Low titer group O whole blood and risk of RhD alloimmunization: Rationale for use in Finland.

BACKGROUND: Prehospital low-titer group O whole blood (LTOWB) used for patients with life-threatening hemorrhage is often RhD positive. The most important complication following RhD alloimmunization is hemolytic disease of the fetus and newborn (HDFN). Preceding clinical use of RhD positive LTOWB, we estimated the risk of HDFN due to LTOWB prehospital transfusion in the Finnish population. STUDY DESIGN AND METHODS: We collected data on prehospital transfusions in Tampere and Helsinki University Hospital areas. Using the mean of reported alloimmunization rates in trauma studies (24%) and a higher reported rate representing trauma patients of 13-50 years old (42.7%), we estimated the risk of HDFN and extrapolated it to the whole of Finland. RESULTS: We estimated that in Finland, with the current prehospital transfusion rate we would see 1-3 cases of severe HDFN due to prehospital LTOWB transfusions every 10 years, and fetal death due to HDFN caused by LTOWB transfusion less than once in 100 years. DISCUSSION: The estimated risk of serious HDFN due to prehospital LTOWB transfusion in the Finnish population is similar to previous estimates. As Finland routinely screens expectant mothers for red blood cell antibodies and as the contemporary treatment of HDFN is very effective, we support the prehospital use of RhD positive LTOWB in all patient groups.

Multifaceted implementation and sustainability of a protocol for prehospital anaesthesia: a retrospective analysis of 2115 patients from helicopter emergency medical services.

BACKGROUND: Prehospital emergency anaesthesia (PHEA) is a high-risk procedure. We developed a prehospital anaesthesia protocol for helicopter emergency medical services (HEMS) that standardises the process and involves ambulance crews as active team members to increase efficiency and patient safety. The aim of the current study was to evaluate this change and its sustainability in (i) on-scene time, (ii) intubation first-pass success rate, and (iii) protocol compliance after a multifaceted implementation process. METHODS: The protocol was implemented in 2015 in a HEMS unit and collaborating emergency medical service systems. The implementation comprised dissemination of information, lectures, simulations, skill stations, academic detailing, and cognitive aids. The methods were tailored based on implementation science frameworks. Data from missions were gathered from mission databases and patient records. RESULTS: During the study period (2012-2020), 2381 adults underwent PHEA. The implementation year was excluded; 656 patients were analysed before and 1459 patients after implementation of the protocol. Baseline characteristics and patient categories were similar. On-scene time was significantly redused after the implementation (median 32 [IQR 25-42] vs. 29 [IQR 21-39] minutes, p < 0.001). First pass success rate increased constantly during the follow-up period from 74.4% (95% CI 70.7-77.8%) to 97.6% (95% CI 96.7-98.3%), p = 0.0001. Use of mechanical ventilation increased from 70.6% (95% CI 67.0-73.9%) to 93.4% (95% CI 92.3-94.8%), p = 0.0001, and use of rocuronium increased from 86.4% (95% CI 83.6-88.9%) to 98.5% (95% CI 97.7-99.0%), respectively. Deterioration in compliance indicators was not observed. CONCLUSIONS: We concluded that clinical performance in PHEA can be significantly improved through multifaceted implementation strategies.

Characteristics of Nontrauma Patients Receiving Prehospital Blood Transfusion with the Same Triggers as Trauma Patients: A Retrospective Observational Cohort Study.

Objective: While prehospital blood transfusion (PHBT) for trauma patients has been established in many services, the literature on PHBT use for nontrauma patients is limited. We aimed to describe and compare nontrauma and trauma patients receiving PHBT who had similar hemodynamic triggers. Methods: We analyzed 3.5 years of registry data from a single prehospital critical care unit. The PHBT protocol included two packed red blood cell units and was later completed with two freeze-dried plasma units. The transfusion triggers were a strong clinical suspicion of massive hemorrhage and systolic blood pressure below 90 mmHg or absent radial pulse. Results: Thirty-six nontrauma patients and 96 trauma patients received PHBT. The nontrauma group had elderly patients (median 65 [interquartile range, IQR, 56-73] vs 37 [IQR 25-57] years, p < 0.0001) and included patients with gastrointestinal bleeding (n = 15; 42%), vascular catastrophes (n = 9; 25%), postoperative bleeding (n = 6; 17%), obstetrical bleeding (n = 4; 11%) and other (n = 2; 6%). Cardiac arrest occurred in nine (25%) nontrauma and in 15 (16%) trauma patients. Of these, 5 (56%) and 10 (67%) survived to hospital admission and 3 (33%) and 2 (13%) to hospital discharge. On admission, the nontrauma patients had lower hemoglobin (median 95 [84-119] vs 124 [108-133], p < 0.0001), higher pH (median 7.40 [7.27-7.44] vs 7.30 [7.19-7.36], p = 0.0015) and lower plasma thromboplastin time (median 55 [45-81] vs 72 [58-86], p = 0.0261) than the trauma patients. Conclusions: We identified four nontrauma patient groups in need of PHBT, and the patients appeared to be seriously ill. Efficacy of prehospital transfusion in nontrauma patients should be evaluated futher in becoming studies.

Incidence of hyperoxia and factors associated with cerebral oxygenation during cardiopulmonary resuscitation.

BACKGROUND: High oxygen levels may worsen cardiac arrest reperfusion injury. We determined the incidence of hyperoxia during and immediately after successful cardiopulmonary resuscitation and identified factors associated with intra-arrest cerebral oxygenation measured with near-infrared spectroscopy (NIRS). METHODS: A prospective observational study of out-of-hospital cardiac arrest patients treated by a physician-staffed helicopter unit. Collected data included intra-arrest brain regional oxygen saturation (rSO2) with NIRS, invasive blood pressures, end-tidal CO2 (etCO2) and arterial blood gas samples. Moderate and severe hyperoxia were defined as arterial oxygen partial pressure (paO2) 20.0-39.9 and ≥40 kPa, respectively. Intra-arrest factors correlated with the NIRS value, rSO2, were assessed with the Spearman's correlation test. RESULTS: Of 80 recruited patients, 73 (91%) patients had rSO2 recorded during CPR, and 46 had an intra-arrest paO2 analysed. ROSC was achieved in 28 patients, of whom 20 had paO2 analysed. Moderate hyperoxia was seen in one patient during CPR and in four patients (20%, 95% CI 7-42%) after ROSC. None had severe hyperoxia during CPR, and one patient (5%, 95% 0-25%) immediately after ROSC. The rSO2 during CPR was correlated with intra-arrest systolic (r = 0.28, p < 0.001) and diastolic blood pressure (p = 0.32, p < 0.001) but not with paO2 (r = 0.13, p = 0.41), paCO2 (r = 0.18, p = 0.22) or etCO2 (r = 0.008, p = 0.9). CONCLUSION: Hyperoxia during or immediately after CPR is rare in patients treated by physician-staffed helicopter units. Cerebral oxygenation during CPR appears more dependent, albeit weakly, on hemodynamics than arterial oxygen concentration.

Arterial and end-tidal carbon dioxide partial pressure difference during prehospital anaesthesia in critically ill patients.

BACKGROUND: Normoventilation is crucial for many critically ill patients. Ventilation is routinely guided by end-tidal capnography during prehospital anaesthesia, based on the assumption of the gap between arterial partial pressure of carbon dioxide (PaCO2 ) and end-tidal carbon dioxide partial pressure (PetCO2 ) of approximately 0.5 kPa (3.8 mmHg). METHODS: We retrospectively analysed the airway registry and patient chart data of patients who had been anaesthetised and intubated endotracheally by the prehospital critical care team and had their prehospital arterial blood gases analysed. Bland-Altman analysis was used to estimate the bias and limits of agreement. RESULTS: Altogether 502 patients were included in the study, with a median age of 58 years. The most common patient groups were post-resuscitation (155, 31%), neurological emergencies (96, 19%), intoxication (75, 15%) and trauma (68, 14%). The median of the gap between PaCO2 and PetCO2 was 1.3 kPa (interquartile range 0.7 to 2.2) (9.8 (5.3-16.5) mmHg). Mean bias of PetCO2 was -1.6 kPa/12.0 mmHg (standard deviation 1.7 kPa/12.8 mmHg) with 95% confidence limits of agreement -4.9 to 1.9 kPa (-36.8 to 14.3 mmHg). The gap was ≥ 1.0 kPa (>7.5 mmHg) in 297 (66%, 95% confidence interval 55 to 63) patients. CONCLUSION: Our results suggest that end-tidal capnography alone might not be an adequate method to achieve normoventilation for critically ill patients intubated and mechanically ventilated in prehospital setting. Thus, an arterial blood gas analysis might be useful to recognize patients with an increased gap between PaCO2 and PetCO2 .

Mechanisms of early glucose regulation disturbance after out-of-hospital cardiopulmonary resuscitation: An explorative prospective study.

BACKGROUND: Hyperglycemia is common and associated with increased mortality after out-of-hospital cardiac arrest (OHCA) and return of spontaneous circulation (ROSC). Mechanisms behind ultra-acute hyperglycemia are not well known. We performed an explorative study to describe the changes in glucose metabolism mediators during the prehospital postresuscitation phase. METHODS: We included patients who were successfully resuscitated from out-of-hospital cardiac arrest in two physician-staffed units. Insulin, glucagon, and glucagon-like peptide 1 (GLP-1) were measured in prehospital and hospital admission samples. Additionally, interleukin-6 (IL-6), cortisol, and HbA1c were measured at hospital admission. RESULTS: Thirty patients participated in the study. Of those, 28 cases (71% without diabetes) had sufficient data for analysis. The median time interval between prehospital samples and hospital admission samples was 96 minutes (IQR 85-119). At the time of ROSC, the patients were hyperglycemic (11.2 mmol/l, IQR 8.8-15.7), with insulin and glucagon concentrations varying considerably, although mostly corresponding to fasting levels (10.1 mU/l, IQR 4.2-25.2 and 141 ng/l, IQR 105-240, respectively). GLP-1 increased 2- to 8-fold with elevation of IL-6. The median glucose change from prehospital to hospital admission was -2.2 mmol/l (IQR -3.6 to -0.2). No significant correlations between the change in plasma glucose levels and the changes in insulin (r = 0.30, p = 0.13), glucagon (r = 0.29, p = 0.17), or GLP-1 levels (r = 0.32, p = 0.15) or with IL-6 (r = (-0.07), p = 0.75), cortisol (r = 0.13, p = 0.52) or HbA1c levels (r = 0.34, p = 0.08) were observed. However, in patients who did not receive exogenous epinephrine during resuscitation, changes in blood glucose correlated with changes in insulin (r = 0.59, p = 0.04) and glucagon (r = 0.65, p = 0.05) levels, demonstrating that lowering glucose values was associated with a simultaneous lowering of insulin and glucagon levels. CONCLUSIONS: Hyperglycemia is common immediately after OHCA and cardiopulmonary resuscitation. No clear hormonal mechanisms were observed to be linked to changes in glucose levels during the postresuscitation phase in the whole cohort. However, in patients without exogenous epinephrine treatment, the correlations between glycemic and hormonal changes were more obvious. These results call for future studies examining the mechanisms of postresuscitation hyperglycemia and the metabolic effects of the global ischemic insult and medical treatment.

Intravitreal triamcinolone acetonide as an adjuvant therapy to panretinal photocoagulation for proliferative retinopathy with high risk characteristics in type 1 diabetes: case report with 22 weeks follow-up.

PURPOSE: To describe a new treatment protocol to deliver panretinal photocoagulation that may avoid further deterioration of vision in patients with type 1 diabetes mellitus with proliferative retinopathy with high risk characteristics for severe visual loss and cystoid macular oedema. METHODS: Fundus photography, measurement of foveal thickness with optical coherence tomography and best corrected visual acuity (BCVA) determined by Snellen and ETDRS charts were measured before and after treatment in a 28-year-old man. RESULTS: Over 9 weeks, BCVA improved from 0.05 to 0.25 and the number of letters read at 2 metres from four to 39 after panretinal photocoagulation and adjuvant intravitreal triamcinolone injection under intraconal anaesthesia. Foveal thickness decreased from 691 microm to 239 microm and cysts disappeared by 15 weeks. By 22 weeks, foveal thickness had increased to 282 microm and small cysts had reappeared, but BCVA remained at 0.2 and the number of letters read at 30. CONCLUSION: Proliferative retinopathy regressed, cystoid macular oedema disappeared and vision improved after panretinal photocoagulation and adjuvant intravitreal triamcinolone acetonide injection under intraconal anaesthesia. This represents a feasible option in cases where pain during laser treatment and impairment of vision afterwards due to cystoid macular oedema result in poor compliance with standard laser treatment under topical anaesthesia.