Safe, convenient and reliable infusion is the basic requirement for treating patients with acute and critical illnesses. In the past, this was mainly realized through intravenous access, based on the method and principle of “8 parts and 16 points of the whole body” for the establishment of veins, so that it could be chosen for different patients in different situations. However, even the most convenient and fastest points require specialized medical staff and may be subject to conditions that make it difficult to achieve the “platinum ten minutes”. Are there any remedies or alternatives when it is difficult to establish intravenous access? The answer is yes, and that is the use of bone marrow infusion (IO), a technique that has been around for a long time, but for various reasons has been “hidden” for a long time, and is now being re-recognized and used around the world. [History and development] Early technology has been re-emerging in the light and heat In 1922, Drinker proposed the concept that the sternum can be used as the infusion site in animal experiments. 1934, Josefson reported that the sternal infusion for the treatment of pernicious anemia had achieved good results. 1940, Tocantins et al. observed that the dye appeared in the heart 10s after it was injected into the tibial cavity of the rabbit, and he designed a clinical IO special injection needle. In 1942, Papper demonstrated that infusion via IO or IV access had similar circulation times. The largest sample size to date was reported in 1947, when 982 IOs were performed in 495 patients, with only 18 failures and 5 cases of osteomyelitis. In World War II, IO techniques were widely used by U.S. Army field medical treatment facilities and saved the lives of more than 4,000 severely injured soldiers, and were considered a standard measure by the U.S. Army for treating severely injured patients. Unfortunately, the success of the IO technique did not spread from the military to the local level when David Boyd and others founded the first emergency medical service in Chicago in 1968. Many trauma surgeons were unfamiliar with military IO techniques and were content with the existing IV techniques, which, coupled with the rapid development of IV infusion methods, had been all but invisible for some time. It was not until 1984 that James, while visiting cholera-endemic India, discovered that the use of IO technology for infusion and drug delivery had saved many patients who might have died from cholera, and wrote the review My Kingdom of Intravenous Access to advocate for the use of IO technology in pediatrics. This revived interest in IO and it was first adopted by pediatric providers as an advanced life-saving technique for children, and in 1986, the American College of Cardiology formally endorsed the inclusion of IO in pediatric emergency resuscitation procedures. In 2003, the Journal of Trauma-Injury Infection and Resuscitation organized an in-depth discussion on fluid resuscitation and provided the most comprehensive and scientific summary of the IO technique since its inception: the bone marrow can be regarded as a vein that will never atrophy, and the indications for IO include the field, the battlefield, technological limitations, and the presence of a large number of casualties. According to the characteristics of IO, combined with the theory of tolerable hypoperfusion resuscitation, some scholars have proposed bone marrow single-dose hypertonic saline-glycolic anhydride low-volume resuscitation strategy. In recent years, IO has been used on the battlefield again in local wars, and its simplicity can be mastered by the soldiers as the first rescuer, which shows its great potential in popularization. At the same time, domestic scholars have also begun to use IO in clinical practice and gained valuable experience. Clinical application】Make up for the short board of the establishment of venous access The American Heart Association, the European Resuscitation Council, and the International Liaison Committee for Resuscitation pointed out in the 2000 resuscitation guidelines that: in the process of first aid, the establishment of vascular access should be considered as early as possible to use the bone marrow intramural vascular access. Bone marrow endovascular access has the same time to peak blood concentration as central venous cannulation and has fewer complications. Intramedullary vascular access is preferred in adult cardiac arrest. Establishment of endovascular access to the bone marrow is the standard method of resuscitation in patients with cardiac arrest. Indications Include (1) failed attempts to establish intravenous fluids, (2) bulk injuries and illnesses that urgently require infusion access, and (3) infusion access for cardiopulmonary resuscitation. The success rate of bone marrow cavity puncture can reach 80%~97% at one time. Commonly used puncture sites The more commonly reported puncture sites in the literature are the tibia, ilium, sternum, etc., but also the humerus, femur, clavicle, and the inner ankle of the tibia according to personal experience. In adults, the upper end of the tibia is often chosen, and the most commonly used puncture site is about 3 cm below the tibial plateau.Warren et al. showed that the distal tibia, distal femur, and proximal humerus can be used as the infusion site, and the efficacy is similar to that of vein; iliac, sternum, and clavicle, which are rich in red bone marrow, can be used, but they are not as convenient as long bones of limbs with a high success rate. In conclusion, as long as the bone marrow cavity can be accessed, many sites can be established bone marrow cavity access. Speed and success rate of establishing access The establishment of marrow cavity access is very fast. Zhang Jixin et al. reported that in prehospital emergency treatment of traffic accidents, the average time to establish bone marrow access was 2.4 min in the group, and 11.8 min in the transvenous group; Rhee Iwana et al. reported that the average time to establish venous access for children in respiratory and cardiac arrest was 7.8 min, and more than 10 min was used in 24% of the cases; and the establishment of IO of the lower limbs was only 1-2 min, and it did not interfere with the operation of resuscitation. Success rates for establishing bone marrow access were approximately 80% in the emergency room and 78% when performed by paramedics outside the hospital; 85% in children aged 1-2 years, 67% in children aged 3-9 years, and 50% in children aged 10 years or older, with high success rates in infants and children, where venous access is most difficult to establish. Infusion rate Warren et al. studied the IO rate of different sites in adults and found that at normal pressure and pressurized to 39.9 kPa, the IO rate of humerus was 11.1 ml/min and 41.3 ml/min; the lower end of femur was 9.3 ml/min and 29.5 ml/min; the inner and outer ankles were 8.2 ml/min and 24.1 ml/min; the tibia was 4.3 ml/min and 17.0 ml/min. It can fully meet the need of rapid volume expansion. Drugs that can be infused The fluids and drugs that can be infused through the bone marrow cavity pathway include: basic fluids, vasoactive drugs, respiratory stimulants, and drugs that affect the heart rhythm, etc. Many of these drugs are stimulants. Many of these drugs are irritants and are not suitable, or even prohibited, for peripheral intravenous infusion. Infusion apparatus Bone marrow cavity infusion device categories are more, foreign countries mainly FAST infusion device, bone marrow infusion gun, hand turn bone marrow cavity infusion device, straight needle bone infusion device, electric drill bone infusion device, etc., of which the electric drill bone infusion device is more stable and reliable. Due to the high price of imported products, it is difficult to popularize the application in China in the short term. There are also related or substitute products in China, mainly 16~20 gauge bone puncture needles with needle core, standard butterfly needles, standard lumbar puncture needles, pen-point intraosseous puncture needles, sternal or iliac bone marrow aspiration needles, etc. There are even successful reports on the use of scalp needles for sternal puncture. Domestic products use human power to feed the needle, which is cheap and practical. At the beginning of the 21st century, Sheng Zhiyong academician of the Chinese Academy of Engineering, a famous trauma/burn expert, put forward the idea of improving the first-aid infusion technology and developing lightweight and practical infusion technology for the battlefield and disaster site. Under the guidance of Academician Sheng, the author’s group chose the ejection type bone marrow infusion device for research and development, and achieved stage-by-stage results. The Warfighter Rapid Bone Marrow Infuser was approved by the Ministry of Health of the General Logistics Department of the Chinese People’s Liberation Army for expanded clinical trials. It has been completed in the lower tibia, distal radius, anterior superior iliac spine, posterior superior skeletal spine and other parts of cardiopulmonary resuscitation, shock rehydration, bone marrow puncture and other nearly 30 cases of clinical application observation, the effect is good. Complications and contraindications] Bone injury, bone dysplasia with caution Although complications of IO are uncommon, they have been reported, including the following. Subcutaneous and subperiosteal fluid swelling. The most common cause is extravasation of subcutaneous and subperiosteal fluid from the puncture site, especially in pressurized infusion or prolonged application. Extravasation of irritating fluids, such as sodium bicarbonate, can cause local inflammation or infection in mild cases and tissue necrosis in severe cases, at which time the IO should be terminated, and a localized compression bandage can be applied at the same time. Literature reports that the incidence of local cellulitis and subcutaneous abscesses caused by fluid extravasation and infiltration is 0.7%. Fluid extravasation can also occur in bone injuries with cracks in the cortex, and IO is contraindicated in affected bones. Osteomyelitis. The incidence of osteomyelitis has not exceeded 1% in decades of IO treatment statistics.Rosetti reported 4,270 cases of IO, and osteomyelitis occurred in only 27 cases, or 0.6%. Fractures. Rarer. Others. Includes reports of sternal puncture with mediastinitis, subperiosteal infusion, bone marrow injury, inadvertent intra-articular entry, localized skin infection, loose bone pins, broken bone pins, infant growth plate injury, sepsis, and potential fat embolism. Hypertonic solutions can cause bone marrow necrosis and fibrin deposition, and increased periosteal reactions, based on histologic and radiologic changes in the bone marrow after infusion. Histologic examination of experimental animals that developed IO adverse reactions showed that sternal bone trabeculae and bone marrow fat were not damaged, but hematopoietic cells disappeared or decreased 1-2 d after infusion, and bone specimens at the injection site at 2-6 weeks showed that the oligocellular areas had been replaced by fibrous tissue; the above changes were seen only within a diameter of 0.6 cm of the injection site, and there was no functional or histologic evidence of pulmonary embolism, and the physiologic effects were mild. In conclusion, it is concluded that IO should not be established in bones that have undergone fracture, in patients with osteogenesis imperfecta, in patients with severe osteoporosis, and in those who have developed cellulitis at the puncture site, and that re-IO should be avoided in the same bone.