Learning Critical Care Medicine

Pathophysiology of sepsis explains that after fluid resuscitation with 20-30 ml/kg ( which is the pressure volume of intravascular space), it is unlikely that septic shock will respond to additional fluid resuscitation. There may be transient response, as only five percent of the crystalloid will remain in the intravascular space, and rest of the fluid will accumulate in third space, giving rise to further organ damage. Fluid resuscitation further exacerbates the deranged physiology including vasodilatation. Multiple Clinical trials have suggested that positive fluid balance independently causes increased morbidity and mortality. Vasopressors should not be delayed after initial fluid resuscitation with 20-30ml/kg. Thereafter further fluid boluses may be given based on dynamic parameters of fluid responsiveness.

“Central venous pressure measurement is not a surrogate of intravascular volume or ventricular preload for fluid resuscitation. For this, fluid responsiveness has to be assessed.” This discussion is for physiological purpose only. Invasive pressure monitoring of central venous pressure, is measurement of intramural pressure (Pim) of the vessel.                                                                                              Flow across a vessel is a function of intramural pressure gradient and resistance to the flow.                                     Force driving flow (F) = ∆P/ R                                                       According to Poiseuille equation resistance is inversely proportional to fourth power of radius.                                                                                ( ⁿ = viscosity of fluid, L= length of tube, r= radius of tube) Radius of a distensible tube depends on transmural pressure (Ptm),

BASIC LIFE SUPPORT (BLS) : Compression rate is modified to a range of 100 to 120/min. (Should not exceed 120/min ).  Compression depth for adults is modified to at least 2 inches (5 cm). (Should not exceed 2.4 inches (6 cm). To allow full chest wall recoil after each compression, rescuers must avoid leaning on the chest between compressions.  Criteria for minimizing interruptions is clarified with a goal of chest compression fraction as high as possible, with a target of at least 60%.  For patients with ongoing CPR and an advanced airway in place, a simplified ventilation rate of 1 breath every 6 seconds (10 breaths per minute) is recommended. For witnessed OHCA with a shockable rhythm , it may be reasonable to delay positive-pressure ventilation (PPV) by using a strategy of up to 3 cycles of 200 continuous compressions with passive oxygen insufflation and airway adjuncts. ADVANCE CARDIAC LIFE SUPPORT (ACLS) :     Vasopressin has been removed from the