OBJECTIVES: To measure the prevalence of interventions used to circumvent intensive care access block and to estimate the attributable mortality and additional hospital bed-days associated with them. DESIGN AND SETTING: Retrospective observational study of 11 adult public hospital intensive care units (ICUs) in Melbourne, Victoria, July 2004 - June 2006. MAIN OUTCOME MEASURES: Prevalence of five interventions in response to access block; attributable fatalities and/or increased length of stay associated with each. RESULTS: 21 896 ICU admissions and 3039 inhospital deaths (13.9%) were screened. All hospitals reported ICU access block. There were 6787 interventions for access block (mean, 9.3/day) -- 4070 (18.6% of admissions) instances of after-hours step-down from an ICU to a low-acuity ward; 1115 (5.1%) delays in an emergency department > 8 hours; 895 (4.1%) postponed major surgeries; 487 (2.2%) interhospital transfers; and 220 (1.0%) instances of premature cessation of intensive care. Based on published risk estimates, these interventions may have resulted in 91.1 (95% CI, 34.7-147.2) attributable deaths and 4368 (95% CI, 333-10 050) additional hospital bed-days each year. CONCLUSIONS: Intensive care access block is frequent, and measures to circumvent it increase mortality and length of stay. Further study of the health and financial implications of access block are warranted.

Black Saturday: the immediate impact of the February 2009 bushfires in Victoria, Australia.

OBJECTIVE: To examine the response of the Victorian State Trauma System to the February 2009 bushfires. DESIGN AND SETTING: A retrospective review of the strategic response required to treat patients with bushfire-related injury in the first 72 hours of the Victorian bushfires that began on 7 February 2009. Emergency department (ED) presentations and initial management of patients presenting to the state's adult burns centre (The Alfred Hospital [The Alfred]) were analysed, as well as injuries and deaths associated with the fires. RESULTS: There were 414 patients who presented to hospital EDs as a result of the bushfires. Patients were triaged at the emergency scene, at treatment centres and in hospital. National and statewide burns disaster plans were activated. Twenty-two patients with burns presented to the state's burns referral centres, of whom 18 were adults. Adult burns patients at The Alfred spent 48.7 hours in theatre in the first 72 hours. There were a further 390 bushfire-related ED presentations across the state in the first 72 hours. Most patients with serious burns were triaged to and managed at burns referral centres. Throughout the disaster, burns referral centres continued to have substantial surge capacity. CONCLUSIONS: Most bushfire victims either died, or survived with minor injuries. As a result of good prehospital triage and planning, the small number of patients with serious burns did not overload the acute health care system.

Avoiding common problems associated with intravenous fluid therapy.

Inappropriate intravenous fluid therapy is a significant cause of patient morbidity and mortality and may result from either incorrect volume (too much or too little) or incorrect type of fluid. Fluid overload has no precise definition, but complications usually arise in the context of pre-existing cardiorespiratory disease and severe acute illness. Insufficient fluid administration is readily identified by signs and symptoms of inadequate circulation and decreased organ perfusion. Administration of the wrong type of fluid results in derangement of serum sodium concentration, which, if severe enough, leads to changes in cell volume and function, and may result in serious neurological injury. In patients whose condition is uncomplicated, we recommend a restrictive approach to perioperative intravenous fluid replacement, with initial avoidance of hypotonic fluids, and regular measurement of serum concentration of electrolytes, especially sodium.

The functional outcome of patients requiring over 28 days of intensive care: a long-term follow-up study.

OBJECTIVE: To measure functional outcome of long-stay intensive care unit patients in the Australian population. METHODS: All 68 patients admitted between July 2000 and July 2002 who spent 28 consecutive days or longer in a 30-bed university-affiliated medical-surgical ICU. MAIN OUTCOMES MEASURES: Glasgow Outcome Scores were recorded by chart review or telephone in the third quarter of 2003, giving a follow-up of 1-3 years (mean, 2 years). RESULTS: Patients comprised 22 trauma (32%), 16 cardiothoracic (24%) and 15 each (22%) general medical and surgical patients. Average age was 59.2 years (SD, 18.3 years), and mean APACHE II score was 22.2 (range, 7-52). Fourteen of 68 patients (21%) died during the hospital admission. Of the 54 patients discharged, 53 were followed up, and one was untraceable. Nineteen of these 53 (36%) had died. Of the 34 survivors (64% of hospital survivors, 50% of long-stay ICU patients), 17 (50%) were leading normal active lives, 15 (44%) were disabled but independent, with two (6%) needing daily support. None were in a persistent vegetative state. CONCLUSIONS: Of 68 long-stay ICU patients, an average of 2 years after discharge, 50% were alive, including 25% living normal active lives. The remaining 25% described some disability. In most cases (88%), this was mild: only two patients (3% of the total group) depended on daily support. No patients were left in a persistent vegetative state.

High donor age, low donor oxygenation, and high recipient inotrope requirements predict early graft dysfunction in lung transplant recipients.

BACKGROUND: Early dysfunction in lung transplants is characterized by poor oxygenation, which may then lead to prolonged mechanical ventilation. This may be due to a combination of donor, recipient, and management factors. Our aim was to determine the incidence and severity of hypoxia and graft dysfunction and which factors were directly associated with poor oxygenation within the first 24 hours after lung transplantation. METHODS: A retrospective study of all 128 lung transplants between 1999 and 2002 was undertaken. Multiple linear regression analysis was performed to determine which donor, recipient, operative, and intensive care unit (ICU) parameters were associated with the worst recorded arterial blood gas partial pressure of oxygen (PAO2)/fraction of inspired oxygen (FIO2) ratio in the initial 24 hours after operation. RESULTS: Eighty-three percent of the patients (104 of 128) had a PAO2/FIO2 ratio below 300 within the first 24 hours post-transplantation, and 60% (77 of 128) had a PAO2/FIO2 ratio below 200. A high donor age (p = 0.004), low donor PAO2 (p = 0.007), and high post-operative inotrope requirements (p = 0.02) were correlated with a low PAO2/FIO2 ratio. Recipient diagnosis, ischemic time, use of cardiopulmonary bypass, fluid balance in the ICU, and cardiac index were not related. There was no difference in the long-term outcomes of patients with high or low PAO2/FIO2 ratios. CONCLUSIONS: A low PAO2/FIO2 ratio is a common finding in the first 24 hours after lung transplantation. Donor factors such as age and PAO2, and the need for increasing inotrope requirements in ICU predict early graft dysfunction and hypoxia.