H1N1 Update 16 December 2010 sent from the UK Intensive Care Society
As many of you will already be aware, the predicted second wave of swine flu seems to becoming a reality. The HPA have received information that there has been a rise in the number of confirmed H1N1 cases and has restarted regular teleconferences to discuss the current situation and to disseminate the latest advice and information. The initial teleconference was held last Friday and the first question asked was how many cases have units seen. Although the total numbers were not high, the fact that there are confirmed cases throughout the UK gave support to the decision that hospitals should prepare for an increase in the numbers.
Subsequent updates have confirmed that the case numbers are rising and although not all patients admitted to ICUs with a suspected diagnosis of H1N1 have required mechanical ventilation or had H1N1 confirmed. As of Wednesday this week the numbers of H1N1 related ICU cases had risen to 140. An additional concern is that the number of cases with probable H1N1 referred for ECMO is now 13 and this has resulted in a policy that there should be support for all the centers in the UK who can provide ECMO.
It is still too early to predict what the level escalation is going to be required, but there are real concerns that the combination of adverse weather conditions, the current financial restrictions in the NHS, and an H1N1 peak could place ICUs in a more seriously challenging situation than occurred in the previous outbreak.
For this reason, it is recommended that clinicians should once again have a low threshold for considering the possibility of H1N1 in patients who are referred to intensive care. Trusts should reconvene regular meetings to plan for any necessary expansion of critical care services. It is important that staff have up to date training in the use of personal protection equipment. One of the most important points learned from the first outbreak was that early antiviral therapy can reduce the need for mechanical ventilation and it is recommended that any patients admitted to hospital with a history and symptoms suggestive of an influenza-like illness should be given antiviral therapy.
The following points were made in the HPA–led teleconference on 10 December:
be vigilant: have a low threshold for considering the diagnosis.
start antivirals whenever there is a suspicion of flu (oseltamivir 75or 150 mg bd po).
In patients with resistance or not tolerating NG medication, there is an IV preparation which is currently undergoing clinical trial. GSK produces it (zanamavir) and may provide it on patient-name compassionate grounds.
Use ARDSnet ventilation especially for those with normal lung compliance.
Consider HFO for those with poor compliance
Fluid restrict patients
Consider referral for ECMO early if conventional ventilation is failing. ECMO beds are occupied almost all occupied by ‘flu patients and elective surgery has been curtailed to accomodate them. Surge funding has been agreed for extra ECMO. In cases where conventional ventilation is failing and there are no other options, patients should be referred to Glenfield before seven days of MV.
There will be advice re pregnant women after discussion with the RCOG
In some cases, URT specimens may be negative in severe cases and LRT samples may be needed for the diagnosis.
Point of care testing may have inadequate sensitivity for this strain of H1N1
The current rate is 21.5/100,000.
We aim to provide updates on the ICS website and copy of this document is available to download via http://www.ics.ac.uk/ under ‘Latest News – H1N1 Latest News’.
Update by the Executive Committee of the Intensive Care Society.
Sent from the email of:
Pauline Kemp
Head of Secretariat
Given that single-dose etomidate can cause measurable adrenal suppression, its use in patients with sepsis is controversial. A prospective, double-blind, randomised study of patients with suspected sepsis who were intubated in the ED randomised patients to receive either etomidate or midazolam before intubation. The primary outcome measure was hospital length of stay, and no difference was demonstrated. The study was not powered to detect a mortality difference.
This study is interesting as a provider of fuel for the ‘etomidate debate’, but still irrelevant to those of us who have abandoned etomidate in favour of ketamine as an induction agent for haemodynamically unstable patients. Personally I remain unconvinced of the existence of patients who can’t be safely intubated using the limited choice of thiopentone or ketamine. A Comparison of the Effects of Etomidate and Midazolam on Hospital Length of Stay in Patients With Suspected Sepsis: A Prospective, Randomized Study Annals Emergency Medicine 2010;56(5):481-9
Central lines in the ED are more likely to get infected because they’re inserted under less scrupulously aseptic conditions than in ICU, done more urgently, and are more likely to be placed in the mucky old femoral site by clumsy emergency physicians who don’t wash their hands after scratching their arses. Anyway, the intensivists will usually replace them with a ‘more ideal’ line after ICU admission. Right? Well, that’s what’s often taught and assumed to be the case, but a new study from a single centre suggests otherwise. ED-placed central venous catheters (19% of which were femoral) were typically left in for 4 to 5 days. The infection rate was 1.9 per 1,000 catheter-days, similar to that reported for central lines in other ICU case series. Infection and Natural History of Emergency Department–Placed Central Venous Catheters Annals of Emergency Medicine 2010;56(5):492-7
Finding children with serious illness among the multitudes who present with fever is the number one challenge in paediatric emergency medicine.
A two year prospective cohort study was conducted at the Children’s Hospital Westmead in Sydney to develop and test a multivariable model to distinguish serious bacterial infections from self limiting non-bacterial illnesses.
A standardised clinical evaluation that included mandatory entry of 40 clinical features was recorded by physicians on around 15000 febrile kids under age 5. Clinical, laboratory and radiological follow up was undertaken to identify one of three key types of serious bacterial infection (SBI): urinary tract infection, pneumonia, and bacteraemia.
7.2% had SBI – urinary tract infection 3.4%, pneumonia 3.4%, and bacteraemia 0.4%.
A diagnostic model was developed using multinomial logistic regression methods. Physicians’ diagnoses of bacterial infection had low sensitivity (10-50%) and high specificity (90-100%), whereas the clinical diagnostic model provided a broad range of values for sensitivity and specificity.
The authors suggest that a computer assisted diagnostic decision tool could be used to determine the likelihood of serious bacterial infection.
The strongest positive predictors of serious bacterial infection were a generally very unwell appearance, high temperature, chronic disease, and prolonged capillary refill time. For children with pneumonia, other predictors were coughing, difficulty breathing, abnormal chest sounds, and to a lesser extent tachypnoea, chest crackles, and tachycardia. For urinary tract infection, the presence of urinary symptoms was by far the strongest indicator, whereas for bacteraemia, tachycardia and crying were also strong indicators although an editorial points out that only 64 cases of bacteraemia occurred, so this last result should be treated with caution. The accuracy of clinical symptoms and signs for the diagnosis of serious bacterial infection in young febrile children: prospective cohort study of 15 781 febrile illnesses BMJ. 2010 Apr 20;340:c1594
Bloods sampled from both femoral vein and SVC-sited catheters in critically ill patients showed good correlation in lactate levels but the oxygen saturation was not so reliable, with >5% variation in more than 50% and >15% variation in some patients. The authors suggest one reason is that the femoral catheter tip usually sits in the iliac vein and samples blood prior to the mixing of blood returning from intra-abdominal organs. They advise caution in using SfvO2 to guide resuscitation when narrow end points are used, as this may lead to inappropriate vasoactive drug or blood component therapy.
Femoral-Based Central Venous Oxygen Saturation Is Not a Reliable Substitute for Subclavian/Internal Jugular-Based Central Venous Oxygen Saturation in Patients Who Are Critically Ill Chest. 2010 Jul;138(1):76-83
An Iranian study showed 10% of afebrile well appearing infants had petechiae and they remained well on follow up. This is in keeping with previous studies on both afebrile and well-appearing febrile infants. Prevalence and location of petechial spots in well infants Arch Dis Child. 2010 Jul;95(7):518-20
A case report describes the improvement of a critically ill patient with H1N1 ‘flu after the administration of N-acetylcysteine in a dose similar to that used to treat paracetamol (acetaminophen) overdose.
Influenza virus induces reactive oxygen species that activate nuclear factor kappa B to produce cytokines. High-dose N-acetylcysteine, an antioxidant, is thought to reduce the production of this cytokine storm which contributes to the lethality of influenza. More studies are clearly needed. High-Dose N-Acetylcysteine Therapy for Novel H1N1 Influenza Pneumonia Ann Intern Med. 2010 May 18;152(10):687-8
The UK’s National Institute for Health and Clinical Excellence has produced a guideline on the management of bacterial meningitis and meningococcal septicaemia in children.
The guidelines cover when to treat a petechial rash, when to give steroids, when to do an LP (and what to test), how much fluid to give, and a number of other areas that otherwise can cause confusion. The management of bacterial meningitis and meningococcal septicaemia in children and young people younger than 16 years in primary and secondary care NICE guidance
Guidelines for preventing, detecting, and treating Clostridium Difficile infection from the Infectious Diseases Society of America have been published. Clinical Practice Guidelines for Clostridium difficile Infection in Adults: 2010 Update by the Society for Healthcare Epidemiology of America (SHEA) and the Infectious Diseases Society of America (IDSA) Infect Control Hosp Epidemiol 2010;31:431–455 Full Text
It is said that when using crystalloids, two to four times more fluid may be required to restore and maintain intravascular fluid volume compared with colloids, although true evidence is scarce. The ratio in the SAFE study comparing albumin with saline resuscitation was 1:1.3, however.
A single-centre, single- blinded, randomized clinical trial was carried out on 24 critically ill sepsis and 24 non-sepsis patients with clinical hypovolaemia, assigned to loading with normal saline, gelatin 4%, hydroxyethyl starch 6% or albumin 5% in a 90-min (delta) central venous pressure (CVP)-guided fluid loading protocol. Haemodynamic monitoring using transpulmonary thermodilution was done each 30 min to measure, among other things, global end-diastolic volume and cardiac indices (GEDVI, CI). The reason sepsis was looked at was because of a suggestion in the SAFE study of benefit from albumin in the pre-defined sepsis subgroup.
Independent of underlying disease, CVP and GEDVI increased more after colloid than saline loading (P = 0.018), so that CI increased by about 2% after saline and 12% after colloid loading (P = 0.029).
Their results agree with the traditional (pre-SAFE) idea of ratios of crystalloid:colloid, since the difference in cardiac output increase multiplied by the difference in volume infused was three for colloids versus saline.
Take home message? Even though an outcome benefit has not yet been conclusively demonstrated, colloids such as albumin increase pre-load and cardiac index more effectively than equivalent volumes of crystalloid in hypovolaemic critically ill patients. Greater cardiac response of colloid than saline fluid loading in septic and non-septic critically ill patients with clinical hypovolaemia Intensive Care Med. 2010 Apr;36(4):697-701
Central lines in the ED are more likely to get infected because they’re inserted under less scrupulously aseptic conditions than in ICU, done more urgently, and are more likely to be placed in the mucky old femoral site by clumsy emergency physicians who don’t wash their hands after scratching their arses. Anyway, the intensivists will usually replace them with a ‘more ideal’ line after ICU admission. Right? Well, that’s what’s often taught and assumed to be the case, but a new study from a single centre suggests otherwise. ED-placed central venous catheters (19% of which were femoral) were typically left in for 4 to 5 days. The infection rate was 1.9 per 1,000 catheter-days, similar to that reported for central lines in other ICU case series.
