HERMES: International Survey and Portable External Power Evaluation During Respiratory Support Transport

Prehospital Transport During Advanced Respiratory Support: An International Survey and Prospective Feasibility Evaluation of Portable External Power

The HERMES Phase I-II study was a two-phase observational investigation designed to characterize contemporary practices and safety-related challenges associated with the transport of patients requiring advanced respiratory support and to assess the operational feasibility of portable external electrical power during ambulance transport.

Phase I consisted of an international electronic cross-sectional survey of healthcare professionals involved in noninvasive ventilation (NIV) management or patient transport. The survey evaluated reported transport indications, ventilator type and positioning, respiratory interfaces, transport-team composition, and perceived patient-, equipment-, and environment-related problems.

Phase II was a prospective descriptive feasibility evaluation involving 25 ambulance transports performed in Albacete and Bilbao, Spain. Patients were transported while receiving high-flow nasal oxygen (HFNO), rescue NIV, or invasive mechanical ventilation. A portable external power supply was used to support continuity of powered respiratory-support equipment during transport. The primary technical feasibility outcome was successful completion of transport while maintaining respiratory support without reported power interruption, clinically relevant equipment alarm, or technical failure.

The two phases were analyzed independently and were intended to characterize respiratory-support transport practices and evaluate technical and operational feasibility rather than establish comparative effectiveness, clinical superiority, or prevention of clinical deterioration.

Patients receiving advanced respiratory support may require prehospital, interhospital, or intrahospital transport for diagnostic procedures, therapeutic interventions, transfer to a higher level of care, or continuation of acute management. Noninvasive ventilation and high-flow nasal oxygen are established forms of respiratory support in acute respiratory failure, while invasive mechanical ventilation remains necessary in patients with more severe or refractory respiratory failure. During transport, continuity of respiratory support must be maintained despite changes in environment, personnel, equipment configuration, oxygen availability, and electrical power supply.

Transport of critically ill patients represents a recognized period of increased clinical and technical vulnerability. International recommendations emphasize adequate stabilization before transport, appropriate physiologic monitoring, trained accompanying personnel, communication between clinical teams, verification of equipment function, sufficient oxygen and power reserves, and contingency planning for foreseeable clinical deterioration or device failure. Prospective cohort studies and systematic reviews have demonstrated that transport-associated adverse events may include physiologic deterioration, equipment malfunction, circuit or airway problems, interruptions in therapy, and organizational or communication failures. The reported frequency of such events varies substantially according to patient population, transport setting, event definitions, urgency, and surveillance methodology.

Against this background, the HERMES Phase I-II program was developed as two analytically distinct observational phases.

Phase I was an international electronic cross-sectional survey targeting healthcare professionals involved in NIV management or patient transport. The objective was to characterize reported clinical and organizational practices related to the transport of patients requiring noninvasive respiratory support and to identify perceived areas of vulnerability during transport.

The available survey records were timestamped from February 20 to May 6, 2023. The dataset contained 224 response records. Survey domains included indications for transport, type and positioning of ventilators, use of respiratory interfaces, composition of the transport team, and categories of patient-, equipment-, and environment-related problems.

The respondent record was the unit of analysis. Reported problems reflected respondents' perceptions or previous clinical experience and were therefore not interpreted as prospectively adjudicated adverse-event incidence. Because the available documentation did not establish the invitation denominator, recruitment channels, participating countries and institutions, reminder procedures, or a prespecified definition of questionnaire completion, a formal response rate and country- or institution-level prevalence estimates were not calculated.

The rationale for this phase was based on the recognized variability in transport organization and on the importance of standardized preparation, appropriately trained personnel, continuous monitoring, equipment checks, adequate resource planning, and predefined safety procedures. Structured transport protocols and checklists may further improve adherence to transport-safety recommendations and promote more consistent preparation before patient transfer.

Phase II was designed as a prospective descriptive feasibility evaluation of portable external electrical power during ambulance transport of patients requiring advanced respiratory support. Twenty-five transport episodes were prospectively recorded at participating units in Albacete and Bilbao, Spain. The cohort included 24 adults and one child.

Respiratory-support modalities included HFNO, rescue NIV, and invasive mechanical ventilation during cardiopulmonary resuscitation. A Zopec Transport UPS 90 external power supply was used during transport to support continuity of powered respiratory-support equipment. Respiratory-support devices, oxygen delivery, monitoring, and other aspects of clinical management remained determined by the treating clinical teams according to local practice.

The primary technical feasibility outcome was completion of ambulance transport while maintaining prescribed respiratory support without reported electrical power interruption, clinically relevant equipment alarm, or technical failure requiring corrective intervention. Additional descriptive variables included respiratory-support modality, transport duration, rescue respiratory support, technical events, operational complexity, and changes in respiratory support.

Electrical continuity represents an important component of transport safety because contemporary respiratory-support systems may depend simultaneou

Phase I - International Healthcare Professional Survey

Inclusion Criteria:

• Healthcare professionals involved in the management of noninvasive ventilation or in the transport of patients requiring respiratory support.
• Participation in the international electronic survey addressing respiratory-support transport practices.

Exclusion Criteria:

• Records not representing participation in the respiratory-support transport survey.
• Records lacking sufficient information for descriptive analysis of the predefined survey domains.

Phase II - Portable External Power Feasibility Evaluation

Inclusion Criteria:

• Patients undergoing ambulance transport while receiving advanced respiratory support.
• Receipt of high-flow nasal oxygen (HFNO), noninvasive ventilation (NIV), or invasive mechanical ventilation during the transport episode.
• Transport performed at one of the participating clinical units included in the prospective feasibility evaluation.
• Availability of transport-level data sufficient to evaluate continuity of respiratory support and the occurrence of power interruption, clinically relevant equipment alarm, or technical failure.

Exclusion Criteria:

• Transport episodes not involving advanced respiratory support.
• Transport episodes for which continuity of respiratory support or the primary technical feasibility outcome could not be determined.