The aim of this study was to advance the conceptualisation of team adaptation by applying social network analysis (SNA) measures in a field study of a paediatric cardiac surgical team adapting to changes in task complexity and ongoing dynamic complexity. Forty surgical procedures were observed by trained human factors researchers, and communication processes amongst team members were recorded. Focusing on who talked to whom, team communication structures, in response to changing task demands, were characterised by various network measures. Results showed that in complex procedures, the communication patterns were more decentralised and flatter. Also, in critical transition phases of the procedure, communication was characterised by higher information sharing and participation. We discuss implications for team adaptation theory and teamwork observation methods. Practitioner Summary: The reasons for this study were to advance our conceptualisation of team adaptation processes and to further quantify team observation methods. We found that the surgical team studied adapted to complexity of surgical procedures by adopting flatter communication patterns. We quantified team observation methods by applying SNA techniques.