Paediatric ketamine sedation: adverse events

Records of 4252 patients aged 0-19 who received ketamine were reviewed for documented adverse events. Patients were all American Society of Anesthesiology Class I or II. 102 (2.4%) had an ‘adverse event’, defined as the occurrence of hypoxia by oxygen saturation lower than 93% on room air or clinical cyanosis, documentation of laryngospasm, airway obstruction, or apnea diagnosed clinically or by capnography, stridor, respiratory distress, or hypoventilation or hypercarbia as assessed by capnography. Cases with adverse events were compared with controls who had received ketamine without adverse events, but were not otherwise matched.

Of the adverse events, laryngospasm was documented to have occurred in 29/4252 cases (0.7%), hypoxia in 81/4252 (1.9%), and positive pressure ventilation was required in 33/4252 (0.8%). Intubation was required in one patient (0.023%). Compared with controls, patients with adverse events were more likely to have received IM, as opposed to IV, ketamine, although children who received IM ketamine were more likely to be younger than those who received IV ketamine (4.1 vs 7.9 years).

The retrospective design and other methodological limitations make it harder to draw conclusions other than what we know from existing literature, to which this large series adds: ketamine is given to a lot of kids with few adverse effects; larygnospasm is a real but infrequent occurrence that usually responds to simple manouevres; and intubation is extremely rarely required, but nevertheless may be necessary and therefore those physicians using ketamine should have advanced airway skills.

Serious Adverse Events During Procedural Sedation With Ketamine
Pediatr Emerg Care. 2009 May;25(5):325-8

Expiratory vs inspiratory films affects interpretation of pneumothorax guidelines

Radiographs of 49 spontaneous pneumothoraces were studied, showing that in the expiratory films, pneumothoraces were on average 9% larger. When applying British Thoracic Society or American College of Chest Physicians guidelines, this difference would have led to a different management strategy.

What is the difference in size of spontaneous pneumothorax between inspiratory and expiratory x-rays?
Emerg Med J. 2009 Dec;26(12):861-3

Subarachnoid haemorrhage guidelines

Guidelines on Subarachnoid Haemorrhage are available from the American Heart Association / American Stroke Association.

Most of the summaries are included below.

The initial bleed

The severity of the initial bleed should be determined rapidly because it is the most useful indicator of outcome after aneurysmal SAH, and grading scales that rely heavily on this factor are helpful in planning future care with family and other physicians

Case review and prospective cohorts have shown that for untreated, ruptured aneurysms, there is at least a 3% to 4% risk of rebleeding in the first 24 hours—and possibly significantly higher—with a high percentage occurring immediately (within 2 to 12 hours) after the initial ictus, a 1% per day to 2% per day risk in the first month, and a long-term risk of 3% per year after 3 months. Urgent evaluation and treatment of patients with suspected SAH are therefore recommended

Diagnosis

  1. A high level of suspicion for SAH should exist in patients with acute onset of severe headache
  2. CT scanning for suspected SAH should be performed, and lumbar puncture for analysis of CSF is strongly recommended when the CT scan is negative
  3. Selective cerebral angiography should be performed in patients with SAH to document the presence and anatomic features of aneurysms
  4. MRA and CTA may be considered when conventional angiography cannot be performed in a timely fashion

The degree of neurological impairment using an accepted SAH grading system can be useful for prognosis and triage and should be recorded in the ED. Examples include the Hunt and Hess Scale, Fisher Scale, Glasgow Coma Scale, and World Federation of Neurological Surgeons Scale.

Medical Measures to Prevent Rebleeding After SAH

  1. Blood pressure should be monitored and controlled to balance the risk of stroke, hypertension-related rebleeding, and maintenance of cerebral perfusion pressure
  2. Bedrest alone is not enough to prevent rebleeding after SAH. It may be considered a component of a broader treatment strategy, along with more definitive measures
  3. Although older studies demonstrated an overall negative effect of antifibrinolytics, recent evidence suggests that early treatment with a short course of antifibrinolytic agents combined with a program of early aneurysm treatment followed by discontinuation of the antifibrino- lytic and prophylaxis against hypovolemia and vasospasm may be reasonable, but further research is needed. Furthermore, antifibrinolytic therapy to prevent rebleeding may be considered in certain clinical situations, eg, in patients with a low risk of vasospasm and/or a beneficial effect of delaying surgery.

Surgical treatment

  1. Surgical clipping or endovascular coiling should be per- formed to reduce the rate of rebleeding after aneurysmal SAH
  2. Wrapped or coated aneurysms and incompletely clipped or coiled aneurysms have an increased risk of rehemorrhage compared with those that are completely occluded and therefore require long-term follow-up angiography. Com- plete obliteration of the aneurysm is recommended whenever possible
  3. For patients with ruptured aneurysms judged by an experienced team of cerebrovascular surgeons and endovascu- lar practitioners to be technically amenable to both endovascular coiling and neurosurgical clipping, endovascular coiling can be beneficial. Nevertheless, it is reasonable to consider individual characteristics of the patient and the aneurysm in deciding the best means of repair, and management of patients in centers offering both techniques is probably indicated
  4. Although previous studies showed that overall outcome was not different for early versus delayed surgery after SAH, early treatment reduces the risk of rebleeding after SAH, and newer methods may increase the effectiveness of early aneurysm treatment. Early aneurysm treatment is reasonable and is probably indicated in the majority of cases

Management of Cerebral Vasospasm

  1. Oral nimodipine is indicated to reduce poor outcome related to aneurysmal SAH. The value of other calcium antagonists, whether administered orally or intravenously, remains uncertain.
  2. Treatment of cerebral vasospasm begins with early management of the ruptured aneurysm, and in most cases, maintaining normal circulating blood volume and avoiding hypovolemia are probably indicated
  3. One reasonable approach to symptomatic cerebral vasospasm is volume expansion, induction of hypertension, and hemodilution (triple-H therapy)
  4. Alternatively, cerebral angioplasty and/or selective intraarterial vasodilator therapy may be reasonable after, together with, or in the place of triple-H therapy, depending on the clinical scenario

Management of Hydrocephalus
Temporary or permanent CSF diversion is recommended in symptomatic patients with chronic hydrocephalus after SAH
Ventriculostomy can be beneficial in patients with ven- triculomegaly and diminished level of consciousness after acute SAH

Management of Seizures
The administration of prophylactic anticonvulsants may be considered in the immediate posthemorrhagic period

Management of Hyponatremia

  1. Administration of large volumes of hypotonic fluids and intravascular volume contraction should generally be avoided after SAH
  2. Monitoring volume status in certain patients with recent SAH using some combination of central venous pressure, pulmonary artery wedge pressure, fluid balance, and body weight is reasonable, as is treatment of volume contraction with isotonic fluids
  3. The use of fludrocortisone acetate and hypertonic saline is reasonable for correcting hyponatremia
  4. In some instances, it may be reasonable to reduce fluid administration to maintain a euvolemic state

Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage: A Statement for Healthcare Professionals From a Special Writing Group of the Stroke Council, American Heart Association
Stroke 2009;40;994-1025 (Full Text)

Other AHA Stroke Guidelines

Standards for Capnography in Critical Care

The Intensive Care Society has published guidelines on the use of capnography in critical care. The recommendations are:

  1. Capnography should be used for all critically ill patients during the procedures of tracheostomy or endotracheal intubation when performed in the intensive care unit.
  2. Capnography should be used in all critically ill patients who require mechanical ventilation during inter-hospital or intra- hospital transfer.
  3. Rare situations in which capnography is misleading can be reduced by increasing staff familiarity with the equipment, and by the use of bronchoscopy to confirm tube placement where the tube may be displaced but remains in the respiratory tract.

Other findings:

  1. Capnography offers the potential for non-invasive measurement of additional physiological variables including physiological dead space and total CO2 production.
  2. Capnography is not a substitute for estimation of arterial CO2.
  3. Careful consideration should be given to the type of capnography that should be used in an ICU. The decision will be influenced by methods used for humidification, and the advantages of active or passive humidification should be reviewed.
  4. Capnometry is an alternative to capnography where capnography is not available, for example where endotracheal intubation is required in general ward areas.

Link to Full Guideline Document

Epinephrine and Dexamethasone in Children with Bronchiolitis

A multicentre double blind trial in 800 infants with bronchiolitis aged between 6 weeks and 12 months compared placebo with nebulised adrenaline, oral dexamethasone, or both. Only the combination led to a decrease in the primary endpoint of reduced hospital admission up to 7 days after enrollment, with an absolute risk reduction of 9% (from 26 to 17%). They also found an apparent benefit from combined therapy on their secondary outcomes: infants in the combined treatment group were discharged earlier from medical care and resumed quiet breathing and normal feeding sooner than did those in the placebo group. When the analysis was adjusted for multiple comparisons, the apparent benefit did not reach statistical significance, leading the authors to recommend further study.

Epinephrine and Dexamethasone in Children with Bronchiolitis
N Engl J Med. 2009 May 14;360(20):2079-89

Plasma:red cell transfusion ratio in trauma

In major trauma patients who require blood transfusion, fresh frozen plasma (FFP) to packed red blood cell (RBC) ratios of up to 1:1 have been associated with reduced mortality in retrospective studies, which may be in part due to survival bias (some patients die before they can be given as much FFP as the survivors).

To eliminate this bias, Australian researchers reviewed 331 trauma patients receiving at least 5 units of red cells in the first 4 hours, with a median Injury Severity Score of 36. When deaths in the first 24 hours were excluded, FFP:RBC ratio had no association with mortality. They conclude that prospective randomised controlled trials are needed.

Fresh frozen plasma (FFP) use during massive blood transfusion in trauma resuscitation
Injury. 2010 Jan;41(1):35-9

Self-extrication with a collar on

Using a sophisticated infrared six camera motion capture system, investigators demonstrated decreased cervical spine movement when collared volunteers self-extricated from a mock smashed up Toyota Corolla, when compared with extrication by paramedics using a backboard.

The authors conclude that in ambulatory subjects who do not complain of back pain, the least motion of the cervical spine may occur when the subject is allowed to exit the car in a c-collar without backboard immobilisation.

Cervical spine motion during extrication: a pilot study
West J Emerg Med. 2009 May;10(2):74-8

Full text article

Standard medication kit for prehospital and retrieval physicians

A very comprehensive (hence the title of the paper) review of medications required for pre-hospital & retrieval medicine missions was undertaken, resulting in recommendations. While the casemix seen by various services may be influenced by local geography or tasking restrictions, the list provides an excellent standard from which locally appropriate modifications can be made.

Defining a standard medication kit for prehospital and retrieval physicians: a comprehensive review.
Emerg Med J. 2010 Jan;27(1):62-71

Appendicitis policy

The American College of Emergency Physicians has produced a policy entitled: ‘Critical Issues in the Evaluation and Management of Emergency Department Patients With Suspected Appendicitis

It contains the following questions and recommendations:

1. Can clinical findings be used to guide decisionmaking in the risk stratification of patients with possible appendicitis?

Level B recommendations. In patients with suspected acute appendicitis, use clinical findings (ie, signs and symptoms) to risk-stratify patients and guide decisions about further testing (eg, no further testing, laboratory tests, and/or imaging studies), and management (eg, discharge, observation, and/or surgical consultation).

2. In adult patients with suspected acute appendicitis who are undergoing a CT scan, what is the role of contrast?

Level B recommendations. In adult patients undergoing a CT scan for suspected appendicitis, perform abdominal and pelvic CT scan with or without contrast (intravenous [IV], oral, or rectal). The addition of IV and oral contrast may increase the sensitivity of the CT scan for the diagnosis of appendicitis.

3. In children with suspected acute appendicitis who undergo diagnostic imaging, what are the roles of CT and ultrasound in diagnosing acute appendicitis?

Level B recommendations.
1. In children, use ultrasound to confirm acute appendicitis but not to definitively exclude acute appendicitis.
2. In children, use an abdominal and pelvic CT to confirm or exclude acute appendicitis.
Level C recommendations. Given the concern over exposing children to ionizing radiation, consider using ultrasound as the initial imaging modality. In cases in which the diagnosis remains uncertain after ultrasound, CT may be performed.

The full document contains a helpful summary of existing literature on clinical scoring systems and laboratory investigations, including positive and negative likelihood ratios for various tests.