C.U.Shah College of Pharmacy & Research

M.pharm Sem-3 (pharmacology Department)

Prepared by Guided by

maulik thakor nimish pathak

Introduction

The objectives of an Intensive Care Department (ICD) are the monitoring and support of failing vital functions in critically ill patients, in order to perform adequate diagnostic measures and medical and/or surgical therapies to improve outcome.

CRITICAL CARE MANAGEMENT

Management of patients on admission to ICU

• Handover from transferring team to ICU staff • Full clinical assessment • Ongoing resuscitation/stabilisation • Establishment of monitoring • Review of medical and social history • Communication (including explanation) with relatives • Investigations to establish or confirm the definitive diagnosis • Formulation and implementation of a management plan

• Monitoring in ICU represents a mixture of clinical and automated recordings.

• Electrocardiogram (ECG), SpO2 (oxygen saturation derived from a pulse oximeter), BP (generally invasive arterial pressure) and usually CVP are established at an early stage, and recordings made at least hourly, on either a 24-hour chart or a computerised system

• Urine output is a sensitive measure of renal perfusion and early catheterisation is required in most patients. Clinical monitoring is particularly important.

• Physical signs such as respiratory rate, the appearance of the patient, restlessness, conscious level and indices of peripheral perfusion (pale, cold skin; delayed capillary refill in the nailbed) are just as important as a set of blood gases or monitor readings.

Daily clinical management in the ICU

• Review of progress reports from ICU nursing and medical staff, and any specialist opinions.

• Review of 24-hour charts. • Examination: general (including skin, line sites,

wounds etc.) and specific: – cardiovascular, including haemodynamics,

fluids and inotropes – respiratory, including ventilator settings and

ABGs – gastrointestinal, including nutrition (calorie,

protein intake, route), nasogastric aspirate and bowel function

– renal, including urine output, overall fluid balance, urea and electrolytes, and renal replacement therapy

– neurological, including sedation level, GCS and pupil responses where appropriate.

• Laboratory results: haematology, including coagulation, and biochemistry.

• Microbiology: temperature, white blood count, line sites and other possible sources of infection, results of cultures, antibiotic therapy.

• Drug therapy: review with pharmacist, consider side-effects and interactions, and identify therapy that can be discontinued.

• Imaging: review X-rays and other specialist investigations.

• Monitoring: are all measures still required? • Management plan: formulate an integrated

plan, with specific goals for each organ system.

Sedation and analgesia • Sedation is required for most patients in order to

relieve anxiety, allow tolerance of an endotracheal tube, mechanical ventilation and invasive procedures, and control intracranial pressure in neurological disease.

• Over-sedation is a common occurrence, and can delay weaning from ventilation and prolong ICU stay. Daily sedation 'pauses' can allow better patient assessment, prevent sedative accumulation and have been shown to reduce ICU stay.

• Standard sedation consists of a mixture of either the short-acting anaesthetic agent propofol or the benzodiazepine midazolam, and an opioid analgesic, traditionally morphine Analgesia is required to relieve post-operative and other pain.

Muscle relaxants • Muscle relaxants are used less now than

previously. They are required to facilitate endotracheal intubation, to facilitate ventilation in patients with critical oxygenation and/or poor lung compliance, and to aid control of critically increased intracranial pressure.

Delirium• Delirium is a feature of severe illness, especially

when patients are subjected to major organ dysfunction, metabolic derangement and polypharmacy. Haloperidol in 2.5-5 mg doses (i.v.) and the α2-adrenergic agonist clonidine are useful in immediate management.

CRITICAL CARE MANAGEMENT

Circulatory support

Respiratory support

Renal support

Gastrointestinal and hepatic support

Neurological support

CRITICAL CARE MANAGEMENT

Circulatory support Correct hypoxaemia Oxygen therapy • Consider ventilation

– Intractable hypoxaemia – Hypercapnia: PaCO2 > 6.7 kPa (50 mmHg)

– Respiratory distress – Impaired conscious level

• Assess circulation Heart rate • BP: direct arterial pressure • CVP • Peripheral perfusion

Optimise volume status • Fluid challenge(s)

– CVP < 6 mmHg: 250 mL 0.9% saline or colloid – CVP > 6 mmHg or poor ventricular function

suspected: 100 mL boluses and consider measuring cardiac output, e.g. PA catheter or oesophageal Doppler

Optimise haemoglobin concentration • 70-90 g/L; 100 g/L if ischaemic heart disease • Red cells as required • Septic patients can become profoundly anaemic

with crystalloid/colloid resuscitation due to haemodilution and require blood transfusion

Achieve target BP Use vasopressor/inotrope once hypovolaemia is

corrected

Achieve adequate CO and D O2

• Inotropic agent if fluid alone inadequate Other measures • Establish monitoring, including invasive

measures, as resuscitation starts • Trends in haemodynamics, ABG, H+, base

deficit and lactate guide further treatment

Respiratory support• Clinical conditions requiring mechanical

ventilation Post-operative e.g. After major abdominal or cardiac surgery Respiratory failure • ARDS • Pneumonia • COPD • Acute severe asthma • Aspiration • Smoke inhalation, burns Circulatory failure• Low cardiac output: cardiogenic shock • Pulmonary oedema • Following cardiac arrest

Neurological disease Coma of any cause • Status epilepticus • Drug overdose • Respiratory muscle failure (e.g. Guillain-Barré

syndrome, poliomyelitis, myasthenia gravis) • Head injury: to avoid hypoxaemia and

hypercapnia, and reduce intracranial pressure • Bulbar abnormalities causing risk of aspiration

(e.g. cerebrovascular accident, myasthenia gravis

Terms used in mechanical ventilatory support

• Intermittent positive pressure ventilation (IPPV)

• Controlled mandatory ventilation (CMV) • Pressure-controlled ventilation (PCV) • Pressure support ventilation (PSV)/Assisted

spontaneous breathing (ASB)• Positive end-expiratory pressure (PEEP)• Continuous positive airways pressure

(CPAP) • Bi-level positive airway pressure

(BiPAP/BIPAP) • Non-invasive positive pressure ventilation

(NIPPV/NIV)

Tracheostomy• is usually performed electively when

endotracheal intubation is likely to be required for over 14 days. Box 8.23 describes the advantages and disadvantages.

• Tracheostomy is usually carried out using a percutaneous technique in the ICU, avoiding the need for transfer to the operating theatre. This has led to its earlier and more frequent use.

• A recent multicentre RCT found that early tracheostomy (< 3 days) did not lead to earlier weaning or shorter ICU stay.

Advantages and disadvantages of tracheostomy

Advantages• Patient comfort • Improved oral hygiene • Reduced sedation requirement • Enables speech with cuff deflated and a speaking

valve attached • Earlier weaning and ICU discharge • Access for tracheal toilet • Reduces vocal cord damage Disadvantages• Immediate complications: hypoxia, haemorrhage • Tracheal damage; late stenosis • Tracheostomy site infection

Renal supportIndications for renal replacement therapy

Hyperkalaemia: potassium > 6 mmol/L despite medical treatment

• Fluid overload; pulmonary oedema • Metabolic acidosis: H+ > 56 nmol/L (pH < 7.25) • Uraemia:

– Urea > 30-35 mmol/L (180-210 mg/dL) – Creatinine > 600 μmol/L (> 6.78 mg/dL)

• Drug removal in overdose • Sepsis: tentative evidence for mediator removal • The preferred renal replacement therapy in ICU

patients is pumped venovenous haemofiltration.

• This is associated with fewer osmotic fluid shifts and hence greater haemodynamic stability than haemodialysis.

• It is carried out using a double-lumen central venous catheter placed percutaneously.

• Haemofiltration should be continuous in the early phase of treatment; higher rates of filtration (preferably > 35 mL/kg/hr) are associated with improved outcome.

• Obstruction of the renal tract should always be excluded by abdominal ultrasound and, if present, relieved.

Gastrointestinal and hepatic support

• Gastrointestinal symptoms, such as nausea, vomiting and large nasogastric aspirates, may be the earliest signs of regional circulatory failure, and when associated with a tender, distended, silent abdomen, indicate the probable site of the primary pathology.

• Ischaemic bowel is difficult to diagnose in the critically ill patient but in the context of an otherwise unexplained lactic acidosis, hyperkalaemia and coagulopathy, urgent laparotomy must be considered

• Manifestations of MOF within the gastrointestinal tract include loss of gastric acid production, erosive gastritis, stress ulceration, bleeding, ischaemia, pancreatitis and acalculous cholecystitis.

• • Ranitidine and sucralfate are both used to reduce

the risk of gastrointestinal haemorrhage, although ranitidine is the more effective. Both agents are associated with an increased incidence of nosocomial pneumonia.

• Proton pump inhibitors are only required if upper GI bleeding due

Three distinctive hepatic dysfunction syndromes occur in the critically ill:

• Shock liver or ischaemic hepatitis• Hyperbilirubinaemia ('ICU jaundice')• Transaminitis

Neurological support Intensive care is required to:• manage acute brain injury with control of raised

intracranial pressure (ICP) • protect the airway, if necessary by endotracheal

intubation • provide respiratory support to correct hypoxaemia and

hypercapnia • treat circulatory problems, e.g. neurogenic pulmonary

oedema in subarachnoid haemorrhage, autonomic disturbances in Guillain-Barré syndrome, spinal shock following high spinal cord injuries

• manage status epilepticus using anaesthetic agents such as thiopental or propofol.

• ICP is generally measured via pressure transducers inserted directly into the brain tissue.

• The normal upper limit for ICP is 15 mmHg and management should be directed at keeping ICP < 20 mmHg. Sustained pressures > 30 mmHg are associated with a poor prognosis.

Strategies to control intracranial pressure

• Prevent coughing with sedation, analgesia and occasionally paralysis

• Nurse with 30° head-up tilt and avoid excessive flexion of the head or pressure around the neck that may impair cerebral venous drainage

• Control epileptiform activity with appropriate anticonvulsant therapy; an electroencephalogram (EEG) may be necessary to ensure that this is achieved

• Maintain good glycaemic control with blood glucose between 5.5 and 8 mmol/L (∼99-144 mg/dL)

• Aim for a core body temperature of between 36 and 37°C

• Maintain sodium > 140 mmol/L using i.v. 0.9% saline • Avoid volume depletion or fluid overload • Provide ventilation aiming to reduce the PaCO2 to 4-4.5

kPa (∼30-34 mmHg) for the first 24 hours

• Osmotic diuretic, mannitol 20% 100-200 mL (0.25-0.5 g/kg), coupled with volume replacement

• Hypnotic infusion, thiopental, titrated to 'burst suppression' on EEG

• Surgery: drainage of haematoma or ventricles; lobectomy, decompressive craniectomy

DISCHARGE FROM INTENSIVE CARE

• The critical care team should give the receiving team a detailed handover, a written summary with relevant recent investigations, remain available for advice, and ideally visit the patient on the ward within the 24 hours after discharge