hypertension & diabetes in surgery . presented by: dr. saifuddin ahmed
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Hypertension &
DiabetesIn surgery.
Presented by: Dr. Saifuddin Ahmed.
Dr. Sammya Das Gupta.
Surgery with Hypertension
What is HYPERTENSION Hypertension is defined as a rise in blood pressure over and above the normal range for the age of a patient for three consecutive setting.
Types: According to cause
ESSENTIAL
SECONDARY
NE release (stress)Thickened arterial wall Altered vasomotor Endocrine,
Renal, ICP, coarctation
, contracep-
tives, pregnancy,
etc.
Category Systolic mmHg Diastolic mmHg
Optimal < 120 and < 75Normal < 130 and < 85Mild HTN 140-159 or 90-
99Moderate 160-179 or 100-109Severe > 180 or > 110Isolated SBP HTN > 140 and < 90Pulse Pressure > 65mmHg
Orthostatic changes Hyper response > 20 mmHg Hypo response < 20
mmHG
Classification
0
10
20
30
20 30 40 50 60 70 80 90Age
Prev
alen
ce %
Women
Men
Circulation 2006;114:2780-7
Risk increases with age; Prevalence is more in women
Hypertension in surgical patient
High blood pressure is discovered during routine physical examination for a surgical disorder.
Patient on medical treatment for essential hypertension may develop a surgical condition that requires treatment.
Surgical treatment is required for a disorder causing secondary hypertension.
Importance of hypertension in surgical patient:
Higher risk of coronary artery disease.
High fluctuations in blood pressure during surgery, often associated with myocardial ischemia.
These blood pressure fluctuations correlates with post operative cardiac morbidity.
Therefore, control of blood pressure preoperatively should help to reduce blood pressure fluctuations during surgery and perioperative myocardial ischemia.
This is the rationale behind ensuring that the resting BP is controlled prior to surgery.
Systolic Blood Pressure
Adverse events are higher with isolated systolic blood pressure HTN, than with diastolic blood pressure HTN
Kannel, Framingham Heart Study
Perioperative risks and their management
In hypertensive patients, induction of anaesthesia is often associated with large reductions in arterial pressure. This may precipitate myocardial ischaemia as the diastolic pressure falls thus reducing both the coronary and the cerebral perfusion pressures. In these circumstances vasopressors may be indicated.
Laryngoscopy and intubation often cause large increases in blood pressure. As hypertension associated with tachycardia can cause myocardial ischaemia, prevention of the hypertensive response to laryngoscopy, intubation, and extubation is advisable.
Consequences of pressure surges include bleeding from vascular suture lines, cerebrovascular haemorrhage, and myocardial ischaemia/infarction.
The mortality rate of such events may be as high as 50%.
Perioperative hypertensive crises are generally caused by a sympathetically mediated increase in peripheral vascular resistance. The choice of the most appropriate antihypertensive therapy depends upon the clinical scenario, i.e. whether there is tachycardia, myocardial ischaemia, cardiac failure, or renal functional impairment.
Clinical assessment of preoperative hypertension:
It is desirable that the hypertensive patient undergoes full cl inical assessment prior to surgery. This should focus on three issues.
First, careful review of whether existing medications, if they are controll ing the blood pressure and when necessary, additional therapy is instituted.
Second, target organ (Heart, Kidney) damage. Any target organ damage increases the operative risks.
Third, to exclude rare secondary causes of hypertension, e.g. PhaeochromocytomaAbdominal bruit [Renal artery stenosis]Hypokalaemia [Conn’s syndrome]Radiofemoral delay [Coarctation of Aorta]
Preoperative Management of hypertension
Anti hypertensive medication should be continued throughout the perioperative period in order to maintain control of blood pressure and prevent rebound hypertension.
If blood pressure needs to be controlled more before surgery, then, some manipulation of the patient’s oral therapy can normally be undertaken with a successful result in a few days and hence, surgery does not need to be delayed unduly.
If surgery is required more urgently, rapidly acting agents specially beta blockers can be used to control blood pressure in a few minutes or hours.
Untreated & sub optimally treated hypertension do not appear to significantly increase risk when the pressure is below 160/ 105 mmHg since it is relatively easy to reduce it with anaesthesia and parenteral agents. When the pressure exceeds 180/ 110 mmHg, the incidence of perioperative HTN increases along with the need for prolonged parenteral treatment & observation as well as the risk of complication.
List of anti hypertensive drugs:
The five classes of drugs commonly used are:
Thiazide diuretics, Beta blockers, Ca Antagonists, ACE inhibitors. Angiotensin-II receptor antagonists.
If a new anti hypertensive is introduced, a stabilization period of at least 2 weeks should be allowed.
Bailey & Love 26th ed. ch 16, page 232.
Causes of postoperative hypertension Post operative acute retention of
urine Pain Hypothermia Peri operative Volume overload Hypercarbia & hypoxia Post operative Hyper adrenergic
state
Surgery with Diabetes
Normal Diabetic
DiabetesDiabetes is a metabolic disorder resulting
from insulin deficiency or intolerance.Associated with acute and long term
systemic problems.Diagnosed by a random plasma glucose
>11.1mmol/l and a fasting glucose>7.0mmol/l (WHO criteria).
The two most common forms of diabetes are Insulin Dependant Diabetes Mellitus (Type 1) and Non Insulin Dependant Diabetes Mellitus (Type 2).
Diabetes and Surgery Surgery is a form of physical trauma It results in catabolism, increased metabolic
rate, increased fat and protein breakdown, glucose intolerance and starvation.
In a diabetic patient, the pre existing metabolic disturbances are exacerbated by surgery
The risk of significant end-organ damage increases with the duration of diabetes, although the quality of glucose control is more important than the absolute time
Metabolic Responses to SurgeryHormonal
◦Secretion of stress hormones Cortisol Catecholamines Glucagon Growth Hormone Cytokines
◦Relative decrease in insulin secretion
◦Peripheral insulin resistance
Metabolic◦Increased
gluconeogenesis and glycogenolysis
◦Hyperglycaemia◦Lipolysis◦Protein
breakdown
Metabolic Response to Surgery with DiabetesHypoglycaemia Hyperglycaemia Ketoacidosis Electrolyte imbalance
Underlying Systemic Complications of Diabetes
and SurgeryCardiac:◦Ischaemic Heart Disease - Often silent
ischaemia ◦Coronary artery disease ◦HypertensionRenal: ◦Renal dysfunction◦Urinary infection
Underlying Systemic Complications of Diabetes
and SurgeryImmune and infectious risk
◦Diabetics are susceptible to infection and have delayed wound healing
◦Hyperglycaemia facilitates proliferation of bacteria and fungi depresses the immune system management
◦Proteolysis and decreased amino acid transport retards wound healing.
◦Loss of phagocytic function increases the risks of post-operative infection
Determinents of the management plan1. Type of DM2. Treatment, diet, oral ant diabetic drugs,
insulin3. Previous H/O hypoglycemic or hyperglycemic
attack and hospital admissions. 4. Metabolic status5. Vascular status: cardiac, renal, cerebral6. Surgery: Type: emergency or elective Minor or major procedure Type of anesthesia Post operative oral intake 29
Pre-operative AssessmentThis is the most important step in the
management of the diabetic patient Involves a thorough history and physical
examination Review prior anaesthetic records to determine
whether there were any difficulties with intubation or anaesthetics
Lab investigations◦ blood glucose - K+◦ BUN - creatinine◦ ketones - proteinuria◦ HbA1c (to assess how well controlled diabetes
is)
Principle of Pre-operative management
Metabolic stress of surgery and anesthesia cause increased elaboration of catecholamins, glucocorticoids, glucagon, and growth hormone, all producing their metabolic effects resulting in hyperglycemia in the pre-operative period.
The glycemic control is aimed to achieve a fasting plasma glucose of < 140 mg % and post prandial plasma glucose of < 200 mg %.
Insulin dependent diabetic patients can be admitted 2-3 days prior to surgery to achieve satisfactory control.
31
Principle of Pre-operative management
In NIDDM patients if the control is good with oral antidiabetic drugs , these drugs are stopped on the day of the surgery and intravenous fluids and insulin are given , if not are advised to stop drugs one week before surgery and admitted for insulin therapy.
On the day of surgery, It is preferable to take diabetic patients for surgery in the morning as first case.
32
Surgical Management of Insulin Dependant Diabetes Mellitus
Aim to keep blood glucose 5 to10mmol/LPre operative
◦NBM for 6 hrs prior to surgery (4 hrs for clear fluids)
◦ Initiate glucose/ potassium/ insulin regime after commencing NBM (check K+ as well) 500ml 10% glucose solution with 20mmol
K+ 15 unit short acting insulin at 1ml.kg-1.hr.
◦Hourly capillary glucose is measured until operation
Surgical Management of Insulin Dependant Diabetes Mellitus
Intra-operative◦Hourly glucose monitoring
keep between 5-10 mmol/L◦Two hourly potassium monitoring
keep between 3.5-4.5 mmol/L◦Anaesthesia determined by patient
physiology and surgical requirements◦Set up additional IV for resuscitation fluids
Surgical Management of Insulin Dependant Diabetes Mellitus
Post-operative◦Continue Glucose/Potassium/Insulin
regime until patient can take orally◦Oral medication with first meal◦Allow for pain resulting in increased
insulin requirements
Surgical Management of Non Insulin Dependant Diabetes Mellitus
Treat as insulin dependant if: ◦ poorly controlled (blood glucose >10 mmo/L) ◦ major surgery
Pre-operative◦ Biguanides must be stopped 48 hours before
hand for fear of lactic acidosis NBM for 12 hours prior to operationStart i.v maintenance fluid
◦ 0.18% NaCl with glucose 4%Hourly capillary glucose is measured until
operation
Surgical Management of Non Insulin Dependant Diabetes Mellitus
Hourly glucose monitoring◦Aim to keep within 5-10mmol/L◦if blood glucose >10 mmol/L, switch to
treating as insulin dependantPost-operative
◦Continue Glucose/Potassium/Insulin regime until patient can take orally.
◦Restart oral anti diabetic with first meal.
Summary: The hypertensive patient requires careful
pre operative assessment to make sure that blood pressure is controlled and to exclude secondary causes. These may require surgery to be delayed somewhat, but hypertension itself seldom causes anything more than a slight delay to surgery. If blood pressure needs to be controlled more before surgery, then, some manipulation of the patient’s oral therapy can normally be undertaken with a successful result in a few days and hence, surgery does not need to be delayed unduly.
Summary: Management of preoperative insulin
therapy depends on baseline blood glucose, level of diabetic control, severity of illness and the proposed surgical procedure
However, aims for all diabetic patients are:◦No excess mortality◦No increase in post-op complications◦Normal wound healing◦No increase in duration of hospitalisation◦No hypoglycaemia, hyperglycaemia or
ketoacidosis
Refference: Essential Surgical Practice – A. Cuschieri. Short practice of Surgery - Bailey & Love. Current Surgical Diagnosis & Treatment – Gerard M.
Doherty. The surgical hypertensive patient - P Foëx, DPhil FRCA
FMedSci, Emeritus Nuffield Professor of Anaesthetics, Nuffield Department of Anaesthetics, The John Radcliffe Hospital, Headley Way, Oxford, PhD FRCA.
Perioperative management of hypertension - Norman M Kaplan, MD
Perioperative hypertension management - Joseph Varon and Paul E Marik.
T H A N K Y O U
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