Lower or Higher Oxygenation Targets for Acute Hypoxemic Respiratory Failure

BACKGROUND

Patients with acute hypoxemic respiratory failure in the intensive care unit (ICU) are treated with supplemental oxygen, but the benefits and harms of different oxygenation targets are unclear. We hypothesized that using a lower target for partial pressure of arterial oxygen (Pao₂) would result in lower mortality than using a higher target.

METHODS

In this multicenter trial, we randomly assigned 2928 adult patients who had recently been admitted to the ICU (≤12 hours before randomization) and who were receiving at least 10 liters of oxygen per minute in an open system or had a fraction of inspired oxygen of at least 0.50 in a closed system to receive oxygen therapy targeting a Pao₂ of either 60 mm Hg (lower-oxygenation group) or 90 mm Hg (higher-oxygenation group) for a maximum of 90 days. The primary outcome was death within 90 days.

RESULTS

At 90 days, 618 of 1441 patients (42.9%) in the lower-oxygenation group and 613 of 1447 patients (42.4%) in the higher-oxygenation group had died (adjusted risk ratio, 1.02; 95% confidence interval, 0.94 to 1.11; P = 0.64). At 90 days, there was no significant between-group difference in the percentage of days that patients were alive without life support or in the percentage of days they were alive after hospital discharge. The percentages of patients who had new episodes of shock, myocardial ischemia, ischemic stroke, or intestinal ischemia were similar in the two groups (P = 0.24).

CONCLUSIONS

Among adult patients with acute hypoxemic respiratory failure in the ICU, a lower oxygenation target did not result in lower mortality than a higher target at 90 days. (Funded by the Innovation Fund Denmark and others; HOT-ICU ClinicalTrials.gov number, NCT03174002.).

Pantoprazole in Patients at Risk for Gastrointestinal Bleeding in the ICU

BACKGROUND

Prophylaxis for gastrointestinal stress ulceration is frequently given to patients in the intensive care unit (ICU), but its risks and benefits are unclear.

METHODS

In this European, multicenter, parallel-group, blinded trial, we randomly assigned adults who had been admitted to the ICU for an acute condition (i.e., an unplanned admission) and who were at risk for gastrointestinal bleeding to receive 40 mg of intravenous pantoprazole (a proton-pump inhibitor) or placebo daily during the ICU stay. The primary outcome was death by 90 days after randomization.

RESULTS

A total of 3298 patients were enrolled; 1645 were randomly assigned to the pantoprazole group and 1653 to the placebo group. Data on the primary outcome were available for 3282 patients (99.5%). At 90 days, 510 patients (31.1%) in the pantoprazole group and 499 (30.4%) in the placebo group had died (relative risk, 1.02; 95% confidence interval [CI], 0.91 to 1.13; P=0.76). During the ICU stay, at least one clinically important event (a composite of clinically important gastrointestinal bleeding, pneumonia, Clostridium difficile infection, or myocardial ischemia) had occurred in 21.9% of patients assigned to pantoprazole and 22.6% of those assigned to placebo (relative risk, 0.96; 95% CI, 0.83 to 1.11). In the pantoprazole group, 2.5% of patients had clinically important gastrointestinal bleeding, as compared with 4.2% in the placebo group. The number of patients with infections or serious adverse reactions and the percentage of days alive without life support within 90 days were similar in the two groups.

CONCLUSIONS

Among adult patients in the ICU who were at risk for gastrointestinal bleeding, mortality at 90 days and the number of clinically important events were similar in those assigned to pantoprazole and those assigned to placebo. (Funded by Innovation Fund Denmark and others; SUP-ICU ClinicalTrials.gov number, NCT02467621 .).

Decreased duration of mechanical ventilation when comparing analgesia-based sedation using remifentanil with standard hypnotic-based sedation for up to 10 days in intensive care unit patients: a randomised trial [ISRCTN47583497]

INTRODUCTION

This randomised, open-label, multicentre study compared the safety and efficacy of an analgesia-based sedation regime using remifentanil with a conventional hypnotic-based sedation regime in critically ill patients requiring prolonged mechanical ventilation for up to 10 days.

METHODS

One hundred and five randomised patients received either a remifentanil-based sedation regime (initial dose 6 to 9 microg kg(-1) h(-1) (0.1 to 0.15 microg kg(-1) min(-1)) titrated to response before the addition of midazolam for further sedation (n = 57), or a midazolam-based sedation regime with fentanyl or morphine added for analgesia (n = 48). Patients were sedated to an optimal Sedation-Agitation Scale (SAS) score of 3 or 4 and a pain intensity (PI) score of 1 or 2.

RESULTS

The remifentanil-based sedation regime significantly reduced the duration of mechanical ventilation by more than 2 days (53.5 hours, P = 0.033), and significantly reduced the time from the start of the weaning process to extubation by more than 1 day (26.6 hours, P < 0.001). There was a trend towards shortening the stay in the intensive care unit (ICU) by 1 day. The median time of optimal SAS and PI was the same in both groups. There was a significant difference in the median time to offset of pharmacodynamic effects when discontinuing study medication in patients not extubated at 10 days (remifentanil 0.250 hour, comparator 1.167 hours; P < 0.001). Of the patients treated with remifentanil, 26% did not receive any midazolam during the study. In those patients that did receive midazolam, the use of remifentanil considerably reduced the total dose of midazolam required. Between days 3 and 10 the weighted mean infusion rate of remifentanil remained constant with no evidence of accumulation or of a development of tolerance to remifentanil. There was no difference between the groups in SAS or PI score in the 24 hours after stopping the study medication. Remifentanil was well tolerated.

CONCLUSION

Analgesia-based sedation with remifentanil was well tolerated; it reduces the duration of mechanical ventilation and improves the weaning process compared with standard hypnotic-based sedation regimes in ICU patients requiring long-term ventilation for up to 10 days.

Electric impedance for evaluation of body fluid balance in cardiac surgical patients

OBJECTIVE

To evaluate whether electric impedance can be used to monitor body fluid balance and fluid distribution in cardiac surgical patients.

DESIGN

Prospective clinical study.

SETTING

Heart Center, Rigshospital, Copenhagen.

PARTICIPANTS

Sixteen consecutive patients scheduled for cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

Body weight, fluid balance, central hemodynamics, and total and segmental body impedance were examined perioperatively. During semisupine rest before surgery, changes in impedance indicated relocation of fluid from the legs to the thorax, mostly in the extracellular space. After surgery, weight and fluid balance increased by 3.87 +/- 0.35 kg and 1.86 +/- 0.16 L (mean +/- SE, p < 0.01) and remained elevated through the next 2 days. Impedance decreased by 30% over the thorax, by 24% over the abdomen, by 2% over the leg, and by 4% over the entire body. Changes in total and thoracoabdominal impedances had the highest correlation to the fluid balance (r = -0.86 and r = -0.87). After correction of impedance values by the constant from the regression model, the mean difference in estimation of fluid changes obtained by electric impedance and by fluid balance was 0 +/- 0.1 L at the range of changes of 4.6 L.

CONCLUSION

Alterations in electric impedance closely follow changes in fluid balance during the perioperative period. This method can be used in clinical practice to control postoperative body fluid balance in cardiac surgical patients.

Pulse oximetry at fibre-optic bronchoscopy in local anaesthesia: indication for postbronchoscopy oxygen supplementation?

The requirement for supplementary oxygen (O2) after fibre-optic bronchoscopy (FOB) was evaluated by means of pulse oximetry in 34 patients (19 men) of median age 62 years (range 28-85) who had had a diagnostic FOB. The patients were allocated at random into two groups, each of 17 persons, which were comparable concerning sex, age and the dose of benzodiazepine (diazepam tablets 10 mg 1 h before FOB and midazolam 2-5 mg i.v. during FOB) used for premedication. Patients in group 1 had lower pulmonary function (FEV1, FVC as a percentage of predicted values) than patients in group 2 (P < 0.02). The oxygen saturation of the haemoglobin (SpO2) in the tip of the index finger was recorded continuously for 30 min after the administration of oral diazepam, during FOB and for 120 min after the FOB procedure. All patients received nasal O2 supplement 21 min-1 during FOB. After FOB, O2 was discontinued in group 1, while group 2 continued to receive O2 21 min-1 for 120 min. The incidence of hypoxaemic episodes (SpO2 < or = 90% for a period of a minimum of > or = 12 s) after oral diazepam, before FOB, was similar in the two groups, 35%. After FOB, the incidence of hypoxaemic episodes was 88% in group 1 and 41% in group 2 (P < 0.01). The cumulated duration of hypoxaemia after FOB was a median of 30 s (range 0-7140) in group 1 and a median of 0 s (0-156) in group 2 (P < 0.0001). Impaired lung function (FEV1 < 75% of predicted value) was a risk factor for hypoxaemia. Postbronchoscopy, O2 supplement should be administered to sedated patients with impaired lung function until the patients have fully recovered.

Classification of pulmonary lesions into central and peripheral with a template applied on chest X-ray

To facilitate the understanding of the anatomical localization of pulmonary lesions and to optimize diagnostic evaluation, a template was designed which, on conventional chest X-rays, could be employed to discriminate between central and peripheral pulmonary lesions. The term 'central' implies that the lesion should be visible in the tracheobronchial tree through a fibre-optic bronchoscope, and the term 'peripheral' suggests that the lesion is not visible through a bronchoscope. In 20 patients examined by fibre-optic bronchoscopy, the bronchoscope was wedged into four pre-selected segmental bronchi in each lung. Using fluoroscopy, the tip of the bronchoscope was marked out on the skin with leadshot. On subsequent chest X-rays, with posterior-anterior and right lateral views, the distances and angles of the markings of the bronchi were mapped out in relation to the main carina. These data were used to design the template.

[Ion generators and bronchial asthma. A double-blind placebo controlled study]

In this double blind, placebo-controlled study we examined the value of using a device for ionizing the air in the immediate environment as a therapy for asthma bronchiale. Nineteen adult patients with stable, reversible asthma were randomised to blind treatment with either an active device or an inactive placebo-device. After four weeks treatment the patients were given the alternative device for another period of four weeks. We measured daily peak-flow, symptomscore, use of medicine and spirometry and found no differences between the two periods. Therapy with ionization of the environmental air in patients with bronchial asthma should not be recommended.

Reversal of benzodiazepine intoxication by flumazenil

In order to firstly evaluate the efficacy of flumazenil in reversing benzodiazepine-induced sedation because of drug overdose and secondly to register adverse events, 13 patients admitted to the intensive care unit because of drug intoxication, were given flumazenil intravenously to a maximum of 1.0 mg. Sedation state was scored on a modified Glasgow Coma Scale and arterial blood pressure, heart rate and arterial blood gases were recorded before and after flumazenil was given, and every 30 min for 2 h. Results showed that flumazenil reversed the sedation due to benzodiazepines effectively increasing the coma score significantly (P less than 0.005). We found no change in arterial blood pressure (apart from one patient), heart rate or arterial blood gases. Two patients gave further information about drug intake after flumazenil was given. Six patients became resedated, only one needed additional flumazenil. One patient developed a hypertensive crisis after flumazenil was given as a result of the unmasking of an untreated hypertension. Another patient aspirated gastric content to the trachea during resedation and needed respiratory support.

[Adult Gaucher's disease with pulmonary involvement]

Gaucher's disease is an autosomal recessive disorder caused by deficiency of the enzyme glucocerebrosidase with accumulation of glucocerebroside in the reticuloendothelial system. Affection of the lungs by this disease is extremely rare. When Gaucher cells infiltrate the lung, fibrosis may result. We describe a case with adult type Gaucher's disease who, besides affection of liver, spleen and bone marrow, had severe pulmonary involvement with extensive interstitial fibrosis, increased pulmonary vascular resistance, and pronounced reduction in diffusion capacity.

[Acute adult respiratory distress syndrome (ARDS) in a patient with amitriptyline poisoning]

A case of "adult respiratory distress syndrome" after amitriptyline overdosage is reported. Amitriptyline is rapidly absorbed from the intestinal tract and the drug is concentrated in the tissues, particularly the brain, heart and lungs. It is suggested that in large quantities it may inhibit surfactant production and thus cause the clinical picture described. The ventilatory treatments are discussed. It seems that inversed ratio ventilation (IRV) has something to offer, avoiding the use of high oxygen fractions in inspired air and high peak airway pressures. Our patient improved with IRV.

Platelet responses to intravenous infusion of Intralipid in healthy volunteers

Platelet function and morphology were studied in eight healthy male volunteers before, immediately after, and 1 d after the infusion of 250 mL of 10% Intralipid. The plasma concentrations of the platelet-release products beta-thromboglobulin (beta-TG), serotonin (5-HT), and platelet factor 4 (PF4) and the threshold to ADP- and adrenaline-induced aggregation were determined ex vivo. In addition the platelets were examined by electron microscopy. Although platelets released beta-TG, PF4, and 5-HT after the infusion, there was no significant change in ex vivo aggregability. About 3% of the platelets had internalized small-sized lipid particles (0.1-0.2 micron) whereas no other morphological changes were detected. The release products may negatively affect the hemorheological properties of the microcirculation in critically ill patients. The release of PF4 may explain the antiheparin effect of parenteral lipid therapy.

Antagonism of diazepam sedation by flumazenil

Forty adult patients undergoing elective surgery, anaesthetized with diazepam, alfentanil and nitrous oxide in oxygen, and paralysed with atracurium were given flumazenil or placebo i.v. in a double-blind randomized study to assess the efficacy of flumazenil. Awake state, heart rate, arterial pressure, rate of ventilation and arterial blood-gas values were measured at 0, 5, 30, 120 and 240 min after administration of flumazenil or placebo. Flumazenil was found to antagonize the sedative effects of diazepam; there was no resedation within the time of observation. There were no intergroup differences in any of the other measured variables. A median dose of diazepam 0.33 mg kg-1 during surgery lasting a median of 98 min was antagonized by a median dose of flumazenil 0.35 mg. No side effects related to flumazenil were observed.