Critical Care

Transfusion-Associated Circulatory Overload in ICUs

Transfusion-associated circulatory overload is frequent in ICU patients, about 5.5% in this review. It was associated with increased ICU and hospital length of stay.

Risk factors included positive fluid balance, the number and type of products transfused, rate of transfusion, and cardiovascular and renal comorbidities. 

In pediatric ICUs, the authors note “The lack of a pediatric-adjusted definition of transfusion-associated circulatory overload may lead to a risk of underdiagnosis of this condition in PICUs”.

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Intra-Abdominal Hypertension in Critically Ill Patients

In a mixed ICU patient cohort, intra-abdominal hypertension (IAH) occurred in almost half of all patients and was twice as prevalent in mechanically ventilated patients. Its presence and severity significantly and independently increased 28- and 90-day mortality.

Body mass index, APACHE II score of 18 or greater, presence of abdominal distension, absence of bowel sounds, and positive end-expiratory pressure greater than or equal to 7 cm H2O were independently associated with its development.

Positive fluid balance (as often occurs after massive resuscitation) appeared more relevant later in ICU stay. BMI was the only identified risk factor that was not directly related to increased mortality and different cutoffs for IAH may apply in obese patients.

IAH was defined as a value > 12 mmHg. The authors note: “presence and severity of IAH during the first 2 weeks of the ICU stay significantly and independently increased 28- and 90-day mortality, whereas the presence of IAH on the day of ICU admission was insufficient to predict these adverse outcomes”.

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In addition to the above full text link, the Abdominal Compartment Society has useful links at its site as well as guidelines for managing IAH and abdominal compartment syndrome.

Neuroanesthesia & Critical Care Guidelines

The Society of Neuroscience in Anesthesiology and Critical Care (SNACC) guidelines and consensus statements are available in full text at the link below.

They encompass guidelines for managing patients at risk of stroke, those with external ventricular/lumbar drains, and anesthetic management of endovascular treatment of acute ischemic stroke.

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Methylprednisolone for AKI in Cardiac Surgery

A sub study of a randomized trial finds: “Intraoperative corticosteroid use did not reduce the risk of acute kidney injury in patients with a moderate-to-high risk of perioperative death who had cardiac surgery with cardiopulmonary bypass. Our results do not support the prophylactic use of steroids during cardiopulmonary bypass surgery”.

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A previous review casts doubt on the use of steroids for various purposes in cardiac surgery, finding that they had “an unclear impact on mortality, increased the risk of myocardial injury, and the impact on atrial fibrillation should be viewed with caution given that large trials showed no effect”. link

Delirium in Older Acute Care Surgery

Patients older than 65 years were followed after acute care surgery. Some 23% had delirium from a validated chart review.

Postoperative delirium risk factors included Foley catheter use, intestinal surgery, gallbladder surgery, appendix surgery, intensive care unit admission and mild to moderate frailty. Risk factors for prolonged postoperative delirium (> 48 hours) included Foley catheter use and mild to moderate frailty. Surgical approach (open v. laparoscopic) and overall operative time were not found to be significant.

The seemingly innocuous Foley urinary catheter consistently appears as a delirium risk factor and protocols to ask every day whether it can be removed are appropriate.

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Vitamin C and ICU Outcome

Vitamin C as a panacea has been an especially persistent philosophy. Cocktails along with Thiamine and Hydrocortisone are being investigated (and hyped) for sepsis, but there is no robust evidence to support the practice at this point.

This systematic review and meta-analysis of a mixed critically ill population finds no significant effect on acute kidney injury, survival, length of ICU or hospital stay. In cardiac surgery, beneficial effects on postoperative atrial fibrillation, ICU or hospital length of stay remain unclear.

Clearly further studies are needed before Vitamin C alone or as part of a cocktail can be recommended for critically ill patients.

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Early Use of Norepinephrine in Septic Shock Resuscitation

The CENSER randomized trial is a single center study comparing early Norepinephrine with standard care in septic shock.

The primary outcome was shock control rate (defined as achievement of mean arterial blood pressure >65mmHg, with urine flow >0.5mL/kg/h for 2 consecutive hours, or decreased serum lactate >10% from baseline) by 6 hours after diagnosis.

Early Norepinephrine use was associated with better shock control at 6 hours, less cardiogenic pulmonary edema, and fewer new arrhythmias.

However 28 day mortality was not different between the groups. More studies are needed before any practice change can occur; nonetheless recent Surviving Sepsis updates recommend that vasopressors can be commenced during or after volume resuscitation, acknowledging that not all patients may need 30mL/kg ( link )

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Pediatric Severe Traumatic Brain Injury Guidelines

These updated guidelines on brain trauma in infants, children and adolescents help in determining our approach to brain trauma. The article does note that while progress has been made, overall the level of evidence informing these guidelines remains low. There is a need for quality randomized trials. With that in mind, the guidelines and evidence level include:

Use of ICP monitoring suggested (III)

If brain tissue oxygenation (PbrO2) used, keep > 10 mm Hg (III)

Excluding elevated ICP from a normal initial (0–6 hr after injury) CT examination of the brain is not suggested in comatose pediatric patients (III)

Routine repeat CT scan after 24 hours is not suggested for decisions about neurosurgical intervention, unless there is either evidence of neurologic deterioration or increasing ICP (III)

ICP target < 20 mm Hg suggested (III)

CPP minimum target 40 mm Hg (40-50 suggested) (III)

Bolus Hypertonic Saline (HTS) (3%) is recommended for intracranial hypertension. Recommended 2 to 5 mL/kg over 10–20 minutes (II)

Continuous infusion HTS is suggested in patients with intracranial hypertension. Suggested 3% saline between 0.1 and 1.0 mL/kg of body weight per hour, administered on a sliding scale. The minimum dose needed to maintain ICP less than 20 mm Hg is suggested (III)

Bolus of 23.4% HTS is suggested for refractory ICP. The suggested dose is 0.5 mL/kg with a maximum of 30 mL (III)

Avoid bolus administration of midazolam and/or fentanyl during ICP crises due to risks of cerebral hypoperfusion (III)

Prophylactic seizure treatment is suggested to reduce the occurrence of early (within 7 d) seizures (III)

Hyperventilation to a PaCO2 less than 30 mm Hg in the initial 48 hours not recommended. If used for refractory intracranial hypertension, advanced neuromonitoring for evaluation of cerebral ischemia is suggested (III)

Prophylactic moderate (32–33°C) hypothermia is not recommended over normothermia (II)

Moderate (32–33°C) hypothermia is suggested for ICP control, with slow rewarding 0.5-1° per 12 – 24 h (III)

High-dose barbiturate therapy is suggested in hemodynamically stable patients with refractory intracranial hypertension despite maximal medical and surgical management (III)

Decompressive craniectomy (DC) is suggested to treat refractory neurologic deterioration, herniation, or intracranial hypertension (III)

Decompressive craniectomy is suggested to treat refractory neurologic deterioration, herniation, or refractory intracranial hypertension (III)

Use of an immune-modulating diet is not recommended (II)

Initiation of early enteral nutritional support (within 72 hr from injury) is suggested (III)

The use of corticosteroids is not suggested to improve outcome or reduce ICP (III)

Full evidence link

Intraoperative Blood Pressure and Outcome

A consensus statement reflects numerous studies suggesting the harms of even brief episodes of intraoperative hypotension. There is strong associations between hypotension and myocardial injury and infarction, renal injury, and death.

The consensus defines significantly harmful levels as systolic < 100, or mean arterial pressure < 60 – 70mm Hg in noncardiac surgery. Upper levels of 160 (or 140 in cardiac surgery) increase the risks.

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Some of the studies showing the harms of hypotension previously published:

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Post Intensive Care Syndromes

This POPPI trial involved a multifaceted intervention that included promotion of a therapeutic environment by ICU staff and targeted stress support sessions delivered by trained ICU nurses to ICU patients who demonstrated acute stress symptom.

Overall, there was no significant difference in the primary outcome of PTSD symptom severity.

Neither was there any significant differences in secondary outcomes, including days alive and free from sedation at day 30, length of ICU stay, symptoms of depression and anxiety, and health-related quality of life. 

Future targeting may involve better selection of at-risk populations, timing, frequency, specific techniques, staff training, and implementation issues. Amelioration of agitation and delirium may also be worthwhile endeavours.

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