Category: Pharmacology

Sleep Deprivation on the ICU

ICM Case Summaries1 Comment

A 70-year-old lady was admitted to the Intensive Care Unit (ICU) with respiratory failure and septic shock secondary to pneumococcal pneumonia. She developed multi- organ failure, requiring a prolonged period of mechanical ventilation and weaning, and also developed acute kidney injury requiring haemofiltration. Once a tracheostomy was performed and sedative infusions weaned, she was noted to be acutely delirious. Her sleep pattern was severely disrupted, with extended periods of nighttime wakefulness and sleep fragmentation, increased daytime sleep and difficulty with sleep initiation requiring pharmacological intervention.

Following exclusion of organic causes including CT brain imaging, the delirium was managed with a combination of antipsychotic medications including haloperidol, mirtazapine and quetiapine. Benzodiazepine-based night sedation was used but found to be ineffective in establishing sustained sleep.

A trial of night sedation with infusion of Propofol did not have any ongoing or long-lasting benefit other than the immediate sedative effects and providing control of agitation. A trial of Dexmedetomidine infusion also yielded similar results, although a more sustained daytime anxiolytic effect was noted. Benzodiazepine therapy was changed to supplementation of Melatonin. At around this time, the delirium began to resolve and the patient was able to more actively engage in physiotherapy and patient care. By the time of ICU discharge over thirty days later, and following successful weaning and decannulation, the patient’s sleep pattern had improved significantly.

What are the implications of sleep deprivation in the critically ill patient and how can it be managed?

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ICP Monitoring and Acute Liver Failure

ICP Monitoring and Acute Liver Failure

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A 28-year-old lady presented to the medical team jaundiced with cramping upper abdominal pain and multiple episodes of vomiting over the previous day. She admitted ingesting Paracetamol 8 grams 3 days previously (staggered throughout the day) ostensibly to treat a frontal headache. She had been commenced on Citalopram 1 week previously for depression but denied taking any intentional overdose. On examination, she was slightly drowsy but GCS 15. HR 109, BP 136/92. Sats 98%on air. Her chest was clear, she was warm peripherally but jaundiced with some epigastric and RUQ tenderness on palpation. Her urine output was 10-20ml/hr.

Full Blood Count revealed Hb 152, WCC 24.7, Plats 301. She was in acute liver failure with Bil 189, AST 22970, ALT 13040, ALP 426 and coagulopathic with PT 82, APTT 72, Fib 0.7 Urea 5.7, Cr 193. Paracetamol and Salicylate were not detected. She was not acidotic with H+ 35, OCI2 3.7, pO2 17, Bic 20, BE –3. Lactate 7.1.

She was commenced on N-acetylcysteine and transferred to Critical Care. She was reviewed by the Hepatobiliary surgical team and placed on the super-urgent list for liver transplant. 

On Day 2, she became encephalopathic with GCS E3M5V5 and she was intubated and ventilated.Her PT had increased to 168 (INR >15) and she became anuric. She commenced FFP and Cryoprecipitate transfusions that improved her PT to 17, APTT 34 and Fibrinogen 1.5. An Intracranial Pressure (ICP) monitor was inserted and an opening pressure of 19mmHg was found. 2 hours post-insertion, it was noticed that her right pupil had increased in size from 2mm to 4mm and was poorly reactive. ICP remained at 16 and pCO2 4.1.

A brain CT showed a large haematoma in the right frontal region around the ICP bolt (which was not in the brain parenchyma but sitting in the skull) and mass effect with 5mm midline shift. There was also some lack of grey-white matter differentiation and sulcal effacement in keeping with diffuse oedema and mass effect.

INR was 1.7 and so further FFP was given. She was discussed with the neurosurgical registrar (in a separate hospital) who advised they would not drain at present but he would discuss with his Consultant and call back. 

Soon after, her right pupil increased to 8mm and the left to 7mm. Repeat CT brain showed slightly increased right frontal haematoma with 6mm midline shift and global oedematous cortical changes but no herniation. The ICP readings were thought to be inaccurate due to proximal placement and she was medically treated for raised ICP with hypertonic saline, mannitol and then therapeutic hypothermia. Despite this treatment, her pupils were fixed and dilated and so a thiopentone infusion was commenced.

The neurosurgeons advised that they would insert a further ICP monitor when INR <1.3 and so further FFP was given. An ICP bolt was inserted and the opening pressure was >120.

Discussions between the ICU, hepatobiliary and neurosurgical teams confirmed that she had a non-survivable injury and so this was discussed with her family. She was rewarmed, paralysis and then sedation were discontinued, brain stem death testing took place and she was extubated in the presence of her family. She died on Day 3 and was referred to the Coroner for further investigation.

What is the rationale for measuring ICP in acute liver failure?

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Albumin Use in Critical Illness

ICM Case Summaries2 Comments
A 70-year-old woman was admitted to the surgical ward with abdominal pain. CT scans showed some dilated loops of small bowel. She remained on the surgical ward for 5 days with minimal resolution of her symptoms. She was taken to theatre for exploratory laparotomy where she was diagnosed with faecal peritonitis from a perforated diverticulum. She had a washout and a Hartmanns procedure was performed.
She became unstable during her laparotomy requiring vasopressors and was taken to the intensive care unit postoperatively.  She was left with a laparostomy with a VAC dressing applied. She was treated with lung protective ventilation and remained cardiovascularly unstable. Two days later she was taken back to theatre for a further washout and closure of her abdomen. She developed an ileus and was then started on total parenteral nutrition. An oesophageal doppler monitor was placed to help guide her fluid status. She was extubated on day 4 post op but her filling status remained a problem to gauge. Her fluid balance became very positive and she became very oedematous. Her albumin level dropped significantly. It was then decided to give her daily intravenous albumin.
What evidence is there for the use of albumin in critically ill patients?

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Heparin Induced Thrombocytopaenia

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A 75 year old was admitted to the Cardiac Intensive Care Unit following aortic valve replacement for severe aortic stenosis. He had no other significant past medical history. He remained intubated and ventilated overnight until cardiovascularly stable, and was extubated the following morning. He suffered bleeding into the pericardial drains, and went back to theatre on day 3. He remained intubated on his return from theatre. On day 7 it was noticed that he had developed thrombocytopenia, with a platelet count of 34, reducing from 103 the previous day. A heparin induced thrombocytopenia (HIT) screen was sent, and he was changed to alternative anticoagulation.

The HIT screen was positive. His platelet count fell further and he continued to bleed slowly from any puncture sites and from around his mouth and gums. He remained intubated and ventilated and developed a requirement for inotropic support. Transfusions of platelets were required for any intervention. He was anticoagulated with lepirudin to prevent thrombosis. His platelet count continued to remain in single figures over the next 10 days despite treatment with steroids. Unfortunately he deteriorated, suffering an arterial thrombosis in his arm, renal failure and developed a necrotic skin rash all over his body, likely to be related to the HIT. Following discussions with his family, who felt he was suffering and would not want a poor quality of life, treatment was withdrawn on day 26 of his intensive care stay and she died.

What are the clinical implications of heparin-induced thrombocytopaenia?Read More »

Transplantation After Brainstem Death

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A 38-year-old previously fit man suffered a grade five subarachnoid haemorrhage. Attempts at coiling failed and he suffered a catastrophic rebleed on-table whereupon his pupils became fixed and dilated. After a suitable sedation washout period he underwent testing which confirmed brainstem death at which point he was referred to the specialist nurse for organ donation. Following counselling of the family and appropriate assessment, donation of his kidneys, liver and heart was agreed.

Upon confirmation of brainstem death, mechanical ventilation was continued to ensure PaO2 greater than 10 kPa and limit peak inflation pressure to less than 30 cmH20. Vasoactive support was switched from noradrenaline to vasopressin 0.02 iu/kg/min. Methylprednisolone and intravenous triiodothyronine were administered whilst awaiting harvest. Blood antibody testing for HIV1+2, Hepatitis B and C, HTLV-1 and CMV IgG were all negative. A transthoracic echocardiogram confirmed good biventricular function; following discussion with the transplant retrieval team a pulmonary artery catheter was floated. Clinical measurements of cardiac output and mixed venous oxygen saturation were satisfactory. Adequate hydration was maintained with crystalloid by infusion and glucose control optimised in the range 8-10 mmol/L with insulin. The dedicated retrieval team performed the organ retrieval eighteen hours after confirmation of brainstem death.

How can we optimise organ function for organ donation?Read More »

Use of Bicarbonate in Lactic Acidosis

Steve Mathieu3 Comments

Five days post emergency colorectal surgery, an elderly woman, following a brief period of chest pain a few hours earlier, developed progressive hypotension and tachycardia on the ward. She had a background of hypertension, type 2 diabetes and a chronic left foot ulcer. On examination she was found to be clammy, mottled and peripherally vasoconstricted with a GCS of 15/15. Her abdomen was soft and non-tender. Her initial ECG had showed no ischaemic changes and subsequent ECGs showed only a sinus tachycardia.

Initial blood gas analysis showed a metabolic acidosis (pH 7.21 Lactate 2.8mmol/l, HCO3 11.1mmol/l with a pCO2 of 2.7kPa).  A starting differential diagnosis of a cardiac event, a pulmonary embolism, critical ischaemia or sepsis related to a hip or foot ulcer were made. Urgent orthopaedic and vascular review were obtained, and it was deemed that neither the hip, ulcer or vascular insufficiency were a likely source for the deterioration. Initially it was planned to transfer her for a CTPA, however she became progressively unstable, was no longer fluid responsive, and was intubated on the ward and transferred to the intensive care unit (ICU) for stabilisation.

On arrival on ICU she continued to deteriorate, and in addition to fluid resuscitation required a high dose noradrenaline infusion to maintain her blood pressure. Broad spectrum antibiotics were started, a bedside echocardiogram and blood tests performed and hydrocortisone started. Her metabolic acidosis continued to deteriorate, subsequent arterial blood gas showed a pH 6.91, Lactate of 13.7mmol/l, HCO3 7.7mmol/l, base excess -25mmol/l with a pCO2 of 5.4kPa. It was decided to correct this acidosis with a bicarbonate infusion and initially 200ml of 8.4% was given over an hour, based on correcting half the calculated bicarbonate deficit (bicarbonate deficit (mmol) = base deficit 0.3xbodyweight(kg)1).  The blood gas following this infusion showed improvement in the metabolic acidosis despite the increasing Lactate (pH 7.07, Lac 14.0mmol/l, HCO3 10mmol/l, BE -18.6mmol/l with a pCO2 of 4.85kPa). She continued to deteriorate and the results from her blood tests, troponin and bedside echo suggested a primary myocardial infarction to cause this decline. She was too unstable for primary coronary intervention and her condition continued to deteriorate. She died 6 hours post admission.

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Metformin Associated Lactic Acidosis

Metformin Associated Lactic Acidosis

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A 65-year-old female, presented with epigastric pain and a 3-day history of diarrhoea and vomiting, dry mouth and breathlessness. She had also experienced a transient loss of vision three days earlier. Her past medical history included type 2 Diabetes, hypertension (on ramipril), hypothyroidism. On arrival, her GCS was 15/15. She was tachypnoeic (respiratory rate 31 breaths/minute) but maintained oxygen saturations at 98% on high-flow oxygen. On auscultation, she had bibasal crepitations.  She was tachycardic (irregularly irregular pulse of 130 beats/minute), had cool peripheries and dry mucous membranes. Her BP was 105/39mmHg. She had tenderness in her lower abdomen. Her initial arterial blood gas revealed a marked metabolic acidosis (pH <6.8, pO2 23.1, pCO2 1.9) with unrecordable bicarbonate and lactate levels. She was referred to the surgical and critical care teams with a working diagnosis of ischaemic bowel secondary to an embolic phenomenon (atrial fibrillation and possible amaurosis fugax).

She was resuscitated in ED with 4 litres of crystalloid but rapidly deteriorated, requiring vasopressor support to maintain her blood pressure. Her metabolic disturbance did not not correct with resuscitation and her lactate now registered as >15. Bloods showed Na 140, K+ 6.3, urea 35, Cr 1105. A decision to intubate was made in view of a deteriorating conscious level and need for urgent filtration and invasive monitoring. Noradrenaline (0.3mcg/kg/min) and dobutamine (26mcg/kg/min) were required to achieve a satisfactory blood pressure and she was commenced on CVVHDF. She was considered to unstable for transfer to CT or an emergency laparotomy. Her metabolic disturbance remained severe (pH<6.8 and lactate 13.9).

Within 24 hours her metabolic state had improved (pH 7.19, pO2 7.19, PCO2 2.5, HCO3 10, BE -28.1, Lac 6.7) and she became more cardiovascular stability. A CT effectively excluded an intra-abdominal catastrophe. Renal failure secondary to dehydration complicated by Metformin Associated Lactic Acidosis (MALA) appeared to be the most likely presentation. Her condition continue to stabilise and her vasopressor support and RRT was weaned over the next 7-10 days

What are the risk factors, clinical features and management of metformin associated lactic acidosis?Read More »

Major Haemorrhage and Recombinant Factor VIIa Concentrate

Major Haemorrhage and Recombinant Factor VIIa Concentrate

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A 40-year-old female intravenous drug user presented with a diffusely swollen right lower leg. She had injected heroin into her right thigh one week previously. The swelling started 3 days later. Initial observations revealed T 39.6, HR 135, NIBP 100/87, RR 32, Sats 96% on air. On examination, she was pale and sweaty. She had a swollen right lower leg with mottling of her foot and poor pedal pulses. Following initial fluid resuscitation, chest X-ray, cultures and broad-spectrum antibiotics (Flucloxacillin, Metronidazole and Gentamicin), she underwent CT angiogram of her lower limbs which showed oedematous and expanded muscle compartments of the thigh and calf but patent arterial flow to the feet. There was also right common femoral vein thrombosis with some vessel patency. Initial labs revealed neutrophilia (9.2), thrombocytopaenia (16) and deranged coagulation (PT 16, APPT 33, Fib 2.6). CK was 57000. She underwent right leg fasciotomies and was brought to ICU ventilated and on Noradrenaline to maintain MAP >65. She commenced Immunoglobulin IV 1gram/kg per day for 2 days for suspected Streptococcus Group A sepsis. That night she had massive transfusion requirements due to ongoing haemoserous ooze from her fasciotomy sites, losing up to 1 litre of haemoserous fluid per hour. Overnight she received 10 units RCC, 8 x FFP, 6 x Platelets and 2 x Cryoprecipitate, as well as Vitamin K (guided by Hb on ABG, formal lab results and thromboelastography). She was discussed with the Haematology Consultant and it was decided that, if rapid blood loss continued despite full correction of her clotting factors, fibrinogen and platelets then Factor VII could be given. However, over the next 2 hours, losses were much reduced following product replacement, and since she already had clot in her femoral vein, Factor VII Concentrate was not given.

What is the role of Recombinant Factor VIIa in major haemorrhage?

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Secondary Complications of Subarachnoid Haemorrhage

Secondary Complications of Subarachnoid Haemorrhage

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A thirty eight year old female smoker was admitted via A+E following sudden onset occipital headache with visual disturbance and collapse with loss of consciousness lasting approximately five minutes. She had complained of unusual headaches a week prior to this event, but these were short lived and not associated with any neurology. On arrival in resus she had recovered to a Glasgow coma score (GCS) of 14/15. She demonstrated neck stiffness and photophobia, as well as general irritability. Plain computerised tomography
scan (CT) performed showed a subarachnoid haemorrage in the region of the middle cerebral artery, with the presence of blood in the sylvian fissure.

She was transferred to the ITU for monitoring and blood pressure control with invasive arterial and central venous pressure monitoring. She was treated with nimodipine to prevent vasospasm. Contrast CT performed showed an aneurysm at the bifurcation of the middle cerebral artery, and this was felt to be the origin of the bleed. She underwent uneventful endovascular coiling of this aneurysm the following day under general anesthesia, and was discharged to the neurosurgical team for ongoing care afterwards.

What are the secondary complications of subarachnoid haemorrhage and how are they managed?

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Steroids in Cervical Spine Injury

Steroids in Cervical Spine Injury

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A previously fit and well 46 year-old was admitted via the emergency department having sustained a neck injury whilst horse riding. She was unable to move her arms and legs immediately after the fall. On arrival to the Emergency Department, she was alert and orientated. Examination of the cardiovascular and respiratory system was unremarkable although there was evidence of diaphragmatic breathing.

Examination of her neurological system revealed:

•A sensory level at C6
•Absent upper limb reflexes except for brisk bicep reflex bilaterally
•⅖ power in shoulder abductors bilaterally
•Flaccid paralysis of her lower limbs
•No anal tone

She was initially managed in a hard neck collar with full spinal immobilisation. CT brain was reported to be normal. CT neck showed an obviously displaced fracture of C5 and C6 vertebral bodies. She was transferred to the intensive care unit for cardiovascular, respiratory and neurological monitoring while a definitive treatment plan was being considered. After discussions with the orthopaedic surgeons, it was decided not to commence high-dose steroids. This decision was reinforced after discussion with the local neurosurgical and spinal units. It was also decided not to surgically stabilise the c-spine due to the higher risk of respiratory complications. She was transferred to the spinal rehabilitation unit after 2 days.

What is the role of steroids in cervical spine injury?Read More »