A recruitment maneuver increases oxygenation after intubation of hypoxemic intensive care unit patients: a randomized controlled study

Abstract

Introduction: Tracheal intubation and anaesthesia promotes lung collapse and hypoxemia. In acute lung injury patients, recruitment maneuvers (RMs) increase lung volume and oxygenation, and decrease atelectasis. The aim of this study was to evaluate the efficacy and safety of RMs performed immediately after intubation.

Methods: This randomized controlled study was conducted in two 16-bed medical-surgical intensive care units within the same university hospital. Consecutive patients requiring intubation for acute hypoxemic respiratory failure were included. Patients were randomized to undergo a RM immediately (within 2 minutes) after intubation, consisting of a continuous positive airway pressure (CPAP) of 40 cmH2O over 30 seconds (RM group), or not (control group). Blood gases were sampled and blood samples taken for culture before, within 2 minutes, 5 minutes, and 30 minutes after intubation. Haemodynamic and respiratory parameters were continuously recorded throughout the study. Positive end expiratory pressure (PEEP) was set at 5 cmH2O throughout.

Results: The control (n = 20) and RM (n = 20) groups were similar in terms of age, disease severity, diagnosis at time of admission, and PaO2 obtained under 10-15 L/min oxygen flow immediately before (81 +/- 15 vs 83 +/- 35 mmHg, P = 0.9), and within 2 minutes after, intubation under 100% FiO2 (81 +/- 15 vs 83 +/- 35 mmHg, P = 0.9). Five minutes after intubation, PaO2 obtained under 100% FiO2 was significantly higher in the RM group compared with the control group (93 +/- 36 vs 236 +/- 117 mmHg, P = 0.008). The difference remained significant at 30 minutes with 110 +/- 39 and 180 +/- 79 mmHg, respectively, for the control and RM groups. No significant difference in haemodynamic conditions was observed between groups at any time. Following tracheal intubation, 15 patients had positive blood cultures, showing microorganisms shared with tracheal aspirates, with no significant difference in the incidence of culture positivity between groups.

Conclusions: Recruitment maneuver following intubation in hypoxemic patients improved short-term oxygenation, and was not associated with increased adverse effects.

Trial registration: NCT01014299.

Figure 1

Design of the study. During the inclusion period, patients were randomized to a control or recruitment manoeuvre (RM) group. Clinical parameters were recorded and arterial blood gases (ABG 1) sampled at inclusion. Preoxygenation was performed for a three-minute period. Immediately after tracheal intubation (TI), a second set of ABG measurements were taken (ABG 2). Less than two minutes after intubation, an RM was performed (RM group); no RM was administered to patients in the control group. Protective mechanical ventilation with positive end-expiration pressure (PEEP) at 5 cmH₂O was commenced immediately after intubation. Five and thirty minutes after intubation, ABG measurements were again performed (ABG 3 and ABG 4). At inclusion, and 5 and 30 minutes after intubation, blood samples were taken for culture. Troponin Ic levels were sampled at inclusion and six hours after intubation. Thirty minutes after intubation, endotracheal aspiration was performed on all patients. VT: tidal volume.

Figure 2

Flow chart of the study. From September 2007 to September 2008, 67 patients required tracheal intubation. Twenty-three patients were intubated for reasons other than acute respiratory failure. The remaining 44 patients were thus randomized to our two groups. Three patients were excluded before intubation because of cardiac arrest after induction (n = 2) or systolic blood pressure below 50 mmHg. The two patients excluded for cardiac arrests were patients with severe hypoxemia. Blood gases at inclusions were partial pressure of arterial oxygen (PaO₂) 37 mmHg, partial pressure of arterial carbon dioxide (PaCO₂) 22 mmHg, pH 7.11, serum potassium 3.9 for the first patient and PaO₂ 41 mmHg, PaCO₂ 33 mmHg, pH 7.26, serum potassium 4.1 for the second. In both cases, cardiac arrests were recovered after cardiopulmonary resuscitation. One patient was excluded because of selective intubation. Forty patients were thus ultimately included in the study. FiO₂: fraction of inspired oxygen; IDS: intubation difficult scale; PEEP: positive end-expiratory pressure; VT: tidal volume.

Figure 3

Individual PaO₂ values at different study times. Individual partial pressure of arterial oxygen (PaO₂) at inclusion, immediately after intubation (TI), 5 minutes after intubation, and 30 minutes after intubation of patients in the control group (top), and RM group (bottom). A full circle represents an individual value. Bars represent median values. One patient had a PaO₂ of 504 mmHg after RM. These data are not shown in the Figure.