title: Therapeutic hypothermia and early waking: Waking unconscious survivors following out-of-hospital cardiac arrest to positively neurologically prognosticate

authors: Watson, Noel

subjects: therapeutic hypothermia

abstract: Introduction: Cardiac arrest is a significant global health challenge, which leads to substantial morbidity and mortality, impacting 50 to 100 individuals per 100,000 in the general population. Ischemic heart disease is the primary cause, particularly in developed countries. Historically, survival rates following cardiac arrest with a good neurological outcome were low; however, advancements in emergency response, including early Cardio-Pulmonary Resuscitation (CPR), access to defibrillation, coronary revascularisation, intensive care and Targeted Temperature Management (TTM), have notably improved patient outcomes. The practice of TTM has evolved over the past two decades, advocating that Therapeutic Hypothermia (TH) enhances neurological outcomes; although there has been much controversy over optimal temperature ranges. Notwithstanding, international resuscitation guidelines continue to endorse TTM as a post-resuscitation neuroprotective strategy, recommending temperatures between 32° and 36° Celsius. To ensure patient comfort and prevent shivering during the administration of TTM, sedatives and neuromuscular blockers are administered, preventing an accurate neurological assessment. Despite the challenges of neurological prognostication post-cardiac arrest, current guidelines recommend a multimodal approach, including clinical examination, electrophysiological studies, biomarkers, and neuroimaging, to predict outcomes accurately. 

Aim: This research sought to develop and evaluate a protocol (Therapeutic Hypothermia and eArly Waking, THAW) for early waking of unconscious Out-of-Hospital-Cardiac-Arrest (OHCA) survivors for the purpose of performing a comprehensive neurological assessment. 

Methods: A mixed methods approach was used. In the development of the THAW protocol, qualitative data were obtained from a series of focus groups, which included the research team, the National Health Service Ethics committee, a clinical expert panel, OHCA survivors and their family members as well as the Essex Cardiothoracic Centre’s Clinical Governance Committee. Thematic analysis was undertaken to capture the varied perspectives and insights from the different stakeholder groups to inform the THAW protocol interventions. A prospective non-randomised sampling strategy was selected for the implementation of the THAW protocol and neurological indicators collected over a 72-hour period. 

Results: The THAW protocol assessed the safety and feasibility of an early waking protocol for unconscious survivors of OHCA treated with TTM at 33° Celsius, with a focus on the potential to reduce Intensive Care Unit (ICU) stay and mechanical ventilation duration through early neurological assessments. Despite an expected 50 percent mortality rate, largely due to neurological injuries, findings demonstrated that early waking and extubation with a mean mechanical ventilation duration of 21.4 hours, was feasible for 24 percent of patients, significantly reducing ICU length of stay without adverse events. Of these, seven patients (14%) were able to be transferred from the ICU to the cardiology High Dependency Unit (HDU) within the first 72 hours of their admission. The THAW protocol employed a combination of Intravenous Temperature Management (IVTM) and a counter-shivering strategy to manage core temperature, alongside physiological assessments and standard neurological exams like the Glasgow Coma Scale (GCS) and the Full Outline of UnResponsiveness (FOUR) score. Notably, the neuro biomarker and neurophysiological tests performed as part of the THAW protocol interventions, were not used to inform clinical decision-making, instead to be used in post hoc analysis to maintain objectivity. 

Conclusion: The THAW protocol demonstrated the safety and feasibility of an early waking protocol in OHCA survivors undergoing TTM at 33° Celsius. Highlighting the potential to expedite neurological prognostication and reduce ICU length of stay and mechanical ventilation duration. Through careful patient selection, the implementation of IVTM with a counter-shivering strategy, early neurological assessments can be integrated into critical care practices without adverse effects on patients.

text: Therapeutic hypothermia and early waking: Waking unconscious survivors following out-of-hospital cardiac arrest to positively neurologically prognosticate Introduction: Cardiac arrest is a significant global health challenge, which leads to substantial morbidity and mortality, impacting 50 to 100 individuals per 100,000 in the general population. Ischemic heart disease is the primary cause, particularly in developed countries. Historically, survival rates following cardiac arrest with a good neurological outcome were low; however, advancements in emergency response, including early Cardio-Pulmonary Resuscitation (CPR), access to defibrillation, coronary revascularisation, intensive care and Targeted Temperature Management (TTM), have notably improved patient outcomes. The practice of TTM has evolved over the past two decades, advocating that Therapeutic Hypothermia (TH) enhances neurological outcomes; although there has been much controversy over optimal temperature ranges. Notwithstanding, international resuscitation guidelines continue to endorse TTM as a post-resuscitation neuroprotective strategy, recommending temperatures between 32° and 36° Celsius. To ensure patient comfort and prevent shivering during the administration of TTM, sedatives and neuromuscular blockers are administered, preventing an accurate neurological assessment. Despite the challenges of neurological prognostication post-cardiac arrest, current guidelines recommend a multimodal approach, including clinical examination, electrophysiological studies, biomarkers, and neuroimaging, to predict outcomes accurately. 

Aim: This research sought to develop and evaluate a protocol (Therapeutic Hypothermia and eArly Waking, THAW) for early waking of unconscious Out-of-Hospital-Cardiac-Arrest (OHCA) survivors for the purpose of performing a comprehensive neurological assessment. 

Methods: A mixed methods approach was used. In the development of the THAW protocol, qualitative data were obtained from a series of focus groups, which included the research team, the National Health Service Ethics committee, a clinical expert panel, OHCA survivors and their family members as well as the Essex Cardiothoracic Centre’s Clinical Governance Committee. Thematic analysis was undertaken to capture the varied perspectives and insights from the different stakeholder groups to inform the THAW protocol interventions. A prospective non-randomised sampling strategy was selected for the implementation of the THAW protocol and neurological indicators collected over a 72-hour period. 

Results: The THAW protocol assessed the safety and feasibility of an early waking protocol for unconscious survivors of OHCA treated with TTM at 33° Celsius, with a focus on the potential to reduce Intensive Care Unit (ICU) stay and mechanical ventilation duration through early neurological assessments. Despite an expected 50 percent mortality rate, largely due to neurological injuries, findings demonstrated that early waking and extubation with a mean mechanical ventilation duration of 21.4 hours, was feasible for 24 percent of patients, significantly reducing ICU length of stay without adverse events. Of these, seven patients (14%) were able to be transferred from the ICU to the cardiology High Dependency Unit (HDU) within the first 72 hours of their admission. The THAW protocol employed a combination of Intravenous Temperature Management (IVTM) and a counter-shivering strategy to manage core temperature, alongside physiological assessments and standard neurological exams like the Glasgow Coma Scale (GCS) and the Full Outline of UnResponsiveness (FOUR) score. Notably, the neuro biomarker and neurophysiological tests performed as part of the THAW protocol interventions, were not used to inform clinical decision-making, instead to be used in post hoc analysis to maintain objectivity. 

Conclusion: The THAW protocol demonstrated the safety and feasibility of an early waking protocol in OHCA survivors undergoing TTM at 33° Celsius. Highlighting the potential to expedite neurological prognostication and reduce ICU length of stay and mechanical ventilation duration. Through careful patient selection, the implementation of IVTM with a counter-shivering strategy, early neurological assessments can be integrated into critical care practices without adverse effects on patients.

year: 2024

title: Effects of a pre-flower phloem girdle on root pressure and partitioning of carbohydrate in Actinidia chinensis var. deliciosa 'Hayward'

authors: Haisman, Nicola Ann

subjects: kiwifruit

abstract: The objective of this research is to understand the impacts of applying a pre-flower trunk girdle to the kiwifruit cultivar ‘Hayward’ (Actinidia chinensis var. deliciosa).  The pre-flower girdle is a recent addition to the management of ‘Hayward’ kiwifruit orchards since it was discovered that it can reduce flower budrot. However, the effects of a trunk girdle in early spring on the partitioning of resources through the vine and the impacts on vine growth are unknown. 
Two approaches were used to address the objective. The first approach was to  use mature ‘Hayward’ vines at the Plant and Food Research Orchard, Te Puke in the Bay of Plenty.  The aims were to determine if xylem mobile sugars are important in the development of spring root pressure, and to define the impacts of a pre-flower girdle on root pressure, carbohydrate partitioning and storage, and vine phenology within the vine.  The second section of research used the detection of Bremmstrahlung radiation to trace the in vivo movement of radiolabelled photosynthate through ‘Hayward’ scions recently grafted onto Bruno rootstocks. The aim was to understand how stem girdling effects the movement of carbohydrate between source and sink tissues of young developing vines. 
Key results of this research were that the refilling of xylem vessels and the establishment of hydrostatic pressure in early spring occurs gradually from the roots up the trunk of the vine.  Fructose in the fine roots was identified as a key carbohydrate in the generation of the hydrostatic pressure required to refill xylem conduits after winter dormancy.  After a pre-flower trunk phloem girdle was applied there was a loss of xylem pressure that lasted for two weeks. The cause has not been resolved though results from this study suggest a relationship with loss of phloem flow, or cavitation induced air embolisms in the xylem preventing xylem pressure recovery.  
Leaves from girdled vines exported less carbohydrate than non-girdled vines which suggests a delayed transition to an autotrophic status.  Root and trunk carbohydrates showed little short-term effect of the pre-flower girdle.  However, there was a location effect seen with the trunk bark carbohydrates that suggest the utilisation of ‘local’ reserves is exploited in preference to long-distant transport of reserves.  There was no detectable short-term impacts of the pre-flower girdle on phenology. 
Further research is proposed to understand the long-term impacts of a pre-flower girdle on root pressure, carbohydrate storage and the development of seasonal organs.

text: Effects of a pre-flower phloem girdle on root pressure and partitioning of carbohydrate in Actinidia chinensis var. deliciosa 'Hayward' The objective of this research is to understand the impacts of applying a pre-flower trunk girdle to the kiwifruit cultivar ‘Hayward’ (Actinidia chinensis var. deliciosa).  The pre-flower girdle is a recent addition to the management of ‘Hayward’ kiwifruit orchards since it was discovered that it can reduce flower budrot. However, the effects of a trunk girdle in early spring on the partitioning of resources through the vine and the impacts on vine growth are unknown. 
Two approaches were used to address the objective. The first approach was to  use mature ‘Hayward’ vines at the Plant and Food Research Orchard, Te Puke in the Bay of Plenty.  The aims were to determine if xylem mobile sugars are important in the development of spring root pressure, and to define the impacts of a pre-flower girdle on root pressure, carbohydrate partitioning and storage, and vine phenology within the vine.  The second section of research used the detection of Bremmstrahlung radiation to trace the in vivo movement of radiolabelled photosynthate through ‘Hayward’ scions recently grafted onto Bruno rootstocks. The aim was to understand how stem girdling effects the movement of carbohydrate between source and sink tissues of young developing vines. 
Key results of this research were that the refilling of xylem vessels and the establishment of hydrostatic pressure in early spring occurs gradually from the roots up the trunk of the vine.  Fructose in the fine roots was identified as a key carbohydrate in the generation of the hydrostatic pressure required to refill xylem conduits after winter dormancy.  After a pre-flower trunk phloem girdle was applied there was a loss of xylem pressure that lasted for two weeks. The cause has not been resolved though results from this study suggest a relationship with loss of phloem flow, or cavitation induced air embolisms in the xylem preventing xylem pressure recovery.  
Leaves from girdled vines exported less carbohydrate than non-girdled vines which suggests a delayed transition to an autotrophic status.  Root and trunk carbohydrates showed little short-term effect of the pre-flower girdle.  However, there was a location effect seen with the trunk bark carbohydrates that suggest the utilisation of ‘local’ reserves is exploited in preference to long-distant transport of reserves.  There was no detectable short-term impacts of the pre-flower girdle on phenology. 
Further research is proposed to understand the long-term impacts of a pre-flower girdle on root pressure, carbohydrate storage and the development of seasonal organs.

year: 2019

title: Spat survival of Paphies ventricosa (Toheroa) in an aquaculture setting

authors: Chew, Martyn Andrew

abstract: The toheroa (Papris ventracosta) is a large intertidal surf cam endemic to New Zealand. This species has a long history with the people of New Zealand in both cultural and economic sense. Exploitation and environmental change have greatly diminished the wild stocks of these animals making a sustainable fishery no longer feasible. Aquaculture has been widely discussed as a potentially profitable option for this species due to its large size, esteemed taste and its social and cultural significance. Aquaculture of toheroa could generate many benefits for the people of the toheroa beaches, as aquaculture has done in other regions of New Zealand. However, the suitability of toheroa for aquaculture is largely unknown, with many questions needing to be answered before that can become a reality. The purpose of this research is to gain a better understanding of the environmental conditions which will support the successful cultivation of wild caught toheroa spat in recirculating aquaculture systems (RAS). This is done by answering questions around knowledge gaps in the biology of the animal. Three experiments were conducted on aspects of the animal’s environment and biology. The first experiment sought to identify the presence of microphytobenthos’s within the wild population beds of the toheroa. As evidence suggests from research conducted on other species, microphytobenthos is an essential part of the animal’s ecosystem which might be a necessary component of a successful spat rearing operation. The experiment showed elevated chlorophyll levels (a proxy for microphytobenthos) within toheroa beds relative to other areas of the beach. The second experiment compared survival and growth rates in sediment vs. non-sediment holding systems. The results of this study indicated the benefits of housing spat in sediments, as demonstrated by differences in measured growth and mortality. A third experiment sought to test for size dependent mortality rates within the RAS. Somewhat surprisingly, it was found that smaller toheroa (0-10mm) performed better within a system compared to larger ones (20-30). Larger toheroa tended to eject themselves from the sediment constantly, an act which may have compromised their growth and survivorship. The result of these experiments answered questions and raise many more.  Potentially through understanding these questions we can create tools which industry and conservation can use. This research show that successful toheroa spat can be successfully integrated into an aquaculture system. With mortality settling the animals feeding and showing healthy condition. However, the next stage would be to optimize this. Toheroa aquaculture being in its infancy requires a wide variety of research before considered feasible. However, results and observations made from this research can help in identifying and specializing future research objectives.

text: Spat survival of Paphies ventricosa (Toheroa) in an aquaculture setting The toheroa (Papris ventracosta) is a large intertidal surf cam endemic to New Zealand. This species has a long history with the people of New Zealand in both cultural and economic sense. Exploitation and environmental change have greatly diminished the wild stocks of these animals making a sustainable fishery no longer feasible. Aquaculture has been widely discussed as a potentially profitable option for this species due to its large size, esteemed taste and its social and cultural significance. Aquaculture of toheroa could generate many benefits for the people of the toheroa beaches, as aquaculture has done in other regions of New Zealand. However, the suitability of toheroa for aquaculture is largely unknown, with many questions needing to be answered before that can become a reality. The purpose of this research is to gain a better understanding of the environmental conditions which will support the successful cultivation of wild caught toheroa spat in recirculating aquaculture systems (RAS). This is done by answering questions around knowledge gaps in the biology of the animal. Three experiments were conducted on aspects of the animal’s environment and biology. The first experiment sought to identify the presence of microphytobenthos’s within the wild population beds of the toheroa. As evidence suggests from research conducted on other species, microphytobenthos is an essential part of the animal’s ecosystem which might be a necessary component of a successful spat rearing operation. The experiment showed elevated chlorophyll levels (a proxy for microphytobenthos) within toheroa beds relative to other areas of the beach. The second experiment compared survival and growth rates in sediment vs. non-sediment holding systems. The results of this study indicated the benefits of housing spat in sediments, as demonstrated by differences in measured growth and mortality. A third experiment sought to test for size dependent mortality rates within the RAS. Somewhat surprisingly, it was found that smaller toheroa (0-10mm) performed better within a system compared to larger ones (20-30). Larger toheroa tended to eject themselves from the sediment constantly, an act which may have compromised their growth and survivorship. The result of these experiments answered questions and raise many more.  Potentially through understanding these questions we can create tools which industry and conservation can use. This research show that successful toheroa spat can be successfully integrated into an aquaculture system. With mortality settling the animals feeding and showing healthy condition. However, the next stage would be to optimize this. Toheroa aquaculture being in its infancy requires a wide variety of research before considered feasible. However, results and observations made from this research can help in identifying and specializing future research objectives.

year: 2022