Ventilatory support of patients with sepsis or septic shock in resource-limited settings.

Introduction

Research evidence for ventilatory support recommendations in sepsis and septic shock management has been mainly gathered from investigations in resource-rich settings. Often, it is not practical to directly translate this evidence to resource-limited settings. Indeed, resource-limited intensive care units (ICUs) are frequently restricted in the availability of equipment, laboratory support and skilled staff. We report on a set of pragmatic recommendations for ventilatory support in sepsis and septic shock management in resource-limited settings, built upon two previous sets of guidelines for sepsis management, the most recent Surviving Sepsis Campaign guidelines [1] and the recommendations for sepsis management by the Global Intensive Care Working Group of the ESICM [2], as well as upon an updated literature search and expert opinions [3].

An international team of physicians from resource-rich and -limited settings with hands-on experience in resource-limited ICUs critically appraised a list of questions regarding ventilatory support by partly using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tools [4] and by reviewing the literature for any additional evidence from resource-limited settings. The quality of evidence was scored from very high (A) to very low (D), and the strength of recommendations was strong (1) or weak (2) considering the indirectness of the evidence, the magnitude of effects, availability and feasibility in resource-limited ICUs, and safety. In the absence of evidence from resource-limited ICUs, evidence from resource-rich ICUs was adopted after pragmatic, experience-based appraisal. Full scoring details are available in the online supplement.

Results and recommendations for ventilatory support in resource-limited ICUs

Although ventilatory support is generally seen as a simple and potentially life-saving intervention, there is increasing evidence for its possible harmful effects. Therefore, besides grading the evidence for general ventilatory settings (ventilation mode, oxygen concentration, tidal volume, positive end-expiratory pressure (PEEP) and recruitment maneuvers), we weighted strategies that might obviate the need for invasive ventilation, or shorten the duration of ventilation through accelerated weaning. The literature search for additional evidence from resource-limited settings identified several investigations that could be used to grade the evidence for use in resource-limited ICUs, amounting to one randomized controlled trial [5] and eight observational studies [6-12]. Key recommendations are provided in Table 1 and more detailed information on the literature search and grading of recommendations is included in the online supplement. In cases of strong recommendations, we use the wording ‘we recommend …’; in cases of less strong recommendations, we use the wording ‘we suggest …’.

Table 1

Recommendations and suggestions on ventilatory support in patients with sepsis or septic shock in resource-limited settings (with grading)

ARDS diagnosis	Use CXR and ABG in septic patients with acute respiratory failure to diagnose ARDS (2B); where feasible, ultrasound exam of lungs and heart may be used to narrow down the diagnosis of non-cardiogenic pulmonary edema (2D); oxygen pulse saturation relative to delivered oxygen concentration (S/F) may be an alternative for the arterial oxygen pressure relative to delivered oxygen concentration (P/F) for decision-making and continuous monitoring in settings where blood gas analyzers are absent (2D); in patients with acute respiratory failure with or without ARDS diagnosis should be managed employing the principles of lung-protective mechanical ventilation (2B)
Semi-recumbent position	For ventilated septic patients use elevated head-of-bed ranging from 30° to 45° unless their hemodynamic state precludes this (1B); lower patient’s position to less than 30° head-of-bed elevation transiently for the necessary procedures and during the resuscitation of the shock-state until hemodynamic status is improved (1B) or longer in cases of sacral decubitus ulcer (1C)
NIV	Use invasive mechanical ventilation in cases of severe hemodynamic disturbance (i.e., shock), and/or severe hypoxemia (1A). NIV could be used in selected cases of mild respiratory failure with preserved or relatively stable hemodynamic status (2A); frequent reassessments of therapeutic effect of NIV are required in order to prevent delay in intubation and mechanical ventilation (1B)
Spontaneous breathing trials	Use spontaneous breathing trials early and regularly, preferably daily, in all ventilated patients (1A) (notably, to increase the success of this strategy, excessive sedation should be prevented); use the low level of pressure support technique (2D); perform spontaneous breathing trials and extubate if the trial is passed successfully only at times when sufficient staff are available (2D); develop a local guideline for spontaneous breathing trials (2C)
Tidal volume size	Use low tidal volume ventilation in patients with ARDS diagnosis (1A) and in all ventilated patients (2B) (i.e., prevent tidal volumes higher than 10 ml/kg PBW, and consider tidal volumes of 5–7 ml/kg PBW in all patients); titrate tidal volume size using PBW and not the actual body weight (2D); timely recognize under-ventilation, where respiratory rates should be adjusted (2D); accept higher respiratory rates (i.e., do not increase sedation if the respiratory rate rises with the use of lower tidal volumes) (2C); end-tidal CO2 monitoring could be helpful in timely recognition of under- or overventilation (2D)
PEEP	Use a minimum level of PEEP (5 cm H2O) in all patients with sepsis or septic shock with acute respiratory failure (2B); consider using higher levels of PEEP only in patients with moderate or severe ARDS (2A); if lack of CXR and ABG availability hampers making an ARDS diagnosis, we suggest against liberal use of higher levels of PEEP (2D); when the team is trained and experienced in using respiratory dynamic compliance, PEEP could be titrated based on this parameter (2D); so-called PEEP/FiO2 tables could be used for titrating PEEP, but this approach generally requires frequent ABGs (2B); patients who need higher levels of PEEP are preferably closely monitored, preferably by using an arterial line, as hypotension and circulatory depression may develop (1A)
FiO2 versus PEEP	Low FiO2 is preferred over high FiO2 (2B); the target should be PaO2 >8 kPa (60 mmHg) and/or SpO2 88–95 % (2A); PEEP/FiO2 tables can be used to find the best PEEP–FiO2 combination (2B); staff with experience in using PEEP could prefer to use higher levels of PEEP to treat hypoxia; in centers with little experience in using PEEP, the initial response to hypoxia should be higher FiO2 before using higher levels of PEEP (2D)
Recruitment maneuvers	Use recruitment maneuvers in patients with moderate or severe ARDS (2B), in patients with refractory hypoxemia in whom an ARDS diagnosis cannot be made due to lack of CXR and/or ABG (2D), and only when the staff are trained and experienced in performing these maneuvers (2D); use the simplest maneuver, i.e., ‘sustained inflation’ (2D); when using recruitment maneuvers, the patient should be closely monitored, preferably by using an arterial line, to promptly detect hemodynamic compromise (2B)
Modes of ventilation	We recommend using ‘volume-controlled’ modes of ventilation over ‘pressure-controlled’ modes of ventilation (2D); we cannot recommend on whether assisted ventilation (‘support’ mode) is preferred over assist ventilation (‘controlled’ mode) in all patients; use a short course of muscle paralysis (<48 h), and thus controlled ventilation, only in patients with moderate or severe ARDS (2B)

Grading: see online supplement for explanations

CXR chest radiograph, ABG arterial blood gas, ARDS acute respiratory distress syndrome, PBW predicted body weight, PEEP positive end expiratory pressure, NIV non-invasive ventilation

We suggest identifying patients with ARDS diagnosis in the ICUs where this is feasible, as this may improve proper selection of additional ventilator strategies—we do recognize that this is not the case in the majority of ICUs with limited resources and therefore our overall strength of recommendation for this matter is downgraded to a suggestion; in settings where blood gas analyzers are unavailable, the SpO2 relative to delivered oxygen concentration (S/F) could be used for decision-making and continuous monitoring; in the absence of chest radiography, use of ultrasound exam of lungs and heart could be helpful in narrowing down the diagnosis of non-cardiogenic pulmonary edema, where feasible; regardless of the feasibility of diagnosing ARDS, septic patients with acute respiratory failure should be managed by employing the principles of lung-protective ventilation; we recommend that the elevated head-of-bed position should be maintained in all ventilated patients to decrease the risk of aspiration; we recommend the use of invasive mechanical ventilation in cases of severe hemodynamic disturbance or severe hypoxemia, and suggest a trial of non-invasive ventilation only in patients with minor hemodynamic and oxygenation disturbances; and in these patients, we recommend close monitoring and frequent reassessments regarding the need for intubation to assure that mechanical ventilation is instituted without the delay; we suggest using a minimum level of PEEP of 5 cm H2O in all patients with sepsis or septic shock with acute respiratory failure, and suggest using higher levels of PEEP only in patients with moderate or severe ARDS; we suggest a preference for a low FiO2 aiming at low oxygenation goals [i.e., 8 kPa (60 mmHg) and/or SpO2 (88–95 %)], and we suggest using PEEP/FiO2 tables to find the best PEEP–FiO2 combination; we suggest applying recruitment maneuvers only in patients with moderate or severe ARDS with refractory hypoxia, and only when the staff are trained and experienced in performing these maneuvers; patients who need higher levels of PEEP and recruitment maneuvers are preferably closely monitored, preferably by using an arterial line, as hypotension and circulatory depression may develop; we recommend using low tidal volumes in patients with ARDS (and to avoid tidal volumes larger than 10 ml/kg predicted body weight, and to consider tidal volumes between 5 and 7 ml/kg predicted body weight in all patients); where feasible, end-tidal CO2 monitoring could be helpful in timely recognition of dislodgement of the endotracheal tube and under- or overventilation; ‘volume-controlled’ modes could be safer than ‘pressure-controlled’ modes as minute ventilation and tidal volume size is guaranteed with volume-controlled modes; we cannot recommend a preference for ‘support’ modes of ventilation over ‘control’ modes, but do recommend checking regularly whether a patient tolerates ‘support’ mode; we also suggest performing spontaneous breathing trials to timely identify patients who are ready for extubation, but also to plan extubating patients when sufficient staff are around to guarantee safe re-intubation, if necessary.

Conclusion

We provide a set of simple, readily available and affordable recommendations for the ‘safe’ ventilatory support in patients with sepsis or septic shock in resource-limited ICUs. Most evidence has come from resource-rich settings; therefore, there is an urgent need for related studies in resource-limited settings. Given the immense variability and range of capabilities, preparedness, and staffing of ICUs in resource-limited ICUs, each ICU practitioner will have to rationally and practically further adapt the guidelines based on their site-specific circumstances.

Supplementary material 1 (DOC 476 kb)