Provision of Critical Care in hospitals – By Dr. Gnana Sankaralingam
Hospital patients are grouped together by major speciality, according to specific organ dysfunction, which may not quite be appropriate for initial management of critically ill ones, because there is often no established diagnosis. Grouping of patients together in units according to their severity of illness, overcomes problem of givng close care to specific need. Critical care in hospitals is given in intensive care units (ICU), High dependency units (HDU), post-operative recovery rooms, coronary care units (CCU), acute admission wards and A+E resuscitation bays. This set up confers benefit in getting multiple expert opinion.
Admission and discharge guidelines need to be followed when moving patients in and out of these units. Every case should be evaluated on its own merits and rigid rules to cover admission or discharge from ICU or HDU is destined to fail. Admitting those who have nothing to gain from critical care as either they are too well or have no realistic prospect of recovery, may cause unnecessary suffering or loss of valuable resources. Existence of empty beds does not justify admissions and scarcity of beds should not pressurise discharges. If the appropriateness of admission remains uncertain, benefit of the doubt should be given to the patients and continued active treatment reviewed, as more information becomes available. Discharge is appropriate when physical reserve is such that patient can survive independent of the close monitoring and therapy available in intensive care. Dischrges should preferably be within normal working hours and must include detailed handover to the receiving team. Premature discharges often lead to readmissions and inconvenience to relatives.
Monitoring of patients is done by the bed side nurses, observing, recording and reacting to the information provided by monitors such as ECG, CVP, arterial BP, temperature and ventillatory data. The trends observed over time and interpreted in relation to changes in therapy, are important guidelines to progress of the patients. Regular clinical examination should never be neglected. Physical signs such as restlessness, respiratory rate, appearance of patient, consciuos level and indices of poor peripheral perfusion (pale cold skin, delayed capillary refill in the nail bed) are as much important as numbers displayed on the monitors. If there is discrepancy between clinical assessment and information on the monitor, monitor should be presumed to be wrong until all potential sources of error have been checked and eliminated. Many monitors have alarms which will activate when mistakes occur.
Monitoring of circulation is done using ECG, Blood Pressure and Central Venous Pressure (CVP). Standard monitor displays single lead ECG, records rate and identify rhythm changes. Blood pressure is measured intermittently using automated sphygmomanometer but in critically ill patients continuous intra-arterial monitoring, using a line placed in radial artery is preferable. CVP is monitored using a catheter placed either into internal Jugular or subclavian vein to measure right atrial pressure. This is useful in assessing circulating blood volume and determining the appropriate rate of intravenous fluid replacement. Monitoring respiratory function is done using oxygen saturation (SpO2) and arterial blood gases . SpO2 is measured by a probe attached to finger or ear lobe using spectrophotometric analysis to determine the relative proportions of saturated and desaturated haemoglobin. Oxygenation is satisfactory if SpO2 is more than 90%. Sudden fall in SpO2 could be due to pneumothorax, fall in cardiac output, thick secretions blocking proximal bronchial tree or a detached probe. Arterial Blood Gases (ABG) are measured several times a day in a ventilated patient so that inspired oxygen (FiO2) and minute volume can be adjusted to achieve the desired PaO2 and PaCO2 respectively. ABG is also a useful means to monitor disturbance of acid-base balance. In ventilated patients lung function is monitored using tidal volume, minute volume, airway pressure and compliance, which are measures of adequacy of ventilation. Assessing of fluid balance is important. Weighing daily is difficult in bed-bound patients. Fluid balance charts show records of inputs such as oral, naso-gastric and intravenous and outputs such as urine, naso-gastric, vomitus and diarrhoea. Urinary flow a sensitive measure of renal perfusion, is recorded accurately on an hourly basis by having catheter in place in the urethra.
Over 60% of admissions to ICU require mechanical ventilation and hence these are placerd under care of Anaesthesiologists. Partial or complete replacement of inspiratory function of a patient by external support can improve gas exchange and reduce the load off lungs and heart. To prevent airway obstruction and alveolar collapse, regular suctioning has to be done to clear secretions. Air must be humidified to prevent inspissation of secretions. Ventilation could be through endo-tracheal tube or in those needing for long term through tracheostomy. To prevent biting of tube, they are sedated and to prevent fighting machine, they are paralysed with drugs. In others with significant oxygen desaturation (SaO2 < 94%), supplementary oxygen must be administered via face mask or nasal canulae, at appropriate FiO2 to correct the problem. Chest X-rays should be taken regularly for checking.
Other emergency cases admitted to ICU include shock due to acute circulatory failure where oxygen delivery is unable to meet metabolic requirements of tissues, failure of organs such as heart, liver and kidneys, massive loss of fluid needing rapid replacement as in pancreatitis, burns, diabetic coma (DKA) and major trauma. Shock can be hypovolaemic due to loss of fluid, cardiogenic following heart attack or severe heart failure, obstructive such as pulmonary embolism or cardiac tamponade, Inappropriate vasodilatation as in anaphylaxis or sepsis and neurogenic as in upper spinal cord injury. Sepsis is a major problem in critical care. At any one time, over half of ICU patients would be on antibiotic course and in most of these, infection would have been acquired after admission (nosocomial). Adequate nutrition is an essential means of damage control in critical care caused by negative nitrogen balance. Enteral nutrition is the optimum strategy and total parenteral nutrition must be started only if all attempts at enteral feeding have failed. Maintaining good renal function as reflected by urine flow, acid-base balance, serum potassium and creatinine levels is important. Pressure sores must be prevented by frequent repositioning and soft supportive surfaces.
Communication with patient whenever possible, with family, with the referring clinician and between members of critical care team is crucial. Failure in it damages working relations, causes stress and unrealistic expectations and leads to unpleasentness.
