Re-evaluating high-frequency oscillation for ARDS: Would a targeted approach be successful?

High-Frequency Oscillation for Adult Patients with Acute Respiratory Distress Syndrome. A Systematic Review and Meta-Analysis

RATIONALE

By minimizing tidal lung strain and maintaining alveolar recruitment, high-frequency oscillatory ventilation (HFOV) may protect against ventilator-induced lung injury.

OBJECTIVES

To summarize the current evidence in support of the use of HFOV in adult patients with acute respiratory distress syndrome.

METHODS

We conducted a systematic review and meta-analysis of randomized trials comparing mortality rates with the use of HFOV versus conventional mechanical ventilation for adult patients with acute respiratory distress syndrome. Eligible trials were identified from previously published systematic reviews and an updated literature search. Data on 28-day mortality, oxygenation, adverse events, and use of rescue therapies were collected; effects were pooled using random effects models weighted by inverse variance. Strength of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation methodology.

RESULTS

Six trials were eligible for inclusion (total n = 1,715 patients). Four trials mandated lung-protective ventilation in the control group and one trial applied a higher positive end-expiratory pressure (PEEP) ventilation strategy in the control group. None of the trials were judged to be at high risk of bias, though all were unblinded. In trials that did not systematically employ any cointerventions with HFOV and that targeted low tidal volumes in the patients randomized to conventional ventilation (primary analysis), HFOV had no significant effect on mortality (three trials; risk ratio [RR], 1.14; 95% confidence interval [CI], 0.88 to 1.48; evidence grade = high). Pooled analysis of all six trials also did not suggest a significant mortality reduction (RR, 0.94; 95% CI, 0.71 to 1.24; evidence grade = low). The single trial that employed a conventional ventilation strategy with both lower tidal volumes and higher PEEP as control reported higher mortality in patients receiving HFOV (RR, 1.41; 95% CI, 1.12 to 1.79). HFOV was not associated with improved oxygenation after 24 hours (five trials; mean increase of 10 mm Hg; 95% CI, -16 to 37 mm Hg). Rates of barotrauma were not different between HFOV and conventional ventilation, although significant benefit or harm could not be excluded (RR, 1.15; 95% CI, 0.61 to 2.17).

CONCLUSIONS

Published randomized trials suggest that HFOV is not associated with a mortality benefit, and may even be harmful in comparison to ventilation with low tidal volumes and higher levels of PEEP.

Is the use of high frequency oscillatory ventilator beneficial in managing severe chest injury with massive air leak?

Severe thoracic trauma can be associated with immediate life-threatening injuries including major air leak syndrome that can lead to acute respiratory failure and refractory hypoxaemia. Such injuries invariably require thoracotomy following failure of conventional ventilation strategy and paucity of other non-operative interventions. We describe a case in which we used high frequency oscillatory ventilation (HFOV) as a part of management of such injury and averted the need for thoracotomy.

[Atrial fibrillation in the ICU. Distinct entity--special treatment?]

Atrial fibrillation (AF) is the single most frequent arrhythmia in the intensive care unit, occurring among 44-61 % of all patients with arrhythmias in the intensive care unit. The success rate of electrical cardioversion (DC-CV) early after surgery is as low as 10-35 % in postoperative AF but 6 weeks after discharge 90 % are in sinus rhythm (SR). Several guidelines recommend rate control in these patients and rate control with β-blockers and calcium channel blockers is not inferior with respect to outcome, 6 min walk test, and quality of life. DC-CV is recommended in unstable and heart failure patients. The term resistant AF is suggested for that distinct situation of AF not amenable to cardioversion solely in the acute phase of critical illness.